PREPARATION OF P-TERT-BUTYLBENZALDEHYDE

PURPOSE:To obtain the titled compound useful as an intermediate for odorants, agricultural chemicals, etc., industrially at a low cost, by brominating p-tert- butylbenzyl chloride prepared by chloromethylating tert-butylbenzene, and hydrolyzing the resultant bromination product. CONSTITUTION:tert-Butylbenzen is chloromethylated to give p-tert-butylbenzyl chloride, which is then brominated with an equimolar amount of bromine at 100-200 deg.C to afford a p-tert-butylbenzal halide consisting essentially of p-tert- benzal chlorobromide. The resultant p-tert-butylbenzal halide is then hydrolyzed with an about equimolar amount of water at e.g. 105-125 deg.C to give p-tert-butylbenzaldehyde. The unreacted p-tert-butylbenzyl chloride in the bromination reaction is treated with hexamethylenetetramine at 4-4.5pH and oxidized to give the p-tert-butylbenzaldehyde. Thus, the yield can be improved.