Process for preparing 2-methoxy-3, 6-dichlorobenzoic acid and product thereof

摘要

2 - Methoxy - 3,6 - dichlorobenzoic acid is prepared by a method comprising reacting 3,6-dichlorosalicylic acid with methyl chloride in an aqueous medium which has a pH higher than 10. The pH of the solution may be brought to the desired pH by adding a hydroxide or carbonate of an alkali metal or alkaline earth metal. The required acid is then produced partly as a metal salt and partly as a methyl ester which is hydrolysed by heating with additional base. The free acid may then be obtained from the salt by acidification, preferably with a mineral acid.