New synthesis processes of polyetheramines: Comparison of three different developed amination routes

Abstract

ABSTRACTIn this work, three different novel processes are reported for the preparation of polyetheramines (PEAs) from polyethylene glycols (PEGs) and polypropylene glycols (PPGs). The processes are the nucleophilic substitution, oxidation/reduction, and catalytic aminations. The novelties of the processes lay in environmentally friendly routes, the variety of possible precursors (i.e., PEG and PPG with different molecular weights), and extraction methods. The formation of the PEAs with no chain cleavage was confirmed by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) results. Based on the comparison study, the nucleophilic substitution and catalytic aminations were the most efficient (conversion >90%) and shortest (yield >90%) methods, respectively. For nucleophilic substitution, the amination of PEG and PPG intermediates was performed in different solvent media due to the difference in solubility parameters of PEGs and PPGs. The catalytic route (using [Zn(tu)3]SO4/aqueous ammonia system) can be considered a green method; however, catalytic amination of the PPGs is impossible due to insolubility of PPGs in aqueous ammonia. Therefore, the oxidation/reduction method using Leuckart reaction appears to be the most environmentally friendly route for the amination of PPGs. Moreover, PEGs and PPGs with different molecular weights showed various behaviors during reaction and separation protocols.