Developing N-alkylated fatty amines based on glycerol-derivable building blocks.

Abstract

Nouryon is a leading company in specialty chemicals and a pioneer in surface active molecules. One of its key product classes is nonionic surfactants, widely used in agriculture, personal care, oilfield and more. Currently, Nouryon produces alkoxy lated nonionic surfactants, where the hydrophilic headgroup is based on epoxides sourced from fossil raw materials. Alkoxylated amines are paticulary important in agriculture, where they serve as effective adjuvants in glyphosate based herbicides. Due to environmental concerns and the interest in fully bio-based alternatives to alkoxylated surfactants, alternative synthetic routes and starting materials for the hydrophilic headgroup is being investigated in this study. One readily available bio based material which could act as a good alternative to epoxides is glycerol. In this study, alternative synthetic routes based on glycerol derivable building blocks are being investigated with the intention of producing fully bio-based nonionic sufac tants, focusing on the N-alkylation of fatty amines. The synthesis is conducted in labscale and evaluated with NMR and GC-MS/FID. The results showed that reacting glycerol carbonate and fatty amines with cata lyst such as Ca(OH)2, MgO or ZnO, at temperatures above 190 °C yielded sig nificant amount of alkylated products such as N-alkyl serinol carbamates, 2,3 dihydroxypropyl amines and bis-2,3-dihydroxypropyl amines. While total amount of alkylation was similar across catalyst, Ca(OH)2 resulted in higher yields of both 2,3-dihydroxypropyl amines and bis-2,3-dihydroxypropyl amines. Under one set of optimized conditions (2 eq. glycerol carbonate, 0.3 eq. Ca(OH)2 and 1 eq. of fatty amine, 220 °C, 6h.), 86 % yield of alkylated product was reached. Additionally, doing a onepot synthesis starting with readily available materials such as urea and glycerol instead of glycerol carbonate, resulted in less selectivity towards alkylated products. For both approaches, the reaction showed to be heavily shifted towards N alkyl serinol carbamates, which limits formation of bis-2,3-dihydroxypropyl amines. The yield of 2,3-dihydroxypropyl amines could be increased by base hydrolysis of N-alkyl serinol carbamates. Based on these findings, by applying the optimized conditions, it is possible to attach a hydrophilic headgroup with a hydrophobic tail from sources that could be derived from renewable materials with this chemistry. The hydrophilic headgroup could be based on polyglycerol carbonates derived from recycled and bio-based CO2 or urea and polyglycerol. The hydrophobic tail could be based on fatty amines derived from either tallow or coconut.