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United States Department of Agriculture

Agricultural Research Service

Title: Synthesis of Estolides from Oleic and Saturated Fatty Acids

Authors
item Cermak, Steven
item Isbell, Terry

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2001
Publication Date: N/A

Interpretive Summary: What sort of products do your car and SUV use to keep the engine and components running smoothly? Right now they're probably petroleum-based lubricants and fluids, ie oil and power steering fluid, along with additive packages which help make the petroleum-based products work better. The current petroleum products that leak from our automobiles are contaminating the groundwater supplies and killing the fish in our favorite lakes, this makes the environment messy. There is a serious need for biodegradable, vegetable-based lubricants and fluids that have excellent physical properties without the addition of toxic additive packages. Our lab is trying to create these new biodegradable vegetable-based lubricants and fluids from estolides which are easier on animals and plants than petroleum products. We mainly use oleic acid, an oil like cooking oil from sunflower seeds, to make estolides. Estolides are, therefore, a renewable U.S.-based crop oil that will help ease the dependence on foreign, petroleum-based oils. This way we can continue to enjoy the lifestyles to which we have become accustomed without sacrificing the environment.

Technical Abstract: Oleic acid and various saturated fatty acids, butyric through stearic, were treated with 0.4 equivalents of perchloric acid at either 45 C or 55 C to produce complex estolides. Yields varied between 45-65% after Kugelrohr distillation. The estolide number (EN), average number of fatty acid units added to a base fatty acid, varied between the two different temperatures as well as with the change in saturated fatty acids. The shorter chain, saturated fatty acids, ie butyric and hexanoic acid, provided material with higher degrees of oligomerization (EN = 3.31) than stearic acid (EN = 1.36). The independent, saturated fatty acid estolides each have very different characteristics, such as color and type of byproducts. The higher temperature reactions had faster rates at the expense of yield, with lactones seen as the predominant side products. At the higher temperature, 55 C, the lactone yields increased, but the delta/gamma-lactone ratio decreased; this lead to lower estolide yields. The opposite trend was observed for the 45 C reaction. The saturate-capped, oleic estolides were esterified with 2-ethylhexyl alcohol and the chemical composition of these new estolides remained consistent throughout the course of the reaction. The new estolide esters had superior properties, and were suitable as a basestock for biodegradable lubricants and functional fluids.

Last Modified: 12/18/2014
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