Sodium benzoate for various industries

Sodium Benzoate is an organic compound and the sodium salt of benzoic acid. Its chemical formula is C₇H₅O₂Na, with a molar mass of 144.10 g/mol and a density of 1.44 g/cm³.  

Physical Properties:

- Appearance: White granules or crystalline powder  

- Odor: Odorless or with a faint aromatic (benzoin-like) scent  

- Solubility:  

  - Highly soluble in water (forms a slightly alkaline solution)  

  - Slightly soluble in ethanol  

  - Soluble in glycerol and methanol  

- Hygroscopicity: Absorbs moisture when exposed to air  

Chemical Properties:

- Reacts with acids to precipitate benzoic acid  

- Reacts with carbonates to produce gas (effervescence)  

- Can undergo reactions with alkalis and vitamin C  

Applications

1.Food Preservation Field： 

Sodium benzoate is an acidic preservative with no bactericidal or bacteriostatic effects in alkaline media. Its optimal preservative pH range is 2.5–4.0 . It is commonly used to preserve highly acidic fruits, berries, juices, jams, beverage syrups, and other acidic foods. It can also be combined with low-temperature sterilization methods for complementary effects. The typical application method involves dissolving an appropriate amount of sodium benzoate in water before mixing it evenly into the food .  

(1) Beverages: Widely used in acidic beverages such as carbonated drinks, fruit juices, functional beverages, flavored water, and iced tea. Sodium benzoate effectively prevents microbial contamination, enabling these beverages to maintain a longer shelf life under acidic conditions.  

(2) Jams and Jellies: Sodium benzoate extends the shelf life of jams and jellies by inhibiting mold growth, particularly in products that require prolonged storage after opening.  

(3) Pickled Foods:In pickled products such as cucumbers, pickles, and chili peppers, sodium benzoate effectively prevents excessive fermentation caused by lactic acid bacteria and other microorganisms.  

(4) Condiments: Used in acidic condiments like soy sauce, ketchup, salad dressing, and chili sauce to prevent spoilage during long-term storage.  

(5) Baked Goods: Sodium benzoate is also applied in certain bakery products, such as packaged cakes, pies, and fillings, to prevent microbial-induced deterioration.  

Sodium benzoate is widely used as a preservative in food processing and preservation, though its usage is restricted in certain foods in some countries. Since benzoic acid exerts its preservative effect in its free state, it performs particularly well in strongly acidic foods. Benzoic acid is commonly used in carbonated beverages, soy sauce, sauces, preserved fruits, and vegetable/fruit drinks. In soy sauce and beverages, it can be synergistically combined with parabens (p-hydroxybenzoates) for enhanced efficacy. Both benzoic acid and sodium benzoate are often employed to preserve highly acidic fruits, jams, beverage syrups, and other acidic foods, sometimes in combination with low-temperature sterilization for a cooperative effect.  

Sodium benzoate is generally limited to foods with higher protein content. Its antimicrobial mechanism is the same as that of benzoic acid, but since it is a sodium salt, achieving equivalent bactericidal effects requires a dosage 1.2 times that of benzoic acid.  

2.Pharmaceutical Industry： 

In the pharmaceutical sector, sodium benzoate is also widely used as a preservative, primarily in liquid drug formulations to ensure stability and prevent microbial contamination:  

(1) Syrups and Oral Solutions:Used in medicinal syrups and oral liquids to extend shelf life and inhibit microbial growth.  

(2) Topical Medications: Incorporated into certain dermatological preparations as a preservative to maintain stability and safety.  

(3) Injectables and Eye Drops:Although its use in injectables is limited, sodium benzoate is sometimes added to multi-use eye drops to prevent microbial contamination.  

3.Personal Care Products：  

Sodium benzoate is a common preservative in cosmetics and personal care products:  

- Tonics and Facial Toners:Prevents bacterial and fungal growth, ensuring product hygiene.  

- Shampoos, Cleansers, and Mouthwashes:Safeguards against microbial contamination for safe usage.  

4.Industrial Applications

Sodium benzoate is utilized in industrial settings as a corrosion inhibitor, lubricant additive, and rust preventive:  

- Corrosion Inhibitor:Added to coolants and antifreeze to protect metal surfaces.  

- Lubricants and Rust Preventives:Functions as an additive to inhibit oxidation and rust formation.  

5.Chemical Experiments  

In laboratories, sodium benzoate is used for:  

- Buffer Solution Preparation:Regulates pH in experiments.  

- Analytical Standards: Serves as a calibration standard for instruments like mass spectrometers.  

6.Animal Feed and Health  

Sodium benzoate is added to animal feed, particularly swine diets, as an antibiotic-alternative additive:  

- Feed Preservative:Extends shelf life and prevents mold growth.  

- Digestive Aid:Lowers gastric pH in pigs to enhance digestion and nutrient absorption.  

7.Water Treatment  

Sodium benzoate forms a loose anodic corrosion-inhibiting film on ferrous metals. It can be combined with nitrites to protect such metals. As a corrosion inhibitor in water treatment, it performs well under slightly acidic conditions but is ineffective in alkaline environments. Typically, sodium benzoate is converted into its active form (benzoic acid) during application. It is often compounded with other water treatment agents for synergistic effects.  

When used alone, its corrosion inhibition efficiency is limited (e.g., 20.9% at 500 mg/L). However, when combined with sodium gluconate at the same total dosage, the inhibition rate increases to 93.7%.

Mechanism of Preservation in the Above Applications:The preservative mechanism of benzoic acid-based preservatives (e.g., sodium benzoate) primarily relies on the action of their undissociated molecules. Undissociated benzoic acid exhibits strong lipophilicity, allowing it to easily penetrate microbial cell membranes. Once inside the cell, it disrupts membrane permeability, hindering the absorption of amino acids. Additionally, the benzoic acid molecules acidify intracellular alkali reserves and inhibit the activity of respiratory enzyme systems, thereby exerting its antimicrobial effect.  

Human Safety Considerations:

After ingestion, sodium benzoate is metabolized into benzoic acid in the human body. The benzoic acid then conjugates with glycine to form hippuric acid (urinary excretion) or with glucuronic acid to form glucuronides, both of which are entirely excreted via urine without accumulation in tissues. At normal usage levels, sodium benzoate poses no toxic effects and is considered a safe preservative.  

Package :25kg/bag