DE3206007A1 - Process for the preparation of chrysanthemum-monocarboxylic acid - Google Patents

Description

Process for the production of chrysanthemum monocarboxylic acid.

The invention relates to a process for the production of chrysanthemum monocarboxylic acid the formula

CHo

■ C = CH - CH - CH - COOH (I)

OV ^ \ /

3 C

PU VU
Uno UHq

by complete or selective hydrolysis of the chrysanthemum monocarboxylic acid ester the general formula

CH-

^ C = CH - CH - CH - COOR (II),

CHn UHq

wherein R is C.-Cg-alkyl, preferably C, _{-C 4} -alkyl.

The chrysanthemum monocarboxylic acid obtained in this way is very pure and contains no unwanted by-products.

In the synthesis of pyrethroid insecticides (cynerin, allethrin, phthaltrin, Permethrin, Cypermelhrin, Decamethrin) usually become the lower ones Alkyl esters of the corresponding cyclopropanecarboxylic acids used as starting material. The synthesis is carried out in such a way that the esters are first hydrolyzed to the free acids, which are then converted into in a manner known per se with the alcohol components of the active ingredients. be esterified.

The commonly used acidic or basic hydrolysis methods show have many disadvantages so that they are difficult to apply in industry. Since the hydrolysis usually takes place in an organic solvent is carried out, it requires a large volume. After the hydrolysis, the organic solvent must be removed from the reaction mixture and the cyclopropanecarboxylic acid from the solution obtained as residue with a further organic solvent

are obtained, which then, to isolate the free acid, also must be removed.

In the known syntheses, the cyclopropanecarboxylic acid esters are in Obtained forrr a mixture of cis and trans isomers. There the two Isoireren, however, to pyrethroid active substances of different activities lead, in certain cases it is necessary to separate the isorreres from one another to separate. According to the known methods, the isorrhoid separation takes place Free acids predominantly through crystallization from one: organic Solvent (J. Chern. Soc. (1945), 283).

The aim of the invention was to develop a process that industrially is applicable and which allows

the cyclopropanecarboxylic acid esters without the use of a solvent to be completely hydrolyzed or

selectively hydrolyze the trans isomer from the mixture of isomeric esters.

It was found,

that the cyclopropanecarboxylic acid esters in the absence of organic solvents hydrolyzed with aqueous alkali hydroxides in the heterogeneous phase can be if the aqueous phase contains a phase transfer catalyst and

that the rate of hydrolysis of the trans isomer of the cyclopropanecarboxylic acid ester is greater than that of the cis isomer, so that the two isomers can be separated from one another with good selectivity under appropriate reaction conditions. This makes it possible to use the cyclopropanecarboxylic acid ester either completely, i.e. while maintaining the isomer ratio, or partially, i.e. while changing the isomer ratio, to hydrolyze.

The invention relates to a process for the production of chrysanthemum monocarboxylic acid the formula

° ^ C = CH - CH - CH - COOH (I)

^CH 3 ^ V

by hydrolysis of the Chrysanthemum monocarboxylic acid ester of the general formula

CH-
- ³ ^ -C = CH - CH - CH - COOR (II),

CHo CHo

wherein RC ₁ - Cg-alkyl, preferably C ₁ - C ₄ -alkyl, characterized in that one

the hydrolysis of the ester in the absence of an organic solvent in the heterogeneous phase with 2-50% by weight, preferably 4-30% by weight, aqueous alkali metal hydroxide solution, in the presence of 0.01-5% by weight, preferably 0.1 -1% by weight -. based on the amount of the ester - phase transfer catalyst, in the temperature range 20-120 ⁰ C, preferably from 50 - 10O ⁰ C, is carried out, wherein for the complete hydrolysis of the ester while maintaining the isomer ratio from 100 to 150 wt%. , preferably 102-130% by weight, of the amount of alkali metal hydroxide equivalent to the ester, for selective hydrolysis of the ester while changing the isomer ratio 70 -HO% by weight, preferably 80-95% by weight. the amount of alkali metal hydroxide equivalent to the trans isomer of the ester is used,

the hydrolyzate obtained is worked up in a manner known per se to the chrysanthemum monocarboxylic acid, which, if desired _{, can be purified by recrystallization from an aliphatic C 5} -C ^ hydrocarbon, and

optionally the unhydrolyzed one enriched in the cis isomer Separates off the ester and purifies it in a manner known per se.

Contain the cyclopropanecarboxylic acid esters used as starting material no hydrolyzable impurities, the free acid can be isolated in pure form. In addition, the impurities

separate easily and the chrysanthemum monocarboxylic acid ester can be removed from the By-products of the synthesis are recovered.

The selectivity of the hydrolysis is at low alkali metal concentration and better at low temperatures and when the alkali metal hydroxide solution is added in portions. As a result, the partial Hydrolysis 70-110% by weight, preferably 80-95% by weight, of the trans-isorrer of the ester equivalent amount of the alkali metal hydroxide used.

Sodium or potassium hydroxide is preferably used as the alkali hydroxide, which is preferably used in the form of 5-30% strength aqueous solutions will.

The phase transfer catalyst used according to the invention must not be sensitive to bases be. Some examples of this are: quaternary amines or other phase transfer catalysts, such as cation-active, anion-active or non-ionic emulsifiers.

After the hydrolysis has been carried out, the non-hydrolyzed ones are separated off cis-isomer-enriched esters as well as the non-hydrolyzable impurities from the aqueous phase due to their different specific weights, e.g. by extraction with a solvent (such as chlorinated solvents, aliphatic or aromatic hydrocarbons) or by steam distillation.

From the aqueous solutions of the salts of Chrysanthemum monocarboxylic acid the acid is released by mineral acids. The insoluble in the aqueous phase Chrysanthemum monocarboxylic acid can be used as a melt or in crystalline Fortr can be isolated. But it can also be an organic one Solvent extracted and - if desired - from a solvent (preferably an aliphatic hydrocarbon) recrystallized will.

The Chrysanthemum monocarboxylic acid obtained in this way is very pure and suitable for Synthesis of pyrethroid active ingredients without further purification suitable.

Further details of the invention are provided by the following examples explained in more detail.

example 1

20 g of ethyl chrysanthemum monocarboxylate / 2,2-dimethyl-3- (2,2-dirrethyl-vinylJ-cyclopropane-i-carboxylic acid ethyl ester ^ (degree of purity 98 % \ cis / trans ratio 14:86) are added to 20 g 25% aqueous sodium hydroxide solution and 0.02 g of p-nonyl-phenyl-polyglycol ether, stirred for 180 minutes at 95 ° C. At the beginning there are two phases which change into a homogeneous phase after about 30-40 minutes, followed by complete hydrolysis, and the ethanol formed is distilled off. by mixing the solution obtained as the residue of the Natriurcsalzes Chrysanthemummonocarbonsäure with 50 g of 10% hydrochloric acid under stirring at 50 ⁰ C, the Chrysanthemummonocarbonsäure separates out. If the upper oily phase was cooled, the crystallized Chrysanthemum- monocarboxylic acid and can be isolated in solid form.
Yield: 16 _S 2 g (96 %).

When repeating Example 1 with the exception that instead of p-Nonyl-phenyl-polyglycol ether triethylbenzyl-ammonium bromide is used the same results as in Example 1 are obtained.

Example 2

20 g of ethyl chrysanthemum monocarboxylate 2,2-dimethyl-3- (2,2-dirrethyl-vinyn-cyclopropane-i-carboxylic acid ethyl ester (degree of purity 98 %; cis / trans ratio 38:60) are mixed with 6 ecm of water and 0.01 g of sodium dodecylbenzenesulphonate and then stirred with 4 g of 20% strength aqueous sodium hydroxide solution. After adding two portions of 4 ml of sodium hydroxide solution each, the hydrolysis is carried out at 70 ^° C. for 240 minutes and, after the reaction mixture has cooled, the unreacted ester is separated off receives 8.3 g of ester whose degree of purity is 95 % and whose cis / trans ratio is 78:22.

6.4 g of 33% strength hydrochloric acid are added to the aqueous phase and the precipitated chrysanthemum monocarboxylic acid is isolated as in Example 1. Yield 9.6 g; cis / trans ratio 10:90.

Claims (4)

Chinoin Gyögyszer es Vegyeszeti Termekek Gyära RT., H 1045 Budapest, Τδ utca 1-5, Hungary Claims \) J Process for the production of the Chrysanthemum monocarboxylic acid of Forrrel CFU "^ C = CH - CH - CH - COOH CH ₃ - ^" \ _c ' (D by hydrolysis of the Chrysanthemum monocarboxylic acid ester of the general Forrrel CHo
⁰ ^ C = CH - CH - CH - COOR ^CH 3 ^ N ' where RC _{1 is} Cg-alkyl, characterized in that the hydrolysis of the ester in the absence of an organic solvent with 2-50% aqueous alkali hydroxide solution in the presence of 0.01 - 5 wt.% - based on the amount of the ester - phase transfer catalyst in the temperature range '20-120 ⁰ C performs, where for the complete hydrolysis of the ester 100 to 150 wt% of the equivalent amount of the ester Alkylihydroxids. for partial hydrolysis of the ester 70-110% by weight of the trans isomer equivalent amount of the alkali hydroxide are used, the hydrolyzate obtained is worked up in a manner known per se to the Chrysantherrurr rronocarboxylic acid, which can be purified by crystallization from an aliphatic C _{5 -C 10} hydrocarbon and optionally separating the ester enriched in cis isomers and purifying in a manner known per se. 2) Method according to claim 1, characterized in that rran to complete Hydrolysis of the ester 102-130% by weight of the ester equivalents Amount of alkali hydroxide used. 3) Method according to claim 1, characterized in that rran for partial Hydrolysis of the ester 80-95% by weight of the trans-isor equivalents Amount of alkali hydroxide used- 4) Method according to claim 1, 2 or 3, characterized in that rran a phase transfer catalyst of the quaternary type Arrins or a voir type of an anion-active or cation-active and / or non-ionic emulsifier is used.