GB689286A - Improvements in or relating to chloromethylated benzenes - Google Patents

Abstract

Chloromethylated alkyl benzenes are prepared by mixing together formaldehyde, preferably as paraformaldehyde, a liquid saturated primary alcohol, chlorosulphonic acid and an alkylbenzene of the formula <FORM:0689286/IV (b)/1> where R1 is an alkyl group of 7 to 18 carbon atoms and R2 and R3 may be hydrogen or an alkyl group of not over eight carbon atoms, the total number of carbon atoms in R2 plus R3 being not more than eight. In preferred embodiments of the invention, paraformaldehyde is mixed with chlorosulphonic acid and the alcohol, which may be of the formula ROH, where R is an alkyl group of one to eight carbon atoms, e.g. methanol or ethanol, or may be a glycol such as ethylene glycol, the mixing being performed at 0-50 DEG C., and the resulting mixture is reacted with the alkyl benzene at 0-70 DEG C. The proportions of paraformaldehyde, alcohol and chlorosulphonic acid may be within the ratios 1 : 1 : 1 and 1 : 1.5 : 1.5 and the proportion of paraformaldehyde to alkylbenzene is suitably between 1.25 : 1 and 1.75 : 1. In examples, there were prepared by the above procedures, heptyl-; octyl-; nonyl-; methyl dodecyl-; octadecyl-; tetradecyl-; butyl dodecyl-; di-octyl- and dodecyl dimethyl-; benzyl chlorides. Alkyl benzenes are obtained by the reaction of the corresponding olefine with benzene or a substituted benzene in the presence of a catalyst such as concentrated sulphuric acid, boron trifluoride or anhydrous hydrogen fluoride. Specified alkyl benzenes are the heptyl-, octyl-, nonyl-, decyl-, octadecyl-, octyl methyl-, dodecyl methyl-, butyl dodecyl- and dioctyl-benzenes and dodecyl xylene.