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United States Department of Agriculture

Agricultural Research Service

Research Project: VEGETABLE OIL-BASED FUELS, ADDITIVES AND COPRODUCTS

Location: Bio-oils Research Unit

Title: Improving the cold flow properties of biodiesel by skeletal isomerization of fatty acid chains

Authors
item Dunn, Robert
item Ngo, Helen
item Haas, Michael

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2014
Publication Date: May 4, 2014
Citation: Dunn, R.O., Ngo, H., Haas, M.J. 2014. Improving the cold flow properties of biodiesel by skeletal isomerization of fatty acid chains [abstract]. American Oil Chemists' Society Annual Meeting & Expo. p. 44.

Technical Abstract: Biodiesel is defined as the mono-alkyl fatty acid esters made from vegetable oil or animal fat lipids. Despite its many advantages, biodiesel from most lipid feedstocks has generally poor cold flow properties. The present study evaluates the fuel related properties of branched-chain fatty acid methyl esters (BC-FAME) as potential additives or diluents in admixtures with biodiesel from conventional feedstocks. These esters were synthesized by skeletal isomerization of oleic acid using a zeolite catalyst followed by methylation to yield BC-FAME isomer mixtures. Both saturated and unsaturated BC-FAME were tested in mixtures with biodiesel from soybean, canola, and palm oils (SME, CaME, PME). Cold flow property results for saturated and unsaturated BC-FAME isomers (iso-stearates and iso-oleates) indicated cloud point = -13.9°C and pour point = -25°C with relatively low kinematic viscosities ("v") = 5.6-6.0 mm²/s at 40°C. The cloud point, pour point, and "v" of FAME mixtures with BC-FAME concentrations at both additive (= 1 mass%) and diluent (2-50 mass%) scales were also measured. Mixtures with higher concentrations of BC-FAME were more effective in decreasing cloud point and pour point without compromising "v". Furthermore, it was observed that the iso-stearate isomers were more effective than the iso-oleate isomers under certain conditions.

Last Modified: 12/22/2014
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