CH632237A5 - Process for the preparation of benzyl esters having pesticidal action - Google Patents

Description

The invention relates to a process for the production of certain esters of the so-called “synthetic pyrethroid” type which are effective as insecticides.

It is known from DE-AS 2 231 312 that certain synthetic pyrethroids can be produced by reacting a substituted cyclopropanecarbonyl halide

3rd

632 237

with a benzaldehyde substituted in the 3-position in the presence of an aqueous sodium or potassium cyanide. In this process, pyrethroids of the following type are obtained:

(I)

cooch

It has now been found that both the ester represented by formula I and other esters which come under the term “synthetic pyrethroids” can be produced more easily and with better yield if a specific catalyst is used for this purpose.

The process according to the invention for the preparation of esters of the general formula:

a r.co.o -

(II)

where R represents an optionally substituted alkyl or cycloalkyl group and A represents phenoxy, phenylthio or benzyl, consists therefore in that a benzaldehyde of the general formula:

a och

(III)

in the presence of water, a water-soluble cyanide, an essentially water-insoluble aprotic solvent and a phase transfer catalyst with an acid halide of the formula R.CO. Hal (in which shark is a bromide or chloride).

The phase transfer catalyst can be any reagent that has the ability to accelerate interphase reactions in aqueous organic two-phase systems.

The phase transfer catalyst can thus be an onium compound, in particular a quaternary onium compound of the general formula:

R

R2-X-R ^

f u3

where X is a nitrogen, phosphorus or arsenic atom and R1, R2, R3 and R4 each represent an alkyl, aralkyl, alkaryl or aryl group, while Y is a monovalent ion, e.g. B. represents a halide such as a chloride, bromide or iodide, or an alkyl sulfate such as methyl sulfate or ethyl sulfate; it can also be a sulfonium compound of the general formula:

15

20th

25th

30th

35

45

50

55

60

65

FT r5-s-r7

act in which R5, R6 and R7 each represent an alkyl group, while Y here also represents a monovalent ion, e.g. represents a halide, such as a chloride, bromide or iodide, or an alkyl sulfate, such as a methyl sulfate or ethyl sulfate. The alkyl groups preferably contain 1 to 18 carbon atoms and the aralkyl and alkaryl groups up to 10 carbon atoms; the aryl group is preferably phenyl.

Examples of suitable onium compounds are: tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, methyltri-2-methylphenylammonium chloride, tetramethylphosphonium iodide, tetra-n-butylphosphonium bromide, methyltriphenylarsonium iodide,

Ethyl 2-methylpentadecyl 2-methylundecylsulfoniumethyl sulfate,

Methyldinonyl sulfonium methyl sulfate and n-hexadecyldimethylsulfonium iodide.

Very good results have been obtained with quaternary ammonium compounds.

The onium compound can be a hydroxide or a salt and can be used as a functional part of a strongly basic anion exchange resin having a structural part (polymer matrix) and a functional part (ion-active group). Polystyrene resins, such as copolymers of aromatic monovinyl and aromatic polyvinyl compounds, in particular styrene / divinylbenzene copolymers, are of particular importance. The functional part is a quaternary ammonium, phos-phonium or arsonium group. Examples of strongly basic anion exchange resins that can be used are those derived from trimethylamine (such as those under the trade names “Amberlite IRA-400”, “Am-berlite IRA-401”, “Amberlite IRA-402”, “Amberlite IRA- 900 "," Duolite A-101-D "," Duolite ES-111 "," Dowex 1 "," Dowex 11 "," Dowex 21K "and" Ionac A-450 "known products) and the resins derived from dimethylethanolamine ( such as the products known under the trade names "Amberlite IRA-410", "Amberlite IRA-911", "Dowex 2", "Duolite A-102-D", "Ionac A-542" and "Ionac A-550". Very good results were obtained with the exchange resins derived from trimethylamine.

Other suitable phase transfer catalysts are macrocyclic polyethers known as "crown ethers". These compounds and their preparation are described in the literature, see e.g. Tetrahedron Letters No. 18 (1972), pp. 1793 to 1796, and are generally designated by the total number of atoms forming the macrocyclic ring, together with the number of oxygen atoms in this ring. The macrocyclic polyether, the formal chemical name of which is 1,4,7,10-13,16-hexaoxacyclooctadecane, is referred to as «18-crown-6». Other examples of suitable macrocyclic polyethers are 3,4-benzo-1,6,9,12,15,18,21-hepta-oxacyclotricos-3-ene and 3,4-benzo-1,6,9,12 -tetraoxa-cyclotetradec-3-en. 18-crown-6 is particularly suitable.

Other suitable phase transfer catalysts are surface-active agents as defined in Kirk-Othmer, “Encyclopedia of Chemical Technology”, 2nd edition, volume 19 (1969), p. 508: “Organic compounds which combine two different structural groups in the same molecule, from to which one is water-soluble and the other water-insoluble ».

632237

The surfactant is preferably non-ionic, e.g. a poly (alkyleneoxy) derivative formed by reacting a higher alcohol or alkylphenol or a higher fatty acid with ethylene or propylene oxide. Suitable alcohols, alkylphenols or fatty acids contain an alkyl group of 8 to 20 carbon atoms and the number of alkyleneoxy units is 1 to 50. A particularly suitable nonionic surfactant (referred to in the examples as “Dobanol 91-6”) is formed from a C9 -C1A-n-alkanol mixture and contains an average of six ethyleneoxy units. The nonionic surfactant can be an alkylbenzene with a straight alkyl group. Suitable alkylbenzenes contain an alkyl group with 8 to 20 carbon atoms.

The molar ratio of the amount of phase transfer catalyst to the amount of benzaldehyde of the general formula III can vary widely, but is expediently between 1: 5 and 1: 500. The use of low molar ratios causes a longer duration of the reaction, while the use of higher molar ratios of course the production cost for a certain amount of ester increases. The choice of reaction time and the molar ratio of catalyst to benzaldehyde is therefore independent of one another and depends in individual cases on the local economic conditions. Very good results are usually obtained with molar ratios from 1:10 to 1: 100.

Another advantage of the process according to the invention is that the molar ratio of the amount of acid halide (R.CO.Hal) to the amount of benzaldehyde is 1: 1 or slightly more; it is preferably in the range of 1.1: 1.0 to 1.0: 1.0.

The molar ratio of water-soluble cyanide to aromatic aldehyde is advantageously 1.5: 1 to 1.0: 1.0 and is preferably 1.3: 1 to 1.02: 1.00. A “water-soluble cyanide” is understood to mean a water-soluble salt of hydrocyanic acid, among which the alkali metal cyanides and the alkaline earth metal cyanide are preferred. Sodium cyanide is particularly preferred because it causes the formation of the esters according to formula II in the shortest reaction time.

The temperature is expediently kept above 0 ° C. when the process is carried out and is preferably in the range from 10 to 50 ° C., particularly good results being obtained in the range from 15 to 40 ° C. A particular advantage of the process is that it can be carried out well at room temperature.

Examples of suitable, essentially water-immiscible aprotic solvents are alkanes or cycloalkanes or mixtures thereof; the following may be mentioned: n-hexane, n-heptane, n-octane, n-nonane, n-decane and their isomers (for example 2-methylpentane, 3-methylpentane, 2-methylhexane, 3-methylhexane and 2,4,4-trimethylpentane ) as well as cyclohexane and methylcyclohexane. Gasolines rich in alkane are also very suitable, e.g. those with a boiling range between 40 and 65 ° C, 60 and 80 ° C or 80 and 110 ° C at normal pressure. Particularly good results have been obtained with n-heptane and cyclohexane.

Other particularly suitable, essentially water-immiscible, aprotic solvents are aromatic hydrocarbons and chlorinated hydrocarbons, e.g. Benzene, toluene, o-, m- and p-xylene, the trimethylbenzenes, dichloromethane, 1,2-dichloromethane, chloroform, mono-chlorobenzene and 1,2- and 1,3-dichlorobenzene. Very good results were obtained with toluene and xylene.

In the process according to the invention, it is possible to start from unsaturated or saturated aqueous solutions of water-soluble cyanide, in which case solid water-soluble cyanide may still be present. With some solvents, it was found that the presence of solid, water-soluble cyanide improves the yield and shortens the reaction time.

The use of alkanes or cycloalkanes in combination with aqueous cyanide solutions, in which there is no solid water-soluble cyanide, enables the reaction time to be reduced to a minimum. If aromatic or chlorinated hydrocarbons are used in combination with aqueous cyanide solutions in which there is no solid water-soluble cyanide, the reaction time is somewhat longer, but this procedure is sometimes preferred, since the reaction mixture can then be used immediately to prepare pesticides without the ester is separated from the solvent beforehand. The use of aromatic hydrocarbons and chlorinated hydrocarbons in combination with solid water-soluble cyanide leads to short reaction times. Solid water-soluble cyanide can, however, also be used in the presence of alkanes or cycloalkanes.

Suitable reaction times are obtained when the molar ratio of the amount of water to the total amount of water-soluble cyanide is higher than 0.05: 1.

Other examples of essentially water-miscible aprotic solvents are dialkyl ethers and practically water-immiscible alkanones, e.g. B. diethyl ether, diisopropyl ether and diisobutyl ketone. Mixtures of solvents, e.g. from alkanes and aromatic hydrocarbons can also be used; e.g. Mixtures of n-heptane with up to 10% by weight of benzene and / or toluene.

Group A in the general formula II is preferably a phenoxy radical, since this substituent leads to the formation of the most active form of the pyrethroid pesticides.

The group R in the general formula RC (0) Hal is defined as an optionally substituted alkyl or cycloalkyl group. The alkyl group can be straight-chain or branched and preferably contains up to 10 carbon atoms. In the alkyl groups, a tertiary or quaternary carbon atom is preferably bonded to the group -C (0) Hal. Examples of such alkanoyl halides are 2-methyl-propanoyl chloride, 2,2-dimethylpropanoyl chloride and 2-methylbutanoyl bromide. Very good results have been obtained with 2-methylpropanoyl chloride. The alkyl group can be used as a substituent B. Carry hydrocarbonyloxy or substituted phenyl groups e.g. a halophenyl group. Very good results have been obtained with l- (4-chlorophenyl) -2-methyl-propyl groups. The cycloalkyl group itself preferably contains 3 to 6 carbon atoms and optionally carries one or more alkyl, alkenyl or haloalkenyl groups as substituents, each of which expediently has up to eight carbon atoms. Examples of cycloalkyl groups are the cyclopropyl, the cyclobutyl and the cyclohexyl group. Very good results have been obtained with optionally substituted cyclo-propane carbonyl halides, in particular with 2,2,3,3-tetra-methylcyclopropane carbonyl halides and 2- (2,2-dichloro-vinyl) -3,3-dimethylcyclopropane carbonyl halides. The latter halides can have an ice or trans structure or can be a mixture of such structures; they can be in the form of a pure optical isomer or a mixture of optical isomers.

The substituent shark in the general formula RC (0) -Hal is preferably a chlorine or bromine atom, in particular a chlorine atom.

The process according to the invention can be carried out by gradually adding the acid halide, preferably with stirring, to a mixture of the others

4th

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

Starting compounds (particularly advantageous if R in the general formula RC (0) Hal for a 2,2,3,3-tetramethylcyclopropyl group, a 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropyl group or a 1- (4-chlorophenyl) -2-methylpropyl group). Instead, the total amount of starting materials can be combined and the reaction can be carried out with vigorous stirring of the mixture.

The process is of particular interest if the aromatic aldehyde 3-phenoxybenzaldehyde and the acid 10 halide2- (4-chlorophenyl) -3-methylbutanoyl chloride, 2,2,3,3-tetramethylcyclopropanecarbonyl chloride or 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarbonyl chloride, since the esters then formed a-cyano-3-phenoxybenzyl-2- (4-chlorophenyl) -3-methylbutanoate or a-cyano-3-phen- 15 oxybenzyl-2,2,3, 3-tetramethylcyclopropane carboxylate or a-Cyano-3-phenoxybenzyl-2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarboxylate are particularly active ingredients in pesticides.

Regarding the examples that serve to explain the invention in more detail, it should be said that all tests were carried out at a temperature of 23 ° C. The Reak632 237

tion mixture was stirred vigorously and analyzed by gas-liquid chromatography to determine the yield of ester formed. The reaction mixtures were filtered off from the precipitated sodium chloride and, if present, from the solid sodium cyanide, and the filtrates were dried over anhydrous sodium sulfate. The solvent was stripped off in a film evaporator at a pressure of 15 mm Hg. All yields are calculated on the aromatic aldehyde used as the starting material.

example 1

Preparation of a-cyano-3-phenoxybenzyl-2- (4-chlorophenyl) -3-methylbutanoate in the presence of n-heptane A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 12 mmol of sodium cyanide, water, optionally a catalyst and 20 ml of n-heptane, whereupon the mixture was stirred vigorously. In this way, six individual tests were carried out, which are listed in Table 1.

Table I

1

Vers. No.

Catalytic converter designation

Amount in mol%,

bez. added to aldehyde. Water in ml

Response time inh

6

Educ. at

% Ester

3rd

4th

5

6

7

Methyl-tri-2-methyl

heptylammonium

chloride

Tetra-n-butyl

ammonium chloride

Tetra-n-butyl

ammonium chloride

Tetra-n-butylphos-

phonium bromide n-hexadecyldimethyl

sulfonium iodide

1,4,7,10,13,16-

Hexaoxacyclooctadecane

1.0 1.0

1.0 2.0 1.0 1.0 1.0

3 18 2

5 5 3 3 3

86> 99 96

99 99 99 97 94

1 not according to the invention

In Table I in column 1 is the number of the experiment, in column 2 the catalyst, in column 4 the amount of water which was added to the starting mixture (apart from the water present in the sodium cyanide) and in

Column 5 listed the reaction time. The ester yield is shown in column 6. The sodium cyanide was completely dissolved.

Example 2

Preparation of a-cyano-3-phenoxybenzyl-2- (2,2dichloro-cyanide, water, optionally a catalyst and 20 ml of vinyl) -3,3-dimethylcyclopropane carboxylate n-heptane. The mixture was stirred vigorously.

in the presence of n-heptane eo The six experiments listed in Table II were carried out

A 50 ml equipped with magnetic stirrer. The quantities are in columns 3, 4 and 5

Round-bottom flasks were charged with 10 mmol of 3-phenoxybenz catalyst, or water or acid chloride. The aldehyde, a certain amount of 2- (2,2-dichlorovinyl) -3,3- ester yield is shown in column 7, dimethylcyclopropanecarbonyl chloride, 12 mmol sodium

632237

6

Table!!

1

Vers. No.

Catalytic converter designation

Amount in mol%, calculated on aldehyde

4 5 6 7

added Acyl reaction yield at

Water chloride time ester in in ml in mmol in h%

l1 - 1.0 10.2 3 49

21 94

44 99

2 methyl-tri-2-methyl- 5 1.0 10.2 1 96 heptylammonium

chloride

3 tetra-n-butyl-2 1.0 10.5 1 90 ammonium chloride 4 99

4 Amberlite IRA 4002 (lg) 1.0 10.5 5 95

5 Dobanol 91-63 2 1.0 10.0 2 80

6 1,4,7,10,13,16- 2 1,0 10,0 2 76 hexaoxacyclo-

octadecan

1 comparison test, not according to the invention.

2 Protected trade name for a strongly basic anion exchange resin with a styrene / divinylbenzene copolymer as a polymer matrix and a quaternary ammonium group as an ion-active group; the chloride form was used.

3 Protected trade name for a nonionic surfactant in the form of a mixture of C9-Cj! Alcohols with an average of six ethyleneoxy units; the alcohol mixture consists of 85% n-alcohols and 15% 2-alkylalkanols.

Example 3

Preparation of a-cyano-3-phenoxybenzyl-2,2,3,3-tetra-methylcyclopropane carboxylate in the presence of n-heptane

The process variants listed below under A and B were used to prepare the ester. The example shows that a gradual addition of the acid chloride to the reaction mixture over a period of half an hour to two hours leads to a substantial increase in the yield.

Implementation form A

A 50 ml round bottom flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2,2,3,3-tetramethylcyclopropanecarbonyl chloride, 12 mmol of sodium cyanide, 1.0 ml of water, optionally a catalyst and 20 ml n-heptane. The molar ratio of water to NaCN was 4.64 with no solid sodium cyanide present. The catalyst was added in an amount of 0.20 mmol, the mixture was stirred for 1 Vi hours and analyzed.

Implementation form B (gradual addition of acid chloride)

A flask as under A was charged with 10 mmol of 3-phenoxybenzaldehyde, 12 mmol of sodium cyanide, 10 ml of n-heptane, 1.0 ml of water and optionally 0.20 mmol of catalyst so that the molar ratio of water to NaCN was 4.64. Then 10 mmol of 2,2,3,3-tetramethylcyclopropanecarbonyl dissolved in 10 ml of n-heptane were added over a period of 70 to 75 minutes. The ester yield was determined after this period.

Five experiments were carried out in this way, for which the type and amount of the catalyst and the yield of ester are listed in Table III.

Table III

Vers. No.

catalyst

Ester yield in% through-through form

A B

40

1 * 2

45 3

4th

50 5

1,4,7,10,13,16-hexaoxa-cyclooctadecane

Tetra-n-butyl ammonium chloride

Methyl-tri-2-methyl-heptylammonium chloride

Dobanol 91-6 **

17th

18th

20 18 44

40

97

98 96 98

* Comparative experiment, not according to the invention. ** See Table II for an explanation of this expression.

55 The catalysts were used in experiments 2 to 4 in an amount of 2 mol% and in experiment 5 in an amount of 10 mol%, based on the 3-phenoxybenzaldehyde.

60 The reaction mixture obtained in test 4, implementation form B, was filtered and the filtrate was washed out twice with 20 ml of a one-molar aqueous sodium bicarbonate solution and once with 20 ml of water. After the filtrate had dried, the n-heptane was flamed and the ester was kept as a pale yellow oil, which was dissolved in 2.5 ml of methanol at 23 ° C. After cooling the solution to - 20 ° C, the ester separated out as a precipitate, which had a purity of more than 98% after filtering.

632 237

Example 4

Preparation of a-cyano-3-phenoxybenzyl-2- (4-chlorophenyl) -

3-methylbutanoate on a larger scale The above implementation forms A (comparison, not according to the invention), B and C for the preparation of the desired ester were compared.

Implementation A (comparative test in the absence of a phase transfer catalyst)

A 500 ml round-bottom flask equipped with a propeller stirrer was charged with 100 mmol of 3-phenoxybenzaldehyde, 100 mmol of 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 120 mmol of sodium cyanide, 10 ml of water (in which all the sodium cyanide dissolved) and 200 ml of n-heptane. After stirring for 45 hours, the mixture was warmed to a temperature between 40 and 50 ° C and filtered. The filtrate was washed twice with 50 ml each of a molar aqueous sodium bicarbonate solution and once with 50 ml of water and dried, whereupon the n-heptane was flamed from the dried solution; the desired ester was obtained in a yield of 99% and a purity of 96%.

10th

15

Implementation form B (according to the invention, in the presence of an onium compound)

The experiment under A was repeated in the presence of 2 mol% tetra-n-butylammonium chloride, calculated on 3-phenoxybenzaldehyde. After two hours the ester was obtained in 99% yield and 94% purity.

Implementation Form C (According to the Invention, in the Presence of a Nonionic Surfactant)

The experiment described under A was repeated in the presence of 10 mol% “Dobanol 91-6” (for the meaning of this trade name, see Table II), calculated on 3-phenoxybenzaldehyde. After stirring for three hours, the reaction mixture was heated to a temperature between 40 and 50 ° C and filtered. 50 ml of ethanol were then added to the filtrate in order to break the emulsion formed and the filtrate was washed twice with 50 ml each of a molar aqueous sodium bicarbonate solution and once with 50 ml of water and dried. After the n-hep-tane had been driven off from the dried solution, the ester was obtained in a yield of 98% and a degree of purity of 97%. The results are shown in Table IV.

Table IV

Vers. No.

Catalytic converter designation

Amount in mol%,

calc. on aldehyde

Response time in hours

Yield of ester in%

Degree of purity of the ester in%

Tetra-n-butylammonium chloride Dobanol 91-61

3 Dobanol 91-61 10

1 For an explanation of this trade name, see Table II.

45 2

99 99

98

96 94

97

Example 5

Preparation of a-cyano-3-phenoxybenzyl-2- (4-chlorophenyl) -3-methylbutanoate in the presence of solid cyanide A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10.5 mmol 2- (4-chlorophenyl) -3-methylbutanoyl-

chloride, 12 mmol sodium cyanide, 20 ml toluene, a phase transfer catalyst and water. The mixture was stirred for various times and then analyzed. Six tests were carried out, the results of which are shown in Table V, which also gives the catalysts and the amount of water added. The catalysts were used in an amount of 0.20 mmol.

Table V

1

2nd

3rd

4th

5

6

Verse.

catalyst

water

Molver

reaction time

Educ. at

No.

additional ratio in h

Esters

in ml

Water to NaCN

in %

1

1,4,7,10,13,16-hexa-

-

0.012

2nd

60

oxacyclooctadecan

20th

91

80

97

2nd

1,4,7,10,13,16-hexa-

0.02

0.105

3rd

100

oxacyclooctadecan

3rd

1,4,7,10,13,16-hexa-

1.00 *

4.64

2nd

95

oxacyclooctadecan

4th

98

20th

100

4th

Tetra-n-butyl

0.012

2nd

30th

ammonium bromide

22

32

5

Tetra-n-butyl

0.02

0.105

2nd

81

ammonium bromide

18th

98

6

Tetra-n-butyl

1.00 *

4.64

2nd

71

ammonium bromide

22

81

* In these experiments (3 and 6), no solid cyanide was present for reasons of comparison.

632237

8th

The sodium cyanide used was in the form of particles with a largest diameter of 0.5 mm and contained 0.44% by weight of water, which was taken into account in addition to the water which may have been added. For comparison purposes it should be stated that the molar ratio of water to sodium cyanide in a saturated aqueous sodium cyanide solution at 23 ° C. is 4.1.

Claims (18)

632 237 PATENT CLAIMS 1. Process for the preparation of an ester of the general formula: A ÇN ç .CO.O - CH ^ (II) wherein R is an optionally substituted alkyl or cycloalkyl group and A is a phenoxy, phenylthio or benzyl radical, characterized in that a benzaldehyde of the formula: / l OCH (III) with an acid halide of the formula R.CO. Hal (in which shark is a bromide or chloride), the reaction being carried out in the presence of water, a water-soluble cyanide, an essentially water-insoluble aprotic solvent and a phase transfer catalyst. 2. The method according to claim 1, characterized in that an onium compound, a macrocyclic polyether or a surface-active agent is used as the phase transfer catalyst. 3. The method according to claim 2, characterized in that a quaternary onium compound of the general formula: R i 2 4 R -X-R wherein X represents a nitrogen, phosphorus or arsenic atom and R1, R2, R3 and R4 each represents an alkyl, aralkyl, alkaryl or aryl group and Y represents a monovalent ion, or a sulfonium compound of the general formula: 6 -1 r5-s-r7 wherein R5, R6 and R7 are alkyl groups and Y represents a monovalent ion. 4. The method according to claim 2 or 3, characterized in that a quaternary ammonium compound is used as the phase transfer catalyst. 5. The method according to claim 2, characterized in that a poly (alkyleneoxy) derivative is used as the surface-active agent. 6. The method according to claim 5, characterized in that one uses a poly (alkyleneoxy) derivative which is formed by reacting an alkanol having 8 to 20 carbon atoms with ethylene oxide or propylene oxide. 7. The method according to any one of the preceding claims, characterized in that in the reaction mixture the molar ratio of phase transfer catalyst to the benzaldehyde according to formula III is 1: 5 to 1: 500. 8. The method according to any one of the preceding claims, characterized in that one carries out the reaction at 10 to 50 ° C. 9. The method according to any one of the preceding claims, s characterized in that one is considered essentially with Water-immiscible aprotic solvent an Al-kan or cycloalkane or a mixture of both or an aromatic or chlorinated hydrocarbon is used. 10. Process according to claim 9, characterized in that n-heptane is used as the alkane. 11. The method according to claim 9, characterized in that toluene or xylene is used as the aromatic hydrocarbon. 15 12. The method according to any one of the preceding claims, characterized in that one carries out the reaction in the presence of solid, water-soluble cyanide. 13. The method according to one of the preceding claims. 20 che, characterized in that the initial molar ratio of water to the total amount of water-soluble cyanide in the reaction mixture is greater than 0.05: 1. 14. The method according to any one of the preceding claims, characterized in that in the reaction mixture 25 molar ratio of acid halide of the general formula RC (0) Hal to benzaldehyde of the formula III is in the range from 1.1: 1.0 to 1.0: 1.0. 15. The method according to claim 14, characterized in that in the reaction mixture the molar ratio of acid 30 halide of the general formula RC (0) Hal to benzaldehyde is 1: 1 or slightly more. 16. The method according to any one of the preceding claims, characterized in that sodium cyanide is used as the water-soluble cyanide. 35 17. The method according to any one of the preceding claims, characterized in that in the general formulas II and III, the substituent A is a phenoxy group. 18. The method according to any one of the preceding claims, characterized in that in the general form 40 mei RC (0) Hal Hai means a chlorine atom. 19. The method according to any one of the preceding claims, characterized in that in the general formula II and in the formula RC (0) Hal R an l- (4-chlorophenyl) -2-methylpropyl group, a 2,2,3, 3-tetramethylcy- 45 is a clopropyl group or a 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropyl group. 20. The method according to any one of the preceding claims, characterized in that the total amounts of benzaldehyde, acid halide, water, water-soluble cyanide and water-insoluble aprotic solvent are combined and the mixture formed is stirred. 21. The method according to any one of claims 1 to 19, characterized in that a mixture of the benzaldehyde, the water, the water-soluble cyanide and 55 gradually add the acid halide to the water-insoluble aprotic solvent while stirring. 65 60