Valorization of Vegetable Oils via Metathesis Reactions: Cross- Metathesis of Methyl Oleate with 1-Hexene on Supported Hoveyda-Grubbs catalysts

JUAN ZELÍN; PABLO D. NIERES; ANDRÉS F. TRASARTI; CARLOS R. APESTEGUÍA

Pittsburg

Congreso; 24th North American Meeting on Catalysis (24thNAM); 2015

North-American Society of Catalysis

Fatty acid methyl esters (FAME) are usually obtained from the ransesterification of natural oils and fats with lower alcohols. Most of all oleochemistry reactions of FAME are carried out in the carboxy functions, but the synthesis of products formed by reactions of the C=C bonds such as epoxidation, metathesis and ozonolysis is becoming increasingly important at industrial level. FAME metathesis has been studied in homogeneous catalysis using mainly Grubbs? Ru complexes. In particular, second generation Hoveyda-Grubbs (H-G) Ru catalystspresent high activity and selectivity, and exhibit remarkable stability to the presence of moisture and oxygen. Nevertheless, only a limited number of industrial processes use homogeneous olefin metathesis because of the high cost of Ru complexes, the difficulties associated with removing ruthenium from the reaction media and the expensive separation/recovery steps required to obtain high-purity products. This situation turns clearly attractive the development of active and stable immobilized supported complexes that would allow straightforward catalyst separation. However, very few papers deal with the use of supported H-G catalysts for the metathesis of functionalized substrates [1]. Cross-metathesis of FAME with lower olefins allows shortening of the long-chainFAME molecules to form less abundant medium-chain fatty acid esters that arevaluable intermediates in fine chemistry. Here, we study the cross-metathesis of methyl oleate (MO) with 1-hexene (C6) on silica-supported Hoveyda-Grubbs complexes (Figure 1). 9-TDO is a valuable pheromone precursor while 9-DCO is used in the synthesis of fragrances and prostaglandins.