| 摘要 |
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 phenylenediamine of the formula IN WHICH X is hydrogen, chloro, trichloromethyl, trifluoromethyl, nitro, lower alkyl, lower alkoxy or phenoxy and R and R1 are alkyl or when X is hydrogen, R may be hydrogen when R1 is tertiary alkyl or R and R1 together with the nitrogen atom is a heterocycle selected from the group consisting of pyrrolidinyl, 2,5-dimethyl pyrrolidinyl, piperidino and hexahydro-1H-azepin-1-yl. |
