Method for producing chloroacetic acid

The invention discloses a method for producing chloroacetic acid. The method for producing chloroacetic acid comprises the following steps: putting 2-4 tons of high-purity chloroacetic acid and 400-1600kg of sulphur into a chlorination reaction kettle, and introducing chlorine gas at the temperature of 38-42 DEG C for carrying out reaction for 16-20 hours, so that 2.2-5 tons of high-purity chloroacetyl chloride is obtained; rectifying in a rectifying still, so that a high-purity chloroacetyl chloride catalyst is obtained; pumping 5 tons of glacial acetic acid into a chlorination kettle, adding 0.3 ton of high-purity chloroacetyl chloride, and introducing chlorine gas at the temperature of 120 DEG C for carrying out reaction for 35 hours, so that 8 tons of chloroacetic acid semifinished product is obtained; crystallizing the obtained 8 tons of chloroacetic acid semifinished product into a crystallization kettle, cooling to the temperature below 20 DEG C when crystal particles account for more than 95%, and stopping crystallization; and centrifuging and separating, so that the high-purity chloroacetic acid finished product and dichloroacetic acid mother liquor are obtained. The method for producing chloroacetic acid has the advantages that the high-purity chloroacetyl chloride is taken as a catalyst, a risk that combustion and explosion can be easily caused when acetic anhydride is taken as the catalyst originally is avoided, environmental protection effect is obvious, and economic benefit is considerable.