Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
1999-06-29
2001-09-18
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S485000, C560S124000, C554S024000, C252S079000
Reexamination Certificate
active
06291409
ABSTRACT:
BACKGROUND OF THE INVENTION
Vegetable oils are obtainable in large volumes from renewable resources and in general are characterized as readily biodegradable or “environmentally friendly”. As a result, such oils and related unsaturated polyol fatty acid ester stocks are potentially attractive for use in a wide variety of applications.
With respect to use for lubrication purposes, especially as machine lubricants, vegetable oils have not been fully desirable. Many vegetable oils do not possess the desired spectrum of characteristics relating to: pour point; oxidative stability; and compatibility with additives among others. Vegetable oils do however possess many desirable properties for use as a lubricant. In particular, vegetable oils typically provide good boundary lubrication, good viscosity, high viscosity index and high flash point. In addition, vegetable oils are generally nontoxic and readily biodegradable. For example, under standard test conditions (e.g., OCED 301D test method), a typical vegetable oil can biodegrade up to 80% into carbon dioxide and water in 28 days, as compared to 25% or less for typical petroleum-based lubricating fluids.
Two characteristics, which are often major limitations to the utilization of vegetable oils as lubricants, relate to stability and low temperature behavior. In particular, vegetable oils often contain substantial amounts of unsaturation (i.e., one or more carbon-carbon double bonds distributed along the fatty acyl chains). The sites of unsaturation may be associated with sufficient oxidative reactivity to render the oils insufficiently stable for use as lubricants. If efforts are made to reduce the unsaturation, for example by hydrogenation, generally undesirable changes in pour point and/or viscosity index result.
SUMMARY OF THE INVENTION
The present invention relates to modified unsaturated fatty acid and/or ester-based stocks which may be employed as lubricant additives and/or lubricant base stocks. The modified unsaturated fatty acid and/or ester-based stocks may include modified unsaturated polyol fatty acid ester stocks such as cyclopropanated triacylglycerol oils. It particularly concerns modifications of selected vegetable oils to produce liquid products with advantageous properties for use, for example as lubricant base stocks or in related applications. Unsaturated triacylglycerol fatty acid ester stocks are typically derived from plant sources, such as an oil seed, or animal sources, such as tallow.
A process for modifying an unsaturated polyol fatty acid ester stock, such as an unsaturated vegetable oil stock, to enhance its fluidity and/or oxidative stability is provided. The process includes reacting unsaturated polyol fatty acid ester stock with cyclopropanating agent to form a cyclopropanated product. The cyclopropanated product formed from the reaction with the cyclopropanating agent includes polyol fatty acid ester (e.g., triacylglycerols) which has at least one fatty acyl chain modified to include a cyclopropyl group. Polyol fatty acid esters having at least one fatty acyl chain that includes one or more cyclopropyl groups are referred to herein as “cyclopropanated polyol fatty acid esters.” It will be understood that the cyclopropanation of the starting ester stock will not necessarily be uniform, but rather may result in cyclopropanation of some fatty acyl chains and not of others. If desired, the cyclopropanated product may be fractionated using conventional techniques to alter the spectrum of modified and unmodified esters present. For example, the cyclopropanated product may be fractionated to remove at least a portion of the saturated esters, thereby enhancing the fluidity properties of the fractionated cyclopropanated product with respect to the cyclopropanated product.
The term “unsaturated polyol fatty acid ester stock” as used herein refers to fatty acid esters of alcohols which include two or more hydroxy groups (“polyols”), where at least some and, typically, a majority (i.e., more than 50%) of the fatty acyl chains include at least one unsaturated carbon-carbon bond. The mixture of fatty acids isolated from complete hydrolysis of a specific unsaturated polyol fatty acid ester stock is referred to herein as a “fatty acid composition.” In other words, by the term “fatty acid composition” reference is made to the identifiable fatty acids derived from the fatty acyl residues in the various polyol esters in a given stock. The present unsaturated polyol fatty acid ester stocks typically include esters of a mixture of fatty acids, e.g., a mixture of saturated and unsaturated fatty acids.
Herein, when reference is made to the terms “unsaturated triacylglycerol oil” or “unsaturated triacylglycerol stock,” the intent is to refer to a material comprising triacylglycerols, whether altered or not, derived from various plant and animal sources, such as oil seed sources. The unsaturated triacylglycerol oil may also be produced synthetically, e.g., via a reaction between glycerol with fatty acid and/or fatty acid alkyl esters at least a portion of which include unsaturated fatty acyl chains. The term at least includes within its scope: (a) such materials which have not been altered after isolation; (b) materials which have been refined, bleached and/or deodorized after isolation; (c) materials obtained by a process which includes fractionation of an unsaturated triacylglycerol oil; and, also, (d) oils obtained from plant or animal sources and altered in some manner, for example through partial hydrogenation. It will be understood that the unsaturated triacylglycerol oil may include a mixture of triacylglycerols, and a mixture of triacylglycerol isomers. By the term “triacylglycerol isomers”, reference is meant to triacylglycerols which, although including the same esterified acid residues, may vary with respect to the location of the residues in the triacylglycerol. For example, an unsaturated triacylglycerol oil such as a vegetable oil stock can include both symmetrical and unsymmetrical isomers of a triacylglycerol which includes two or three different fatty acyl chains (e.g., includes both stearate and oleate groups). This can include triacylglycerol isomers that contain trans as well cis unsaturation and combinations thereof.
Herein, the result of adding cyclopropanating agent to an unsaturated polyol fatty acid ester stock, such as vegetable oil stock, will be referenced as an “cyclopropanated product.” The term “cyclopropanated product” includes within its scope the product of reacting one or more cyclopropanating agents (i.e., reagent(s) capable of adding a methylene group to a carbon-carbon double bond to form a cyclopropyl group) with an unsaturated polyol fatty acid ester stock. As noted above, the individual fatty acid esters which include at least one cyclopropyl group are referred to herein as cyclopropanated fatty acid esters. As used herein, the term “cyclopropyl group” refers to an adduct produced by the reaction of cyclopropanating agent with a carbon-carbon double bond, such as a double bond in a fatty acyl chain of a triacylglycerol, to add a methylene moiety and form a three membered ring. One example of a cyclopropanated product is the adduct produced by a Simmons-Smith reaction between CH
2
Br
2
or CH
2
I
2
and double bonds in the fatty acyl chain of a vegetable oil stock. The inventors have developed a modified Simmons-Smith reaction for forming a cyclopropanated fatty acid ester. In this method, zinc copper couple is formed in situ using halotrialkylsilane and 1,2-dihaloethane as activators, wherein halogens include chlorine, bromine and iodine and alkyl includes lower alkyls such as methyl, ethyl, butyl and propyl. Preferably, zinc copper couple is formed in situ by contacting zinc and copper halide with chlorotrimethylsilane and 1,2-dibromoethane. Copeer halide includes copper chloride, bromide and iodide. Preferably copper halide is copper(I)chloride. According to this method, the activated zinc is then combined with a mixture of unsaturated polyol fatty acid and dihalomethane, preferab
Kodali Dharma R.
Li Keqiang
Cargill Inc.
McAvoy Ellen M.
Merchant & Gould P,C,
LandOfFree
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