PURPOSE: To obtain the titled compound in high yield useful as an intermediate for drugs, agricultural chemicals, etc. through the hydrolysis of a dihalomethyl group only, by hydrolyzing 2-trifluoromethylbenzal halide using a specific amount of conc. sulfuric acid at a specified temperature.
CONSTITUTION: A 2-trifluoromethylbenzal hydride shown by the formula (X and Y are halogen) is hydrolyzed to prepare 2-trifluoromethylbenzaldehyde. The hydrolysis is carried out at ≤150°C, preferably at 70W120°C by adding dropwise 0.1W1pts.wt. conc. sulfuric acid based on 1pts.wt. compound shown by the formula, and, if necessary, a calculated amount or a little excess amount of water to it. The dihalomethyl group is hydrolyzed completely without hydrolyzing the trifluoromethyl group.
YOSHIDA TSUTOMU
SUEFUJI MASAHIRO
| US2180772A | 1939-11-21 |