Abstract: The reaction of p-nitrotoluene in the ethanol/sodium polysulfide solution resulting in {p-aminobenzaldehyde} has been applied to industry. However the reaction mechanism is not accepted commonly since the accordant conclusion among the proposed mechanisms was not reached due to lacking of the verification mutually. In this paper, we monitored the reaction intermediates and their transition regularity by high resolution mass spectra. The results show that the condensation compounds emerged during the reaction at 80 ℃ with the reaction starting up to 120 min, strongly supporting the condensation and oxidation mechanisms proposed by Shchukina and Chen, respectively, that is, p-aminobenzaldehyde is derived from the hydrolysis of poly Schiff base. Meanwhile, we propose the possibility of formation process of poly Schiff base, which is different from that reported in literatures.

Key words: Intermediate, Mass spectrum, Mechanism, Redox, p-Aminobenzaldehyd