Acetic acid is an organic compound with the chemical formula CH3COOH. It is also known as Ethanoic Acid. It is one of the simplest carboxylic acids and mainly produced as a precursor to poly-vinyl-acetate and cellulose acetate. Acetic acid is an important chemical reagent for both industrial and household purposes.
General Properties of Acetic Acid:
- It is a colourless liquid
- It has a distinctive sour taste
- It is pungent smelling
- It is corrosive by nature
- It is a natural antibacterial agent
- It is a polar solvent, and dissolves both polar as well as non-polar compounds such as oils, sulphur and iodine.
Production of Acetic Acid:
Acetic acid can be produced synthetically, as well as through bacterial fermentation. There are many ways in which acetic acid is produced. But majorly, the industrial production of acetic acid is by the carbonylation of methanol. In this method, methanol is made to react with carbon monoxide, the overall reaction is indicated as:
CH3OH + CO → CH3COOH
The reaction mechanism involves 3 steps:
CH3OH + HI → CH3I + H2O
CH3I + CO → CH3COI
CH3COI + H2O → CH3COOH + HI
The process needs a metal catalyst that is a metal carbonyl, for the carbonylation. There are two catalysts used Rhodium and Iridium, of which using Iridium is greener and more efficient. Acetic acid to be used in the food industry is produced biologically, through anaerobic fermentation.
Acetic Acid has a wide range of applications in various areas such as medicine, biotechnology, in food and beverages, polymers, etc. It is also used as a raw material for the production of many downstream products in industries. Some of the important applications are:
It is an approved food additive and is present in many packaged food products as an acidity regulator and as a condiment. It is the main ingredient for the production of vinegar. Acetic acid is also used as an antimicrobial agent.
Acetic acid is used as a polar organic solvent for production of Purified Terephthalic Acid (PTA).PTA acts as a precursor and is used in the production of polyethylene terephthalate (PET).It is also used to produce many organic and inorganic salts such as silver acetate, palladium acetate, etc.
It is used for manufacturing synthetic fibres in the textile industry. They are used for textile processing and printing. During the dyeing process, acetic acid plays a vital role in maintaining accurate and constant pH.
It is used for medicinal purposes such as for outer ear infections, to help prevent the growth of fungus and bacteria. It is also used as an effective tool for cervical cancer screening and has also been known to have used in controlling some symptoms of diabetes. In clinical laboratory acetic acid is used for the testing of blood samples.
Acetic acid is used for manufacturing perfumes, fragrances, pesticides and insecticides. It is used in the printing industry as a component of inks and dyes, in polymer industry for manufacturing rubber, plastics, soft drink bottles, etc. It is even used to produce cellulose acetate for photographic films.