A method of inhibiting polymerization of unsaturated carboxylic acid esters and improved unsaturated carboxylic acid ester compositions are described. The method comprises, and the compositions are prepared by, incorporating into the ester composition a N-(nitroalkyl)phenylenediamine of the formula ##STR1## in which R is lower alkyl, R' is hydrogen, nitro or lower alkyl and X is hydrogen, lower alkyl or lower alkoxy.
Base Catalysis Of Azolesulfenamides And Sulfur To Aminodithioazoles