Acetic Acid | Properties of Acetic Acid | Acetic Acid formation | Uses

 

Acetic Acid

Organic Name- Acetic Acid or Ethanoic Acid.

Molecular formula – CH₃COOH

Strength – Weak

Acetic acid or ethanoic acid is a colorless hydrophilic or polar protic solvent, similar to ethanol and water like a liquid organic compound with the chemical formula CH3COOH. In undiluted/solid condition, it is called glacial Acetic acid. It is the simplest second carboxylic acid. Household vinegar produces from Acetic acid.  It is an essential reagent and industrial chemical that is used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibers and fabrics.

Chemical formula

The hydrogen center in the carboxyl group (−COOH) in acetic acid can separate from the molecule by ionization:

CH₃-COOH ⇌ CH₃-COO⁻ + H⁺

Because of this release of the proton (H⁺), it has an acidic character. Acetic acid is a weak mono-protic acid. In an aqueous solution, Acetic acid has a pKa value of 4.76.

Properties of Acetic Acid

i. The chemical formula of Acetic acid is CH₃COOH.

ii. Liquid acetic acid is a hydrophilic or polar protic solvent, similar to ethanol and water.

iii. Melting point 16-17°C and boiling point 118-119°C.

iv. Acetic acid is a weak mono-protic acid.

v. Colorless liquid.

vi. It has a distinctive sour test and pungent smell vinegar-like.

vii. It engages in similar intermolecular hydrogen bonding interactions.

viii. The Flashpoint of Acetic acid is 40°C.

ix. It is usually fully ionized to acetate.

x. Its viscosity 1.22 mPa s.

Acetic Acid formation

Acetic acid is industrially produced both synthetically and by bacterial fermentation. Around 75% of acetic acid made for use in the chemical industry is produced by the carbonylation of methanol. A maximum amount of acetic acid is produced by methanol carbonylation. In this formation process, methanol and carbon monoxide react with each other and produce acetic acid according to the equation:

CH₃-OH + CO = CH₃COOH

The process involves iodomethane as an intermediate process and it occurs in three steps. A metal carbonyl catalyst is needed for carbonylation.

CH₃OH + HI → CH₃I + H₂O

CH₃I + CO → CH₃COI

CH₃COI + H₂O → CH₃COOH + HI

There are two related processes related to the carbonylation of methanol: the rhodium-catalytic Monsanto process and the iridium-catalytic Cativa process. The subsequent process is greener and more efficient and often provides the process in large quantities in the same production plants. Catalytic amounts of water are used in both processes, but the Cativa process requires less, and a small number of by-products are formed. By changing the process conditions, acetic anhydride may be produced using rhodium catalysts in the same plant.

Uses of Acetic Acid

i. Acetic acid is used in the production of vinyl acetate monomers.

ii. Its esters are commonly used as solvents for inks, paints, and coatings.

iii. The major application of acetic acid is acetic anhydride production, and it uses approximately 25% to 30% of the global production of acetic acid.

iv. It is used as a solvent in the production of terephthalic acid and 20% of acetic acid was used for TPA production.

v. It is often used as a solvent for reactions involving carbocations.

vi. Glacial acetic acid is used in analytical chemistry for the formation of weakly alkaline products such as organic amides.

vii. It has been used as an injection into a tumor to treat cancer.

viii. It is an effective antiseptic when used as a 1% solution.

ix. Directly vinegar is used as a condiment and in the pickling of vegetables and other foods.

Safety

Concentrated acetic acid is corrosive to the skin. These burns or blisters may not appear for several hours. Concentrated acetic acid can burn not only with difficulty with temperature and pressure but also ignites at temperatures above 39°C and can form explosive mixtures with air at high temperatures.