Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
1998-05-19
2001-08-28
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S025000, C554S026000
Reexamination Certificate
active
06281373
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to dimeric fatty acid alkyl esters and processes for their preparation.
BACKGROUND OF THE INVENTION
Processes for the preparation of dimeric fatty acids are known to the art.
Dimeric fatty acids are used as intermediates for the preparation of polyamides useful, inter alia, as a component of ink compositions, adhesives, surface coating materials, and sealants.
SUMMARY OF THE INVENTION
The present invention relates to processes for the preparation of mixtures of dimeric fatty acid C
1-4
alkyl esters from soybean oil condensate obtained from the deodorization of refined soybean oil, wherein the condensate contains less than 30% by weight of free and esterified oleic acid based on the total weight of free and esterified fatty acids in the condensate.
DETAILED DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term “about”.
The process of the invention relates to the preparation of dimeric fatty acid C
1-4
alkyl esters comprising the steps of
A) reacting a soybean oil condensate obtained from the deodorization of refined soybean oil and which contains less than 30% by weight of free and esterified oleic acid based on the total weight of free and esterified fatty acids in said condensate, with a C
1-4
alkanol in the presence of a zinc oxide catalyst to convert free fatty acids and fatty acid sterol and glyceride esters to fatty acid C
1-4
alkyl esters;
B) removing excess C
1-4
alkanol, volatile reaction by-products, water, and the zinc oxide catalyst from the resulting reaction mixture;
C) heating the reaction mixture from step B) under vacuum to obtain fatty acid C
1-4
alkyl esters and a residue;
D) separating the fatty acid C
1-4
esters obtained from step C) into a first fraction containing a major amount of C
16-18
saturated fatty acid C
1-4
alkyl esters and a second fraction containing a major amount of C
16-18
unsaturated fatty acid C
1-4
alkyl esters in which the oleic acid C
1-4
alkyl ester content is less than about 35% by weight thereof; and
E) dimerizing the second fraction in the presence of montmorillonite clay to produce dimeric C
16-18
fatty acid C
1-4
alkyl esters.
The advantages of the present process include good color of the dimeric fatty acid C
1-4
alkyl esters, easy separation of unreacted monomers, easy catalyst separation, convenient handling and storage, efficient production of fatty acid ester products, readily available raw materials, and the convenient production of commercially valuable by-products.
Step A) can be carried out at a temperature in the range of from 100 to 250° C., preferably from 175 to 210° C., and more preferably from 180 to 200° C. with stirring in pressure equipment such as an autoclave for a period of from 1 to 5 hours, preferably from 1.5 to 2.5 hours, depending on the reaction temperature. Reaction pressures can range from 200 to 500 psig, preferably from 300 to 350 psig.
The ratio by weight of C
1-4
alkanol to soybean oil concentrate is from 1:1 to 0.25:1, preferably from 0.75:1 to 0.4:1, and more preferably 0.5:1 to 0.6:1. The zinc oxide catalyst is present in from 0.05% to 0.5%, preferably from 0.1 to 0.2% by weight, based on the weight of the soybean oil concentrate.
The soybean oil concentrate used in the present process is commercially available, and can be obtained by the steam deodorization of refined soybean oil, which can be either partially hydrogenated or non-hydrogenated.
The C
1-4
alkanol can be methanol, ethanol, propanol, isopropyl alcohol, n-butanol, or isobutyl alcohol, but methanol is strongly preferred.
Step B) is carried out in a preferred method by cooling the reaction mixture from step A) to a temperature of from 50 to 100° C., preferably from 70 to 80° C., and then removing the excess alkanol, volatile by-products, and water by vacuum stripping. Zinc oxide is then removed, preferably by washing the resulting reaction mixture with dilute sulfuric acid, washing to neutral with water, and then vacuum drying. The resulting reaction mixture typically contains small quantities of free fatty acids, e.g. 3 to 5% based on the fatty acid ester content.
Step C) can be carried out by heating the reaction mixture, preferably to a temperature of 125 to 175° C., more preferably 150 to 160° C. under vacuum, e.g. from 1 to 4 Torr to obtain a distillate of fatty acid alkyl esters and a residue. The distillation is preferably carried out in a wiped film still.
In order to recover additional fatty acid alkyl esters, the residue can be treated in a continuous fractional distillation column equipped with a wiped film reboiler, using a pressure of 1-10 Torr, preferably 1-2 Torr, and a bottom plate temperature of 190-225° C., preferably about 200-210° C. The reboiler is operated at a temperature of from 200-250° C., preferably 210-230° C. Additional fatty acid alkyl esters are obtained as a distillate, with the residue being a tocopherol/sterol concentrate. The latter concentrate can be separated by known methods into its commercially valuable components.
The fatty acid alkyl esters obtained above are combined with the initially obtained distillate of fatty acid alkyl esters and used in step D).
Step D) can be carried out by fractionating the fatty acid alkyl esters under vacuum in a fractionating column to obtain a first distillate (fraction) containing a major amount (i.e. over 50%) of C
16-18
saturated fatty acid C
1-4
alkyl esters. The temperature in the fractionating column is preferably in the range of 165-200° C. at the top of the column, and 200-230° C. at the bottom of the column, using a vacuum of 1-20 Torr, preferably 3-15 Torr. The temperature and pressure will of course be somewhat dependent on the selection of the C
1-4
alkyl group in the fatty acid esters.
The residue from the fractionating column is then distilled, preferably in a wiped film evaporator, to produce a second distillate (fraction) containing a major amount of C
16-18
unsaturated fatty acid C
1-4
alkyl esters, in which the oleic acid C
1-4
alkyl ester content is less than 35% by weight based on the weight of the distillate. The temperature in the wiped film evaporator is preferably in the range of 200-225° C., with a pressure of from 1 to 5 Torr.
The first distillate can be further processed by sulfonation to give &agr;-sulfoesters, useful as wash-active substances. It can also be used as a solvent for pesticides, as a synthetic lubricant, as leather fat liquor after transesterification with oils and fats, in the preparation of textile softeners by hydrogenation and transamidation, and in the preparation of ethoxylated alkyl esters by ethoxylation.
The second distillate is then dimerized in step E) in the presence of a montmorillonite clay, preferably in the further presence of a lithium compound such as lithium hydroxide or lithium octanoate, and hypophosphorous acid. The dimerization reaction is preferably carried out in an autoclave purged with an inert gas, conveniently nitrogen, at a temperature of from 240-300° C., preferably 240-285° C., and at a pressure of from 30-55 psig preferably from 40-50 psig. When the dimerization reaction is completed, usually after from about 1 to 5 hours, the reaction mixture is cooled to 140-170° C., preferably 150-160° C., and a mineral acid, preferably phosphoric acid, added to the reaction mixture. After stirring, the reaction mixture is filtered, distilled under vacuum, preferably in a wiped film still at a temperature of 240-280° C., preferably 250-265° C. and a pressure of from 1-25 Torr, preferably 10-20 Torr. The distillate comprises unreacted esters, which can be used as a textile softener or as a PVC lubricant.
The residue is the dimeric C
16-18
fatty acid C
1-4
alkyl esters. Such dimeric esters can be reacted with polyamines to produce polyamides, useful as ink resins, and as curing agents for epoxy resins.
The dimeric C
16-18
fatty acid C
1-4
alkyl es
Blewett C. William
de Moura Carlos Alberto
Sato Setsuo
Sublett Michael
Carr Deborah D.
Drach John E.
Henkel Corporation
Millson, Jr. Henry E.
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