Synthesis and characterization of amide based palm oil polyol via ring opening reaction

Abstract

The used of epoxidized palm oil (EPO) as intermediate for polyol production has been the main interest due to the ability of the epoxy group to react with various nucleophiles such as hydroxyl and amines. However, there are relatively limited number of articles that discuss the mechanism of ring opening reaction of EPO with nucleophiles. In this study, the epoxy ring of EPO underwent ring opening reaction using isopropanolamine (IPA) as the nucleophile and boron trifluoride ethanol complex as catalyst. The mechanism of this reaction was following unimolecular nucleophilic substitution reaction (SN1) based on detail analysis using Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). Reaction time, reaction temperature, catalyst amount and molar ratio of EPO:IPA were varied in order to investigate the efficiency of IPA as the ring opening reagent. It was found that the ring opening reaction occurred after 6 hours of reaction at 60oC with 1 mL of boron trifluoride ethanol complex catalyst and at the ratio of 1:3 EPO:IPA. However, small trace of unopened epoxy ring was detected by FTIR and NMR analyses at 824-830 cm-1 and 2.89 ppm. Further analysis with FTIR and NMR revealed that IPA preferred to attack the ester linkages over the epoxy ring, thus producing amide polyols as the main product. Findings from mass spectroscopy analysis and gel permeation chromatography showed that amide polyols had shorter chain length with the molecular weights ranging from 400 to 600 Da with broad distribution. From hydroxyl value analysis, amide polyols have functionality of 2, thus suitable to be used as precursor in many chemical reactions. Further investigation with thermogravimetric analysis showed that amide polyols had thermal decomposition at temperatures of 600oC, indicating that they can be used at high- temperature reactions.