Benzoic acid

Description

Benzoic acid, the simplest benzene-based carboxylic acid, has been known since the 16th century. One of its discoverers was the legendary clairvoyant Nostradamus. Its most common natural source is gum benzoin, a resin found in the bark of trees of the genus Styrax.

The Uses of Benzoic acid

Benzoic acid is a simple organic compound employed as a preservative. Benzoic acid and sodium benzoate (C6H5COONa) are used as food preservatives and added to foods, juices, and beverages that are acidic. It also is often found in topical antifungal preparations.

Background

As a fungistatic compound Benzoic acid is widely used as a food preservative. It is conjugated to GLYCINE in the liver and excreted as hippuric acid. As the sodium salt form, sodium benzoate is used as a treatment for urea cycle disorders due to its ability to bind amino acids. This leads to excretion of these amino acids and a decrease in ammonia levels. Recent research shows that sodium benzoate may be beneficial as an add-on therapy (1 gram/day) in schizophrenia. Total Positive and Negative Syndrome Scale scores dropped by 21% compared to placebo.

Production

Sodium benzoate is an important benzoic acid derivative produced industrially by neutralization of benzoic acid using sodium hydroxide or sodium bicarbonate solution. Calcium benzoate, potassium benzoate, and other benzoate salts are also produced. Its first industrial synthesis was the hydrolysis of benzotrichloride to calcium benzoate, followed by acidification. This method has been completely displaced by the air oxidation of toluene, which avoids the problem of product contamination with chlorinated byproducts.