Ionic liquid-catalyzed aminolysis of poly(ethylene terephthalate) waste

摘要

Aminolytic depolymerization of poly(ethylene terephthalate) (PET) bottle waste with ethanolamine and hydrazine hydrate under atmospheric conditions was investigated in the presence of room temperature ionic liquids. 1-Hexyl-3-methylimidazolium trifluoromethanesulfonate (Hmim.TfO) and 1-butyl-3-methylimidazolium hydrogen sulfate (Bmim.HSO _4). (Hmim.TfO) was found to be the most efficient catalyst to obtain high yields of the aminolysis products bis(2-hydroxy ethylene) terephthalamide and terephthalic dihydrazide using ethanolamine and hydrazine hydrate, respectively. These products were characterized by IR spectroscopy, ~1H NMR, ~(13)C NMR, mass spectroscopy, and differential scanning calorimetry. The influence of experimental parameters, such as the amount of catalyst, reaction time, molar ratio of ethanolamine, and hydrazine hydrate with respect to PET was investigated. This protocol proves to be efficient and environmentally benign in terms of high yields (>84%) and low reaction times (up to 30 min).