Trichloroacetic Acid

(Ph. Eur. monograph 1967)

C₂HCl₃O₂    163.4    76-03-9

Trichloroacetic Acid Solution

Ph Eur

2,2,2-Trichloroacetic acid.

98.0 per cent to 100.5 per cent.

White or almost white, crystalline mass or colourless crystals, very deliquescent.

Very soluble in water, in alcohol and in methylene chloride.

First identification   A.

Second identification   B, C.

A. Infrared absorption spectrophotometry (2.2.24).

Comparison   Ph. Eur. reference spectrum of trichloroacetic acid.

B. To 0.5 mL of solution S (see Tests) add 2 mL of pyridine R and 5 mL of strong sodium hydroxide solution R. Shake vigorously and heat in a water-bath at 60-70 °C for 5 min. The upper layer shows an intense red colour.

C. Solution S is strongly acidic (2.2.4).

Dissolve 2.5 g in water R and dilute to 25 mL with the same solvent.

Solution S is clear (2.2.1) and not more intensely coloured than reference solution BY₇ (2.2.2, Method II).

Maximum 100 ppm.

Dilute 5 mL of solution S to 15 mL with water R. The solution complies with the limit test for chlorides.

Maximum 0.1 per cent, determined on 1.0 g.

Dissolve 0.150 g in 20 mL of water R. Titrate with 0.1 M sodium hydroxide, determining the end-point potentiometrically (2.2.20).

1 mL of 0.1 M sodium hydroxide is equivalent to 16.34 mg of C₂HCl₃O₂.

In an airtight container.

Ph Eur