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1.What is Benzoic Acid?

Benzoic acid, a white, crystalline organic compound belonging to the family of carboxylic acids, widely used as a food preservative and in the manufacture of various cosmetics, dyes, plastics, and insect repellents. First described in the 16th century, benzoic acid exists in many plants; it makes up about 20 percent of gum benzoin, a vegetable resin. It was first prepared synthetically about 1860 from compounds derived from coal tar. It is commercially manufactured by the chemical reaction of toluene (a hydrocarbon obtained from petroleum) with oxygen at temperatures around 200° C (about 400° F) in the presence of cobalt and manganese salts as catalysts. Pure benzoic acid melts at 122° C (252° F) and is very slightly soluble in water. Among the derivatives of benzoic acid are sodium benzoate, a salt used as a food preservative; benzyl benzoate, an ester used as a miticide; and benzoyl peroxide, used in bleaching flour and in initiating chemical reactions for preparing certain plastics.

2.How is Benzoic Acid produced?

20 g of benzaldehyde are treated in a thick-walled vessel with a cold solution of 18g of potassium hydroxide in 12 g of water. The mixture is mixed until a permanent emulsion is formed. The mixture in the thick-walled vessel is then tightly closed by a cork and allowed to stand for at least 6 hours or overnight. To the crystalline paste (potassium benzoate) separating out, water is added until a clear solution is obtained from which benzyl alcohol is extracted by repeatedly shaking with ether. After the evaporation of the ether the residue is subjected to distillation whereby benzyl alcohol passes over at 206oC (Yield about 8g). The benzoic acid is precipitated from the alkaline solution on acidifying with hydrochloric acid and purified by crystallization from hot water yielding product, which melts at about 121oC.

3.Why Benzoic Acid is less common in food?

But its uses in food and beverage are not common compared with sodium benzoate and potassium benzoate, as three main issues (especially the solubility): Solubility: slightly soluble in water, not easy to use PH: It is an acid that will influence the PH of food and drink Taste: Its solution has an acid taste, will affect the taste That’s why it is always made to its salt – sodium benzoate although it is benzoic acid that has the antimicrobial activity. Typical use levels of benzoic acid and sodium benzoate in food are between 0.05–0.1%.

4.What is Benzoic Acid used for?

Benzoic acid is most commonly used in industrial manufacturing, to manufacture a wide variety of products such as perfumes, dyes, and insect repellents. Benzoic acid salt (sodium benzoate) is commonly used as a PH adjustor and preservative in food, preventing the growth of microbes to keep food safe. It works by changing the internal PH of microorganisms to an acid state that is incompatible with their growth and survival. Production of phenol involves the use of benzoic acid. Benzoic acid is an ingredient in many cosmetic and personal care products such as lipsticks, facial cleanser and mouthwash. Because of its anti-fungal properties, it is an ingredient in topical antifungal cream, ointments and lotions that can help treat althlete’s foot and ringworm. Benzoic acid is also present in various products including sauces, jams, jellies and candied fruits.