N-METHYLATION OF ANILINE WITH METHANOL .1. N-METHYLATION OF ANILINE WITH METHANOL OVER MGO CATALYST

N-Methylation of aniline with methanol over MgO catalyst was carried out by using a continuous flow reactor at an atmospheric pressure. The reaction proceeded both acidic and basic positions as active sites, and N-methylaniline was selectively produced. The optimum conditions for this reaction were as follows: reaction temperature was 480°C and contact time was 6.7g-cat.hr.mol-1. The reaction order was of 0.5 with respect to aniline, and of 0.4 with respect to methanol. The observed activation energy was 16.2kcal/mol. The effects of substituents on this reaction were discussed on the basis of the Hammett law: the reaction constant ρ was -1.73, indicating that this reaction is an electrophilic one. The reaction constant and the rate equation for substituted anilines suggest that the rate-determining step of this reaction is an attack of methylation on aniline. The order of the catalytic activity of MgO containing an additional substance was found to change in the following order: MgO(containing 2wt% SO42-)> MgO (prepared from Mg(OH)2) =MgO(containing2wt%PO42-)>MgO(prepared from 4MgCO3.Mg(OH)2.5H2O). The influence of calcination temperature on the catalytic activity was less for MgO(containing 2wt% SO42-) than for other MgO catalysts. © 1979, The Chemical Society of Japan. All rights reserved.