SODIUM BENZOATE

From a chemical and molecular perspective, Sodium Benzenecarboxylate has the empirical molecular formula C7H5NaO2 and the structural formula C6H5COONa (molecular weight 144.11 g/mol), consisting of a planar six-membered aromatic benzene ring covalently bonded to a polar carboxylate anion (-COO-) that is ionically coordinated with a sodium cation (Na+). This amphiphilic ionic architecture imparts extraordinary aqueous solubility of 556 to 660 g/L at 0 °C to 25 °C while allowing the salt to establish a pH-dependent dissociation equilibrium in acidic media (pKa 4.19 to 4.20), converting into lipophilic undissociated benzoic acid (C6H5COOH) molecules that readily permeate microbial cell membranes to collapse intracellular pH and inhibit phosphofructokinase glycolysis.

Formulators and process engineers overwhelmingly prefer Benzoate of Soda over unneutralized parent benzoic acid because the sodium salt dissolves nearly 200 times faster and more completely in cold process water (63 g/100 mL versus 0.29 g/100 mL at 20 °C), eliminating heated pre-dissolution tanks, undissolved crystal precipitation, and localized preservative gradients in high-speed beverage and cosmetic batching lines. Compared to competing preservatives and technical additives such as potassium sorbate, parabens, isothiazolinones, and sodium nitrite, Monosodium Benzoate delivers superior oxidative and Maillard color stability in clear acidic beverages, a hypoallergenic and paraben-free clean-label profile for green cosmetics, and non-nitrosamine-forming multi-metal passivation in modern organic acid technology engine coolants.

CAS Number: 532-32-1
EC Number: 208-534-8
Molecular Formula: C7H5NaO2 (Structural Formula: C6H5COONa)
Molecular Weight: 144.11 g/mol (144.105 g/mol)
INCI Name: SODIUM BENZOATE
E Number: E211 (INS 211 / Food Additive E 211)
Melting Point: 410 °C to 436 °C (770 °F to 817 °F, decomposes above 430 °C to 450 °C without boiling; consistently > 300 °C under OECD Test Guideline 102)
Boiling Point: Not Applicable for anhydrous crystalline C7H5NaO2 (undergoes thermal decarboxylation and pyrolytic decomposition above 430 °C to 450 °C prior to boiling at 101.3 kPa; parent benzoic acid sublimes/boils at 248 °C to 249 °C; 10% to 33% w/w aqueous solutions of Sodium Benzoate boil at 100.8 °C to 104.5 °C at 101.3 kPa)
Viscosity: Not Applicable as a dry crystalline powder, extruded granule, or spherical prill; in aqueous solution at 25 °C, dynamic viscosity is 1.15 mPa.s (cP) at 5% w/w, 1.42 mPa.s at 10% w/w, 2.15 mPa.s at 20% w/w, and 4.10 to 4.80 mPa.s at 33% w/w commercial liquid concentration
Density: True crystal density of 1.440 to 1.497 g/cm3 (1,440 to 1,497 kg/m3) at 20 °C; apparent loose bulk density of 0.35 to 0.50 g/cm3 (350 to 500 kg/m3) for fine crystalline powder, 0.55 to 0.72 g/cm3 (550 to 720 kg/m3) for extruded granular noodles, and 0.68 to 0.82 g/cm3 (680 to 820 kg/m3) for spherical prills; 33% w/w aqueous solution specific gravity of 1.145 to 1.155 g/cm3 at 20 °C

Most Frequently Encountered Synonyms:
Sodium Benzoate
Benzoic Acid, Sodium Salt
Benzoic Acid Sodium Salt
Sodium Benzenecarboxylate
Benzoate of Soda
Monosodium Benzoate
Sodium Monobenzoate
E211
E 211
Preservative E211
E211 Sodium Benzoate
INS 211
Natrium Benzoicum
Natrii Benzoas
Benzoas Natricus
Phenylformic Acid, Sodium Salt
Phenylformic Acid Sodium Salt
Phenylcarboxylate Sodium
Sodium Salt of Phenylcarboxylic Acid
Sodium Salt of Benzenecarboxylic Acid
Dracylic Acid, Sodium Salt
Dracylic Acid Sodium Salt
Carboxybenzene Sodium Salt
Benzeneformic Acid Sodium Salt
Benzenecarboxylic Acid, Sodium Salt
Benzenecarboxylic Acid Sodium Salt
Benzenemethanoic Acid Sodium Salt

PRODUCT IDENTIFICATION, CHEMICAL NOMENCLATURE AND MOLECULAR ARCHITECTURE

Sodium Benzoate (CAS 532-32-1, EC 208-534-8) is the neutral monosodium salt of benzoic acid (benzenecarboxylic acid), representing one of the most widely utilized organic carboxylate salts in the global food, beverage, pharmaceutical, personal care, plastics, and metal-protection industries. In international chemical nomenclature and regulatory inventories, this essential raw material is systematically indexed under the IUPAC name Sodium Benzenecarboxylate and the Chemical Abstracts Service index name Benzoic acid, sodium salt (1:1). Across regional pharmacopeias, food additive directories, and industrial procurement catalogs, buyers and formulators routinely specify the compound using its well-established synonyms, including Benzoate of Soda, Preservative E211, INS 211, Natrium Benzoicum, Natrii Benzoas, Phenylformic Acid Sodium Salt, Dracylic Acid Sodium Salt, Sodium Salt of Benzenecarboxylic Acid, Sodium Salt of Phenylcarboxylic Acid, Monosodium Benzoate, and in Turkish chemical commerce, Sodyum Benzoat or Benzoik Asit Sodyum Tuzu.
From a structural and crystallographic standpoint, Sodium Benzoate possesses the empirical formula C7H5NaO2 and the condensed structural formula C6H5COONa, with a calculated molar mass of 144.105 g/mol (standardly rounded to 144.11 g/mol in analytical certificates). Each formula unit of Benzoic Acid Sodium Salt comprises two distinct electronic and steric domains that govern its dual physical behavior in aqueous, biological, and polymeric systems:

1. The Hydrophobic Aromatic Benzene Ring (C6H5-): The core of the molecule is a planar, sp2-hybridized six-membered carbon ring characterized by a delocalized pi-electron cloud with carbon-carbon bond lengths of approximately 1.39 Angstroms and bond angles of 120 degrees. When protonated in acidic media to form undissociated benzoic acid (C6H5COOH), this lipophilic phenyl ring provides the thermodynamic octanol-water partition coefficient (log Pow = +1.87 to +1.88 for free benzoic acid) required to partition into and traverse the phospholipid bilayer membranes of yeasts, molds, and pathogenic or spoilage bacteria. In solid-state polymer processing and metallic surface chemistry, the rigid planar phenyl ring of Sodium Benzenecarboxylate also provides epitaxial pi-stacking alignment for isotactic polypropylene crystal nucleation and hydrophobic steric shielding on passivated steel, cast iron, and aluminum oxide surfaces.

2. The Hydrophilic Ionic Carboxylate Headgroup (-COO- Na+): Directly conjugated to the C1 position of the aromatic ring is an sp2-hybridized carboxylate functional group (-COO-) carrying a delocalized negative charge shared equally between two equivalent carbon-oxygen bonds (bond length ~1.26 Angstroms), balanced by an electrostatically coordinated sodium cation (Na+). Because the resonance-stabilized carboxylate group forms strong ion-dipole interactions and hydrogen bonds with surrounding water molecules, unprotonated Benzoate of Soda exhibits an exceptionally low octanol-water partition coefficient (log Pow = -2.13 to -2.27 at pH 7.0) and an extraordinary water solubility of 556 g/L at 0 °C and 625 to 660 g/L at 20 °C to 25 °C (with compendial saturation benchmarks frequently cited between 53 g/100 mL and 66 g/100 mL depending on measurement method and hydration equilibrium). In solid crystal lattices, the alternating packing of polar Na+ / -COO- ionic layers and nonpolar phenyl bilayers creates a thermally robust crystal structure that resists melting up to 410 °C to 436 °C.

A fundamental stoichiometric parameter that every food technologist, cosmetic chemist, and pharmaceutical formulator must account for when dosing Preservative E211 is the molecular weight conversion factor between Sodium Benzoate (MW = 144.11 g/mol) and free Benzoic Acid (C7H6O2, MW = 122.12 g/mol). Because regulatory maximum residue limits in food legislation (such as European Union Regulation 1333/2008 and Codex Alimentarius GSFA) and cosmetic directives (such as EU Regulation 1223/2009 Annex V) are expressed as milligrams per kilogram (mg/kg or ppm) or weight percent of "benzoic acid equivalent," the stoichiometric conversion ratio is exactly 122.12 / 144.11 = 0.8474 (or 84.74%). Consequently, 1.000 gram of anhydrous Benzoate of Soda yields 0.8474 grams of active benzoic acid upon acidification, and conversely, 1.180 grams of E211 Sodium Benzoate must be weighed into a batch to deliver 1.000 gram of equivalent free benzoic acid.

Ataman Kimya supplies high-purity Sodium Benzoate across multiple pharmacopeial, food-codex, cosmetic, and industrial grades—and in three distinct engineered solid particle morphologies (Fine Crystalline Powder, Dust-Free Extruded Granular Noodles, and Free-Flowing Spherical Prills/Beads) plus 33% w/w Liquid Solution—ensuring that every customer receives the optimal physical form and purity profile for their specific mixing equipment and regulatory framework.

PHYSICAL AND CHEMICAL PROPERTIES (NUMERICAL DATA AND ANALYTICAL SPECIFICATIONS)

To support precision quality control, regulatory compliance, and process engineering calculations, the following quantitative physical, chemical, thermodynamic, solution, and purity parameters define commercial Food/FCC/E211 Grade, Pharmaceutical (USP/BP/Ph. Eur.) Grade, Cosmetic (INCI) Grade, and Industrial/Technical Grade Sodium Benzoate (Benzoic Acid Sodium Salt) supplied by Ataman Kimya:
1. Molecular and Stoichiometric Constants:
Chemical Name: Sodium Benzoate / Benzoic Acid Sodium Salt / Sodium Benzenecarboxylate
CAS Registry Number: 532-32-1
EC / EINECS Number: 208-534-8
E Number / INS Number: E211 / INS 211
INCI Monograph Name: SODIUM BENZOATE
FEMA Flavoring Number: 3025
FDA UNII Code: OJ245FE5EU
Empirical Molecular Formula: C7H5NaO2
Condensed Structural Formula: C6H5COONa
SMILES Notation: [Na+].[O-]C(=O)c1ccccc1
InChIKey: WXMKPNITSTVMEF-UHFFFAOYSA-M
Molecular Weight: 144.105 g/mol (standard specification value: 144.11 g/mol)
Theoretical Elemental Composition (Anhydrous Basis): Carbon (C) 58.34% w/w; Hydrogen (H) 3.50% w/w; Oxygen (O) 22.20% w/w; Sodium (Na) 15.96% w/w
Active Benzoic Acid Equivalent Factor: 0.8474 g C6H5COOH per 1.0000 g C6H5COONa (84.74% w/w); Inverse Conversion Factor: 1.1801 g C6H5COONa per 1.0000 g C6H5COOH
2. Physical State, Sensory Profile, and Polymorphic Morphology:
Appearance at 20 °C and 101.3 kPa: White or colorless crystalline, amorphous, or granular solid available in three physical morphologies: (a) Fine Micronized/Crystalline Powder (D90 < 150 microns, or ultra-fine < 10 microns for polymer nucleation), (b) Dust-Free Cylindrical Extruded Granules (Noodles/Pellets, typical diameter 0.8 to 2.0 mm, length 2.0 to 8.0 mm), and (c) Dense Spherical Prills/Beads (typical diameter 0.5 to 2.0 mm); also available as a clear, colorless 33% w/w aqueous liquid solution
Odor Profile: Odorless, or possessing an extremely faint, pleasant benzoin-like aromatic note
Taste Profile: Slightly sweetish and weakly saline initially, followed by a characteristic mildly astringent or tangy aftertaste in concentrated aqueous solutions; virtually imperceptible at typical beverage preservation dosages of 0.015% to 0.10% w/w (150 to 1,000 ppm)
Hygroscopicity in Air: Stable and non-deliquescent in ambient air below 50% to 60% relative humidity at 20 °C, absorbing less than 0.3% moisture; at relative humidities exceeding 75% to 80%, anhydrous Benzoate of Soda progressively absorbs atmospheric moisture and can cake if left unsealed
3. Thermal Transitions, Melting Point, Boiling Point, and Pyrolysis Data:
Melting Point (OECD TG 102 / DSC): 410 °C to 436 °C (770 °F to 817 °F; 683 K to 709 K); official compendial monographs frequently cite > 300 °C because Natrium Benzoicum remains completely solid across standard capillary melting baths
Onset of Thermal Decomposition (TGA / DTA): Above 430 °C to 450 °C under nitrogen or air atmosphere, Sodium Benzenecarboxylate undergoes endothermic fusion accompanied by rapid exothermic decarboxylation and free-radical pyrolysis, yielding a solid residue of sodium carbonate (Na2CO3, ~36.8% of initial mass) while evolving volatile benzene, biphenyl, benzophenone, carbon monoxide (CO), carbon dioxide (CO2), and carbonaceous char
Boiling Point at 101.3 kPa: Not Applicable for anhydrous ionic solid C7H5NaO2 (decomposes above 430 °C prior to reaching a vapor-liquid boiling transition; note that reference tables citing 248 °C to 249 °C reflect the boiling/sublimation point of the conjugate parent Benzoic Acid C6H5COOH); for commercial aqueous solutions of Sodium Benzoate at 101.3 kPa, boiling point is 100.8 °C at 10% w/w, 101.9 °C at 20% w/w, and 104.0 °C to 104.5 °C at 33% w/w
Flash Point (Closed Cup / Open Cup): Not Applicable for aqueous solutions; for dry solid powder, flash point exceeds 300 °C (self-ignition temperature of dispersed airborne dust clouds is > 500 °C per VDI 2263 / IEC 60079-20)
Minimum Ignition Energy (MIE) of Fine Dust: > 100 mJ for fine powder (< 63 microns); Dust Explosion Class St 1 (weakly to moderately explosible dust only when finely dispersed in air at > 50 g/m3); extruded granules and spherical prills are essentially dust-free
Vapor Pressure at 20 °C to 25 °C: < 1.0 x 10^-6 Pa (< 7.5 x 10^-9 mmHg, effectively zero volatility in the unprotonated salt form)
Specific Heat Capacity (Cp) at 25 °C: 1.28 to 1.32 J/(g.K) (185 to 190 J/(mol.K)) for crystalline solid
Standard Enthalpy of Solution in Water (Delta H_sol at 25 °C): Approximately -1.8 to -2.2 kJ/mol (very weakly exothermic dissolution, explaining why the aqueous solubility of Phenylformic Acid Sodium Salt remains remarkably flat between 15 °C and 50 °C)
4. Density, Bulk Density, and Granulometric Parameters:
True Crystal Density (Helium/Liquid Pycnometry at 20 °C): 1.440 to 1.497 g/cm3 (1,440 to 1,497 kg/m3)
Apparent Loose Bulk Density (Fine Powder Grade): 0.35 to 0.50 g/cm3 (350 to 500 kg/m3)
Tapped Bulk Density (Fine Powder Grade): 0.52 to 0.68 g/cm3 (520 to 680 kg/m3; Hausner Ratio 1.30 to 1.45; Carr Compressibility Index 23% to 31%)
Apparent Loose Bulk Density (Extruded Granular / Noodle Grade): 0.55 to 0.72 g/cm3 (550 to 720 kg/m3; Hausner Ratio 1.10 to 1.18)
Apparent Loose Bulk Density (Spherical Prill / Bead Grade): 0.68 to 0.82 g/cm3 (680 to 820 kg/m3; Hausner Ratio 1.05 to 1.12; Angle of Repose 24 to 29 degrees, enabling rapid, bridge-free silo discharge and pneumatic conveying)
Specific Gravity of 33% w/w Aqueous Liquid Grade (at 20 °C): 1.145 to 1.155 g/cm3 (Baume ~18.5 to 19.5 degrees)
5. Solubility Profile Across Aqueous and Organic Solvents:
Water Solubility at 0 °C: 556 g/L (55.6 g per 100 mL of water, corresponding to 35.7% w/w saturated solution)
Water Solubility at 15 °C: 625 g/L (62.5 g per 100 mL of water)
Water Solubility at 20 °C: 628 to 630 g/L (62.8 to 63.0 g per 100 mL of water, corresponding to 38.6% w/w saturated solution; approximately 1.8 mL of water dissolves 1.0 g of Sodium Benzoate)
Water Solubility at 25 °C: 530 to 660 g/L (53.0 to 66.0 g per 100 mL of water depending on test protocol; thermodynamic saturation equilibrium is 63.0 to 66.0 g per 100 mL of water, or ~38.7% to 39.8% w/w saturated solution)
Water Solubility at 50 °C: 665 to 680 g/L (66.5 to 68.0 g per 100 mL of water)
Water Solubility at 100 °C: 715 to 742 g/L (71.5 to 74.2 g per 100 mL of water, corresponding to 41.7% to 42.6% w/w saturated solution; approximately 1.4 mL of boiling water dissolves 1.0 g of Benzoate of Soda)
Solubility in Ethanol (90% v/v at 20 °C to 25 °C): Approximately 13.0 to 23.0 g/L (1.3 to 2.3 g per 100 g; 1 gram dissolves in ~45 to 75 mL of 90% ethanol)
Solubility in Absolute Ethanol (99.9% at 20 °C): 8.1 to 13.3 g/L (0.81 to 1.33 g per 100 mL; 1 gram dissolves in ~75 to 120 mL of cold absolute ethanol, or ~50 mL of boiling 95% ethanol)
Solubility in Methanol (at 20 °C to 25 °C): 82.0 g/L (8.2 g per 100 mL)
Solubility in Propylene Glycol (1,2-Propanediol at 25 °C): 150 to 220 g/L (15.0 to 22.0 g per 100 mL, enabling concentrated liquid preservative blends with phenoxyethanol, benzyl alcohol, or potassium sorbate)
Solubility in Glycerol (Glycerin at 25 °C): 220 to 280 g/L (22.0 to 28.0 g per 100 mL)
Solubility in Nonpolar Organic Solvents (Acetone, Diethyl Ether, Chloroform, Benzene, Toluene, Hexane, Mineral Oil, Vegetable Oils): Practically insoluble (< 0.01 g/100 mL)
6. Viscosity, Surface Tension, Refractive Index, Freezing Point, and Solution Thermodynamics:
Dynamic Viscosity of Aqueous Solutions at 25 °C (Brookfield / Ubbelohde Capillary Viscometry):
- 1.0% w/w Aqueous Solution: 0.92 mPa.s (cP)
- 5.0% w/w Aqueous Solution: 1.15 mPa.s (cP)
- 10.0% w/w Aqueous Solution: 1.42 mPa.s (cP)
- 20.0% w/w Aqueous Solution: 2.15 mPa.s (cP)
- 30.0% w/w Aqueous Solution: 3.65 mPa.s (cP)
- 33.0% w/w Commercial Liquid Solution: 4.10 to 4.80 mPa.s (cP) at 25 °C (free-pumping Newtonian fluid)
Crystallization / Freezing Point of 33% w/w Aqueous Solution: Approximately -11 °C to -13 °C (enabling unheated indoor tank storage in temperate climates)
Refractive Index (nD20) of Aqueous Solutions: 1.3490 at 10% w/w; 1.3665 at 20% w/w; 1.3895 to 1.3920 at 33% w/w
Surface Tension at 20 °C (0.1% to 1.0% w/w in Water, OECD TG 115): 71.0 to 72.2 mN/m (dyn/cm, confirming that Monosodium Benzoate is a non-surface-active, non-foaming aromatic electrolyte)
7. Dissociation Constant (pKa), Solution pH, and Active Undissociated Acid Equilibrium:
pH of Aqueous Solution (5.0% to 10.0% w/w in Carbon-Dioxide-Free Deionized Water at 25 °C): 7.0 to 8.5 (typically 7.5 to 8.0, mildly alkaline due to weak conjugate base hydrolysis of the benzoate anion: C6H5COO- + H2O <-> C6H5COOH + OH-)
Acid Dissociation Constant (pKa of Conjugate Benzoic Acid at 25 °C): 4.19 to 4.20 (Ka = 6.31 x 10^-5 to 6.46 x 10^-5 mol/L)
Octanol-Water Partition Coefficient (log Pow at 20 °C): -2.13 to -2.27 for ionized Sodium Benzoate at pH 7.0; +1.87 to +1.88 for undissociated Benzoic Acid at pH < 2.5
Percentage of Undissociated Antimicrobial Benzoic Acid (C6H5COOH) as a Function of Formulation pH (Henderson-Hasselbalch Equation: % Undissociated = 100 / [1 + 10^(pH - 4.20)]):
- At pH 2.00: 99.37% 
- At pH 2.50: 98.04% 
- At pH 3.00: 94.06% 
- At pH 3.50: 83.37% 
- At pH 3.80: 71.53% 
- At pH 4.00: 61.31% 
- At pH 4.20 (pH = pKa): 50.00% 
- At pH 4.50: 33.39% 
- At pH 4.80: 20.08% 
- At pH 5.00: 13.68% 
- At pH 5.50: 4.77% 
- At pH 6.00: 1.56% 
- At pH 6.50: 0.50% 
- At pH 7.00: 0.16% 

8. Compendial Assay, Purity, and Trace Impurity Limits (FCC / E211 / USP-NF / Ph. Eur. / BP Grades):
Assay (Purity on Dried Basis, Non-Aqueous Titrimetry with 0.1 N Perchloric Acid in Glacial Acetic Acid): 99.0% to 100.5% w/w C7H5NaO2 (typical Ataman Kimya batch assay: 99.4% to 99.9% w/w)
Loss on Drying (4 hours at 105 °C): Maximum 1.5% w/w (USP-NF / FCC / E211 limit; typical production value: 0.3% to 0.8% w/w; Ph. Eur. limit: Max 2.0% w/w)
Water Content (Karl Fischer Titration): Maximum 1.5% w/w
Acidity or Alkalinity (Titration of 2.0 g in 20 mL carbon-dioxide-free boiling water against Phenolphthalein): Requires not more than 0.20 mL of 0.1 N NaOH or 0.1 N HCl (or 0.1 N H2SO4) to achieve neutralization (corresponding to < 0.04% free NaOH or < 0.12% free benzoic acid)
Clarity and Color of Solution (10% w/w in Water): Clear and colorless (APHA / Hazen Color Index <= 10 to 20; UV absorbance at 425 nm <= 0.02)
Readily Carbonizable Substances (Sulfuric Acid Test per USP / FCC): Color of solution in 95% H2SO4 is not darker than Matching Fluid A (confirms absence of charring organic tars or polycyclic impurities)
Readily Oxidizable Substances (Potassium Permanganate Test): Pink color of 0.1 N KMnO4 in sulfuric-acidified solution persists for at least 15 minutes (confirms absence of benzaldehyde, benzyl alcohol, cinnamic acid, or unsaturated organics)
Volatile Organic Impurities (GC-FID / Headspace GC): Toluene < 10 ppm; Benzaldehyde < 20 ppm; Benzyl Alcohol < 20 ppm; Benzene Not Detected (< 0.1 ppm)
Chlorinated Organic Compounds (Total Organically Bound Chlorine as Cl, EU E211 / Ph. Eur. Monograph 0123 Limit): Maximum 0.06% w/w (600 ppm as total chlorine, corresponding to <= 0.07% monochlorobenzoic acid; modern halide-free toluene-oxidation grades supplied by Ataman Kimya typically contain < 20 to 50 ppm)

Polycyclic Aromatic Hydrocarbons (PAHs): Passes compendial UV-spectrophotometric absorption test in cyclohexane across 250 to 400 nm
Phthalic Acid Impurity (HPLC): Maximum 100 mg/kg (100 ppm)
Sulfate (SO4^2-): Maximum 0.02% to 0.10% w/w (200 to 1,000 ppm)
Chloride (Inorganic Cl- Ion): Maximum 0.014% to 0.020% w/w (140 to 200 ppm; total chlorine <= 300 ppm per Ph. Eur.)
Heavy Metals (Total as Pb): Maximum 10 mg/kg (10 ppm)
Lead (Pb, ICP-MS / AAS per EU Reg. 231/2012 & FCC): Maximum 2.0 mg/kg (2.0 ppm; USP/Ph. Eur. ICH Q3D compliant; typical < 0.2 ppm)
Arsenic (As, ICP-MS / Hydride AAS): Maximum 3.0 mg/kg (3.0 ppm; typical < 0.2 ppm)
Mercury (Hg, Cold-Vapor AAS): Maximum 1.0 mg/kg (1.0 ppm; typical < 0.05 ppm)
Cadmium (Cd, ICP-MS): Maximum 1.0 mg/kg (1.0 ppm; typical < 0.05 ppm)

INDUSTRIAL MANUFACTURING PROCESS, PURIFICATION AND PARTICLE MORPHOLOGY ENGINEERING

Commercial production of high-purity Sodium Benzoate (CAS 532-32-1, E211) is executed through a continuous, closed-loop two-stage synthetic sequence consisting of (1) halide-free catalytic liquid-phase air oxidation of toluene to produce purified benzoic acid, followed by (2) stoichiometric aqueous neutralization with high-purity sodium hydroxide or sodium carbonate, multi-bed activated-carbon adsorption, and precision drying or spray-fluidized granulation.

Stage 1: Halide-Free Catalytic Liquid-Phase Oxidation of Toluene to Benzoic Acid:
In the late 19th and early 20th centuries, industrial Benzoic Acid Sodium Salt was manufactured either by alkaline hydrolysis of benzotrichloride (alpha,alpha,alpha-trichlorotoluene, C6H5CCl3) derived from ring/side-chain chlorination of toluene, or by decarboxylation of phthalic anhydride. Today, the benzotrichloride route is completely obsolete for Food (E211/FCC), Cosmetic (INCI), and Pharmaceutical (USP/Ph. Eur.) grades because it inevitably leaves trace residues of ortho-, meta-, and para-chlorobenzoic acids that impart medicinal chlorophenol off-odors and violate European Pharmacopoeia total chlorine limits.
Instead, modern world-scale manufacturing begins exclusively with sulfur-free, nitration-grade petrochemical toluene (methylbenzene, C6H5CH3, purity >= 99.85%, benzene content < 50 ppm). Liquid toluene is metered continuously into a jacketed, corrosion-resistant titanium-clad or hastelloy/316L stainless-steel bubble-column oxidation reactor maintained at 145 °C to 170 °C under an operating gauge pressure of 0.6 to 1.2 MPa (6 to 12 bar). Compressed air (or oxygen-enriched air) is sparged through high-shear bottom sintered diffusers in the presence of a homogeneous, oil-soluble transition-metal carboxylate catalyst—specifically Cobalt(II) 2-ethylhexanoate (cobalt octoate) or Cobalt(II) naphthenate, optionally promoted with Manganese(II) acetate, at a dissolved metal concentration of 50 to 250 mg/kg (ppm)—completely free of bromine or chlorine radical initiators.
Through a free-radical autoxidation chain mechanism involving benzyl radicals (C6H5CH2.), benzylperoxy radicals (C6H5CH2OO.), benzyl hydroperoxide (C6H5CH2OOH), benzaldehyde (C6H5CHO), benzoyl radicals (C6H5CO.), and perbenzoic acid (C6H5COOOH), the methyl group of toluene is selectively oxidized to crude Benzoic Acid (C6H5COOH) and water of reaction:
2 C6H5CH3 + 3 O2 -> 2 C6H5COOH + 2 H2O (Exothermic Enthalpy of Reaction: Delta H = -649 kJ per mole of toluene oxidized)
To prevent catalyst deactivation, suppress oxidative ring-opening, and minimize high-boiling ester by-products (such as benzyl benzoate C6H5COOCH2C6H5, biphenyl, and methylbiphenyls), single-pass toluene conversion in the reactor is strictly controlled between 40% and 60%. Reactor off-gas passes through cryogenic condensers and regenerable activated-carbon beds to recover volatile organics before catalytic thermal oxidation, while the liquid reactor effluent enters a multi-column vacuum rectification train. Unreacted toluene, reaction water, and intermediate benzaldehyde are flashed overhead in a primary stripping column and recycled to the oxidation reactor (where benzaldehyde acts as a beneficial co-initiator that eliminates the autoxidation induction period). The molten crude benzoic acid bottom stream is then purified by high-vacuum fractional distillation (operating at 180 °C to 215 °C under 20 to 45 mbar absolute pressure) and optional dynamic falling-film melt crystallization, yielding refined molten Benzoic Acid with an assay purity >= 99.8% w/w and zero chlorinated aromatic contaminants.

Stage 2: Stoichiometric Aqueous Neutralization and Multi-Stage Carbon Purification:
Refined molten benzoic acid (maintained at 130 °C to 135 °C above its 122.4 °C melting point) is metered continuously into a baffled 316L stainless-steel neutralization reactor containing high-purity deionized water and an equimolar aqueous solution of membrane-cell Sodium Hydroxide (NaOH, caustic soda) or food-grade Sodium Carbonate (Na2CO3, soda ash) at 75 °C to 90 °C:
C6H5COOH + NaOH -> C6H5COONa + H2O (Neutralization with Membrane-Grade Caustic Soda; Delta H = -56.5 kJ/mol)
2 C6H5COOH + Na2CO3 -> 2 C6H5COONa + H2O + CO2 (Neutralization with Food-Grade Soda Ash)
When sodium carbonate is utilized, evolved carbon dioxide gas (CO2) is stripped from the hot solution by steam sparging and mild vacuum degassing so that residual carbonate/bicarbonate alkalinity does not distort compendial titrations. Dual redundant inline high-temperature pH probes continuously trim the reactor feed ratio to maintain the 36% to 42% w/w aqueous Sodium Benzoate mother liquor at an exact pH of 7.5 to 8.0. This precise endpoint guarantees complete conversion of poorly soluble free benzoic acid (< 0.05% residual free acid) while ensuring that free sodium hydroxide alkalinity remains well below the USP/FCC/Ph. Eur. maximum limit (<= 0.20 mL of 0.1 N acid per 2.0 g sample).
The hot neutral solution of Benzoic Acid Sodium Salt is then pumped through a two-stage steam-stripping deodorizer to remove the last parts-per-million of volatile benzaldehyde, followed by fixed-bed adsorption columns packed with acid-washed, steam-activated microporous coconut-shell carbon and food-grade cellulose/diatomaceous earth polishing filters at 80 °C. This polishing train removes trace chromophores, trace cobalt/manganese catalyst ions (reducing heavy metals to < 0.2 ppm), and any UV-absorbing polycyclic impurities, producing a water-white 38% to 40% w/w Sodium Benzenecarboxylate liquor with an APHA/Hazen color index below 5 to 10.

Stage 3: Precision Drying and Particle Morphology Engineering (Powder, Extruded Granules, and Spherical Prills):
Because industrial end-users operate vastly different solids-handling and mixing systems—ranging from high-speed ribbon blenders and tablet presses to pneumatic bulk silos and open-top beverage syrup tanks—the purified aqueous E211 Sodium Benzoate liquor is processed into four tailored commercial forms:

1. Fine Crystalline and Micronized Powder Grades: The concentrated mother liquor is fed onto internally steam-heated double-drum dryers (operating at 130 °C to 155 °C surface temperature) or into agitated vacuum pan crystallizer-dryers. The dried crystalline film is detached by precision doctor blades and passed through stainless-steel pin mills or air-classifying jet mills equipped with rare-earth magnetic traps (12,000 Gauss) and ultrasonic vibratory sifters. Standard Food/USP Powder grades are classified to > 95% passing 80 to 100 mesh (< 150 to 180 microns, loose bulk density 0.35 to 0.50 g/cm3), whereas specialized Polymer Nucleating and Effervescent Tablet Lubricant grades are jet-milled to an ultra-fine D50 particle size of 1.5 to 5.0 microns (D99 < 15 microns).

2. Dust-Free Extruded Granular (Noodle / Pellet) Grades: Partially dried Sodium Benzoate paste (conditioned to a controlled moisture content of 8% to 13% w/w) is fed into low-shear twin-screw or basket extruders and compressed through precision-drilled 316L stainless-steel die plates (aperture diameter 0.8 mm, 1.0 mm, 1.2 mm, or 1.5 mm). The emerging cylindrical strands ("noodles" or pellets, length 2.0 to 6.0 mm) are gently dried on a multi-zone perforated-plate fluidized-bed dryer at 105 °C to 125 °C until final moisture drops below 0.5% to 1.0% w/w, cooled with dehumidified air below 35 °C, and screened to remove fines (< 1% below 150 microns). Extruded Granular Benzoate of Soda provides dust-free occupational handling and rapid, clump-free wetting in batch mixing tanks.

3. Free-Flowing Spherical Prill (Bead) Grades: Concentrated 40% w/w Sodium Benzoate solution is atomized through two-fluid nozzles directly into an upward-flowing stream of heated air (140 °C to 180 °C) inside a continuous spray-fluidized-bed granulator (spray-prilling tower). Concentric onion-skin layers of Sodium Benzenecarboxylate crystallize continuously onto suspended seed nuclei until dense, smooth spherical beads reach a target diameter of 0.5 to 2.0 mm (loose bulk density 0.68 to 0.82 g/cm3), which are continuously discharged via a zig-zag air classifier. Spherical Prills exhibit the highest mechanical crush strength, zero attrition dust during dense-phase or dilute-phase pneumatic conveying, and a low angle of repose (24 to 29 degrees) that prevents rat-holing or bridging in 30-ton factory storage silos.

4. Commercial 33% w/w Liquid Solution Grade: For high-volume automated beverage syrup rooms, liquid detergent plants, and automotive coolant blenders that prefer zero dry-bag handling, purified mother liquor is standardized with deionized water to 33.0% +/- 0.5% w/w Sodium Benzoate (specific gravity 1.145 to 1.155 g/cm3 at 20 °C, viscosity 4.1 to 4.8 mPa.s at 25 °C) and filtered through 0.2-micron membrane cartridges into IBC totes or bulk road tankers.

MECHANISM OF ACTION: PH-DEPENDENT ANTIMICROBIAL BIOCHEMISTRY, CORROSION PASSIVATION, AND POLYMER NUCLEATION

The extraordinary cross-industry utility of Sodium Benzoate (CAS 532-32-1) arises from three distinct physicochemical mechanisms depending on whether the molecule is deployed in an aqueous biological matrix, a corrosive metallic electrolyte, or a molten semicrystalline polyolefin:
1. Biochemical Mechanism of Antimicrobial Preservation (pH-Dependent Intracellular Acidification and Glycolytic Blockade):
In aqueous food, beverage, cosmetic, and pharmaceutical formulations, fully ionized Sodium Benzenecarboxylate (C6H5COO- and Na+) is itself virtually unable to cross the negatively charged, hydrophobic phospholipid bilayer of microbial cytoplasmic membranes because of its strong hydration shell and negative octanol-water partition coefficient (log Pow = -2.27). However, when dissolved in an acidic matrix (pH <= 4.5 to 5.0), the benzoate anion protonates instantaneously according to the Henderson-Hasselbalch equilibrium (pKa = 4.19 to 4.20 at 25 °C) to generate electrically neutral, lipophilic undissociated Benzoic Acid (C6H5COOH, log Pow = +1.87 to +1.88):

C6H5COO- + H3O+ <-> C6H5COOH + H2O (pKa = 4.20)
Because undissociated C6H5COOH is uncharged and lipid-soluble, it diffuses passively across the outer cell wall and cytoplasmic phospholipid bilayer of yeasts, filamentous molds, and bacteria down its chemical potential gradient without requiring active membrane transporters. Once inside the microbial cytoplasm—where homeostatic intracellular pH (pHi) is physiologically maintained near neutrality (pH 6.5 to 7.5)—the entering C6H5COOH molecule encounters an aqueous environment more than 2.3 to 3.3 pH units above its pKa. Consequently, over 99.5% to 99.8% of the intracellular benzoic acid immediately dissociates into a membrane-impermeable benzoate anion (C6H5COO-) and a free proton (H+).
This continuous "proton shuttle" or "ion-trapping" cycle exerts four synergistic antimicrobial effects that arrest microbial growth and metabolism:
- Collapse of Intracellular pH and Transmembrane Proton-Motive Force (Delta p): As protons (H+) are released inside the cytoplasm faster than the cell can extrude them, intracellular pH plunges from 7.0 down below 5.5 to 5.0. This collapses the transmembrane proton gradient (Delta pH) that drives secondary active symport of essential amino acids, phosphate, and sugars across the microbial cell membrane.
- Depletion of Cellular ATP via Plasma-Membrane H+-ATPase Exhaustion: In an effort to counteract cytoplasmic acidification and expel trapped benzoate anions (via inducible ATP-binding cassette efflux pumps such as Pdr12p in yeasts), the microbial plasma-membrane H+-ATPase hydrolyzes up to 60% to 85% of the cell's entire adenosine triphosphate (ATP) pool. This uncouples catabolic energy generation from anabolic biomass synthesis, inducing immediate bacteriostasis and fungistasis.

- Direct Allosteric Inhibition of Rate-Limiting Glycolytic and TCA-Cycle Enzymes: Once intracellular pH drops below 5.5 and intracellular benzoate anions accumulate to 10 to 60 mM through Henderson-Hasselbalch ion trapping, benzoate and protons act directly on Phosphofructokinase-1 (PFK-1)—the allosteric pacemaker enzyme of the Embden-Meyerhof-Parnas glycolysis pathway that converts fructose-6-phosphate to fructose-1,6-bisphosphate—inhibiting its catalytic velocity by 80% to 95%. Concurrently, intracellular Benzoic Acid Sodium Salt inhibits hexokinase, pyruvate kinase, and the tricarboxylic acid (TCA / Krebs) cycle enzymes alpha-ketoglutarate dehydrogenase and succinate dehydrogenase, completely shutting down fermentative CO2 production and oxidative phosphorylation.

- Perturbation of Membrane Lipid Ordering: Intercalation of the planar hydrophobic phenyl ring (C6H5-) into the acyl-chain region of the cytoplasmic phospholipid bilayer increases membrane passive proton permeability and disrupts membrane-bound respiratory electron-transport complexes.
Quantitative Minimum Inhibitory Concentration (MIC) Benchmarks Across Microbial Taxa (at pH 3.5 to 4.2):
- Fermentative and Beverage-Spoilage Yeasts: Saccharomyces cerevisiae (MIC 100 to 300 mg/L), Candida krusei / Pichia anomala (MIC 150 to 400 mg/L), Torulopsis / Rhodotorula mucilaginosa (MIC 100 to 350 mg/L), Schizosaccharomyces pombe (MIC 250 to 500 mg/L), Zygosaccharomyces bailii (preservative-tolerant osmotolerant yeast: MIC 600 to 1,200 mg/L alone; reduced to 150 to 300 mg/L when synergized 1:1 with Potassium Sorbate).
- Filamentous and Mycotoxigenic Molds: Aspergillus niger (MIC 200 to 600 mg/L), Penicillium expansum / Penicillium glaucum (MIC 150 to 500 mg/L), Mucor racemosus (MIC 100 to 400 mg/L), Rhizopus nigricans (MIC 150 to 450 mg/L), Fusarium oxysporum (MIC 200 to 500 mg/L), Byssochlamys nivea (MIC 250 to 600 mg/L).

- Gram-Negative and Gram-Positive Foodborne & Cosmetic Bacteria: Escherichia coli O157:H7 (MIC 300 to 800 mg/L at pH 4.0), Salmonella enterica Typhimurium (MIC 300 to 800 mg/L), Pseudomonas aeruginosa (MIC 400 to 1,000 mg/L at pH 4.5), Staphylococcus aureus (MIC 400 to 1,000 mg/L), Listeria monocytogenes (MIC 500 to 1,200 mg/L), Bacillus subtilis / Bacillus cereus (MIC 400 to 1,000 mg/L), Leuconostoc mesenteroides and Lactobacillus plantarum (MIC 600 to 1,500 mg/L).

2. Electrochemical Mechanism of Anodic Metal Corrosion Passivation:
In neutral to mildly alkaline aqueous electrolytes—such as automotive ethylene glycol / propylene glycol engine coolants (pH 7.8 to 9.0), industrial chilled-water loops, water-based aerosol cans, and vapor-phase packaging films—Sodium Benzoate functions as an anodic (oxidative-site) adsorptive passivator for cast iron, carbon steel, solder, brass, and aluminum alloys. Rather than reacting stoichiometrically with the bulk metal, the negatively charged carboxylate oxygen atoms (-COO-) chemisorb selectively onto positively charged iron (Fe2+/Fe3+) and aluminum (Al3+) oxide/hydroxide lattice defect sites at incipient anodic dissolution zones on the metal surface, forming insoluble surface iron(III) or aluminum(III) benzoate complexes that plug microscopic pores in the native gamma-Fe2O3 or Al2O3 passive film.
Simultaneously, the outward-facing hydrophobic aromatic benzene rings (C6H5-) orient perpendicular to the metal-electrolyte interface, creating a tightly packed, water-repellent monomolecular shield that electrostatically and sterically repels aggressive pitting anions such as chloride (Cl-) and sulfate (SO4^2-). Crucially, unlike oxidizing anodic inhibitors such as sodium nitrite (NaNO2) or chromates—which are termed "dangerous inhibitors" because depletion below a critical threshold concentration accelerates localized galvanic pitting corrosion—Benzoate of Soda is a "safe non-oxidizing anodic inhibitor" that works in synergy with dissolved oxygen to stabilize the passive oxide film without inducing localized pitting even at low residual concentrations.

3. Crystallographic Mechanism of Polyolefin Heterogeneous Nucleation:
When ultra-fine micronized Sodium Benzoate powder (D50 < 2 to 5 microns, crystal melting point > 410 °C) is compounded into isotactic polypropylene (iPP) or polyethylene terephthalate (PET) at 800 to 2,500 mg/kg (0.08% to 0.25% w/w), the refractory ionic crystals remain completely solid and unmelted throughout polymer extrusion and injection molding (200 °C to 270 °C). Within the solid crystal lattice of Sodium Benzenecarboxylate, alternating ionic Na+ / -COO- sheets force the nonpolar aromatic phenyl rings (C6H5-) to project outward along the (001) cleavage planes with a periodic unit-cell spacing (b = 5.42 Angstroms, a = 7.51 Angstroms) that closely matches the c-axis helical repeat distance (6.50 Angstroms) of alpha-monoclinic isotactic polypropylene.
As the molten polymer cools below its equilibrium melting point, polypropylene macromolecular chains epitaxially adsorb and align inside these nonpolar aromatic grooves on the Sodium Benzoate crystal surface. This heterogeneous nucleation lowers the thermodynamic free-energy barrier for crystal initiation, shifting the polymer crystallization peak temperature (Tc by DSC at 10 °C/min cooling rate) upward from ~114 °C (un-nucleated iPP) to 124 °C–128 °C (+10 °C to +14 °C increase). Millions of simultaneous nucleation sites replace coarse 60-to-120-micron spherulites with a fine, uniform microcrystalline morphology (< 5 to 10 microns), shortening injection-molding cooling cycle times by 15% to 25%, increasing flexural modulus by 12% to 22%, raising Heat Deflection Temperature (HDT at 0.45 MPa) by 6 °C to 12 °C, and markedly reducing post-molding part shrinkage anisotropy and warpage.

COMPREHENSIVE APPLICATIONS ACROSS GLOBAL INDUSTRIES

1. Food and Beverage Preservation (Food Additive E211 / INS 211 / FCC Grade):
In the global food and beverage manufacturing sector, E211 Sodium Benzoate is the foundational antimicrobial preservative for high-moisture acidic foods and beverages whose natural or acidulant-adjusted pH falls below 4.5 (and optimally between pH 2.5 and 4.0):
- Carbonated Soft Drinks (CSDs), Concentrates, and Post-Mix Fountain Syrups: Carbonated colas, lemon-lime sodas, orange and citrus sodas, ginger ales, tonic waters, energy drinks, and diet/zero-sugar beverages sweetened with aspartame, sucralose, acesulfame-K, or stevia (typical finished drink pH 2.4 to 3.8, acidified with phosphoric acid E338, citric acid E330, malic acid E296, or tartaric acid E334) rely on 150 to 300 mg/L (0.015% to 0.030% w/w expressed as free benzoic acid per EU Regulation 1333/2008 Category 14.1.4, equivalent to 177 to 354 mg/L of Sodium Benzoate; or up to 350 to 1,000 mg/L under Codex GSFA and US FDA 21 CFR 184.1733 limits) of Dust-Free Granular or Prilled Benzoate of Soda. In concentrated post-mix fountain syrups (diluted 1:5 with carbonated water at the dispenser), Sodium Benzoate is dosed at 900 to 1,800 mg/L in the syrup so that the final dispensed beverage contains 150 to 300 mg/L, protecting both the bulk syrup bag-in-box and the finished drink against osmotolerant yeast fermentation, CO2 bottle-bursting, and mold mycelium flocculation.

- Non-Carbonated Fruit Juices, Nectars, Ready-to-Drink (RTD) Iced Teas, Sports Drinks, and Flavored Waters: Pasteurized, hot-filled, or cold-aseptic fruit juice drinks, isotonic electrolyte beverages, liquid tea concentrates, hibiscus/herbal infusions, and liquid coffee syrups (pH 3.0 to 4.2) incorporate 150 to 600 mg/kg of Preservative E211 (frequently co-formulated in a 1:1 or 1:2 mass ratio with Potassium Sorbate E202) to preserve flavor, color, and microbiological safety after consumer bottle opening.

- Acidified Condiments, Emulsified Sauces, Ketchup, Mustard, and Salad Dressings: Tomato ketchup, barbecue sauces, hot chili and sriracha sauces, soy sauce, Worcestershire sauce, tamarind pastes, prepared yellow and Dijon mustards, grated horseradish, and emulsified pourable salad dressings or reduced-fat mayonnaise (pH 3.2 to 4.2) utilize 500 to 1,000 mg/kg (0.05% to 0.10% w/w; up to 1,000 to 2,000 mg/kg in liquid egg yolks and certain emulsified sauces under EU/Codex rules) of Benzoic Acid Sodium Salt to suppress acid-tolerant heterofermentative Lactobacilli, Acetobacter, and surface-film pellicle yeasts (Candida mycoderma / Pichia membranaefaciens) across repeated restaurant and household opening cycles.

- Jams, Jellies, Marmalades, Fruit Preparations, and Frozen Yogurt Toppings: Low-sugar, reduced-calorie, and diabetic jams, jellies, marmalades, bakery fruit fillings, glacé cherries, candied citrus peel, and dairy/frozen-yogurt fruit ripple toppings (water activity aw > 0.85, pH 3.0 to 3.8) incorporate 500 to 1,000 mg/kg of E211 Sodium Benzoate to prevent xerophilic surface mold growth (Aspergillus, Penicillium, and Eurotium species) when sugar osmotic pressure alone is insufficient.

- Pickled Vegetables, Table Olives, Relishes, and Brined Seafood Delicatessen: Cucumber pickles, gherkins, pickled onions, sauerkraut, kimchi, table olives in acidic brine, beetroot salads, marinated herring fillets, anchovies, cooked shrimp in brine, and semi-preserved fish roe/caviar utilize 500 to 2,000 mg/kg (up to 1,500 to 2,000 mg/kg in semi-preserved fish products and cooked Crangon crangon shrimp per EU Regulation 1333/2008) of Sodyum Benzoat.
- Margarine, Minarine, and Emulsified Fat Spreads: Water-in-oil table spreads, low-fat minarines, and industrial puff-pastry margarines incorporate 500 to 1,000 mg/kg of Sodium Benzenecarboxylate dissolved in the citric- or lactic-acidified aqueous serum phase (pH 4.2 to 4.8) to prevent lipolytic mold and bacterial rancidity within the finely dispersed 2-to-10-micron aqueous droplets.

- Liquid Egg Products, Alcohol-Free Beer, and Liquid Sweeteners: Liquid whole egg, egg white, and egg yolk products (up to 5,000 mg/kg in combination with sorbates per EU Category 10.2), alcohol-free malt beverages (up to 200 mg/L), and table-top liquid sweeteners (up to 500 to 1,500 mg/kg) rely on FCC/E211 Sodium Benzoate for ambient and refrigerated microbial stability.

Critical Formulation Guideline on Ascorbic Acid (Vitamin C) and Chelating Agents in Beverages:
In low-pH beverages containing both Sodium Benzoate (E211) and Ascorbic Acid (E300 / Vitamin C, or naturally occurring vitamin C in citrus juices) in the presence of trace transition-metal cations (specifically Cu2+ >= 0.05 ppm or Fe3+ >= 0.1 ppm) and dissolved oxygen, metal-catalyzed reduction of O2 by ascorbic acid generates hydrogen peroxide (H2O2) and hydroxyl free radicals (.OH) via the Fenton/Haber-Weiss reaction. If uninhibited and exposed to elevated warehouse temperatures (> 35 °C) or direct UV sunlight, these hydroxyl radicals can attack the aromatic carboxylate ring of benzoic acid, inducing trace oxidative decarboxylation into benzene (C6H6) at parts-per-billion (ppb) levels. Beverage technologists completely prevent this pathway and guarantee benzene levels remain undetectable (< 1 ppb, well below the WHO 10 ppb and US EPA 5 ppb drinking water limits) by implementing three standard formulation controls:

(a) Metal Chelation: Adding 25 to 75 mg/L of Calcium Disodium EDTA (E385) or sodium hexametaphosphate (SHMP) to sequester trace Cu2+ and Fe3+ ions from water and fruit concentrates;
(b) Antioxidant / Sugar Radical Scavenging: Utilizing sucrose, glucose-fructose syrup, or polyphenol-rich fruit/tea extracts (which scavenge .OH radicals orders of magnitude faster than benzoate); and
(c) Selective Substitution: Replacing E211 with Potassium Sorbate (E202) in clear diet/sugar-free beverages that are intentionally fortified with high doses of Vitamin C and lack chelating agents.

2. Cosmetics, Personal Care, and Oral Hygiene Formulations (INCI: SODIUM BENZOATE):
Under Annex V (Entry 1) of European Union Cosmetics Regulation (EC) No 1223/2009, the US Cosmetic Ingredient Review (CIR), and ASEAN/Mercosur/NMPA cosmetic regulations, INCI-grade SODIUM BENZOATE is one of the industry's premier "clean-label," paraben-free, formaldehyde-donor-free, and isothiazolinone-free antimicrobial preservatives, certified as a nature-identical preservative under Ecocert, COSMOS, NaTrue, BDIH, and Nordic Swan standards:

- Rinse-Off Shampoos, Conditioners, Shower Gels, and Facial Cleansers: Sulfate-free (glucoside/isethionate/taurate) and conventional surfactant cleansers, hair masks, liquid hand soaps, and intimate hygiene washes formulated at skin-barrier-friendly acidic pH (pH 4.5 to 5.3) incorporate up to 2.5% w/w (expressed as benzoic acid equivalent per EU Regulation 1223/2009 Annex V for rinse-off products; typically dosed at 0.30% to 0.80% w/w in commercial formulations) of INCI Sodium Benzoate. In natural surfactant systems, pairing 0.40% w/w Sodium Benzoate with 0.20% w/w Potassium Sorbate and 0.10% w/w Sodium Phytate or Tetrasodium Glutamate Diacetate (GLDA) at pH 4.8 to 5.2 provides broad-spectrum bactericidal and fungicidal protection meeting ISO 11930 Criteria A.

- Leave-On Skincare Emulsions, Micellar Waters, Serums, and Wet Wipes: Hydrating facial toners, micellar cleansing waters, hyaluronic acid and niacinamide serums, alpha/beta-hydroxy acid (glycolic, lactic, salicylic acid) exfoliating lotions, O/W moisturizers, and non-woven baby wipe or makeup-remover wipe wetting solutions (pH 4.2 to 5.0) utilize up to 0.5% w/w (5,000 ppm as benzoic acid equivalent per EU Annex V leave-on limit, corresponding to 0.59% w/w as Sodium Benzoate) of Benzoate of Soda, often blended with phenoxyethanol, benzyl alcohol, gluconolactone, or pentylene glycol.

- Oral Care and Dental Hygiene Products: Fluoridated and herbal toothpastes, whitening dental gels, alcohol-free mouthwashes, pediatric oral rinses, and denture-cleansing solutions incorporate up to 1.7% w/w (expressed as benzoic acid per EU Annex V oral-care limit; typically 0.20% to 0.60% w/w) of USP/Ph. Eur. Natrium Benzoicum. In oral care, Sodium Benzoate not only preserves the aqueous sorbitol/glycerin/silica paste against microbial contamination during consumer tube squeezing, but also penetrates dental plaque biofilms where weak lactic acid produced by cariogenic Streptococcus mutans protonates the benzoate, arresting bacterial glycolytic acidogenesis and plaque regrowth.

- Internal Corrosion Passivation of Water-Based Cosmetic Aerosol Cans: In water-containing shaving foams, hair styling mousses, body mists, and thermal spring water sprays packaged in tinplate or aluminum aerosol cans, 0.15% to 0.50% w/w of Sodium Benzenecarboxylate serves as an anodic liquid-phase corrosion inhibitor that prevents internal can detinning and pinhole leakage.

3. Pharmaceutical Excipient and Clinical Active Pharmaceutical Ingredient (USP / BP / Ph. Eur. Grades):
In pharmaceutical manufacturing and clinical therapeutics, compendial Natrii Benzoas / Sodium Benzoate fulfills three validated pharmacopeial functions:
- Antimicrobial Preservative for Multi-Dose Oral, Topical, and Parenteral Liquid Medicines: Pediatric analgesic and antipyretic syrups (paracetamol/acetaminophen and ibuprofen suspensions), antitussive and expectorant cough syrups (dextromethorphan, guaifenesin, ambroxol), antacid suspensions, oral rehydration drops, and topical dermatological hydrogels formulated at pH 3.5 to 5.0 utilize 0.02% to 0.50% w/w (200 to 5,000 mg/L) of USP/Ph. Eur. Sodium Benzoate to satisfy USP <51> and Ph. Eur. 5.1.3 Antimicrobial Effectiveness Testing across multi-week patient dosing.

- Water-Soluble Tablet and Capsule Die-Wall Lubricant: Conventional hydrophobic tablet lubricants such as magnesium stearate, calcium stearate, and stearic acid coat compressible granules with an insoluble lipophilic film that retards water penetration, prolongs tablet disintegration time, reduces tablet tensile crushing strength (due to over-lubrication sensitivity), and leaves an unsightly floating soap-scum ring or turbidity when effervescent or soluble tablets are dropped into a glass of water. Micronized Fine Powder USP Sodium Benzoate (dosed at 2.0% to 5.0% w/w of tablet blend weight, D50 < 15 to 45 microns) acts as an effective, 100% water-soluble boundary lubricant on rotary tablet press punches and dies and high-speed capsule dosators. It is the mandatory lubricant for effervescent vitamin C, multivitamin, calcium/magnesium, and analgesic tablets, soluble dispersible tablets, sublingual tablets, and throat lozenges where rapid disintegration (< 60 to 120 seconds) and sparkling crystal-clear aqueous solution clarity are required.

- Clinical Active Pharmaceutical Ingredient (API) for Urea Cycle Disorders, Hyperammonemia, Hepatic Encephalopathy, and CNS Formulations:
  
(a) Nitrogen-Scavenging Therapy in Hyperammonemia: In metabolic medicine and neonatal/pediatric intensive care, sterile USP/Ph. Eur. Sodium Benzoate (administered orally or via intravenous infusion at 250 to 500 mg/kg/day, or 5.5 g/m2/day, either as monotherapy or in fixed 1:1 combination with sodium phenylacetate/phenylbutyrate) is a life-saving FDA- and EMA-recognized treatment for acute hyperammonemia and congenital Urea Cycle Disorders (UCDs, including deficiencies of carbamoyl phosphate synthetase I, ornithine transcarbamylase, and argininosuccinate synthetase) as well as cirrhotic hepatic encephalopathy. Inside hepatic and renal mitochondria, each molecule of benzoate (C6H5COO-) is ligated to Coenzyme A by medium-chain acyl-CoA synthetase (butyryl-CoA / benzoyl-CoA synthetase, consuming 1 ATP -> AMP + PPi) to form benzoyl-CoA, which is then conjugated with the non-essential amino acid glycine by Glycine N-Acyltransferase (GLYAT) to synthesize Hippuric Acid (N-benzoylglycine, C6H5CONHCH2COOH). Because hippurate is actively secreted by renal organic anion transporters (OAT1/OAT3) at five times the glomerular filtration rate, every 1 mole of ingested Sodium Benzoate stoichiometrically scavenges and excretes 1 mole of waste nitrogen in the urine, bypassing the defective urea cycle and rapidly lowering neurotoxic blood ammonia (NH3/NH4+) levels.
  (b) Hydrotropic Solubilizer for Caffeine (Caffeine and Sodium Benzoate Injection USP): Pure anhydrous caffeine has limited cold-water solubility (~21 g/L at 20 °C), which is insufficient for concentrated parenteral respiratory stimulant and post-dural-puncture headache ampoules. Mixing equal parts by weight (1:1 w/w, typically 125 mg/mL each) of Caffeine and USP Sodium Benzoate forms a highly water-soluble donor-acceptor pi-pi molecular complex in which the electron-rich benzoate ring stacks face-to-face with the electron-deficient xanthine purine ring, elevating caffeine solubility above 400 to 500 g/L at ambient temperature.
  (c) Neuropsychiatric D-Amino Acid Oxidase (DAAO) Inhibition: In clinical neuropharmacology, oral USP Sodium Benzoate (500 to 2,000 mg/day) acts as a competitive inhibitor of flavoenzyme D-amino acid oxidase (DAAO), preventing the catabolic breakdown of endogenous D-serine—the obligatory co-agonist at the glycine modulatory site of N-methyl-D-aspartate (NMDA) glutamate receptors—and is widely investigated as an adjunctive therapy in treatment-resistant schizophrenia, mild cognitive impairment, and early-stage Alzheimer's disease.

4. Automotive Engine Coolants, Heat-Transfer Fluids, Metalworking Fluids, and VCI Corrosion Packaging:
- Organic Acid Technology (OAT) and Hybrid OAT (HOAT) Antifreeze Coolants: Modern extended-life ethylene glycol (MEG) and propylene glycol (MPG) automotive radiator coolants, heavy-duty diesel engine coolants, electric-vehicle battery thermal management fluids, and solar/HVAC heat-transfer brines incorporate 0.5% to 3.0% w/w (5,000 to 30,000 mg/L in concentrate, or 0.25% to 1.5% w/w at 50% dilution) of Industrial or Technical Grade Benzoate of Soda. Conforming to historic British Standard BS 6580 and modern OEM coolant specifications (where Sodium Benzoate is paired with aliphatic dicarboxylates such as sebacate, azelate, or 2-ethylhexanoate, plus azole copper passivators like tolyltriazole), Sodium Benzenecarboxylate passivates cast iron cylinder blocks, carbon steel liners, solder joints, brass radiators, and aluminum water pumps without forming abrasive silicate gels, hard-water calcium phosphate scale, or carcinogenic nitrosamines.

- Volatile and Contact Corrosion Inhibitor (VCI) Kraft Papers, Polyolefin Films, and Emitter Tablets: Unbleached kraft wrapping papers, corrugated export boxes, and co-extruded low-density polyethylene (LDPE) VCI shrink films impregnated or coated with 1.0% to 5.0% w/w of Fine Powder Sodium Benzoate (often combined with benzotriazole and sodium caprylate/sebacate) protect cold-rolled steel coils, precision ball bearings, automotive transmission gears, cast-iron brake rotors, and defense hardware against condensation rust during multi-month ocean container shipping.

- Water-Miscible Metalworking Fluids and Hydraulic Fire-Resistant Fluids: Synthetic and semi-synthetic machining, grinding, sawing, and tube-hydroforming coolants (as well as HFA high-water-content hydraulic fluids) utilize 0.20% to 1.00% w/w of Sodyum Benzoat to prevent flash rusting of freshly machined ferrous chips and cast-iron lathe beds without promoting bacterial or fungal sump rancidity.

5. Polymer Nucleation, Pyrotechnics, Photographic Processing, and Animal Nutrition:
- Isotactic Polypropylene (iPP) and Polyester (PET) Crystal Nucleating Agent: Compounding 0.08% to 0.25% w/w (800 to 2,500 ppm) of ultra-fine jet-milled Sodium Benzoate powder (D50 < 2 to 4 microns, moisture < 0.3%) into homopolymer or impact-copolymer polypropylene resins accelerates melt crystallization, raises crystallization temperature (Tc) by 8 °C to 14 °C, increases flexural modulus by 12% to 20%, boosts Heat Deflection Temperature (HDT) by 6 °C to 12 °C, improves surface gloss, and shortens injection-molding cycle times by 15% to 25% in thin-wall yogurt/margarine tubs, closures, automotive interior trims, and household storage crates.

- Pyrotechnic Whistle Compositions and Acoustic Signalling: In defense flares, artillery simulators, and professional aerial fireworks, anhydrous crystalline Sodium Benzoate (blended at 25% to 30% w/w fuel with 70% to 75% w/w potassium perchlorate KClO4 oxidizer and 0.5% to 2.0% w/w copper(II) oxychloride or iron(III) oxide burn-rate catalyst, consolidated into open-ended tubes under hydraulic pressures of 50 to 150 MPa) serves as the classic non-hygroscopic replacement for toxic potassium picrate or gallic acid in "whistle mix" propellants, generating a high-decibel 2 to 4 kHz acoustic oscillation and strong rocket thrust.

- Photographic Stabilizer and Textile Dyeing Auxiliary: Utilized in silver-halide photographic processing baths as a corrosion inhibitor and pH-buffering biocide, and in textile dyeing/printing pastes as an anti-mildew preservative and leveling assistant.

- Animal Feed and Silage Preservation (EU Feed Additive E211): Authorized in European and international animal nutrition as a technological silage additive and high-moisture feed preservative (dosed at 1,000 to 2,000 mg/kg in ensiled forage, wet brewer's grains, and liquid swine diets) to inhibit aerobic yeast refermentation, heating, and mycotoxin-producing mold growth upon silo face opening.

COMPARATIVE ADVANTAGES: WHY SODIUM BENZOATE IS PREFERRED OVER COMPETING CHEMICALS

Formulators, chemical engineers, and procurement specialists consistently select Sodium Benzoate (CAS 532-32-1) over alternative organic acids, synthetic biocides, tablet lubricants, polymer nucleators, and corrosion inhibitors due to six decisive technical and economic advantages:

1. Sodium Benzoate vs. Unneutralized Benzoic Acid (CAS 65-85-0 / E210):
Although unprotonated Benzoic Acid (C6H5COOH) is the active membrane-penetrating antimicrobial species at low pH, charging dry Benzoic Acid flakes or powder directly into aqueous manufacturing lines creates severe processing bottlenecks: at 20 °C, Benzoic Acid has a water solubility of only 2.9 g/L (0.29 g/100 mL), exhibits poor wetting (floating stubbornly as hydrophobic rafts on the water surface), and requires steam-heated jacketed dissolution tanks at 70 °C to 85 °C or organic co-solvents (ethanol or propylene glycol) to dissolve. By contrast, Benzoate of Soda exhibits a cold-water solubility of 628 to 660 g/L at 20 °C to 25 °C—more than 215 times higher than parent benzoic acid! This allows plant operators to meter Dust-Free Granules or Prills directly into ambient cold-water batching vessels or prepare 33% w/w liquid stock concentrates, achieving instantaneous, crystal-free homogeneity before the batch is acidified to generate active benzoic acid in situ.

2. Sodium Benzoate vs. Potassium Sorbate (CAS 24634-61-5 / E202):
While Potassium Sorbate (conjugate sorbic acid pKa = 4.76) retains higher undissociated activity between pH 4.5 and 6.0 and is highly active against yeasts and molds, it suffers from three major limitations compared to E211 Sodium Benzoate:
(a) Oxidative Yellowing and Maillard Browning: Potassium Sorbate is the salt of a conjugated polyunsaturated fatty acid (2,4-hexadienoic acid, CH3-CH=CH-CH=CH-COOK). In the presence of dissolved oxygen, UV light, heat, and trace amino acids or reducing sugars, its conjugated double bonds undergo autoxidative polymerization and carbonyl-amine Maillard condensation into brown polymeric aldehydes (such as acrolein, malondialdehyde, and fumaraldehyde), causing objectionable yellow-to-amber discoloration and bitter off-notes in water-white lemon-lime sodas, tonic waters, flavored waters, and transparent micellar waters. Because the aromatic benzene ring of Sodium Benzenecarboxylate contains no oxidizable aliphatic double bonds, Sodium Benzoate remains 100% water-white and color-stable across multi-year shelf life.
(b) "Geranium Off-Odor" Liability: Certain lactic acid bacteria (Leuconostoc and Lactobacillus spp.) in wine, cider, and fermented foods can reduce sorbic acid to sorbic alcohol, which rearranges in acid to form 2-ethoxyhexa-3,5-diene—a compound with an intense, offensive crushed-geranium odor at parts-per-trillion levels. Sodium Benzoate cannot undergo this reaction.
(c) Superior Antibacterial Potency and Cost Efficiency: At pH <= 4.0, Sodium Benzoate exhibits stronger bactericidal/bacteriostatic activity against acid-tolerant Gram-negative bacteria (such as E. coli and Salmonella) than Potassium Sorbate, while costing 35% to 60% less per kilogram on a commercial procurement basis. In high-risk non-carbonated beverages and dressings, combining 0.02%–0.05% Sodium Benzoate with 0.02%–0.05% Potassium Sorbate delivers optimal broad-spectrum synergy.

3. Sodium Benzoate vs. Parabens (Methylparaben, Propylparaben) and Isothiazolinones (MIT / CMIT) in Cosmetics:
Alkyl esters of para-hydroxybenzoic acid (parabens) face widespread consumer avoidance and retail "paraben-free" bans due to weak estrogenic receptor binding concerns, while Methylisothiazolinone (MIT), Chloromethylisothiazolinone (CMIT), and formaldehyde-releasing preservatives (DMDM hydantoin, imidazolidinyl urea, quaternium-15) are potent dermal contact allergens restricted or prohibited in leave-on personal care and wet wipes under EU Cosmetics Regulation 1223/2009. Conversely, INCI SODIUM BENZOATE is a nature-identical molecule found naturally in cranberries, lingonberries, prunes, cinnamon, and ripe cloves, is non-sensitizing on normal skin, is rapidly metabolized and excreted without bioaccumulation, and is universally accepted by Ecocert, COSMOS, NaTrue, and Whole Foods Premium Body Care standards.

4. Sodium Benzoate vs. Calcium Propionate (E282) and Sodium Diacetate (E262) in Food Preservation:
Propionates and acetates require high dosage levels (1,500 to 4,000 mg/kg) to inhibit molds and impart a pungent, cheesy, or sharp acetic vinegar odor and flavor that ruins delicate fruit juices, carbonated soft drinks, syrups, and cosmetic lotions. Preservative E211 is completely odorless and effective at 5- to 10-fold lower concentrations (150 to 500 mg/kg) without altering delicate citrus, berry, or floral flavor profiles.

5. Sodium Benzoate vs. Magnesium Stearate in Pharmaceutical Tablet Lubrication:
Hydrophobic Magnesium Stearate forms a water-repellent laminar coating around tablet granules that delays water wicking, slows API dissolution, softens tablets upon prolonged blending, and creates an insoluble floating scum in effervescent solutions. Micronized USP Sodium Benzoate provides clean punch ejection while dissolving 100% clearly in water within seconds.
6. Sodium Benzoate vs. Sodium Nitrite (CAS 7632-00-0) in Engine Coolants and VCI Packaging:
Sodium Nitrite is acutely toxic, classifies as an oxidizing hazardous material (GHS Category 3 Oxidizing Solid, H272), attacks lead-tin solder and brass radiator tubes, and reacts with secondary amines to form carcinogenic N-nitrosamines. Replacing or supplementing nitrite with Benzoic Acid Sodium Salt in OAT antifreeze coolants and VCI packaging eliminates nitrosamine formation, protects multi-metal assemblies (cast iron, steel, aluminum, brass, and solder), is non-oxidizing and non-hazardous for transport, and degrades > 90% in biological wastewater treatment.

PACKAGING, STORAGE AND HANDLING GUIDELINES

To preserve the compendial purity, free-flowing granulometry, low moisture content, and pristine white color of Sodium Benzoate (Benzoic Acid Sodium Salt, CAS 532-32-1), warehouse managers and plant operators should adhere to the following storage and handling protocols:

1. Standard Commercial Packaging Configurations Supplied by Ataman Kimya:
- 25 kg Net Multi-Wall Kraft Paper Bags or Woven Polypropylene (PP) Bags: Equipped with a heat-sealed low-density polyethylene (LDPE) inner moisture-barrier liner (standard palletization: 40 bags = 1,000 kg net or 48 bags = 1,200 kg net on shrink-wrapped, ISPM-15 heat-treated fumigated wooden or hygienic plastic pallets).
- 500 kg and 1,000 kg Net Flexible Intermediate Bulk Containers (FIBCs / Big Bags / Super Sacks): Constructed from UV-stabilized woven polypropylene fabric with an anti-static Type B/C LDPE inner liner, top filling spout, and bottom discharge spout for automated loss-in-weight silo dosing of Extruded Granular Noodles or Spherical Prills.
- 25 kg Fiberboard Drums: Lined with double pharmaceutical-grade polyethylene bags and tamper-evident metallic chime rings for USP / BP / Ph. Eur. Pharmaceutical and INCI Cosmetic grades requiring cleanroom secondary packaging.
- 220 kg HDPE Plastic Drums, 1,100 kg Composite IBC Totes, and Bulk ISO Tankers: Available for 33% w/w Liquid Sodium Benzoate solutions.

2. Warehouse Storage Conditions for Sodium Benzoate:
- Temperature and Humidity Control: Store Benzoate of Soda in a cool, dry, well-ventilated indoor warehouse maintained at ambient temperatures between 5 °C and 30 °C (maximum 35 °C) with relative humidity kept below 60% to 65%, away from direct sunlight, steam pipes, and roof water leaks. Because anhydrous Sodium Benzenecarboxylate becomes progressively hygroscopic when relative humidity exceeds 75%, partially emptied bags or drums of E211 Sodium Benzoate must always have their inner LDPE liners twisted shut and sealed immediately after dispensing to prevent atmospheric moisture absorption and crystalline bridging (caking).
- Pallet Stacking Care: To prevent mechanical compaction and pressure-caking of Fine Powder grades, stack pallets of 25 kg bags no more than two pallets high (or store on single-level pallet racking), and rotate inventory on a First-Expired, First-Out (FEFO) or First-In, First-Out (FIFO) basis.
- Chemical Segregation and Incompatibilities: Store Sodyum Benzoat segregated from strong mineral and organic acids (such as concentrated hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, or glacial acetic acid, which react on contact to precipitate insoluble free benzoic acid), strong oxidizing agents (such as potassium perchlorate, chlorates, nitrates, permanganates, and concentrated hydrogen peroxide, which form energetic pyrotechnic mixtures with dry organic salts), and soluble ferric salts (such as ferric chloride FeCl3 or ferric sulfate Fe2(SO4)3, which react quantitatively with Sodium Benzoate to precipitate insoluble flesh-colored or buff-colored basic ferric benzoate). In pharmaceutical compounding, note that concentrated Sodium Benzoate solutions are also incompatible with calcium salts, heavy-metal salts (silver, lead, mercury), and quaternary ammonium preservatives (such as benzalkonium chloride or cetylpyridinium chloride) or gelatin at low pH due to anionic-cationic complexation.
- Shelf Life and Retest Period: When stored unopened in original moisture-barrier packaging under recommended warehouse conditions, dry crystalline powder, extruded granular, and spherical prill grades of Sodium Benzoate (Benzoic Acid Sodium Salt) maintain full compendial specification compliance for 24 to 36 months (2 to 3 years) from the date of manufacture.

3. Safe Industrial Handling and Dosing Practices:
- Dust Control for Powder vs. Granular/Prill Grades: When handling Fine Crystalline or Micronized Powder Sodium Benzoate, operate local exhaust ventilation (LEV) at bag-dumping stations and electrically bond and ground (earth) all metal chutes, pneumatic transfer pipes, baghouse collectors, and ribbon blenders (resistance to ground < 10 Ohms) to prevent electrostatic spark discharge in airborne dust clouds. Where manual bag dumping into open-top liquid mixing vessels is performed, selecting Ataman Kimya's Dust-Free Extruded Granules (Noodles) or Spherical Prills virtually eliminates inhalable dust exposure and filter-bag blinding.
- Correct Order of Addition in Acidic Formulations (Preventing "Benzoic Acid Snow"): In food, beverage, cosmetic, and pharmaceutical batching, always dissolve Sodium Benzoate (Benzoic Acid Sodium Salt) completely into the main water phase (or neutral surfactant/syrup phase at pH >= 6.0) BEFORE adding acidulants (citric acid, phosphoric acid, malic acid, tartaric acid, lactic acid, or hydrochloric acid). Never dump dry Benzoate of Soda or concentrated 33% liquid Sodium Benzoate directly into a pre-acidified tank (pH < 4.0) without high-shear bottom-entry agitation: if concentrated Sodium Benzenecarboxylate contacts a localized low-pH zone before dispersing, it instantly protonates above the 2.9 g/L solubility limit of free benzoic acid, precipitating a white crystalline "snow" of flaky benzoic acid that floats to the tank surface and requires hours of heating or mechanical agitation to redissolve.

FIRST AID MEASURES AND SAFETY INFORMATION

Although Sodium Benzoate (CAS 532-32-1, E211) has a century-long record of safe human exposure in foods, medicines, and cosmetics with low acute systemic toxicity (oral LD50 in rats: 2,100 to 4,070 mg/kg body weight; dermal LD50 in rabbits: > 2,000 mg/kg; 4-hour inhalation LC50 in rats: > 12.2 mg/L), concentrated dry dust, granules, or solutions of Benzoic Acid Sodium Salt are classified under GHS/CLP as causing serious eye irritation (Eye Irritant Category 2 / 2A, Hazard Statement H319) and can cause mild mechanical respiratory or skin irritation in industrial handling environments. Ensure that the following safety and first aid protocols are readily accessible wherever Sodium Benzenecarboxylate is stored or processed:

1. First Aid Measures by Route of Exposure:
- Eye Contact with Sodium Benzoate: If dry powder, extruded granules, prills, or concentrated aqueous solutions of Sodium Benzoate (Benzoate of Soda) enter the eyes, immediately flush the eyes with plenty of lukewarm, gently flowing clean water or sterile isotonic saline eyewash solution for at least 15 to 20 minutes, holding the upper and lower eyelids wide open and rolling the eyeballs in all directions to irrigate the entire conjunctival sac and remove trapped crystals. Remove contact lenses after the first 5 minutes if present and easy to do, then continue rinsing thoroughly. Because concentrated E211 Sodium Benzoate is a classified eye irritant (H319), obtain prompt medical attention from an ophthalmologist or occupational physician if ocular pain, conjunctival redness, stinging, tearing, or visual blurring persists.

- Inhalation of Sodium Benzoate Dust or Aerosols: If a plant operator inhales airborne dust of Fine Powder Sodium Benzoate or aerosol mist from liquid Sodyum Benzoat solutions, move the exposed person immediately into fresh air and keep them warm and at rest in an upright, comfortable breathing posture. Instruct the conscious individual to blow their nose gently and rinse their mouth, nasal passages, and throat with clean water to clear deposited Phenylformic Acid Sodium Salt particles (water-soluble dust dissolves rapidly on moist mucous membranes). If coughing, sneezing, pharyngeal irritation, or shortness of breath occurs, administer supplemental oxygen if trained and seek medical attention.

- Skin Contact with Sodium Benzoate: If dry Benzoic Acid Sodium Salt or concentrated solution contacts the skin or work clothing, brush off excess dry solid first, remove contaminated garments and shoes, and wash the affected skin thoroughly with mild soap and running lukewarm water for 10 to 15 minutes. While INCI Sodium Benzoate is non-corrosive and non-sensitizing in standard patch tests, sensitive individuals who experience transient non-immunological contact urticaria (localized skin reddening, warmth, or itching triggered by high concentrations of benzoic acid in low-pH matrices) should apply a cool water compress and consult a physician if erythema persists. Wash contaminated work clothes before reuse.

- Accidental Ingestion of Bulk Sodium Benzoate: If large industrial quantities of Monosodium Benzoate are accidentally swallowed, rinse the mouth thoroughly with water, spit out the rinse water, and give the conscious, alert person 200 to 300 mL (1 to 2 glasses) of water to drink in order to dilute the concentrated salt in the stomach. Do NOT induce vomiting unless explicitly instructed to do so by a poison control center or physician, and never give anything by mouth to an drowsy, unconscious, or convulsing person. Swallowing massive multi-gram industrial doses of concentrated Natrium Benzoicum can cause acute osmotic gastric mucosal irritation, nausea, vomiting, epigastric pain, diarrhea, and transient hypernatremia or metabolic acidosis; seek medical attention if gastrointestinal or systemic symptoms develop.

2. Personal Protective Equipment (PPE) and Occupational Hygiene:

- Eye and Face Protection: Wear tight-fitting, indirect-vent chemical safety goggles conforming to EN 166 (European Standard) or ANSI Z87.1 (US Standard) whenever weighing, bag-dumping, milling, or dissolving Sodium Benzoate.

- Respiratory Protection: No respiratory protection is required under normal room ventilation when handling dust-free Extruded Granular Noodles or Spherical Prills; when handling Fine Powder Sodium Benzoate, cleaning dusty baghouse filters, or responding to dry powder spills where airborne particulates may exceed occupational exposure limits (OSHA PEL / ACGIH TLV for nuisance particulates: 10 mg/m3 inhalable dust, 3 to 5 mg/m3 respirable dust; German TRGS 900 AGW for Sodium Benzoate: 10 mg/m3 inhalable fraction with dermal notation), wear a fitted EN 149 FFP2 or NIOSH-approved N95/P95 particulate respirator.

- Hand and Body Protection: Wear impervious chemical-resistant protective gloves made of nitrile rubber, chloroprene (neoprene), butyl rubber, or PVC (minimum glove thickness 0.11 to 0.40 mm, permeation breakthrough time > 480 minutes Class 6 per EN ISO 374-1), along with long-sleeved antistatic cotton/polyester workwear and safety footwear.

- Workplace Hygiene: Maintain plumbed eyewash stations and safety showers within 10 seconds' travel distance of bulk mixing areas; wash hands and face with soap and water before eating, drinking, or smoking.

3. Firefighting Measures and Accidental Spill Response:
- Suitable Extinguishing Media: In the event of an industrial fire involving Sodium Benzoate packaging or bulk storage, extinguish using water spray, water fog, alcohol-resistant foam, dry chemical powder (ABC multi-purpose powder), or carbon dioxide (CO2). Avoid directing high-pressure solid water jets directly into open piles of Fine Powder Benzoate of Soda, as the mechanical blast can loft dry powder into the air and create a secondary dust deflagration hazard.

- Thermal Decomposition Hazards and Firefighter PPE: During high-temperature combustion or pyrolysis in a fire (> 430 °C), Sodium Benzenecarboxylate decomposes to evolve irritating, acrid smoke containing carbon monoxide (CO), carbon dioxide (CO2), volatile benzene and biphenyl vapors, and alkaline sodium oxide / sodium carbonate particulates. Firefighters must wear positive-pressure Self-Contained Breathing Apparatus (SCBA conforming to EN 137 / NFPA 1981) and full structural turnout gear.

- Spill Cleanup and Environmental Fate: Eliminate ignition sources if fine dust is suspended; wearing goggles, nitrile gloves, and an FFP2/N95 mask, vacuum up spilled dry Sodium Benzoate using an industrial HEPA-filtered vacuum cleaner or shovel dampened granules into labeled polyethylene salvage containers (avoid dry sweeping with brooms or blowing with compressed air). Flush trace floor residues with water to an industrial biological wastewater treatment plant, and prevent bulk spills from entering natural waterways or storm drains. In the environment, E211 Sodium Benzoate is classified as Readily Biodegradable (achieving 85% to 94% mineralization to CO2 and water within 28 days under OECD Test Guideline 301B/301D and > 90% within 7 days), exhibits zero bioaccumulation potential (log Pow = -2.27, BCF < 3.2), and shows very low acute aquatic toxicity (96-hour LC50 in Pimephales promelas fathead minnow: 484 mg/L; 96-hour LC50 in Lepomis macrochirus bluegill: > 100 mg/L; 48-hour EC50 in Daphnia magna water flea: > 100 to 650 mg/L; 72-hour EC50 in Raphidocelis subcapitata green algae: > 30.5 mg/L).

REGULATORY, COMPENDIAL AND TOXICOLOGICAL STATUS

Sodium Benzoate (CAS 532-32-1, EC 208-534-8) holds one of the most comprehensive international regulatory approvals of any specialty chemical raw material:

1. United States FDA & Food Chemicals Codex (FCC):
Affirmed by the US Food and Drug Administration as Generally Recognized As Safe (GRAS) as a direct human food ingredient (antimicrobial agent and flavoring agent/adjuvant) under 21 CFR 184.1733, and as an animal feed preservative under 21 CFR 582.3733, with a general current Good Manufacturing Practice (cGMP) usage limit of 0.1% w/w (1,000 ppm) in food as served (and up to 1.0% w/w in specific condiments, relishes, and coatings). Listed as an approved FEMA flavoring substance (FEMA No. 3025) and an FDA Inactive Ingredient for oral, topical, dental, rectal, inhalation, and intravenous/intramuscular pharmaceutical dosage forms (UNII: OJ245FE5EU). Fully compliant with the current Food Chemicals Codex (FCC) monograph.

2. European Union Food Additive Legislation (E211):
Authorized across the European Economic Area and United Kingdom as Food Additive E211 (Preservatives, Group I / specific food categories under Annex II and Annex III of Regulation (EC) No 1333/2008, typically at 150 to 2,000 mg/kg expressed as free benzoic acid). Subject to the mandatory purity specifications of Commission Regulation (EU) No 231/2012 for E 211 Sodium Benzoate (Assay >= 99.0% on anhydrous basis; Loss on drying <= 1.5%; Total organically bound chlorine <= 0.06%; Lead <= 2 mg/kg; Arsenic <= 3 mg/kg; Mercury <= 1 mg/kg).

3. Joint FAO/WHO Expert Committee on Food Additives (JECFA), Codex Alimentarius, and EFSA ADI:
Codified globally in the Codex General Standard for Food Additives (GSFA, CXS 192-1995) under INS 211. Both JECFA and the European Food Safety Authority (EFSA Panel on Food Additives and Nutrient Sources added to Food, 2016 re-evaluation) established a group Acceptable Daily Intake (ADI) of 0 to 5 mg/kg body weight per day (expressed as benzoic acid equivalents for benzoic acid, sodium benzoate, potassium benzoate, and calcium benzoate). In human toxicokinetics, orally ingested Benzoate of Soda is rapidly and completely absorbed from the gastrointestinal tract, conjugated with glycine in hepatic and renal mitochondria to form hippuric acid (N-benzoylglycine), and 75% to 100% excreted in the urine within 6 hours (and > 99% within 24 hours) with zero tissue accumulation.

4. European Union Cosmetics Regulation (EC) No 1223/2009:
Listed under INCI name SODIUM BENZOATE in Annex V (List of Preservatives Allowed in Cosmetic Products, Entry 1). Maximum authorized concentrations in ready-for-use preparations (expressed as free benzoic acid equivalent; multiply by 1.1801 for equivalent Sodium Benzoate concentration):
- Rinse-off cosmetic products (except oral care): up to 2.5% w/w as benzoic acid (equivalent to 2.95% w/w Sodium Benzoate)
- Oral care products (toothpastes, mouthwashes): up to 1.7% w/w as benzoic acid (equivalent to 2.01% w/w Sodium Benzoate)
- Leave-on cosmetic products (creams, lotions, serums, wet wipes): up to 0.5% w/w as benzoic acid (equivalent to 0.59% w/w Sodium Benzoate)

5. International Pharmacopeias (USP-NF / Ph. Eur. / BP / JP):
Official compendial monographs published in the United States Pharmacopeia–National Formulary (USP-NF: Sodium Benzoate), European Pharmacopoeia (Ph. Eur. Monograph 0123: Natrii benzoas), British Pharmacopoeia (BP: Sodium Benzoate), and Japanese Pharmacopoeia (JP).

6. European Union REACH, CLP Classification, and Food-Contact Plastics (EU 10/2011):
Registered under REACH (EC 208-534-8). Under CLP Regulation (EC) No 1272/2008 and UN GHS, classified solely as Eye Irritant Category 2 (Hazard Statement H319: Causes serious eye irritation; Signal Word: Warning). Not classified as a carcinogen by IARC, NTP, OSHA, or EU CLP; negative in Ames bacterial reverse mutation assays and mammalian in vivo micronucleus tests; not a reproductive toxicant or endocrine disruptor; not a PBT or vPvB substance. Authorized as an additive/polymer production aid (FCM Substance No 191, benzoic acid and its sodium salt) in plastic materials and articles intended to come into contact with food under Commission Regulation (EU) No 10/2011 and US FDA 21 CFR 177/178 without specific migration limit (SML) restrictions beyond general food-additive dual-use rules.

7. International Transport Classification (ADR / RID / ADN / IMDG / ICAO-TI / IATA-DGR):
Not regulated as a dangerous good for road, rail, inland waterway, maritime, or air transport (Non-Hazardous Cargo; UN Number: Not Applicable; Packing Group: Not Applicable; Marine Pollutant: No).

8. Halal, Kosher, Vegan, and Allergen Declarations:
Manufactured exclusively from synthetic petrochemical toluene and mineral sodium alkali in dedicated facilities free of animal-derived substances, ethanol fermentation, genetically modified organisms (GMOs), gluten, soy, dairy, nuts, and major food allergens (EU Regulation 1169/2011 Annex II). Fully certified for Halal, Kosher Parve (including Passover), Vegan/Vegetarian, Non-GMO, and BSE/TSE-Free compliance.

FREQUENTLY ASKED QUESTIONS (FAQ)

What is Sodium Benzoate (CAS 532-32-1) and why is it also called Preservative E211 or Benzoate of Soda?
Sodium Benzoate (C7H5NaO2, molecular weight 144.11 g/mol) is the water-soluble monosodium salt of benzoic acid, systematically named Sodium Benzenecarboxylate. In the European Union, UK, and Codex Alimentarius food additive numbering systems, it is designated as Preservative E211 (or INS 211), while across beverage, pharmaceutical, and chemical procurement markets it is widely known as Benzoate of Soda, Benzoic Acid Sodium Salt, Natrium Benzoicum, Phenylformic Acid Sodium Salt, or Sodyum Benzoat.

Why do beverage, food, and cosmetic manufacturers use Sodium Benzoate instead of pure Benzoic Acid?
Although undissociated Benzoic Acid (C6H5COOH) is the active antimicrobial molecule at low pH, pure Benzoic Acid is poorly soluble in cold water (only 0.29 g/100 mL at 20 °C) and floats stubbornly on the surface of mixing tanks. Sodium Benzoate dissolves more than 215 times better in cold water (53 to 66 g/100 mL at 20 °C to 25 °C), allowing manufacturers to dissolve the preservative rapidly in ambient water before acidifying the batch to convert the salt into active benzoic acid in situ.

What is the optimal pH range for Sodium Benzoate (E211) to work as an antimicrobial preservative?
Because its conjugate benzoic acid has a pKa of 4.19 to 4.20 at 25 °C, Sodium Benzoate achieves maximum bacteriostatic and fungistatic efficacy at pH 2.5 to 4.5 (where 33.4% to 98.0% of the total benzoate exists in the membrane-permeable, undissociated C6H5COOH form). At pH 5.0 (where 13.7% remains undissociated) higher dosages or co-preservatives like potassium sorbate are needed, and above pH 6.0 (only 1.56% undissociated) it loses standalone antimicrobial potency, although it remains fully effective as an alkaline corrosion inhibitor or pharmaceutical tablet lubricant.

How do I convert between Sodium Benzoate weight and "Benzoic Acid Equivalent" weight in regulatory formulas?
Because Sodium Benzoate has a molecular weight of 144.11 g/mol and free Benzoic Acid has a molecular weight of 122.12 g/mol, the exact stoichiometric conversion factor is 122.12 / 144.11 = 0.8474 (84.74%). Therefore, 1,000 mg of Sodium Benzoate provides 847.4 mg of Benzoic Acid equivalent; conversely, to achieve a target EU regulatory dose of 150 mg/L as free Benzoic Acid in a carbonated soft drink, you must dose 150 / 0.8474 = 177.0 mg/L of anhydrous Sodium Benzoate.

What is the difference between Sodium Benzoate Powder, Extruded Granules (Noodles), and Spherical Prills (Beads)?
All three physical morphologies share the exact same chemical formula (C7H5NaO2) and >= 99.0% dry-basis purity, but differ in particle geometry and bulk handling behavior: Fine Powder (loose bulk density 0.35 to 0.50 g/cm3) is ideal for dry powder blending, pharmaceutical tablet lubrication, and polypropylene masterbatch compounding; Extruded Granular Noodles (0.55 to 0.72 g/cm3) eliminate airborne dust during manual bag dumping into liquid batch tanks; and Spherical Prills/Beads (0.68 to 0.82 g/cm3) offer the highest bulk density and lowest angle of repose (24 to 29 degrees) for automated pneumatic silo conveying.

In what order should Sodium Benzoate and citric or phosphoric acid be added when batching soft drinks or shampoos?
Always dissolve Sodium Benzoate completely into the main water phase (at neutral pH >= 6.0) BEFORE adding citric acid, phosphoric acid, malic acid, or lactic acid. If dry Benzoate of Soda or concentrated 33% liquid solution is dumped directly into an already-acidified tank (pH < 4.0), localized supersaturation instantly precipitates white flakes of poorly soluble free benzoic acid ("benzoic acid snow") that float on the surface and take hours to redissolve.

How do beverage formulators prevent trace benzene formation when Sodium Benzoate is used alongside Vitamin C (Ascorbic Acid)?
In acidic drinks containing both E211 Sodium Benzoate and E300 Ascorbic Acid, trace dissolved copper (Cu2+) or iron (Fe3+) ions can catalyze hydroxyl free radical (.OH) generation that decarboxylates trace amounts of benzoate under heat or UV light. Beverage technologists completely block this pathway by adding 25 to 75 mg/L of a chelating agent such as Calcium Disodium EDTA (E385) or sodium hexametaphosphate to sequester transition metal ions, utilizing antioxidant sugars, and avoiding prolonged high-temperature UV exposure.

Can INCI Sodium Benzoate be used in paraben-free, sulfate-free, and Ecocert/COSMOS natural cosmetics?
Yes, INCI SODIUM BENZOATE is approved globally as a nature-identical clean-label preservative under Ecocert, COSMOS, NaTrue, and Nordic Swan standards, and is authorized in EU Cosmetics Regulation (EC) No 1223/2009 (Annex V, Entry 1) at up to 0.5% w/w (as acid) in leave-on skin care and baby wipes, up to 1.7% w/w in toothpastes and mouthwashes, and up to 2.5% w/w in rinse-off shampoos and body washes.

Why is USP Sodium Benzoate used as an active drug in hospital medicine for hyperammonemia?
In congenital Urea Cycle Disorders (UCDs) and acute hyperammonemia, USP Sodium Benzoate acts as a metabolic nitrogen scavenger: hepatic mitochondria conjugate benzoate with glycine to form hippuric acid (hippurate), which is rapidly cleared by the kidneys into the urine, removing 1 mole of toxic waste ammonia nitrogen per mole of administered benzoate without requiring a functional urea cycle.

How does Sodium Benzoate function in automotive engine coolants, VCI packaging, and polypropylene plastics?
In Organic Acid Technology (OAT) antifreeze coolants and Volatile Corrosion Inhibitor (VCI) papers/films (dosed at 0.5% to 3.0% w/w), the benzoate carboxylate group chemisorbs onto anodic iron, steel, aluminum, and solder oxide surfaces while the hydrophobic benzene ring forms a water-repellent monolayer that blocks chloride pitting corrosion without toxic nitrites. In isotactic polypropylene (dosed at 0.08% to 0.25% w/w as micronized powder), its high-melting (> 410 °C) crystals act as heterogeneous epitaxial nucleating sites that raise polymer crystallization temperature by 8 °C to 14 °C, boost stiffness, and cut injection-molding cooling times by 15% to 25%.

TECHNICAL SUMMARY AND ATAMAN KIMYA SUPPLY CAPABILITIES

Sodium Benzoate (CAS 532-32-1, EC 208-534-8, E211, C7H5NaO2, MW 144.11 g/mol) stands as one of the global chemical industry's most indispensable multifunctional raw materials—combining extraordinary cold-water solubility (556 to 660 g/L across 0 °C to 25 °C), high thermal stability (melting point 410 °C to 436 °C), potent pH-dependent antimicrobial preservation below pH 4.5, 100% water-soluble pharmaceutical tablet lubrication, clinical metabolic nitrogen scavenging, isotactic polypropylene crystal nucleation, and nitrite-free multi-metal anodic corrosion passivation. Whether specified by food and beverage technologists as Preservative E211 or Benzoate of Soda, by personal care formulators as INCI SODIUM BENZOATE, by pharmaceutical quality assurance directors as USP/BP/Ph. Eur. Natrium Benzoicum or Natrii Benzoas, or by coolant, VCI packaging, and plastics engineers as Benzoic Acid Sodium Salt, Phenylformic Acid Sodium Salt, and Sodium Benzenecarboxylate, achieving consistent batch performance requires a raw material with >= 99.0% dry-basis purity, ultra-low organically bound chlorine (< 0.06%), and tailored particle morphology.

Ataman Kimya is a premier international supplier and distributor of Food Grade (FCC / E211), Pharmaceutical Grade (USP / BP / Ph. Eur.), Cosmetic Grade (INCI: SODIUM BENZOATE), and Industrial/Technical Grade Sodium Benzoate (Sodyum Benzoat / Benzoik Asit Sodyum Tuzu), maintaining comprehensive stock availability across Fine Crystalline and Micronized Powder, Dust-Free Extruded Granular Noodles, Free-Flowing Spherical Prills/Beads, and 33% w/w Liquid Solution formats in 25 kg moisture-barrier bags, 25 kg fiber drums, 500–1,000 kg big bags, and 1,100 kg IBC totes. For technical specifications, batch-specific Certificate of Analysis (COA), Material Safety Data Sheet (MSDS/SDS), Halal/Kosher/Food-Contact regulatory declarations, granulometry selection guidance, or competitive bulk commercial quotations on Sodium Benzoate (Benzoic Acid Sodium Salt / E211), please contact the Ataman Kimya technical sales and international supply team directly.

Ataman Chemicals
Phone: +90 216 577 10 10
Email: info@atamankimya.com