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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: Fatty acids of Thespesia populnea: Mass spectrometry of picolinyl esters of cyclopropene fatty acids

Authors
item KNOTHE, GERHARD
item Rashid, Umer -
item Yusup, Suzana -
item Anwar, Farooq -

Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 12, 2011
Publication Date: August 1, 2011
Citation: Knothe, G.H., Rashid, U., Yusup, S., Anwar, F. 2011. Fatty acids of Thespesia populnea: Mass spectrometry of picolinyl esters of cyclopropene fatty acids. European Journal of Lipid Science and Technology. 113(8):980-984.

Interpretive Summary: Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, used cooking oils, or other feedstocks. Since not enough vegetable oil or other feedstock is available to replace all petroleum-derived diesel fuel, identifying additional feedstocks is important. In this work, a feedstock called Thespesia populnea seed oil not previously utilized for biodiesel purposes is described. The composition and related analysis of both the oil and the biodiesel derived from it are described. Knowledge of the composition of a biodiesel feedstock is important to correlate fuel properties with the various components and, ultimately, judge the suitability of the feedstock.

Technical Abstract: Thespesia populnea belongs to the plant family of Malvaceae which contain cyclopropane and cyclopropene fatty acids. However, previous literature reports vary regarding the content of these compounds in Thespesia populnea seed oil. In this work, the content of malvalic acid (8,9-methylene-9-heptadecenoic acid) in the fatty acid profile of Thespesia populnea seed oil was approximately 7% by gas chromatography. Two cyclopropane fatty acids were identified, including dihydrosterculic acid. The methyl and picolinyl esters of Thespesia populnea seed oil were also prepared. The mass spectrum of picolinyl malvalate was more closely investigated, especially an ion at m/e 279, which does not fit the typical series of ions observed in picolinyl esters. It is shown that this ion is caused by cleavage at the picolinyl moiety and contains the fatty acid chain without the picolinyl moiety. This type of cleavage has not been prominently observed previously in picolinyl esters and may be diagnostic for picolinyl esters of cyclopropene fatty acids. The NMR spectra of Thespesia populnea methyl esters are also discussed.

Last Modified: 9/29/2014
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