title: Remarkably Efficient Microwave-Assisted Cross-Metathesis of Lipids under Solvent-Free Conditions.
abstract: Catalytic transformation of renewable feedstocks into fine chemicals is in high demands and olefin metathesis is a sophisticated tool for biomass conversion. Nevertheless, the large-scale viability of such processes depends on the conversion efficiency, energy efficiency, catalytic activity, selective conversion into desired products, and environmental footprint of the process. Therefore, conversions of renewables by using simple, swift, and efficient methods are desirable. A microwave-assisted ethenolysis and alkenolysis (using 1,5-hexadiene) of canola oil and methyl esters derived from canola oil (COME) and waste/recycled cooking oil (WOME) was carried out by using ruthenium-based catalytic systems. A systematic study using 1st and 2nd generation Grubbs and Hoveyda-Grubbs catalysts was carried out. Among all ruthenium catalysts, 2nd generation Hoveyda-Grubbs catalyst was found to be highly active in the range of 0.002-0.1 mol % loading. The conversions proved to be rapid providing unprecedented turnover frequencies (TOFs). High TOFs were achieved for ethenolysis of COME (21 450 min-1), direct ethenolysis of canola oil (19 110 min-1), for WOME (15 840 min-1) and for cross-metathesis of 1,5-hexadiene with COME (10 920 min-1). The ethenolysis of commercial methyl oleate was also performed with a TOF of 8000 min-1under microwave conditions.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, T6G 2P5, Canada.
authors.forename: Aman
authors.initials: A
authors.lastname: Ullah
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, T6G 2P5, Canada.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Arshad
mesh_terms: D002384:Catalysis; D005030:Ethylenes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D008055:Lipids / Q000737:chemistry*; D008872:Microwaves; D012997:Solvents / Q000737:chemistry*
chemical_list: D005030:Ethylenes; D008055:Lipids; D012997:Solvents; C036216:ethylene
keywords: alkenolysis; biomass conversion; homogeneous catalysis; metathesis; microwave chemistry