Epoxidation of some vegetable oils and their hydrolysed products with peroxyformic acid - optimised to industrial scale

Abstract

Epoxidation increases the polarity and the stability of vegetable oils improving their compatibility with polymers such as polyvinyl chloride (PVC). Hence, epoxidized vegetable oils can be used as plasticizers/stabilizers in the polymer industry. The objective of this work is to establish a method of epoxidised vegetable oils on a relatively large scale which could be scaled up to industrial scale. The fatty acid composition of rubber seed oil, Madhuca oil (Mee oil) and Neem oil were determined by gas chromatography-mass spectrometry (GC-MS). These oils and their hydrolysed products were epoxidized successfully by peroxyformic acid generated ‘in situ' by reacting formic acid (methanoic acid) with hydrogen peroxide. The reaction time was optimised and the possibility of controlling the level of epoxidation was attempted by limiting the reagents; hydrogen peroxide and methanoic acid. The epoxidation was confirmed by iodine value, fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and thin layer chromatography (TLC) analysis. Twelve epoxidised oil derivatives were prepared by optimised conditions on a comparatively large scale without solvent extraction procedures. Products were characterised for iodine value, oxirane content, density and molar masses. Further, solubility parameter values of prepared oil derivatives were determined. It was found that more than 80% of the reaction was completed within three hours at 600C. The level of epoxidation could be controlled reasonably by limiting the reagents. The solubility parameter values were comparable with those of conventional plasticizers used in the PVC industry.

Keywords: Epoxidation, peroxyformic acid, solubility parameters, vegetable oil.

doi: 10.4038/jnsfsr.v37i4.1469

J.Natn.Sci.Foundation Sri Lanka 2009 37 (4): 229-240