SODIUM BENZOATE FOOD GRADE

Sodium benzoate (chemical formula C₇H₅O₂Na) is the sodium salt of benzoic acid. 
It is widely used as an antimicrobial preservative in food and beverage systems, especially those with low pH (acidic media). 
In food additive nomenclature it is commonly labelled E211. 
As a preservative, it primarily inhibits yeasts, molds and certain bacteria in acidic foods and beverages.
Molecular and physical properties
Chemical identity
IUPAC name: Sodium benzoate (sodium salt of benzenecarboxylic acid). 
CAS number: 532-32-1. 
Molecular formula & weight
Formula: C₇H₅O₂Na
Molar mass: ≈ 144.11 g·mol⁻¹ (calculated from formula; see supplier specs). 
Physical properties (typical, food-grade)
Appearance: white to slightly off-white crystalline powder. 
Solubility: highly soluble in water (≈ 556 g·L⁻¹ at 20–25 °C reported for anhydrous). 
Melting/Decomposition: typically >300 °C (product data shows decomposition/very high mp). 
 
pKa (benzoic acid): benzoic acid pKa ≈ 4.20; hence sodium benzoate in aqueous solution establishes an equilibrium with benzoic acid that is pH-dependent (critical for activity). 
 
Solvent behaviour and hygroscopicity
Sodium benzoate is not strongly hygroscopic but must be kept dry to prevent caking and dissolution. Food-grade powders have specifications for loss on drying and residual moisture. 
 
Production and industrial manufacturing methods
Overview of industrial routes
Commercial sodium benzoate production follows two main conceptual steps: (1) production of benzoic acid from petrochemical feedstocks (commonly oxidation of toluene, or alternative routes), and (2) neutralization of benzoic acid with a sodium base (NaOH) followed by isolation of the sodium salt. 
Several patents and industrial documents describe batch and continuous neutralization, decolorization, crystallization and drying steps used to produce food-grade granules or powders. 
Common feedstocks and benzoic acid manufacture
Partial oxidation of toluene with oxygen (autoxidation) in presence of catalyst—dominant commercial route for benzoic acid. Toluene → benzoic acid → sodium benzoate. 
 
Other historic routes include oxidation of benzyl chloride derivatives or hydrolysis of benzotrichloride; modern large-scale production centers typically use toluene oxidation. 
 
Neutralization and downstream processing
Benzoic acid is neutralized with sodium hydroxide (NaOH) at controlled temperature and pH (typical pH target near neutral to slightly basic) to form sodium benzoate in solution. 
The solution is clarified (carbon treatment), filtered, concentrated and crystallized. 
Drying and milling give the final powder or granular product; spray-dry or crystallization/pelletizing may be used for specific particle size. 
Example patent processes specify neutralizing at 95–98 °C, pH 7.5–8.0 then decolorizing with activated carbon and filtering. 
Food-grade finishing
Food-grade sodium benzoate is purified to meet pharmacopoeial/FCC specifications (limits on heavy metals, halogenated organics, oxidizable impurities, moisture, assay). 
Suppliers typically state compliance with Ph. Eur., BP, FCC and/or USP where relevant. 
 
Food-grade specifications and quality standards
Typical specification items (food grade / FCC / Ph.Eur. style):
Assay (dry basis): commonly 99.0–100.5% (typical supplier spec). 
Loss on drying: ≤1% (typical). 
Heavy metals (as Pb): ≤0.001% or lower; limits exist for arsenic, cadmium depending on pharmacopeial monograph. 
Halogenated compounds, oxidizable impurities: controlled to low ppm. 
Microbial limits: usually low (since crystalline preservative).
Appearance, solubility and pH of solution also tested.
Labeling and purity
Food-grade suppliers provide Certificates of Analysis (COA) and Certificates of Origin; traceability is expected for food applications. 
Many suppliers indicate conformity to E211 / FCC / Ph.Eur. specifications. 
 
Mechanism of antimicrobial action
Sodium benzoate itself is the deprotonated salt; antimicrobial efficacy arises from benzoic acid, the undissociated form. 
The key points:
In aqueous solution, sodium benzoate ⇄ benzoic acid + Na⁺. 
The proportion of undissociated benzoic acid increases as pH decreases (pKa ≈ 4.2). Benzoic acid, being more lipophilic than its anion, penetrates microbial cell membranes. 
Once inside (higher intracellular pH), it dissociates, acidifying the cytoplasm and disrupting metabolic processes, inhibiting growth and replication. 
Activity is therefore pH-dependent, most effective at pH < 4.5. 
 
Sodium benzoate is particularly effective against yeasts and molds and many Gram-negative bacteria adapted to acidic environments, but is less effective against spore-forming bacteria at low concentrations—hence it is used in combination with other hurdles (low pH, refrigeration, sugar, etc.). 
 
The antimicrobial effect is also concentration- and temperature-dependent and may be influenced by the food matrix (solids, fats, buffers) which change effective pH and availability of undissociated acid. 
 
Typical food applications and functional uses
Primary use: antimicrobial preservative in acidic foods and beverages.
Common categories where sodium benzoate (E211) is used:
Carbonated soft drinks and acidified beverages (colas, fruit drinks). Regulatory maximums often apply. 
 
Fruit juices and fruit preparations (especially low-pH juices). 
Pickles, relishes, sauces, dressings (acidified condiments).
Jams, preserves and marmalades (though high sugar + heat processing often sufficient, benzoates may be used in some products).
Salad dressings, condiments, and some dairy-derived acid beverages.
Certain bakery fillings, syrups, and other acidified preparations.
Functional roles:
Microbial growth inhibition (extension of shelf life).
Sometimes used as a flavor adjuvant or to stabilize certain formulations, but main role is preservative.
Typical usage levels: practical concentrations in finished foods often range from tens to a few hundred mg·kg⁻¹ (mg·L⁻¹), depending on local regulations and the food matrix. 
Regulatory maxima (e.g., soft drinks) may be set (e.g., 150 mg·L⁻¹ in some jurisdictions), and general limits like “not to exceed 0.1% in food” are used in some regulatory texts

SAFETY INFORMATION ABOUT SODIUM BENZOATE FOOD GRADE
 

 
 
 
 
 
First aid measures:
Description of first aid measures:
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
 
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately. 
Wash off with soap and plenty of water.
Consult a physician.
 
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
 
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
 
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment. 
 
Avoid breathing vapours, mist or gas. 
Evacuate personnel to safe areas.
 
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste. 
Keep in suitable, closed containers for disposal.
 
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
 
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place. 
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
 
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
 
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles. 
Faceshield (8-inch minimum). 
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
 
Skin protection:
Handle with gloves. 
Gloves must be inspected prior to use. 
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product. 
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. 
Wash and dry hands.
 
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
 
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. 
 
If the respirator is the sole means of protection, use a full-face supplied air respirator. 
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions. 
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
 
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company. 
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product