SODIUM GLUCONATE

From a chemical and molecular perspective, D-Gluconic Acid Monosodium Salt possesses the empirical molecular formula C6H11NaO7 and the linear condensed structural formula HOCH2-CH(OH)-CH(OH)-CH(OH)-CH(OH)-COONa (molecular weight 218.14 g/mol), consisting of an open-chain six-carbon D-gluconate backbone bearing five vicinal secondary and primary hydroxyl (-OH) groups and a terminal resonance-stabilized carboxylate anion (-COO-) coordinated with a sodium cation (Na+). This dense array of six oxygen donor atoms enables Monosodium D-Gluconate to act as a hexadentate/polydentate chelating ligand that forms water-soluble five- and six-membered chelate rings with divalent and trivalent metal cations—especially Fe3+, Al3+, Cu2+, and Ca2+—exhibiting its highest complexation stability constants in concentrated caustic alkali (pH 11.0 to 14.0+) where deprotonation of secondary alcohol groups creates ultra-stable alkoxide-carboxylate chelates alongside a cold-water solubility of 590 g/L at 20 °C to 25 °C.

Formulators and process engineers overwhelmingly prefer Sodium Gluconate over traditional synthetic aminopolycarboxylates (such as EDTA, DTPA, and NTA) and inorganic polyphosphates (STPP and SHMP) because Gluconic Acid Sodium Salt is 100% bio-based from fermented plant glucose, readily biodegradable (> 98% mineralization within 28 days), phosphorus-free (preventing aquatic eutrophication), and vastly more effective at chelating ferric iron (Fe3+) and calcium (Ca2+) in boiling concentrated caustic soda solutions where EDTA precipitates and polyphosphates hydrolyze into orthophosphate sludge. Compared to parent 50% liquid gluconic acid or glucono-delta-lactone (GDL), anhydrous crystalline Sodium Pentahydroxycaproate delivers neutral aqueous pH (6.5 to 7.5), zero shipping cost for 50% water weight, non-corrosive dry-bag storage stability, and immediate compatibility with alkaline detergents, dry-mix mortars, and cement superplasticizers.

CAS Number: 527-07-1 (D-Gluconic Acid, Monosodium Salt); 14906-97-9 (DL- / Unspecified Stereochemistry Registry)
EC Number: 208-407-7
Molecular Formula: C6H11NaO7 (Linear Structural Formula: CH2OH-(CHOH)4-COONa)
Molecular Weight: 218.14 g/mol (218.138 g/mol)
INCI Name: SODIUM GLUCONATE
E Number: E576 (INS 576 / Food Additive E 576)
Melting Point: 206 °C to 209 °C with decomposition (403 °F to 408 °F; begins thermal browning and dehydration above 195 °C to 200 °C and decomposes into sodium carbonate and carbonaceous char between 205 °C and 215 °C without a reversible liquid boiling phase)
Boiling Point: Not Applicable for anhydrous ionic solid C6H11NaO7 (decomposes thermally above 206 °C prior to boiling at 101.3 kPa; 10% to 40% w/w aqueous solutions boil at 100.7 °C to 105.2 °C at 101.3 kPa)
Viscosity: Not Applicable as a dry crystalline powder or granular solid; in aqueous solution at 20 °C to 25 °C, dynamic viscosity is 1.18 mPa.s (cP) at 5% w/w, 1.48 mPa.s at 10% w/w, 2.35 mPa.s at 20% w/w, 4.40 mPa.s at 30% w/w, and 9.50 to 12.5 mPa.s at 40% w/w
Density: True crystal density of 1.760 to 1.800 g/cm3 (1,760 to 1,800 kg/m3) at 20 °C; apparent loose bulk density of 0.55 to 0.75 g/cm3 (550 to 750 kg/m3) for fine crystalline powder and 0.72 to 0.92 g/cm3 (720 to 920 kg/m3) for standard crystalline granular grades; tapped bulk density of 0.80 to 1.05 g/cm3; 20% w/w aqueous solution specific gravity of 1.105 g/cm3 at 20 °C (40% w/w solution specific gravity of 1.225 g/cm3)

Most Frequently Encountered Synonyms:
Sodium Gluconate
Sodium D-Gluconate
D-Gluconic Acid, Monosodium Salt
D-Gluconic Acid Sodium Salt
Gluconic Acid, Sodium Salt
Gluconic Acid Sodium Salt
Monosodium D-Gluconate
Monosodium Gluconate
E576
E 576
Sequestrant E576
E576 Sodium Gluconate
Food Additive E576
INS 576

PRODUCT IDENTIFICATION, CHEMICAL NOMENCLATURE AND MOLECULAR ARCHITECTURE

Sodium Gluconate (CAS 527-07-1, EC / EINECS 208-407-7) is the neutral monosodium salt of D-gluconic acid (an aldonic sugar acid derived from the selective C-1 oxidation of D-glucose), representing the highest-volume bio-based chelating agent, concrete set-retarding admixture, and alkaline sequestrant in the global chemical industry. In international chemical inventories, pharmacopeias, and food additive regulations, this indispensable compound is systematically indexed under the IUPAC name Sodium (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoate and the Chemical Abstracts Service name D-Gluconic acid, monosodium salt. Across commercial procurement channels, construction admixture plants, and industrial detergent formulations, buyers and chemists routinely specify the product under its established synonyms: Sodium D-Gluconate, Gluconic Acid Sodium Salt, Monosodium D-Gluconate, Sequestrant E576, INS 576, Natrii Gluconas, Sodium Pentahydroxycaproate, and in Turkish chemical trade, Sodyum Glukonat or Glukonik Asit Sodyum Tuzu.

From a structural and stereochemical standpoint, Sodium Gluconate possesses the empirical molecular formula C6H11NaO7 and the condensed linear formula HOCH2-CH(OH)-CH(OH)-CH(OH)-CH(OH)-COONa, with a molar mass of 218.138 g/mol (standardly reported as 218.14 g/mol). Unlike cyclic D-glucose or cyclic glucono-delta-lactone (GDL, C6H10O6), crystalline Sodium D-Gluconate exists exclusively in the open-chain acyclic hexanoate configuration, featuring four defined chiral centers with the stereospecific (2R, 3S, 4R, 5R) D-gluco configuration:

The Terminal Resonance-Stabilized Carboxylate Headgroup (-COO- Na+ at C-1): At the C-1 position, the oxidized aldehyde carbon of glucose forms a strongly hydrophilic carboxylate anion (-COO-) ionically balanced by a sodium cation (Na+). Because the parent D-gluconic acid has a pKa of 3.60 to 3.86 at 25 °C, the carboxylate group is > 99.9% ionized in neutral and alkaline aqueous media, providing primary electrostatic coordination to metal cations and driving an extraordinary cold-water solubility of 590 g/L at 20 °C to 25 °C.

The Polydentate Polyhydroxy Chain (Four Secondary -OH Groups at C-2 to C-5 and One Primary -OH Group at C-6): Attached along the flexible sp3-hybridized carbon backbone from C-2 to C-6 are five vicinal hydroxyl (-OH) functional groups. In neutral to mildly alkaline solutions, these uncharged hydroxyl oxygens coordinate together with the C-1 carboxylate oxygen around divalent and trivalent metal ions (Ca2+, Mg2+, Fe2+, Fe3+, Cu2+, Zn2+, Al3+, Ni2+) via ion-dipole dative bonds to form stable five- and six-membered chelate rings. Crucially, when the solution pH is raised into the strongly alkaline or caustic regime (pH 11.0 to 14.0+, such as in 2% to 20% w/w sodium hydroxide bottle-washing and metal-cleaning baths or pH 12.5–13.5 Portland cement pore water), the alpha-hydroxyl group at C-2 and adjacent secondary hydroxyls at C-3 and C-4 undergo metal-assisted deprotonation into negatively charged alkoxide anions (-CH(O-)-). This converts Sodium Gluconate into a powerful poly-anionic chelate ligand whose stability constants for Fe3+ (log K ~ 37.2), Al3+, Cu2+, and Ca2+ surpass those of EDTA and NTA in hot caustic solutions!

Stoichiometric Conversion Factors for Formulators: Commercial Sodium Gluconate is crystallized and supplied as an anhydrous, non-deliquescent crystalline powder or granule (C6H11NaO7, MW = 218.14 g/mol). When converting between free D-Gluconic Acid (C6H12O7, MW = 196.16 g/mol), Glucono-delta-Lactone (GDL, C6H10O6, MW = 178.14 g/mol), and Sodium Gluconate (MW = 218.14 g/mol):
- 1.000 g of anhydrous Sodium Gluconate (C6H11NaO7) = 0.8992 g of equivalent free D-Gluconic Acid (C6H12O7) = 0.8166 g of equivalent Glucono-delta-Lactone (C6H10O6).
- Conversely, 1.1121 g of Sodium Gluconate delivers 1.000 g of free D-Gluconic Acid equivalent (and 1.000 kg of dry Sodium Gluconate replaces 2.224 kg of commercial 50% w/w liquid Gluconic Acid).
Ataman Kimya supplies high-purity Sodium Gluconate across Technical/Construction Grade (>= 98.0%–99.0%), Food Grade (FCC / E576), Cosmetic Grade (INCI: SODIUM GLUCONATE), and Pharmaceutical Grade (USP / Ph. Eur. / BP) specifications.

PHYSICAL AND CHEMICAL PROPERTIES (NUMERICAL DATA AND ANALYTICAL SPECIFICATIONS)

To support precision quality control, concrete admixture dosing, alkaline chelation stoichiometry, and regulatory compliance, the following quantitative physical, chemical, thermodynamic, solution, and purity parameters define commercial Sodium Gluconate (CAS 527-07-1, EC 208-407-7, E576) supplied by Ataman Kimya:

1. Molecular, Structural, and Stoichiometric Constants:
Chemical Name: Sodium Gluconate / Sodium D-Gluconate / D-Gluconic Acid Monosodium Salt
CAS Registry Number: 527-07-1
EC / EINECS Number: 208-407-7
E Number / INS Number: E576 / INS 576
INCI Monograph Name: SODIUM GLUCONATE
FDA UNII Code: R6Q3791S76
Empirical Molecular Formula: C6H11NaO7
Condensed Linear Structural Formula: HOCH2-CH(OH)-CH(OH)-CH(OH)-CH(OH)-COONa
SMILES Notation: Na+ . O C C(O) C(O) C(O) C(O) C(=O) O- (D-Gluconate Monosodium Stereochemical Configuration)
InChIKey: RMYFFRJXXBJHMP-IVMDWMLBSA-M
Molecular Weight: 218.138 g/mol (standard specification value: 218.14 g/mol)
Theoretical Elemental Composition (Anhydrous Basis): Carbon (C) 33.04% w/w; Hydrogen (H) 5.08% w/w; Oxygen (O) 51.34% w/w; Sodium (Na) 10.54% w/w
Active Gluconic Acid Equivalent Factor: 0.8992 g C6H12O7 per 1.0000 g C6H11NaO7 (89.92% w/w); Inverse Conversion Factor: 1.1121 g C6H11NaO7 per 1.0000 g C6H12O7

2. Physical State, Sensory Profile, and Crystallographic Morphology:
Appearance at 20 °C and 101.3 kPa: White to off-white (Food/Pharma/Cosmetic Grade) or white to faint yellowish-tan (Technical/Construction Grade) free-flowing crystalline powder or uniform crystalline granules
Crystal System (X-Ray Diffraction): Monoclinic space group P21 (unit cell dimensions: a = 8.70 Angstroms, b = 12.23 Angstroms, c = 5.29 Angstroms, beta = 104.5 degrees, Z = 2; anhydrous non-hydrated crystal lattice)
Odor Profile: Completely odorless
Taste Profile: Mildly pleasant, weakly salty/savory taste without any sourness, bitterness, or metallic aftertaste (acting as a bitter-blocker against potassium chloride KCl and intense sweeteners)
Hygroscopicity in Air: Non-deliquescent and remarkably non-hygroscopic in ambient air up to 75% to 80% relative humidity at 20 °C to 25 °C (absorbing < 0.2% moisture below 70% RH, making it far easier to store in dry powder mixes than hygroscopic gluconic acid or sodium lactate)

3. Thermal Transitions, Melting Point, Boiling Point, and Decomposition Data:
Melting / Decomposition Point (OECD TG 102 / DSC / TGA): 206 °C to 209 °C with decomposition (403 °F to 408 °F); remains 100% thermally stable up to 175 °C to 185 °C, begins endothermic dehydration/caramelization near 195 °C to 202 °C, and undergoes rapid charring and decarboxylation between 206 °C and 215 °C
Boiling Point at 101.3 kPa: Not Applicable for anhydrous solid C6H11NaO7 (decomposes above 206 °C prior to boiling); for aqueous solutions at 101.3 kPa, boiling point is 100.7 °C at 10% w/w, 101.6 °C at 20% w/w, 103.0 °C at 30% w/w, and 105.2 °C at 40% w/w
Flash Point: Not Applicable for aqueous solutions; dry powder is non-flammable under standard flash point tests (dust cloud minimum ignition temperature > 420 °C to 450 °C)
Auto-Ignition Temperature (Solid Layer): > 220 °C to 350 °C (decomposes/chars without flaming ignition)
Vapor Pressure at 20 °C to 25 °C: < 1.0 x 10^-6 Pa (effectively zero vapor pressure)

4. Density, Bulk Density, and Granulometric Parameters:
True Crystal Density (Pycnometry at 20 °C): 1.760 to 1.800 g/cm3 (1,760 to 1,800 kg/m3)
Apparent Loose Bulk Density (Fine Powder Grade, 80 to 200 Mesh): 0.55 to 0.75 g/cm3 (550 to 750 kg/m3)
Apparent Loose Bulk Density (Standard Crystalline Granular Grade, 20 to 80 Mesh / 180 to 850 microns): 0.72 to 0.92 g/cm3 (720 to 920 kg/m3; Hausner Ratio 1.08 to 1.15; Angle of Repose 26 to 32 degrees)
Tapped Bulk Density: 0.80 to 1.05 g/cm3 (800 to 1,050 kg/m3)
Specific Gravity of Aqueous Solutions at 20 °C: 1.050 g/cm3 at 10% w/w; 1.105 g/cm3 at 20% w/w; 1.163 g/cm3 at 30% w/w; 1.225 g/cm3 at 40% w/w

5. Solubility Profile in Water, Caustic Solutions, and Organic Solvents:
Water Solubility at 0 °C: Approximately 420 to 450 g/L (42 to 45 g per 100 mL of water)
Water Solubility at 20 °C: 580 to 590 g/L (58.0 to 59.0 g per 100 mL of water, corresponding to ~36.7% to 37.1% w/w saturated solution)
Water Solubility at 25 °C: 590 to 610 g/L (59.0 to 61.0 g per 100 mL of water, corresponding to ~37.1% to 37.9% w/w saturated solution)
Water Solubility at 50 °C: 820 to 880 g/L (82.0 to 88.0 g per 100 mL of water)
Water Solubility at 80 °C: 1,250 to 1,380 g/L (125 to 138 g per 100 mL of water)
Water Solubility at 100 °C: > 1,550 to 1,600 g/L (> 155 g per 100 mL of boiling water)
Solubility in Aqueous Sodium Hydroxide (5% to 20% w/w NaOH at 20 °C to 80 °C): Freely soluble (up to 300 to 500 g/L without salting out, unlike many surfactants and organic salts)
Solubility in Ethanol (95% v/v at 20 °C): Sparingly / very slightly soluble (~0.2 to 1.0 g/L)
Solubility in Nonpolar Organic Solvents (Diethyl Ether, Acetone, Chloroform, Benzene, Hexane, Mineral Oils): Practically insoluble (< 0.01 g/100 mL)

6. Viscosity, Optical Rotation, pH, and Chelation Stability Constants:
Dynamic Viscosity of Aqueous Solutions at 20 °C to 25 °C (Brookfield / Ubbelohde Viscometry):
- 5.0% w/w Aqueous Solution: 1.18 mPa.s (cP)
- 10.0% w/w Aqueous Solution: 1.48 mPa.s (cP)
- 20.0% w/w Aqueous Solution: 2.35 mPa.s (cP)
- 30.0% w/w Aqueous Solution: 4.40 mPa.s (cP)
- 40.0% w/w Saturated/Supersaturated Solution: 9.50 to 12.5 mPa.s (cP)
Specific Optical Rotation ([alpha]D20, 10% w/w in water): +11.0 to +12.5 degrees (dextrorotatory in the open-chain sodium salt form)
Acid Dissociation Constant (pKa of Conjugate D-Gluconic Acid at 25 °C): pKa1 = 3.60 to 3.86 (C-1 carboxylic acid group); secondary hydroxyl deprotonation constants pKa2 to pKa4 = 13.5 to > 14.5 in free solution, shifting down to pH 10.5 to 12.5 when coordinated to Fe3+, Al3+, Cu2+, or Ca2+
pH of Aqueous Solution (10% w/w in Carbon-Dioxide-Free Deionized Water at 20 °C to 25 °C): 6.2 to 7.8 (compendial USP/FCC/EU E576 range: 6.5 to 7.5; Technical grade range: 6.5 to 8.5)
Octanol-Water Partition Coefficient (log Pow at 20 °C): -5.99 (calculated) / -3.18 to -3.60 (experimental, extremely hydrophilic and zero bioaccumulation)
Surface Tension (1.0% w/w in Water at 20 °C): 71.8 to 72.6 mN/m (non-surface-active, 100% non-foaming electrolyte)
Quantitative Metal Chelation Capacity (Sequestration Power as a Function of pH per 1.00 g of Sodium Gluconate):
- Calcium Ion (Ca2+) Chelation Capacity: At neutral pH 7.0 to 9.0, 1.0 g of Sodium Gluconate chelates 25 to 45 mg of CaCO3; in 3.0% to 5.0% w/w NaOH caustic solution (pH > 13.0) at 20 °C to 80 °C, 1.0 g of Sodium Gluconate chelates 320 to 460 mg of CaCO3 (forming soluble multinuclear calcium-hydroxo-gluconate complexes)!
- Ferric Iron (Fe3+) Chelation Capacity in Caustic Soda: In 3.0% to 15.0% w/w NaOH (pH 13.5 to 14.0), 1.0 g of Sodium Gluconate chelates 250 to 850 mg of Fe3+ (equivalent to 350 to 1,200 mg of Fe2O3 rust), with a conditional stability constant log K(Fe3+-Gluconate) = 35.0 to 37.2, completely preventing ferric hydroxide Fe(OH)3 precipitation even in boiling 20% NaOH!
- Aluminum Ion (Al3+) Sequestration in Alkaline Etching Baths: Prevents sodium aluminate (NaAlO2) decomposition into rock-hard gibbsite/bayerite (Al(OH)3 / Al2O3.3H2O) scale in 5% to 15% NaOH aluminum etching baths at 50 °C to 75 °C when dosed at 2% to 5% of the caustic soda weight.

7. Compendial Assay, Purity, and Trace Impurity Limits (FCC / E576 EU Reg. 231/2012 / USP-NF / Ph. Eur. / Technical Grades):
Assay (Purity on Dried Basis by Complexometric/Perchloric Acid Titration or HPLC):
- USP / Ph. Eur. / FCC / E576 Food & Pharma Grades: 98.0% to 102.0% w/w C6H11NaO7 (typical Ataman Kimya batch assay: 99.1% to 99.8% w/w)
- Technical / Construction Admixture Grade: Minimum 98.0% or 99.0% w/w C6H11NaO7
Loss on Drying (105 °C for 4 hours): Maximum 0.5% w/w for USP/FCC/Food Grade (typical < 0.15% to 0.30% w/w); Maximum 1.0% to 2.0% w/w for EU E576 and Technical grades
pH (10% w/w aqueous solution at 25 °C): 6.5 to 7.5 (Food/USP); 6.5 to 8.5 (Technical)
Reducing Substances (Calculated as D-Glucose, Copper Reduction Method): Maximum 0.5% w/w (USP/FCC/EU E576 limit; typical < 0.10% to 0.25% w/w, critical in concrete admixtures because high free glucose causes erratic over-retardation)
Chloride (Cl-): Maximum 0.05% w/w (500 ppm; typical < 0.01% / 100 ppm, ensuring 100% chloride-free steel rebar safety in reinforced and prestressed concrete)
Sulfate (SO4^2-): Maximum 0.05% w/w (500 ppm; typical < 0.02% / 200 ppm)
Phosphate (PO4^3-): Maximum 0.01% w/w (100 ppm; effectively phosphorus-free)
Lead (Pb, ICP-MS / AAS per EU Reg. 231/2012 & USP/FCC): Maximum 2.0 mg/kg (2.0 ppm; typical < 0.2 ppm)
Arsenic (As, ICP-MS): 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)
Heavy Metals (Total as Pb): Maximum 10 mg/kg (10 ppm)

INDUSTRIAL MANUFACTURING PROCESS: AEROBIC FERMENTATION AND CATALYTIC OXIDATION

Commercial Sodium Gluconate (CAS 527-07-1, E576) is manufactured globally at multi-hundred-thousand-ton scale from renewable plant starch (corn, wheat, potato, or tapioca starch) via two clean, high-selectivity industrial processes: (1) Submerged Aerobic Fermentation with Aspergillus niger or Gluconobacter oxydans (accounting for > 90% of global production), and (2) Heterogeneous Noble-Metal Catalytic Oxidation of D-Glucose.
Process Route 1: Submerged Aerobic Glucose Oxidase Fermentation (Aspergillus niger / Gluconobacter oxydans):

Step 1 — Starch Enzymatic Saccharification: Refined corn or tapioca starch slurry (30% to 35% dry solids) is liquefied at 95 °C to 105 °C using thermostable alpha-amylase and saccharified at 60 °C using amyloglucosidase (glucoamylase) to produce a high-purity D-glucose (dextrose, DE >= 96 to 98) hydrolysate, which is filtered and heat-sterilized.

Step 2 — Aerobic Bioconversion and In-Situ Neutralization: Sterile D-glucose solution (250 to 350 g/L) supplemented with trace mineral salts is fed into 100-to-300 m3 agitated, aerated 316L stainless-steel airlift or stirred-tank bioreactors inoculated with non-pathogenic, non-mycotoxigenic Aspergillus niger or Gluconobacter oxydans strains at 32 °C to 36 °C under 0.15 to 0.30 MPa air/oxygen pressure.
The extracellular/periplasmic flavoenzyme Glucose Oxidase (GOD, EC 1.1.3.4) stereospecifically oxidizes the C-1 aldehyde of beta-D-glucopyranose to D-glucono-1,5-lactone (GDL) while reducing molecular oxygen (O2) to hydrogen peroxide (H2O2). Simultaneously, co-expressed Lactonase (gluconolactonase, EC 3.1.1.17) hydrolyzes GDL to D-gluconic acid, while intracellular Catalase (EC 1.11.1.6) instantaneously decomposes the by-product H2O2 back into water and 0.5 mole of usable oxygen:

Net Enzymatic Reaction: 2 C6H12O6 (D-Glucose) + O2 + 2 NaOH -> 2 C6H11NaO7 (Sodium D-Gluconate) + 2 H2O
To prevent acidic inhibition of Glucose Oxidase (optimal pH 5.5 to 6.5), membrane-grade aqueous Sodium Hydroxide (NaOH, 30% to 50% w/w) is metered continuously into the bioreactor via automated pH-stat controllers. This in-situ neutralization converts D-gluconic acid directly into dissolved Sodium Gluconate as fast as it is formed, driving D-glucose conversion above 98.5% to 99.5% within 24 to 36 hours with < 0.2% residual reducing sugars!

Step 3 — Membrane Ultrafiltration and Activated-Carbon Decolorization: The finished fermentation broth is pasteurized at 80 °C, passed through rotary vacuum filters and 10-kDa ceramic ultrafiltration membranes to remove 100% of fungal mycelium and enzymes, and polished through fixed-bed columns of steam-activated microporous carbon and ion-exchange resins to strip trace color bodies, odors, and multivalent metal ions.

Step 4 — Multi-Effect Evaporative Crystallization and Fluidized-Bed Drying: The crystal-clear 35% to 42% w/w Sodium Gluconate mother liquor is concentrated in energy-efficient Mechanical Vapor Recompression (MVR) falling-film evaporators and fed into continuous draft-tube-baffle (DTB) vacuum crystallizers at 65 °C to 80 °C. Monoclinic crystals of anhydrous Sodium Gluconate (C6H11NaO7) grow to a uniform particle size (20 to 80 mesh), are separated in continuous pusher centrifuges, washed with deionized water, and dried in a two-zone stainless-steel fluidized-bed dryer at 95 °C to 115 °C until residual moisture drops below 0.15% to 0.30% w/w.

Process Route 2: Heterogeneous Catalytic Air Oxidation of D-Glucose (Bi/Pd/Pt on Carbon):
In specialized pharmaceutical and ultra-white cosmetic production plants, a 25% to 35% w/w aqueous solution of crystalline D-glucose is oxidized directly with pure oxygen or air at 45 °C to 60 °C and pH 9.0 to 9.5 (maintained by continuous NaOH dosing) over a heterogeneous bismuth-promoted palladium or platinum catalyst supported on activated carbon (Pd-Bi/C or Pt-Bi/C, or Au/C). This zero-fermentation catalytic route achieves > 99.2% selectivity to Sodium D-Gluconate in 2 to 4 hours, yielding a water-white solution after catalyst filtration that is crystallized and dried directly to USP/EP compendial purity.

MANUFACTURING TECHNOLOGIES AND INDUSTRIAL PRODUCTION ROUTES

Industrial production of Sodium Gluconate (CAS 527-07-1 / E576) from renewable D-glucose feedstocks—typically enzymatic starch hydrolysates derived from corn, wheat, tapioca, or sugar beet—has evolved across four principal synthesis technologies, with submerged aerobic bio-fermentation and noble-metal heterogeneous catalytic oxidation dominating modern high-purity global supply.

Submerged Aerobic Bio-Fermentation and Direct Sodium Hydroxide Neutralization: Over 85% of world supply of Food Grade (E576 / FCC), Cosmetic Grade (INCI: SODIUM GLUCONATE), and Technical Grade D-Gluconic Acid Monosodium Salt is manufactured via submerged aerobic fermentation of food-grade dextrose monohydrate or DE 95–98 glucose syrup using non-pathogenic strains of Aspergillus niger or Gluconobacter suboxydans at 30 °C to 34 °C and 1.0 to 2.5 bar dissolved oxygen pressure. During fermentation, the intracellular and extracellular flavoenzyme glucose oxidase (beta-D-glucose:oxygen 1-oxidoreductase, EC 1.1.3.4) stereoselectively oxidizes beta-D-glucopyranose at the C1 hemiacetal carbon to form D-glucono-1,5-lactone (delta-gluconolactone) and hydrogen peroxide (H2O2). Endogenous catalase immediately decomposes H2O2 into water and molecular oxygen, while gluconolactonase hydrolyzes D-glucono-1,5-lactone into free D-gluconic acid. By continuously metering 30% to 50% w/w purified sodium hydroxide (NaOH) solution into the fermenter to maintain an optimal pH of 5.5 to 6.5, free D-gluconic acid is neutralized in situ to form dissolved Sodium D-Gluconate at molar conversion yields exceeding 95% to 98% within 24 to 36 hours. Following biomass microfiltration, activated carbon decolorization, ion-exchange demineralization, and vacuum multiple-effect evaporation (65% to 75% w/w solids at 55 °C to 70 °C), the purified liquor is crystallized, centrifuged, and fluid-bed dried below 85 °C to produce snow-white, free-flowing crystalline Monosodium D-Gluconate with >= 99.0% assay and < 0.2% reducing sugars (Reduzate).

Direct Spray-Evaporation Technical Grade Production vs. Recrystallization: In large-scale construction admixture manufacturing, direct evaporation or spray-drying of neutralized gluconic acid-sodium gluconate fermentation broth without fractional recrystallization yields a slightly tan or yellowish-white Technical Grade Sodium Gluconate powder (98.0% to 98.9% purity, Reduzate D-glucose <= 0.7% w/w). Trace residual carbohydrates and mild Maillard caramelization during high-temperature drying impart the light cream or tan hue without impairing cement retardation efficiency, PCE compatibility, or alkaline chelation power, offering ready-mix concrete plants a highly cost-effective admixture raw material. Conversely, fractional evaporative crystallization and mother-liquor centrifugation isolate snow-white crystals required for Food (E576), Cosmetic (INCI), and Pharmaceutical (USP / Ph. Eur.) specifications.

Heterogeneous Catalytic Air/Oxygen Oxidation on Bimetallic Noble-Metal Catalysts: To eliminate fermentation broth biomass disposal and reduce batch cycle times to 2 to 6 hours, modern continuous chemical plants oxidize 20% to 40% w/w aqueous D-glucose solutions with molecular oxygen or compressed air at 45 °C to 60 °C and pH 8.5 to 9.5 (maintained by continuous NaOH addition) over carbon-supported bimetallic palladium-bismuth (Pd-Bi/C), platinum-bismuth (Pt-Bi/C), or gold-on-alumina/titania (Au/TiO2, Au/Al2O3) catalysts. This heterogeneous catalytic oxidation route provides smooth, easily controlled reaction kinetics, > 98% selectivity to Gluconic Acid Sodium Salt, and zero biological waste, although periodic catalyst regeneration is required after repeated operating cycles to restore noble-metal activity.

Electrolytic Oxidation (Sub-Bromine Mediated) and Homogeneous Chemical Oxidation: Older industrial synthesis routes include electrolytic oxidation of alkaline or bromide-containing glucose solutions in undivided electrolytic cells at controlled current density (where anodically generated hypobromite or sub-bromine species oxidize the C1 aldehyde of D-glucose to Sodyum Glukonat while regenerating bromide ions) as well as homogeneous chemical oxidation in alkaline medium. Because electrolytic oxidation requires substantial electrical energy consumption (typically 1.8 to 2.5 kWh per kg of product) and strict halide removal to prevent residual bromide/chloride contamination, it has largely been superseded by aerobic bio-fermentation and Pd-Bi/C catalytic oxidation.

MECHANISM OF ACTION: POLYHYDROXY-CARBOXYLATE CHELATION AND CEMENT HYDRATION RETARDATION

Sodium Gluconate (CAS 527-07-1) derives its unmatched cross-industry performance from two fundamental physicochemical mechanisms: (1) pH-Activated Polydentate Metal Chelation in Neutral to Caustic Solutions, and (2) Chemisorptive Surface Poisoning of Hydrating Cement Clinker Phases.

Mechanism of Alkaline and Caustic Metal Chelation (Ca2+, Mg2+, Fe3+, Al3+, Cu2+):
In neutral to mildly alkaline solutions (pH 6.0 to 10.0), the Sodium D-Gluconate anion coordinates metal cations through its ionized C-1 carboxylate oxygen (-COO-) and one or two adjacent neutral secondary hydroxyl groups (C-2 and C-3 -OH), forming weak-to-moderate 1:1 and 1:2 chelate complexes (for example, at pH 7.0 to 8.0, log K is ~1.21 for Ca2+, ~0.70 for Mg2+, and ~2.5 to 3.8 for Cu2+ and Fe2+).
However, a dramatic electronic transformation occurs when the solution pH is raised above pH 11.0 into the strongly alkaline and caustic soda regime (pH 12.0 to 14.0+, corresponding to 0.5% to 25% w/w NaOH):

- Metal-Assisted Deprotonation of Secondary Alcohols: When a high-charge-density metal cation such as Ferric Iron (Fe3+), Aluminum (Al3+), Cupric Copper (Cu2+), or Calcium (Ca2+) coordinates to the C-1 carboxylate group of gluconate, its strong Lewis acidity polarizes the O-H bonds of the adjacent C-2, C-3, and C-4 secondary hydroxyl groups, lowering their effective pKa by 3 to 5 units! In the presence of hydroxide ions (OH-), these secondary hydroxyl protons dissociate to form di-, tri-, or tetra-anionic gluconate ligands (such as [C6H8O7]^3- or [C6H7O7]^4-).

- Formation of Ultra-Stable Five-Membered Alkoxide-Carboxylate Chelate Rings: The deprotonated alkoxide oxygen atoms (-C-O-) and the carboxylate oxygen wrap around the metal ion to form rigid, thermodynamically locked five-membered chelate rings. Whereas standard aminopolycarboxylates like EDTA4- lose their chelating dominance above pH 12.5 because hydroxide ions (OH-) outcompete EDTA's tertiary amine nitrogens and precipitate brown ferric hydroxide Fe(OH)3, the alkoxide-gluconate chelate of Fe3+ actually becomes MORE stable as caustic concentration increases (reaching log K = 37.2 at pH 14)! Similarly, in caustic soda solutions, Sodium Gluconate forms soluble polynuclear calcium-hydroxo-gluconate complexes (such as [Ca3(OH)2(Gluconate)2]^2+) that sequester up to 350 to 460 mg of CaCO3 per gram of Sodium Gluconate, preventing hard-water calcium carbonate, calcium sulfate, and calcium silicate scale deposition on bottle-washing jets and CIP heat exchangers.

Mechanism of Cement Hydration Retardation and Superplasticizer Synergy in Concrete:
In Portland cement concrete, mortar, gypsum, and oilwell cementing slurries (where the aqueous pore solution rapidly reaches pH 12.5 to 13.5 due to dissolution of alkali sulfates and calcium hydroxide portlandite), dosing just 0.02% to 0.15% w/w of Sodium Gluconate by weight of cement (bwoc) exerts a profound, controllable retardation of initial and final setting times alongside a 8% to 12% water-reducing plasticizing effect:

- Selective Chemisorption onto Tricalcium Aluminate (C3A) and Tricalcium Silicate (C3S): Upon water contact, the polydentate gluconate anions (and calcium-gluconate complex ions) rapidly chemisorb via Ca2+-oxygen chelation onto the positively charged hydrating surfaces of Tricalcium Aluminate (3CaO.Al2O3, C3A) and the active dissolution pits / etch sites of Tricalcium Silicate (3CaO.SiO2, C3S / alite).

- Inhibition of Ettringite and Portlandite Nucleation (Induction Period Extension): The adsorbed monolayer of Sodium D-Gluconate poisons the surface nucleation and crystal growth of calcium hydroxide (Ca(OH)2, portlandite) and calcium sulfoaluminate hydrate (ettringite, AFt) needles, while retarding the dissolution of C3S into Calcium-Silicate-Hydrate (C-S-H) gel. This extends the dormant induction period of cement hydration from 2 hours up to 4 to 24+ hours (depending on dosage and temperature) without harming ultimate hydration degree!

- Competitive Co-Adsorption Synergy with PCE and SNF Superplasticizers: When 0.02% to 0.06% bwoc of Sodium Gluconate is co-formulated into Polycarboxylate Ether (PCE) or Polynaphthalene Sulfonate (SNF) high-range water-reducing superplasticizers, the small, fast-diffusing gluconate anions occupy the high-affinity C3A sites first. This prevents C3A and early ettringite from consuming and intercalating the expensive PCE comb polymer molecules, leaving 100% of the PCE polymer available in solution to disperse C3S silicate grains—boosting slump flow retention over 2 to 3 hours in hot weather (30 °C to 45 °C) and increasing 28-day concrete compressive strength by 10% to 18% due to denser C-S-H microstructure.

COMPREHENSIVE APPLICATIONS ACROSS GLOBAL INDUSTRIES

Construction Chemicals, Ready-Mix Concrete, Precast Concrete, and Oilwell Cementing:
The construction and building materials sector represents the largest global industrial consumer of Technical Grade Sodium Gluconate (>= 98.0%–99.0% assay, reducing sugars <= 0.5%):
- Concrete Set-Retarding and Water-Reducing Admixtures (ASTM C494 Type B & Type D / EN 934-2): Dosed at 0.02% to 0.10% by weight of cement (bwoc, i.e., 200 to 1,000 grams per metric ton of cement) in normal concrete, and up to 0.12% to 0.25% bwoc in hot-weather concreting (30 °C to 45 °C), long-haul ready-mix transit, roller-compacted dam concrete, slip-form paving, and massive foundation pours. Sodium Gluconate delays initial and final setting times by 2 to 12 hours, eliminates cold joints between successive concrete pours, reduces peak adiabatic hydration heat cracking in mass concrete, and reduces mixing water demand by 8% to 12%.
- Synergistic Slump-Retention Component in PCE, SNF, and Lignosulfonate Superplasticizers: Blended at 2.0% to 8.0% w/w into liquid Polycarboxylate Ether (PCE, 20%–40% solids) or Naphthalene Sulfonate (SNF) superplasticizer mother liquors. Sodium D-Gluconate prevents slump loss during 90-to-180-minute transit in mixer trucks, reduces the required dosage of expensive PCE polymer by 15% to 25%, and contains zero chloride (< 0.01% Cl-), making it 100% safe for prestressed steel tendons and reinforced concrete bridges.
- Oilwell Cementing Retarders (API Spec 10A): Used at 0.05% to 0.50% bwoc (alone or paired with glucoheptonate or phosphonates) to retard Class G and Class H oilwell cement slurries pumped into deep, high-temperature subterranean boreholes (60 °C to 150 °C).
- Gypsum Plaster, Stucco, and Dry-Mix Mortar Retarder: Dosed at 0.02% to 0.15% w/w in gypsum wallboard, anhydrite floor screeds, and tile adhesives to regulate open working time.

Industrial & Institutional (I&I) Detergents, Bottle Washing, and Dairy/Brewery CIP Cleaning:
Because Sodium Gluconate achieves peak chelating power in concentrated caustic alkali, it is the cornerstone sequestrant for heavy-duty alkaline cleaning:
- Industrial Glass Bottle Washing (Beer, Soft Drink, Milk, and Wine Bottles): In automated returnable glass bottle washers operating with 1.5% to 5.0% w/w caustic soda (NaOH) at 65 °C to 85 °C, adding 0.10% to 0.50% w/w of Sodium Gluconate (typically 5% to 10% based on NaOH weight) performs four critical functions simultaneously: (a) prevents hard-water calcium and magnesium carbonate/phosphate scale from crusting on spray nozzles, conveyor chains, and heating coils; (b) dissolves aluminum foil neck-labels cleanly as sodium aluminate without precipitating rock-hard aluminum hydroxide (bayerite/gibbsite) scale; (c) strips tenacious rust rings (Fe2O3) from bottle mouths left by steel crown caps; and (d) prevents silicate haze or watermark filming on rinsed glass bottles.
- Dairy, Brewery, and Food-Plant Clean-In-Place (CIP) Alkaline Cleaners: Incorporated at 1.0% to 10.0% w/w into liquid and powdered caustic CIP detergents to dissolve "milkstone" (calcium caseinate-phosphate) in pasteurizers and "beerstone" (calcium oxalate) in fermentation vessels without foaming.
- Phosphate-Free & EDTA-Free Dishwashing, Laundry, and Hard-Surface Detergents: Used at 2.0% to 15.0% w/w in automatic dishwashing tablets/gels, commercial warewashing liquids, and eco-labeled laundry detergents as a 100% biodegradable, non-eutrophying water softener and anti-redeposition builder.

Metal Surface Treatment, Alkaline Derusting, Aluminum Etching, and Electroplating:
- Alkaline Steel Derusting, Descaling, and Paint Stripping (Zero Hydrogen Embrittlement): High-strength alloy steels, springs, aircraft landing gear, and precision cast-iron molds cannot be cleaned in hydrochloric or sulfuric acid pickling baths because acid attack causes catastrophic Hydrogen Embrittlement and base-metal pitting. Immersing rusted or painted steel parts in an alkaline bath containing 10% to 25% w/w NaOH + 2% to 10% w/w Sodium Gluconate at 75 °C to 95 °C (with or without anodic/cathodic current) rapidly dissolves iron oxide rust (Fe2O3 / Fe3O4), phosphate coatings, and baked enamel paints via Fe3+-gluconate chelation while leaving the underlying metallic steel 100% unattacked and free of hydrogen embrittlement!
- Aluminum Alkaline Etching Baths ("Rock-Free" Etchant Additive): Prior to anodizing or powder coating, extruded aluminum architectural profiles are etched in 5% to 12% w/w NaOH at 50 °C to 70 °C. Without a sequestrant, dissolved sodium aluminate hydrolyzes above 30 g/L Al3+ to precipitate stone-hard aluminum trihydroxide scale on tank walls and heating coils. Adding 1.5% to 4.0% w/w of Sodium D-Gluconate stabilizes supersaturated aluminate solutions up to 80–120 g/L Al3+, imparts a uniform satin-matte finish, and eliminates jackhammer tank descaling.
- Cyanide-Free Alkaline Electroplating and Electroless Plating: Used at 10 to 80 g/L as a non-toxic complexing ligand in cyanide-free alkaline copper, zinc, tin, nickel, and brass electroplating baths and electroless nickel/copper baths to refine grain structure and increase cathode throwing power.

Food and Beverage Industry (Food Additive E576 / INS 576 / FCC Grade):
Authorized globally as a safe, multi-functional food additive under E576 and US FDA GRAS (21 CFR 182.6757):
- Potassium Chloride (KCl) Bitterness Masker and Sodium-Reduction Synergist: In low-sodium and heart-healthy foods where Sodium Chloride (NaCl, 39.3% Na) is partially replaced by Potassium Chloride (KCl), KCl imparts an unpleasant metallic, bitter, acrid aftertaste. Adding 0.10% to 0.80% w/w of E576 Sodium Gluconate (which contains only 10.54% Na—nearly 4 times less sodium than table salt!) selectively blocks bitter taste receptors on the tongue, masks KCl metallic notes, and restores a clean, rounded savory salt profile in low-sodium breads, processed cheeses, soups, sauces, and cured meats, while also masking the lingering metallic bitterness of stevia, sucralose, acesulfame-K, and saccharin in diet beverages.
- Food Sequestrant, Stabilizer, and pH Buffer: Chelates trace pro-oxidant iron and copper ions in sauces, dressings, canned seafood, and beverages (preventing lipid rancidity, vitamin C destruction, and struvite magnesium-ammonium-phosphate crystal formation in canned shrimp/tuna), acts as a protein cryoprotectant in surimi, and stabilizes milk proteins against heat coagulation in UHT dairy/plant beverages.

Cosmetics, Personal Care (INCI: SODIUM GLUCONATE), Pharmaceuticals (USP / EP), and Textiles:
- Clean-Label EDTA Replacement & Humectant in Cosmetics (INCI: SODIUM GLUCONATE): Approved by Ecocert, COSMOS, NaTrue, and Nordic Swan standards as a 100% bio-based, biodegradable chelating agent (dosed at 0.10% to 1.00% w/w, replacing non-biodegradable Disodium/Tetrasodium EDTA). In shampoos, shower gels, micellar waters, creams, serums, and soaps, it chelates Ca2+, Mg2+, Fe3+, and Cu2+ ions—boosting surfactant foam in hard water, preventing fragrance/oil rancidity, potentiating clean-label preservatives (like sodium benzoate and potassium sorbate) by stripping divalent cations from Gram-negative bacterial outer membranes, and acting as a polyhydroxy skin humectant (at 0.5% to 2.0% w/w).
- Pharmaceutical Electrolyte & Organ-Preservation Solutions (USP / Ph. Eur. Natrii Gluconas): Serves as the physiological metabolizable bicarbonate-precursor anion (at 23 to 50 mmol/L, ~5.02 g/L) in balanced intravenous crystalloid infusion fluids to prevent hyperchloremic metabolic acidosis during surgery and trauma resuscitation, and as an impermeant osmotic cell-swelling inhibitor in University of Wisconsin (UW) and MPS organ-transplant cold-storage solutions.
- Textile Scouring, Peroxide Bleaching, and Reactive Dyeing: Dosed at 0.5 to 3.0 g/L in alkaline cotton scouring and H2O2 bleaching baths to chelate pin-hole-causing iron/copper catalyst specks (preventing catalytic oxycellulose fiber damage) without stripping magnesium stabilizers, and in disperse/reactive dyeing to prevent hard-water dye precipitation.
- Industrial Cooling Water corrosion Inhibitor & Oilfield Fracturing/Chelation: Used in phosphate-free cooling tower corrosion inhibitor packages and as a biodegradable iron-control chelator in oilfield acidizing and H2S chelated-iron iron-redox gas sweetening units.

FORMULATION AND PROCESS ENGINEERING GUIDELINES

Designing high-performance construction, industrial detergent, cooling water treatment, metal finishing, food, and personal care formulations with Sodium Gluconate requires precise attention to dissolution order, dosage calibration, temperature-dependent synergy, and compatibility with co-additives. Following established process engineering protocols ensures that D-Gluconic Acid Monosodium Salt, Gluconic Acid Sodium Salt, and Sequestrant E576 deliver maximum chelation efficiency and batch-to-batch reproducibility across manufacturing plants.

Concrete Admixture Dissolution, PCE Blending, and Structural Pour Engineering: When compounding liquid polycarboxylate ether (PCE) or sulfonated naphthalene formaldehyde (SNF) superplasticizer masterbatches, dissolve Sodium Gluconate in warm metered process water (25 °C to 45 °C) under moderate mechanical agitation (150 to 300 rpm) for 5 to 10 minutes before introducing viscous polymer solutions or defoamers. Because Monosodium D-Gluconate exhibits a water solubility of 590 g/L at 25 °C, pre-dissolving the crystalline powder prevents localized supersaturation or crystal settling at the bottom of unheated storage tanks. In additive formulations designed for tightly reinforced structural elements—such as columns, curtain walls, bridge girders, and beams—as well as heavy-duty industrial floors, combining Sodium D-Gluconate with polycarboxylate-based additives provides an economical admixture design that reaches the targeted consistency class at a lower water-to-binder (W/C) ratio while protecting slump consistency for a much longer time than reference concrete. For winter concrete admixture blends (ambient temperatures below 10 °C), restrict the Sodyum Glukonat dosage to 0.02% to 0.05% by weight of cementitious material (bwoc) to avoid excessive set extension, whereas summer hot-weather mass pours (30 °C to 45 °C) typically require 0.08% to 0.18% bwoc, often paired at a 3:1 to 4:1 weight ratio with sucrose, carbohydrates, or phosphates to prevent false set of C3A while maintaining smooth C3S hydration kinetics.

Caustic Bottle-Washing and Alkaline CIP Compounding Protocol: In concentrated liquid caustic detergent concentrates (containing 30% to 50% w/w NaOH), add Sodyum Glukonat directly into the aqueous phase prior to or during the exothermic dilution of caustic soda lye, leveraging the heat of dilution (40 °C to 65 °C) to achieve rapid dissolution within 3 to 5 minutes. Note that while pure water dissolves nearly 60% w/w Gluconic Acid Sodium Salt at room temperature, salted-out solubility in 35% to 50% w/w NaOH solutions decreases to approximately 8% to 15% w/w; therefore, ultra-concentrated single-drum liquid caustic additives should be formulated within this thermodynamic solubility envelope or stabilized with hydrotropes (such as sodium cumene sulfonate or alkyl polyglucosides) to prevent crystal precipitation during cold winter warehouse storage. In working glass bottle-washing baths (1.5% to 3.0% NaOH at 65 °C to 85 °C), maintaining a free Sodium Gluconate concentration of 0.15% to 0.35% w/w (roughly 10% of the active NaOH weight) removes bottle labels and bottle-neck rust rings cleanly without blocking spray nozzles or recirculation pipelines.

Circulating Cooling Water Corrosion Inhibition and Scale Stabilization: Unlike conventional organic corrosion inhibitors whose protective film efficiency degrades at elevated temperatures, the corrosion inhibition efficiency of Sodium Gluconate in open recirculating cooling water systems and low-pressure boilers actually increases as water temperature rises. When dosed into circulating cooling water above 200 ppm (200 mg/L) or formulated in synergistic coordination packages with molybdate, silicate, polyphosphate, tungstate, or nitrite inhibitors, D-Gluconic Acid Monosodium Salt protects carbon steel and copper heat-exchanger surfaces from pitting corrosion while stabilizing calcium carbonate and calcium sulfate below their scale-precipitation thresholds.

Metal Cleaning, Alkaline Derusting, and Electroplating Bath Control: For heavy-duty electrolytic alkaline derusting and paint stripping baths operating at 70 °C to 95 °C, formulate bath chemistry with 100 to 250 g/L NaOH and 40 to 100 g/L Sodium D-Gluconate, applying periodic-reverse or cathodic current at 3 to 10 A/dm2. Every 100 g/L of D-Gluconic Acid Monosodium Salt in strong caustic holds up to 35 to 45 g/L of dissolved ferric iron (Fe3+) in clear solution without precipitating ferric hydroxide sludge, ensuring that steel billet and metal component surfaces are washed completely clean so subsequent platinum, chromium, tin, nickel, or zinc coatings bond tightly.

Food, Beverage, Oral Care, and Cosmetic Chelating System Design (E576 / FCC / INCI): When incorporating Sequestrant E576 into clear beverages, isotonic hydration drinks, dairy products, diet foods, spice mixes, or meat brines, dissolve Food Grade Sodium Gluconate in the initial water phase before adding hydrocolloids or acidulants. In oral and dental care products such as anti-tartar toothpastes and mouthwashes, adding 0.25% to 1.00% w/w INCI SODIUM GLUCONATE sequesters salivary calcium ions to inhibit dental calculus mineralization and help prevent gingivitis. In sulfate-free shampoos, cleansers, and O/W skin care emulsions, dissolving 0.20% to 0.50% w/w Gluconic Acid Sodium Salt in the deionized water phase (Phase A) at the start of batch compounding binds hard-water calcium, magnesium, iron, and copper ions immediately, boosting lather volume and protecting shelf stability.

COMPARATIVE ADVANTAGES: WHY SODIUM GLUCONATE IS PREFERRED OVER COMPETING CHELATORS

Formulators, concrete technologists, and industrial buyers systematically choose Sodium Gluconate (CAS 527-07-1) over synthetic aminopolycarboxylates, inorganic phosphates, and competing hydroxyacids due to five decisive technical and environmental advantages:

Sodium Gluconate vs. EDTA (Tetrasodium EDTA / Disodium EDTA) and DTPA / NTA:
(a) Ready Biodegradability vs. Environmental Persistence: EDTA and DTPA are recalcitrant, non-biodegradable synthetic petrochemicals that pass through municipal wastewater treatment plants intact and remobilize toxic heavy metals from river sediments; NTA (nitrilotriacetic acid) carries carcinogenic/reproductive scrutiny. By contrast, Sodium Gluconate is 100% bio-based (fermented from plant glucose), non-toxic, and Readily Biodegradable—achieving 89% to 99% mineralization to CO2 and water within 14 to 28 days under OECD Test Guideline 301D/301E.
(b) Superior Caustic Chelation Above pH 12.0: While EDTA has higher Ca2+ binding at neutral pH (pH 6–10), EDTA loses its ferric iron (Fe3+) chelating ability in hot caustic soda solutions (pH > 12.5, precipitating brown Fe(OH)3 rust) and has limited solubility in concentrated 20%–50% NaOH. Conversely, Sodium D-Gluconate undergoes alkoxide deprotonation above pH 11.5, making its Fe3+, Al3+, and Ca2+ chelation power in boiling 5%–25% NaOH bottle-washing, CIP, and metal-derusting baths vastly superior to EDTA, at less than half the raw-material cost per kilogram!

Sodium Gluconate vs. Inorganic Polyphosphates (STPP, SHMP, TKPP) and Phosphonates (HEDP, ATMP):
Sodium Tripolyphosphate (STPP) and Sodium Hexametaphosphate (SHMP) undergo rapid hydrolytic reversion into orthophosphate (PO4^3-) in hot (> 60 °C) or strongly alkaline baths, precipitating insoluble calcium orthophosphate scale. Furthermore, phosphates and phosphonates introduce phosphorus into wastewater effluents, triggering freshwater algal blooms (eutrophication) and facing strict regulatory bans in household and industrial detergents. Sodium Gluconate is 100% phosphorus-free and thermally stable in boiling caustic baths up to 105 °C without hydrolytic reversion.

Sodium Gluconate vs. 50% Liquid Gluconic Acid (CAS 526-95-4 / E574) and Glucono-delta-Lactone (GDL, E575):
Liquid 50% Gluconic Acid is strongly acidic (pH 1.8 to 2.2), corrosive to carbon steel, requires transporting 50% water weight across international freight routes, can crystallize in winter below 10 °C, and consumes expensive caustic soda when added to alkaline formulations. Anhydrous crystalline Sodium Gluconate (>= 99% active) has a neutral pH (6.5 to 7.5), eliminates shipping water weight, never freezes, and can be dry-blended directly into powdered detergents, dry-mix mortars, and spice mixes without acid-base reaction hazards.

Sodium Gluconate vs. Sodium Citrate (E331), Tartaric Acid (E334), and Sucrose in Concrete Retardation:
Sucrose (white sugar) is a "poisonous" non-linear cement retarder: slight overdosing by even 0.05% bwoc causes catastrophic "flash set" or permanent non-setting concrete failure, while citric and tartaric acids reduce early 3-day and 7-day compressive strength. Sodium Gluconate provides linear, predictable, reproducible set retardation across 20 °C to 45 °C, enhances PCE/SNF water reduction, and consistently increases 7-day and 28-day concrete compressive strength by 10% to 18%.

Sodium Gluconate vs. Sodium Glucoheptonate (CAS 31138-65-5):
While Sodium Glucoheptonate (a 7-carbon homologue) offers slightly higher caustic solubility in 50% liquid NaOH, classical HCN-cyanohydrin synthesis of glucoheptonate involves hazardous cyanide intermediates and higher cost. Fermentation-derived 6-carbon Sodium Gluconate is 100% cyanide-free, food/pharma GRAS approved, has a lower molecular weight (218.14 vs. 248.16 g/mol, giving 14% more molar chelating sites per kilogram), and is significantly more economical.

PACKAGING, STORAGE AND HANDLING GUIDELINES

Because anhydrous crystalline Sodium Gluconate (CAS 527-07-1) is non-deliquescent, non-volatile, and thermally stable up to 195 °C, it offers exceptional storage longevity when handled according to standard industrial warehouse protocols:

Standard Commercial Packaging Formats 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 plastic pallets).
- 500 kg, 1,000 kg, and 1,100 kg Net Flexible Intermediate Bulk Containers (FIBCs / Big Bags / Super Sacks): Constructed from UV-stabilized woven polypropylene with an inner polyethylene moisture liner and bottom discharge spout for automated concrete-admixture and detergent batching plants.
- 25 kg Fiberboard Drums: Lined with double pharmaceutical-grade polyethylene bags for USP / Ph. Eur. Pharmaceutical and INCI Cosmetic grades.

Warehouse Storage Conditions for Sodium Gluconate:
- Temperature and Humidity Management: Store Sodium D-Gluconate in a cool, dry, well-ventilated indoor warehouse maintained at ambient temperatures between 5 °C and 35 °C with relative humidity below 70% to 75%, away from direct rain, roof leaks, and steam pipes. Although Sodyum Glukonat is far less hygroscopic than most organic salts, resealing the inner polyethylene liner of partially used 25 kg bags prevents surface moisture pickup and pressure caking during long-term storage.
- Chemical Segregation: Store Gluconic Acid Sodium Salt segregated from strong oxidizing agents (such as concentrated nitric acid, hydrogen peroxide > 30%, perchlorates, chlorates, chromic acid, and permanganates) and strong mineral acids.
- Shelf Life and Retest Period: When stored unopened in original moisture-barrier packaging under recommended dry warehouse conditions, dry crystalline powder and granular grades of Sodium Gluconate maintain full specification compliance for 36 to 60 months (3 to 5 years) from the date of manufacture.

Safe Industrial Handling and Dosing Practices:
- Dust Control: Standard Crystalline Granular Sodium Gluconate (20 to 80 mesh, bulk density 0.72 to 0.92 g/cm3) is virtually dust-free and free-flowing; when handling Fine Powder grades, provide local exhaust ventilation at bag-dumping stations and ground pneumatic transfer equipment to prevent static buildup.
- Dissolution in Aqueous and Caustic Baths: When preparing concentrated stock solutions (e.g., 30% to 40% w/w in water for concrete admixture blending or CIP dosing), charge the water first under mechanical agitation and add Sodium Gluconate steadily; in caustic bottle-washing or aluminum-etching baths, dissolve Sodium Gluconate in the water phase before or after caustic soda addition.

FIRST AID MEASURES AND SAFETY INFORMATION

Sodium Gluconate (CAS 527-07-1, EC 208-407-7, E576) is one of the safest, most benign organic chemicals in industrial and consumer use: it is a natural metabolite of the human pentose phosphate pathway, has an extremely high acute oral LD50 (> 2,000 to 6,000+ mg/kg body weight in rats; dermal LD50 > 2,000 mg/kg), and is NOT classified as a hazardous substance or mixture under European Union CLP Regulation (EC) No 1272/2008 or UN GHS criteria. Nevertheless, standard industrial hygiene and first aid practices should be maintained wherever bulk powders or solutions of D-Gluconic Acid Monosodium Salt are handled:

First Aid Measures by Route of Exposure:

Eye Contact with Sodium Gluconate: If dry crystalline powder, granules, or concentrated solutions of Sodium Gluconate (Sodium D-Gluconate) enter the eyes, immediately flush the eyes with plenty of lukewarm, gently flowing potable water or sterile isotonic saline eyewash solution for at least 10 to 15 minutes, holding the upper and lower eyelids open to rinse out all solid crystals. Remove contact lenses after the first 5 minutes if present and easy to do, then continue rinsing. Because dry crystals of Gluconic Acid Sodium Salt can cause mild transient mechanical eye irritation or redness, consult a physician or ophthalmologist if irritation persists.

Inhalation of Sodium Gluconate Dust: If a worker inhales airborne dust generated during bag dumping of Fine Powder Sodium Gluconate (Sodyum Glukonat), move the person into fresh air and keep them comfortable and at rest. Have the individual blow their nose gently and rinse their mouth and throat with clean water to dissolve and clear deposited Monosodium D-Gluconate particles. Seek medical attention if coughing or throat irritation continues.

Skin Contact with Sodium Gluconate: Brush off excess dry powder and wash the skin with mild soap and running water. INCI Sodium Gluconate is completely non-irritating, non-corrosive, and non-sensitizing on human skin (and is actively used as a soothing skin-conditioning humectant in leave-on cosmetics); launder dust-soiled work clothes before reuse.

Accidental Ingestion of Bulk Sodium Gluconate: Sodium Gluconate (Sequestrant E576 / Natrii Gluconas) is a safe, GRAS food additive and parenteral electrolyte ingredient. If large multi-gram industrial quantities of dry Sodium Pentahydroxycaproate are accidentally swallowed at once, rinse the mouth with water and have the conscious person drink 200 to 300 mL (1 to 2 glasses) of water. Do NOT induce vomiting. Swallowing massive bulk doses (> 30 to 50 grams) may cause mild transient osmotic laxative effects, abdominal bloating, or diarrhea; seek medical advice if discomfort occurs.

Personal Protective Equipment (PPE) for Plant Personnel:

- Eye Protection: Wear standard side-shield safety glasses or dust-resistant safety goggles conforming to EN 166 or ANSI Z87.1 when dumping bags or mixing bulk powders of Sodium Gluconate.
- Respiratory Protection: No respiratory protection is required under normal room ventilation when handling Granular Sodium Gluconate; if handling Fine Powder grades where airborne dust approaches general occupational nuisance dust limits (OSHA PEL / ACGIH TLV: 10 mg/m3 inhalable dust, 3 mg/m3 respirable dust), wear a standard EN 149 FFP1/FFP2 or NIOSH N95 disposable dust mask.
- Hand and Body Protection: Wear standard nitrile, latex, or cotton/leather work gloves and normal plant workwear.

Firefighting and Accidental Spill Response:

Suitable Extinguishing Media: In the event of a fire involving Sodium Gluconate packaging, extinguish with water spray, water fog, foam, dry chemical powder (ABC powder), or carbon dioxide (CO2).

Thermal Decomposition Products: Above 206 °C in a fire, Sodium D-Gluconate chars and decomposes to emit carbon monoxide (CO), carbon dioxide (CO2), water vapor, and non-toxic sodium carbonate ash. Firefighters should wear standard positive-pressure Self-Contained Breathing Apparatus (SCBA).

Spill Cleanup and Environmental Fate: Sweep up or vacuum spilled dry Sodium Gluconate into clean containers for reuse (if uncontaminated) or disposal, and flush trace floor residues with water to a wastewater drain. In aquatic and terrestrial ecosystems, Sodium Gluconate is Readily Biodegradable (achieving 89% to 99% ultimate biodegradation to CO2 and water within 14 to 28 days under OECD 301D/301E), is on the OSPAR PLONOR list (Pose Little or No Risk to the Environment for offshore oilfield discharge), has zero bioaccumulation potential (log Pow = -5.99), and is practically non-toxic to fish, daphnia, and algae (96-hour LC50 and 48-hour EC50 > 1,000 to 10,000 mg/L).

REGULATORY, COMPENDIAL AND ENVIRONMENTAL STATUS

Sodium Gluconate (CAS 527-07-1, EC 208-407-7, E576) holds the highest level of regulatory, food-safety, pharmacopeial, and green-chemistry approvals worldwide:
- United States FDA (21 CFR 182.6757) & Food Chemicals Codex (FCC): Affirmed by the US FDA as Generally Recognized As Safe (GRAS) as a sequestrant in human food when used in accordance with current Good Manufacturing Practice (cGMP), with no numerical upper limit beyond cGMP, and approved for indirect food-contact paper, adhesives, and sanitizers. Listed on the US EPA Safer Chemical Ingredients List (SCIL) with a Full Green Circle (verified low concern). Fully compliant with the official FCC monograph for Sodium Gluconate.
- European Union Food Additive Legislation (E576): Authorized across the European Union and UK under Regulation (EC) No 1333/2008 (Annex II, Group I — authorized at "quantum satis" in almost all processed food categories) as Food Additive E 576 (Sodium gluconate), with purity specifications codified in Commission Regulation (EU) No 231/2012.

- JECFA & Codex Alimentarius (INS 576): Evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) with an Acceptable Daily Intake (ADI) of "Not Specified" (confirming absence of toxicological hazard).
- International Pharmacopeias (USP-NF / Ph. Eur. / BP): Official monographs in the United States Pharmacopeia (USP: Sodium Gluconate), European Pharmacopoeia (Ph. Eur. Monograph 2389: Natrii gluconas), and British Pharmacopoeia (BP).
- Cosmetics & Eco-Labels (INCI: SODIUM GLUCONATE): Approved worldwide without restriction; certified by Ecocert, COSMOS, NaTrue, Nordic Swan, and EU Ecolabel as a 100% bio-based, readily biodegradable chelator.
- Transport Classification (ADR / RID / IMDG / IATA): Not regulated as a dangerous good for road, rail, sea, or air transport (Non-Hazardous Cargo; UN Number: Not Applicable).
- Halal, Kosher, Vegan, Non-GMO, and Allergen-Free Status: Produced exclusively from plant starch glucose and mineral sodium alkali; fully certified for Halal, Kosher Parve (including Passover), Vegan, Non-GMO, and Allergen-Free declarations.

FREQUENTLY ASKED QUESTIONS (FAQ)

What is Sodium Gluconate (CAS 527-07-1) and why is it also called Sequestrant E576 or D-Gluconic Acid Monosodium Salt?
Sodium Gluconate (C6H11NaO7, molecular weight 218.14 g/mol) is the water-soluble monosodium salt of D-gluconic acid, produced by aerobic fermentation of plant-derived D-glucose. In European Union and Codex Alimentarius food additive regulations it is designated as Sequestrant E576 (or INS 576), while in pharmacopeias and industrial chemistry it is known as Sodium D-Gluconate, D-Gluconic Acid Monosodium Salt, Natrii Gluconas, Sodium Pentahydroxycaproate, or Sodyum Glukonat.

Why does Sodium Gluconate outperform EDTA and polyphosphates in caustic bottle-washing, CIP, and metal-cleaning baths?
In strongly alkaline and caustic solutions (pH 11.5 to 14.0+, such as 2% to 20% NaOH), the secondary hydroxyl (-OH) groups on the Sodium Gluconate chain deprotonate in the presence of metal ions to form ultra-stable five-membered alkoxide-carboxylate chelate rings. Whereas EDTA precipitates ferric hydroxide rust above pH 12.5 and polyphosphates (STPP/SHMP) hydrolyze into insoluble orthophosphate sludge at high temperatures, 1.0 gram of Sodium Gluconate chelates up to 320–460 mg of CaCO3 and 250–850 mg of Fe3+ in boiling caustic soda, while being 100% phosphorus-free and readily biodegradable (> 98% in 28 days).

How does Sodium Gluconate work as a set retarder and water reducer in ready-mix concrete and PCE superplasticizers?
When dosed at 0.02% to 0.15% by weight of cement (bwoc), Sodium Gluconate chemisorbs onto the hydrating surfaces of tricalcium aluminate (C3A) and tricalcium silicate (C3S), delaying the nucleation of ettringite and calcium hydroxide to extend concrete setting time and slump retention in hot weather (30 °C to 45 °C). When blended with Polycarboxylate Ether (PCE) or Naphthalene Sulfonate (SNF) superplasticizers, gluconate preferentially blocks C3A sites so that 100% of the PCE polymer remains free to disperse cement grains, cutting water demand by 8% to 12% and boosting 28-day compressive strength by 10% to 18%.

Why is low "Reducing Substances" (<= 0.5% as D-glucose) critical when purchasing Sodium Gluconate for concrete admixtures?
Unfermented residual D-glucose (reducing sugar) is an erratic, uncontrolled cement retarder that can cause severe over-retardation or non-setting concrete if its concentration fluctuates between batches. High-purity Sodium Gluconate supplied by Ataman Kimya (>= 98.0%–99.0% assay) strictly controls reducing substances below 0.5% w/w (typically < 0.15%–0.25%), guaranteeing reproducible, linear set-time control in every concrete batch.

How is INCI Sodium Gluconate used to replace Disodium or Tetrasodium EDTA in natural and clean-label cosmetics?
In shampoos, body washes, micellar waters, creams, and soaps, dosing 0.10% to 0.80% w/w of INCI SODIUM GLUCONATE chelates hard-water Ca2+ and Mg2+ ions (improving lather and rinsing) and sequesters pro-oxidant Fe3+ and Cu2+ ions (preventing fragrance and botanical oil rancidity) while boosting preservative efficacy. Unlike persistent petrochemical EDTA, Sodium Gluconate is 100% plant-derived, Ecocert/COSMOS approved, and doubles as a polyhydroxy skin humectant.

How does E576 Sodium Gluconate mask bitterness in low-sodium foods and potassium-chloride (KCl) salt substitutes?
Sodium Gluconate contains only 10.54% sodium by weight (nearly 4 times less sodium than NaCl at 39.3% Na) and has a clean, mild umami-saline profile. When added at 0.10% to 0.80% w/w alongside Potassium Chloride (KCl) in reduced-sodium breads, cheeses, meats, and soups—or alongside stevia and acesulfame-K in beverages—the gluconate anion inhibits bitter taste receptor signaling on the tongue, eliminating metallic KCl bitterness.

How do I convert between dry Sodium Gluconate and 50% Liquid Gluconic Acid in industrial formulations?
Because anhydrous Sodium Gluconate has a molecular weight of 218.14 g/mol and free D-Gluconic Acid has a molecular weight of 196.16 g/mol, 1.000 kg of dry Sodium Gluconate equals 0.8992 kg of 100% pure D-Gluconic Acid, which is equivalent to 1.798 kg of commercial 50% w/w liquid Gluconic Acid (plus 0.183 kg of solid NaOH neutralization equivalent).

TECHNICAL SUMMARY AND ATAMAN KIMYA SUPPLY CAPABILITIES

Sodium Gluconate (CAS 527-07-1, EC 208-407-7, E576, C6H11NaO7, MW 218.14 g/mol) stands as the global chemical industry's premier green, bio-based polyhydroxy carboxylate salt—combining high cold-water solubility (590 g/L at 20 °C to 25 °C), a neutral aqueous pH (6.5 to 7.5), high thermal decomposition stability (206 °C to 209 °C), unmatched Ca2+, Fe3+, and Al3+ chelation power in concentrated caustic alkali (pH 11 to 14+), precision cement hydration retardation and PCE superplasticizer synergy, clean-label EDTA replacement in cosmetics, and GRAS food/pharmaceutical safety with > 98% ready biodegradability. Whether specified by concrete admixture and detergent engineers as Technical Grade Sodium D-Gluconate, by food technologists as Sequestrant E576 or D-Gluconic Acid Monosodium Salt, by personal care formulators as INCI SODIUM GLUCONATE, or by pharmaceutical QA directors as USP/Ph. Eur. Natrii Gluconas, achieving consistent batch performance requires a raw material with >= 98.0%–99.8% dry-basis purity and ultra-low reducing sugars (< 0.5%).

Ataman Kimya is a leading international supplier and distributor of Technical / Construction Grade, Food Grade (FCC / E576), Cosmetic Grade (INCI: SODIUM GLUCONATE), and Pharmaceutical Grade (USP / Ph. Eur. / BP) Sodium Gluconate (Sodyum Glukonat / Glukonik Asit Sodyum Tuzu), maintaining comprehensive stock availability across Crystalline Granular and Fine Powder formats in 25 kg moisture-barrier bags, 25 kg fiber drums, and 500–1,100 kg FIBC big bags. For technical specifications, batch-specific Certificate of Analysis (COA), Material Safety Data Sheet (MSDS/SDS), Halal/Kosher/Non-GMO/Ecocert regulatory declarations, or competitive bulk commercial quotations on Sodium Gluconate (CAS 527-07-1 / E576), please contact the Ataman Kimya technical sales and international supply team directly.

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