DE2250470A1 - PROCESS FOR DIMERIZING UNSATATURATED FATTY ACIDS AND FATTY ACID ESTERS - Google Patents

Description

Patent application

"Process for the dimerization of unsaturated fatty acids and

• fatty acid ester "

Processes for the dimerization and polymerization of long-chain, unsaturated fatty acids and their magpies have been known for a long time. These processes are purely thermal, at approx. 3QO C. However, it is advantageous to use catalysts with which somewhat lower reaction temperatures are sufficient. For example, a process that works under pressure uses acidic alumina as the catalyst and works in the presence of some water at a reaction temperature of 230.degree. After a reaction time of 3 to 5 hours, 45 to 55 % dimers and polymers are obtained from soy fatty acid or soy fatty acid ester. According to other processes, the polymerization is carried out in the presence of an alumina catalyst modified by the addition of a lithium salt. At reaction temperatures of over 200 ° C., however, catalyst quantities of up to 25 % must be used in order to avoid uneconomically long reaction times. A process is also known in which the polymerization of unsaturated fatty acids is carried out in the presence of aryl sulfochlorides. In this case, however, the reaction requires reaction temperatures of 280 ° C. and reaction times of 6 hours and more.

Especially for the polymerization of fatty acid mixtures that are rich in linolenic acid, a two-step process was developed to achieve yields of around 60%

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the fatty acids are first heated without catalyst at 300 ° C and then continued after the addition of alumina as a catalyst the reaction at 220 to 230 ° C.

In summary, it can be stated that in all previously known processes for the polymerization of unsaturated fatty acids and fatty acid esters require relatively high temperatures or additional complex process measures are.

It has been found that the disadvantages outlined can be avoided by a process which is characterized in that the catalysts used are acidic, macroporous Ion exchangers without gel character and with a high specific surface can be used. Under macroporous Ion exchangers are resins with an average

Pore size from 250 to 300 Å, or a porosity of to understand about 0.3 ml / ml. As a high specific upper

area, for example, the value of HO m per gram should be considered. Such ion exchange resins can be prepared by conventional sulfonation of styrene-divinylbenzene copolymers obtained by suspension polymerization and are described in the literature reference J. Am. Chem. Soc. 84 (1962), pages 305-306, in some properties and as catalysts for the synthesis of tert-butyl methacrylate from isobutylene and methacrylic acid. Ion exchangers of this type are, for example, commercially available under the name Amberlyst II).

The amount of the catalyst to be used according to the invention is not critical; In general, it is possible to use a quantity of 5-20, preferably 6-15, percent by weight of catalyst, based on the fatty acid or fatty acid ester mixture to be used.

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There is no significant loss of activity of the catalyst during the polymerization. The catalyst can do without special activation measures used for further approaches will. Due to the granular structure of the catalyst to be used according to the invention is also a easy separation from the reaction mixture ensured. Furthermore, due to this fact it is easily possible Wash product residues from the catalyst, using conventional organic solvents, especially petroleum ether or higher-boiling gasoline fractions, as well as aromatic hydrocarbons, alcohols or acetic acid are used can be.

In the presence of the catalysts to be used according to the invention the polymerization reaction can be carried out at temperatures between 120 and 180 ° C. With these exceptionally low reaction temperatures, a high degree of polymerization is justifiable at the same time Response times achieved. The reaction times are generally between 1-6 hours; Response times from In general, 3 - 4 hours do not need to be exceeded.

The polymerization process of the present invention can be particularly are advantageously carried out in a continuous manner. In this case, you can, for example, stand vertically Reactors charged with the catalyst to be used according to the invention, by external heating to the desired react

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brought tion temperature and the optionally preheated starting material at the rate that corresponds to its exit speed from the reactor, on the catalyst to be abandoned.

In the present case, the additional use is in contrast to the polymerization processes according to the prior art of water in the reaction mixture is not required. But it is also not necessary to use the starting material subject to special drying measures.

The starting materials used in the process according to the invention are polyunsaturated, straight-chain and branched carboxylic acids having 8 to 22 carbon atoms, for example linoleic acid, linolenic acid, arachidonic acid, clupanodonic acid. These acids can be present in a mixture with one another and in a mixture with corresponding monounsaturated carboxylic acids such as 3-octenoic acid, 10-undecenoic acid, lauroleic acid, myristoleic acid, oleic acid, erucic acid and as a mixture with saturated carboxylic acids, examples of such mixtures being obtained by cleavage of linseed oil , Safflower oil, soybean oil, tall oil, cottonseed oil, corn oil, sunflower oil, rapeseed oil, fish oil obtained fatty acid mixtures are to be mentioned. The above-mentioned fatty acids and fatty acid mixtures can also be used in the form of their esters with, in particular, lower aliphatic alcohols having 1 to k carbon atoms.

The polymerization reaction can be carried out in the usual manner; i.e., the starting material becomes after addition

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the granular catalyst to the desired reaction temperature with stirring and advantageously under a nitrogen blanket brought. The reaction times depend on the reaction temperature and can be determined by taking a sample. After graduation the reaction, the catalyst is filtered off from the reaction product, it is not necessary to use a solvent to be used because the granular structure of the catalyst allows easy separation. When working continuously, ' in which the starting material is passed over a catalyst bed, there is no filtration of the reaction product necessary.

The reaction product is then distilled under reduced pressure, using negative pressures between about 0.1 to 3 mm Hg. The monomeric fatty acids or esters thereof go under the above pressures in the range of 150 to 23O ⁰ C fiber. The distillation residue consists essentially of dimeric fatty acids, ie dibasic unsaturated carboxylic acids with twice the carbon number of the starting material, or the corresponding esters. The proportion of trimeric and higher polymer products can be determined by molecular distillation and is generally 10-20 %, depending on the polymerization conditions.

The polymerized carboxylic acids or their esters obtained in the process according to the invention can be used in many ways, in particular in the fields of epoxy resins, polyamides and polyesters.

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The advantages attainable with the invention consist in particular in that the polymerization at exceptionally low reaction temperatures lent and at the same relatively low response times can be carried out without the degree of polymerization is impaired. Further advantages can be seen in the fact that the granular structure of the catalyst to be used according to the invention permits easy separation of the same from the reaction product, or a continuous reaction, as well as the fact that the catalyst does not lose activity during the reaction and is reused several times can be.

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HENKEL & CIE GMBH Srffi 7 «r Pol.MonMldung O 4 5 7 9 example 1

120 g of soy fatty acid methyl ester mixture, consisting of 28 % oleic acid, 43 % linoleic acid, 7 £ linolenic acid components (remainder of the methyl ester of saturated CL _2. - Cp ₀ - acids) were treated with the amounts of Amberlyst given below and applied to the specified temperatures. The composition of the reaction products present after defined times was determined by separating off the monomeric products passing over at 0.1 mm Hg up to 200 ° G by distillation. Of the. The distillation residue known as "dimers" contains approx. 10 % trimers.

T ( ⁰ C) t (h) catalyst
amount (g) Product composition
Monomeric dimers 31 2 165 1 15th 69 % 50% 165 3 15th 50 % 51 % 165 5 15th 49 2 38 .2 165 3 8th 62 % 47% 165 VJI 8th 53 % 39 2 180 3 8th 61 % 42 2 140 5 24 58%

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120 g linseed oil fatty acid (20 % oleic acid, 15 % linoleic acid, 50 % linolenic acid, remainder saturated C _{1 -C ori} fatty acids) was

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to that with 15 g of Amberlyst-1 ^ and under N "-shield implemented under the temperature and time conditions given below.

T (C) t (h) product composition

Monomeric dimers

HO 6 16 % 51 %

165 3 12% 58 %

Example 3

A vertical reaction column (length 25 cm, diameter 1 cm) was filled with 9 g of Amberlyst-15 ^ and heated to 165 ° C. by external heating. Soy fatty acid methyl ester mixture (composition see Example 1) was passed through the reactor for 1 hour at a rate of 20 ml per hour. The resulting product mixture consisted of 61 % monomers and 39 % dimers, which in turn contained 11% trimers.

example 1

The example demonstrates the reusability of the catalyst. 100 g soy fatty acids (composition as in example 1)

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and 10 g of Amberlyst-liir ⁷ were heated to 140 ° C. in the autoclave for 4 hours. The reaction product contained 52 % dimers. The filtered catalyst was washed with petroleum ether and used under identical conditions in each case with fresh 100 g of soy fatty acids. The conversion products contained in the *

2nd batch 48 % dimers,

3rd batch 43 % dimers,

4th batch 39 % dimers.

A total of 176 g (44%) of dimer fatty acids were thus obtained from 400 g of fatty acid mixture with 10 g of catalyst.

Example 5

120 g of a conjugated soy fatty acid mixture (a total of 91% unsaturated Cg fatty acids, the remainder saturated ^c ^^ ~ ^c ^ 8 ~ fatty acids, content of conjugated diene fatty acids 40-50%) and 12 g Amberlyst- ¹ ^. ^ Were among the following specified conditions according to Example 1 dimerized.

T (° C) t (h) Product composition
Monomeric dimers 46 % 120 5 54 % 56 % 130 6th 44 % 56 56 ■ i4o 5 44 %

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Claims (5)

HENKEL & CIE GMBH SltS 10 «r patents * ·! ^ ..« D ^ 579 2 / bU4 / U patent claims 1.! Procedure for dimerizing one and more times unge-V- / saturated carboxylic acids with 8-22 carbon atoms and their esters with lower aliphatic alcohols by heating in Ge ^ env / type of catalysts, characterized that as catalysts, macroporous acidic ion exchangers with a high specific surface area and without Gel character can be used. 2. The method according to claim 1, characterized in that the dimerizate
can be applied. during dimerization temperatures between 120 and 180 ° C 3. Process according to Claims 1-2, characterized in that the pore size of the catalysts 250-300 A and the specific surface area is approx. * J0 m / g. 4. Process according to Claims 1-3, characterized in that the dimerization takes place without the addition of water. 5. Process according to Claims 1-4, characterized in that the catalysts are used in amounts of 5 to 20, preferably 6-15 percent by weight, based on the starting material. 409816/1134