Chloroacetic acid

Monochloroacetic acid

A colorless, pungent -smelling solid

Fixed

1.58 g · cm -3 ( 20 ° C)

61 ° C

189 ° C.

0.22 hPa ( 20 ° C)

2.87 (25 ° C)

Very well in water ( 4210 g · l-1 at 20 ° C)

Risk

-509.7 KJ / mol

Template: Infobox chemical / molecular formula search available

In monochloroacetic acid (also: monochloroacetic acid ), a hydrogen atom of the methyl group of the acetic acid is replaced by a chlorine atom. Its salts are called ( mono) Chloroacetates.

Representation

The preparation is carried by chlorination of acetic acid at 85 ° C and up to 6 bar, with the addition of catalytic amounts of acetic anhydride or acetyl chloride.

Properties

Chloroacetic acid forms colorless crystals with a pungent ( essigsäureartigem ) odor, melting 53-63 ° C (depending on modification) and is easy to dissolve in water, but also in ethanol, diethyl ether and other organic solvents. The aqueous solution is strongly acidic, much stronger acid than acetic acid.

The reason for this is to stabilize the anion by means of the right electronegative chlorine atom: It acts electron withdrawing and distributed ( delocalized ), the negative charge of the anion throughout the molecule and stabilizes the anion.

Use

Chloroacetic acid is the starting material for carboxymethylcellulose, mercaptoacetic acid, as well as plant protection agents, dyes or medicines. Applied directly is monochloroacetic acid in the cauterization of warts (trade name: Acetocaustin ).

The application of monochloro- and monobromoacetic as a disinfectant and preservative in the beverage industry led in 1985 in Bavaria for beer scandal.

Hazards

Chloroacetic acid and its vapors are toxic and highly corrosive effect on the eyes, the respiratory tract and the skin. The substance is readily absorbed through the skin. Touching the skin, the acid must be immediately rinsed off with water. There is the danger of poisoning, which can result in wetting of 5-10 % of the body surface, from 80 % solution, to death.