The gas-phase pyrolytic reactions of 3-methyl arylmethylidenehydrazinedithiocarboxylate were studied by GC/MS firstly. The results showed that these compounds could be cleavaged to aromatic cyanate, methylthiol and HNCS in the inlet of the GC/MS instrument. The relationship of thermal decomposition with the base temperature of the inlet was studied, finding that the temperature was an important key to the gas-phase pyrolytic reaction. The series of these compounds were decomposed completely at the base temperature of 230 ℃. Meanwhile the pyrolytic cleavage of compounds with different substituents at 210 ℃ was also studied. The results showed that the compounds substituted with electron donating groups could be cleavaged much more completely than the ones substituted with electron withdrawing groups at the same temperature. A possible mechanism for the gas-phase pyrolytic reaction was proposed.

Key words: methyl arylmethylidenehydrazinethiocarboxylate, GC/MS, gas-phase pyrolytic reaction, aromatic cyanate