Reinvestigation of the Nitration of Ethylmesitylene and n-Propylmesitylene. Revision of Early Works.

Abstract

Abstract Ethylmesitylene reacts with fuming nitric acid in dichloromethane at −50°C to give mononitroethyl-mesitylene, 3,5-dimethyl-4-ethylbenzyl nitrate, 2-nitro-3,5-dimethyl-4-ethylbenzyl nitrate and a dinitroethyltri-methylcyclohexenone, while on nitration with mixed acid it yields mono and dinitro derivatives as the major products, together with minor quantities of 2-nitro- and 2,6-dinitro-3,5-dimethyl-4-ethylbenzyl nitrates, diphenyl-methanes, and unidentified nitro-carbonyl compounds, possibly nitrobenzaldehydes. Similar results are obtained from the nitration of n-propylmesitylene. If the hydrocarbons are nitrated by adding into a large excess of the nitrating agent, the major product is 2,6-dinitro-3,5-dimethyl-4-alkylbenzyl nitrate soon after the reaction, or 2,6-dinitro-3,5-dimethyl-4-alkylbenzaldehyde when the mixture is left to stand at room temperature. The nitro compound melting at 123°C, obtained by Smith and Kiess from the nitration of ethylmesitylene and described as trinitro-4-ethyl-o-xylene, is identified as 2,6-dinitro-3,5-dimethyl-4-ethylbenzyl nitrate. An uncharac-terized nitration product (mp 135°C) from n-propylmesitylene, obtained by Töhl and Tripke, is found most likely to be 2,6-dinitro-3,5-dimethyl-4-n-propylbenzyl nitrate (mp 139–140°C).