Put 75 g water and 118 g concentrated sulfuric acid into a 500 mL four-necked flask, add 150 g 2,4-dimethylbenzeneacetonitrile slowly under refluxing, and then vaporize about 30 after keeping warm for 1 hour, and then react for 3 hours at 130~140.
g water, and then at 130 ~ 140 reaction for 3 hours, after the end of the reaction at 100 ~ 110 settlement for 15 min to release the acid water, make up 100 g of water and then heating vaporization to remove low-boiling substances, evaporated about 50 .
g of water after cooling, crystallization and filtration, the wet acid in 100 vacuum dehydration and drying, the finished product (2,4-benzenedimethyl)acetic acid.
