Abstract:

To investigate the reasonability and feasibility to substitute fatty acid diethanolamide by monoethanolamide and methylethanolamide in surfactant production and application, the nitrosation of methylethanolamine or monoethanolamine was compared with diethanolamine. In this study, nitrosamines were prepared from three ethanolamines by nitrosating agents of both tert-butyl nitrite and nitrous acid. The products of nitrosation by tert-butyl nitrite were identified to reveal nitrosation mechanisms, while the yields of the nitrosamines formed by nitrous acid were used to evaluate the easiness of nitrosation among three ethanolamines. Mechanism analysis of nitrosation shows that diethanolamine or methylethanolamine forms the corresponding nitrosamines, while monoethanolamine solely forms trace amount of N-nitroso-diethanolamine owing to the formation of intermediate diethanolamine by disproportionation of monoethanolamine. The experimental results also reveal that methylethanolamine and monoethanolamine are more difficult to form nitrosamines than diethanolamine. Therefore, it is reasonable and feasible to substitute fatty acid diethanolamide by monoethanolamide and methylethanolamide in surfactant production and application, which has theoretical and practical significance for safeguarding human health and safety.

Key words: fatty acid alkanolamides, surfactant, nitrosamine, ethanolamine compound, nitrosation mechanism