Heterogeneous catalysis for valorisation of vegetable oils via metathesis reactions: Ethenolysis of methyl oleate

ANDRÉS F.TRASARTI; J. ZELIN; NIERES PABLO D.; APESTEGUÍA CARLOS R.

Denver

Congreso; 25 th North American Catalysis Society Meeting - NAM 25; 2017

Fatty acid monoesters (FAME), such as methyl oleate (MO), are cheap feedstocksderived from transesterification of seed oils and fats with a lower alcohol. The catalyticmetathesis of FAME is a field of increasing interest in oleochemistry because the formation ofcarbon?carbon double bonds allows the synthesis of useful value-added chemical and polymerintermediates. Conversion of unsaturated fatty acids and oils has been studied usinghomogeneous catalysis, in particular Grubbs? Ru alkylidenes and the second-generation RuHoveyda-Grubbs (HG) complex (Fig. 1) that exhibit high activity and remarkable stability to thepresence of moisture and oxygen. Nevertheless, the industrial use of homogeneous catalysis forFAME metathesis is hindered by the costly catalyst separation and recovery steps required toyield high-purity chemicals as well as by the product contamination by Ru catalyst residues.There is a need then to develop active and selective immobilized supported complexes that wouldallow straightforward catalyst separation and recovery. However, very few papers on the use ofsupported Ru complexes for FAME metathesis have been published, probably because theyfrequently suffer from leaching or losses of activity as a result of the complex immobilization[1]. The cross-metathesis of FAME with simple non-functionalized alkenes like ethylene, 2-butene and 1-hexene has been investigated to obtain lessabundant medium-chain fatty acid esters that are valuableintermediates in fine chemistry [2]. In particular, the crossmetathesis of ethylene has received special attention for along time since this process allows the synthesis of 1-olefins, which have broad range of applications in polymerindustry. However, there are no reports on the use ofimmobilized Ru complexes for promoting the ethenolysisof MO. Precisely, in this work we investigate theethenolysis of MO on silica-supported second generationRu Hoveyda-Grubbs complex (HG/SiO2). The cross-metathesis of MO with ethylene producesmethyl 9-decenoate (9DCE) and 1-decene (1DC), as depicted in Scheme 1. 9DCE is a valuableintermediate for the synthesis of 9-oxo-trans-2-decenoic acid, a honeybee pheromone, while1DC is used as a monomer in copolymers as well as in surfactants, lubricants and epoxides.