Preparation method of salicylhydroxamic acid

The invention relates to a preparation method of salicylhydroxamic acid. The method comprises the following steps: in the presence of an organic solvent and water, adding a phase transfer catalyst, alkali and a hydroxylamine hydrochloride water solution, uniformly stirring, and adding methyl salicylate; after finishing reaction, adding concentrated sulfuric acid to obtain the salicylhydroxamic acid. According to the preparation method of the salicylhydroxamic acid provided by the invention, the organic solvent and the phase transfer catalyst are selected, so that the problems that a salicylhydroxamic acid water phase is easy to cake and difficult to disperse, the hydroxylamine hydrochloride use ratio is low, the salicylhydroxamic acid yield is low, and the like during a production processare solved. 种水杨羟肟酸的制备方法，由以下步骤组成：在有机溶剂和水的存在下，加入相转移催化剂、碱和盐酸羟胺水溶液，搅拌均匀后，加入水杨酸甲酯，反应结束后，加入浓硫酸得到水杨羟肟酸。本发明选用有机溶剂和相转移催化剂，改善水杨羟肟酸水相生产过程中的易结块、难分散、盐酸羟胺利用率低以及水杨羟肟酸产率低等问题。