Synthesis of new derivatives from vegetable sunflower oil methyl ester via epoxidation and oxirane opening

Abstract

Recently, epoxides have received increased attention because they are of interest both as end-products and as chemical intermediates; epoxidized oils, mainly High Oleic Sunflower Oil, and their ester derivatives have thus found important applications as plasticizers and additives for polyvinyl chloride (PVC). Epoxidized esters have been produced classically from High Oleic Sunflower Methyl Esters (HOSME) using H2O2 and formic acid. The epoxidation reaches 90% on pilot scale (5kg). Epoxidized esters produced from HOSME have respectively hydroxyl values of 0, oxirane values of 5.2/4.5 and iodine values of 1.7/1.5. Cleavage trials of the oxirane group of the epoxidized esters with different reactants have been under-taken in order to produce on pilot scale new derivatives to be characterized and tested in different fields of application (lubrication, detergency and as chemical intermediates). Reaction of Epoxy-HOSME with an excess of oleic acid was conducted under atmospheric pressure without any catalyst and solvent. The oxirane opening leads to complete estolide formation: after neutralization, analytical controls (chemical values, GC and HPLC analysis) indicate that the estolides are composed of a mixture of C36 (oleate of methyl hydroxystearate) and C54 (di-oleate of methyl dihydroxystearate). Oxirane opening with alcohols (ethanol and octanol) was preferentially performed by acid catalysis at 100°C under atmospheric pressure. Analytical controls show the formation of different etheralcohols and secondary products resulting from dehydration, transesterification and dimerization side-reactions. Cleavage reaction of Epoxy-HOSME with a primary amine (butylamine) was conducted under pressure, at high temperature (180/200°C). Both transesterification and opening of the oxirane group occur under these conditions. Reaction products are composed of amides formed by transesterification and a mixture of fatty amines/imines obtained by ring opening as established by analytical determinations.