Preparation of esters

Certain carboxylic acid esters also containing a cyano group are prepared by reacting an acid halide, an aldehyde and a water-soluble cyanide in the presence of a water-immiscible aprotic solvent and surface-active agent as catalyst.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a process for the preparation of certain 
cyano-substituted-carboxylic acid esters by reacting an acid halide, an 
aldehyde and a water-soluble cyanide. 
2. Description of the Prior Art 
According to U.S. Pat. No. 3,835,176, addition of substituted 
cyclopropanecarbonyl halides and m-substituted benzaldehydes, if necessary 
dissolved in an aprotic solvent, to an aqueous solution of sodium cyanide 
or potassium cyanide and stirring of the mixture obtained until no more 
conversion takes place, affords the desired esters. The experiment 
described in Example 4 of the above U.S. patent was conducted in the 
absence of a solvent, with an unsaturated aqueous solution of sodium 
cyanide, with a 20% molar excess of the cyclopropanecarbonyl halide 
(calculated on aldehyde) and at a temperature of 0.degree. C. 
Such a process has the disadvantages that the yield of the ester is 
relatively low and that keeping the temperature at 0.degree. C and using 
the said molar excess are expensive. 
The present invention obviates these disadvantages. 
SUMMARY OF THE INVENTION 
The present invention is directed to a process for the preparation of an 
ester of formula I 
##STR1## 
wherein Ar is an optionally substituted aromatic group and R is an 
optionally substituted acyclic or saturated cyclic hydrocarbyl group, by 
contacting an aromatic aldehyde of the formula ArC(O)H and an acyl halide 
of the formula RC(O)Hal, in which formulas Ar and R have the same meanings 
as in formula I and Hal is a halogen atom having an atomic number of from 
9 to 53, inclusive, with water, a water-soluble cyanide, a substantially 
water-immiscible aprotic solvent and a surface-active agent as 
phase-transfer catalyst. 
A "surface-active agent" is defined as in Kirk-Othmer, "Encyclopedia of 
Chemical Technology", second edition, volume 19(1969), page 508: "An 
organic compound that encompasses in the same molecule two dissimilar 
structural groups, one being water-soluble and one being water-insoluble". 
The surface-active agent is preferably non-ionic. Non-ionic synthetic 
surface-active agents may be broadly defined as compounds aliphatic or 
alkylaromatic in nature which do not ionize in water solution. For 
example, a well known class of non-ionic agents is made available on the 
market under the trade name of "Pluronic." These compounds are formed by 
condensing ethylene oxide with an hydrophobic base formed by the 
condensation of propylene oxide with propylene glycol. The hydrophobic 
portion of the molecule which, of course, exhibits water insolubility has 
a molecular weight of from about 1,500 to 1,800. The addition of 
polyoxyethylene radicals to this hydrophobic portion tends to increase the 
water solubility of the molecule as a whole and the liquid character of 
the product is retained up to the point where polyoxyethylene content is 
about 50% of the total weight of the condensation product. 
Other suitable nonionic agents include: (1) The polyethylene oxide 
condensates of alkyl phenols, e.g., the condensation products of alkyl 
phenols having an alkyl group containing from about 6 to 12 carbon atoms 
in either a straight chain or branched chain configuration, with ethylene 
oxide, the said ethylene oxide being present in amounts equal to 10 to 25 
moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in 
such compounds may be derived from polymerized propylene, diisobutylene, 
octene, or nonene, for example. (2) Those derived from the condensation of 
ethylene oxide with the product resulting from the reaction of propylene 
oxide and ethylenediamine. For example, compounds containing from about 
40% to about 80% polyoxyethylene by weight and having a molecular weight 
of from about 5,000 to about 11,000 resulting from the reaction of 
ethylene oxide groups with a hydrophobic base constituted of the reaction 
product of ethylene diamine and excess propylene oxide, said hydrophobic 
base having a molecular weight of the order of 2,500 to 3,000, are 
satisfactory. (3) The condensation product of aliphatic alcohols having 
from 8 to 18 carbon atoms, in either straight chain or branched chain 
configuration, with ethylene oxide, e.g., a coconut alcohol-ethylene oxide 
condensate having from 10 to 30 moles of ethylene oxide per mole of 
coconut alcohol, the coconut alcohol fraction having from 10 to 14 carbon 
atoms. (4) Long chain tertiary amine oxides corresponding to the following 
general formula, R.sub.1 R.sub.2 R.sub.3 N.fwdarw.O, wherein R.sub.1 is an 
alkyl radical of from about 8 to 18 carbon atoms, and R.sub.2 and R.sub.3 
are each methyl or ethyl radicals. The arrow in the formula is a 
conventional representation of a semi-polar bond. Examples of amine oxides 
suitable for use in this invention include dimethyldodecylamine oxide, 
dimethyloctylamine oxide, dimethyldecylamine oxide, 
dimethyltetradecylamine oxide, dimethylhexadecylamine oxide. (5) Long 
chain tertiary phosphine oxides corresponding to the following formula 
RR'R"P.fwdarw.O, wherein R is an alkyl, alkenyl or monohydroxyalkyl 
radical ranging from 10 to 18 carbon atoms in chain length and R' and R" 
are each alkyl or monohydroxyalkyl groups containing from 1 to 3 carbon 
atoms. The arrow in the formula is a conventional representation of a 
semi-polar bond. Examples of suitable phosphine oxides are: 
dimethyldodecylphosphine oxide, 
dimethyltetradecylphosphine oxide, 
ethylmethyltetradecylphosphine oxide, 
cetyldimethylphosphine oxide, 
dimethylstearylphosphine oxide, 
cetylethylpropylphosphine oxide, 
diethyldodecylphosphine oxide, 
diethyltetradecylphosphine oxide, 
bis(hydroxymethyl)dodecylphosphine oxide, 
bis(2-hydroxyethyl)dodecylphosphine oxide, 
2-hydroxypropylmethyltetradecylphosphine oxide, 
dimethyloleylphosphine oxide, and 
dimethyl-2-hydroxydodecylphosphine oxide. 
(6) Dialkyl sulfoxides corresponding to the following formula, 
RR'S.fwdarw.O, wherein R is an alkyl, alkenyl, beta- or 
gamma-monohydroxyalkyl radical or an alkyl or beta- or 
gamma-monohydroxyalkyl radical containing one or two other oxygen atoms in 
the chain, the R groups ranging from 10 to 18 carbon atoms in chain 
length, and wherein R' is methyl or ethyl. Examples of suitable sulfoxide 
compounds are: 
dodecylmethyl sulfoxide 
tetradecylmethyl sulfoxide 
3-hydroxytridecylmethyl sulfoxide 
2-hydroxydodecylmethyl sulfoxide 
3-hydroxy-4-decoxybutylmethyl sulfoxide 
3-hydroxy-4-dodecoxybutylmethyl sulfoxide 
2-hydroxy-3-decoxypropylmethyl sulfoxide 
2-hydroxy-3-dodecoxypropylmethyl sulfoxide 
dodecylethyl sulfoxide 
2-hydroxydodecylethyl sulfoxide 
(7) The ammonia, monoethanol and diethanol amides of fatty acids having an 
acyl moiety of from about 8 to about 18 carbon atoms; 
(8) A sorbitan monoester with a long chain fatty acid of 8 to 20 carbon 
atoms; or 
(9) An alkylbenzene containing a straight-chain alkyl group. Suitable 
alkylbenzenes contain an alkyl group of 8 to 20 carbon atoms. 
Preferred surface-active agents are poly(alkyleneoxy) derivatives formed by 
reacting a higher alcohol, alkylphenol or fatty acid with ethylene oxide 
or propylene oxide. Suitable alcohols, alkylphenols or fatty acids contain 
an alkyl group of from 8 to 20 carbon atoms and the number of alkyleneoxy 
units is in the range of 1 to 50. It is preferable to use an alcohol 
ethoxylate such as the ethoxylates derived by ethoxylation of primary or 
secondary, straight-chain or branched alcohols. A single alcohol may be 
used e.g., octyl alcohol, decyl alcohol, dodecyl alcohol, but preferably a 
mixture of alcohols is used. The mixture of alcohols may contain small 
amounts of alcohols below C.sub.7 and above C.sub.13 but at least 90%w, 
and preferably at least 95%w, of the alcohols thereof are in the C.sub.9 
to C.sub.13 range. Preferred mixtures of alcohols are those mixtures of 
C.sub.9 to C.sub.11 alcohols such as those prepared by hydroformylation of 
olefins. The amount of ethylene oxide used to prepare such ethoxylates is 
suitably such so as to provide an average from 1 to 13 moles, and 
preferably 5 to 9 moles, of ethylene oxide per mole of alcohol (or alcohol 
mixture). Examples of such ethoxylates are "Dobanol.sub.45-11 " formed 
from a C.sub.14 to C.sub.15 straight-chain alcohol mixture and containing 
an average of eleven ethyleneoxy units or preferably "Dobanol.sub.91-6 " 
formed from a C.sub.9 to C.sub.11 straight-chain alcohol mixture with an 
average of six ethyleneoxy units (both trade names are registered trade 
marks). 
The molar ratio of the amount of phase transfer catalyst to the amount of 
aromatic aldehyde of the formula ArC(O)H may vary within wide limits, but 
is suitably from 1:5 to 1:500. The use of low molar ratios will require a 
longer time to complete the reaction, whilst the use of higher molar 
ratios naturally increases the cost to produce a given quantity of ester. 
Thus, the choice of reaction time and molar ratio catalyst to aromatic 
aldehyde are mutually interdependant, and in any individual instance will 
depend on the local economic factors. Very good results are usually 
obtained at molar ratios from 1:10 to 1:100. 
Another advantage of the process according to the present invention is that 
the molar ratio of the amount of (cyclo)aliphatic acyl halide to the 
amount of aromatic aldehyde can be kept so low that a molar excess of the 
halide is not or hardly not required. This molar ratio is preferably in 
the range of from 1.1 to 1.0. When the substantially water-immiscible 
aprotic solvent is a (cyclo)alkane or a mixture of (cyclo)alkanes molar 
ratios equal to 1.0 give excellent results. 
The molar ratio of the amount of water-soluble cyanide to the amount of 
aromatic aldehyde is suitably from 1.5 to 1.00 and preferably from 1.3 to 
1.02. By "water-soluble cyanide" is meant a water-soluble salt of hydrogen 
cyanide. Of the water-soluble cyanides alkali-metal cyanides and 
alkaline-earth-metal cyanides are preferred. Sodium cyanide is 
particularly preferred, because it affords the esters of the formula I in 
the shortest reaction time. 
The temperature at which the process is conducted is suitably above 
0.degree. C and is preferably in the range of from 10.degree. C to 
50.degree. C. Very good results have been obtained at temperatures in the 
range of from 15.degree. C to 40.degree. C. The process has the advantage 
that ambient temperatures are very suitable. 
The most suitable substantially water-immiscible aprotic solvent is a 
(cyclo)alkane or a mixture of (cyclo)alkanes, because they allow the 
shortest reaction times. The use of these solvents is claimed in our 
concurrently filed U.S. application U.S. Ser. No. 765,188, filed Feb. 3, 
1977. Examples of suitable (cyclo)alkanes are those having up to 10 carbon 
atoms, preferably 6 to 10 carbon atoms, e.g., 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) and cyclohexane and methylcyclohexane. Gasolines 
rich in alkanes are also very suitable, for example with a boiling range 
at atmospheric pressure between 40.degree. and 65.degree. C, 60.degree. 
and 80.degree. C or 80.degree. and 110.degree. C. Very good results have 
been obtained with n-heptane and cyclohexane. 
Other very suitable substantially water-immiscible aprotic solvents are 
aromatic hydrocarbons and chlorinated hydrocarbons, for example benzene, 
toluene, p-, m- and p-xylene, the trimethylbenzenes, dichloromethane, 
1,2-dichloromethane, chloroform, monochlorobenzene and 1,2- and 
1,3-dichlorobenzene. Very good results have been obtained with toluene. 
The process according to the present invention may be conducted starting 
from unsaturated or saturated aqueous solutions of water-soluble cyanide 
and in the latter case in the presence or absence of solid water-soluble 
cyanide. The use of solid water-soluble cyanide is covered in our 
concurrently filed U.S. patent application Ser. No. 765,184, filed Feb. 3, 
1977. 
It has been found that when in a given case in which in successive 
comparable experiments less water and more solid water-soluble cyanide are 
applied (starting from a saturated aqueous solution of cyanide containing 
no solid water-soluble cyanide and keeping the total amount of 
water-soluble cyanide constant) the reaction time can be kept shorter and 
shorter, passes a minimum and then becomes longer and longer until it has 
become as long as in the starting case. 
The use of (cyclo)alkanes in combination with aqueous solution of cyanide 
in the absence of solid water-soluble cyanide allows very short reaction 
times. The use of aromatic hydrocarbons or chlorinated hydrocarbons in 
combination with aqueous solutions of cyanide in the absence of solid 
water-soluble cyanide needs longer reaction times, but the use of these 
two groups of solvents in combination with solid water-soluble cyanide 
allows very short reaction times. Solid water-soluble cyanide may also be 
used in the presence of (cyclo)alkanes, but the reaction times can already 
be kept very short in the absence of the former. The above-mentioned 
minimum reaction time is usually obtained when molar ratios of the amount 
of water to the total amount of water-soluble cyanide is higher than 0.05 
and particularly in the range of from 0.05 to 1. For comparison it may be 
stated that the molar ratios of water to sodium cyanide in a saturated 
aqueous solution of sodium cyanide at 10.degree. C and 35.degree. C are 
5.7 and 3.3, respectively. Consequently, extremely small amounts of water 
are sufficient to obtain the shortest reaction times. Furthermore, the 
yield of the ester of the formula I is usually very high and sometimes 
quantitative. In addition to the possibility of using short reaction times 
the use of solid water-soluble cyanide has a cost-saving effect, since 
smaller volumes of water can be handled. 
Other examples of substantially water-immiscible aprotic solvents are 
dialkyl ethers and substantially water-immiscible alkanones, for example 
diethyl ether, diisopropyl ether and diisobutyl ketone. For these solvents 
the above-mentioned minimum reaction time can easily be determined by 
means of simple experiments in which the molar ratio of the amount of 
water to the total amount of water-soluble cyanide is varied. Mixtures of 
solvents, for example of alkanes and aromatic hydrocarbons may be applied, 
for example of n-heptane containing up to 10% by weight of benzene and/or 
toluene. 
The optionally substituted aromatic group Ar in the aromatic aldehyde of 
the formula ArC(O)H may be carbocyclic or heterocyclic. Examples of 
carbocyclic groups are phenyl, 1-naphthyl, 2-naphthyl and 2-anthryl 
groups. Heterocyclic aromatic groups are derived from hetero-aromatic 
compounds which are defined as in Kirk-Othmer, "Encyclopedia of Chemical 
Technology", Second Edition, Volume 2 (1963), page 702: obtained by 
replacement of one or more carbon atoms of a carbocyclic aromatic compound 
by a hetero-atom - for example pyridine, pyrimidine, pyrazine, quinoline 
and isoquinoline - and also include those heterocyclic compounds having 
five-membered rings which show aromatic characteristics and are mentioned 
on page 703 of said volume, for example thiophene, pyrrole, furan, indole 
and benzothiophene. As an aromatic group an optionally substituted phenyl 
group is very suitable. Examples of substituents are hydrocarbyl and 
hydrocarbyloxy groups. Very good results have been obtained with 
phenoxybenzaldehydes, particularly m-phenoxybenzaldehyde. 
The group R in the formula RC(O)Hal may, for example, be an optionally 
substituted alkyl group. The alkyl group may be straight or branched. The 
alkyl groups preferably have a tertiary or quaternary carbon atom bound to 
the group -C(O)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 may carry as substituents, for 
example, hydrocarbyloxy or substituted phenyl groups, such as halophenyl 
or alkylphenyl. Very good results have been obtained with 
1-(4-chlorophenyl)-2-methylpropyl groups. The expression "saturated cyclic 
hydrocarbyl group" in this patent application refers to cyclic hydrocarbyl 
groups in which the ring is saturated; this ring may carry substituents 
for example alkyl groups of 1 to 6 carbon atoms such as methyl, halogen 
atoms having atomic numbers of 9 to 35, inclusive, such as chlorine, 
bromine or fluorine or unsaturated side chains such as isobutenyl, 
dichlorovinyl or dibromovinyl. Examples of saturated cyclic hydrocarbyl 
groups are cyclopropyl, cyclobutyl and cyclohexyl groups. Very good 
results have been obtained with optionally substituted 
cyclopropanecarbonyl halides, particularly with 
2,2,3,3-tetramethylcyclopropanecarbonyl halides and 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarbonyl halides. The later 
halides may have a cis or trans structure or may be a mixture of such 
structures and may be a pure optical isomer or a mixture of optical 
isomers. 
The atom Hal in the formula RC(O)Hal is preferably a chlorine or bromine 
atom and in particular a chlorine atom. 
The process according to the invention may be carried out by gradual 
addition of the acyl halide to a vigorously agitated, e.g. stirred, 
mixture of the other starting compounds (particularly recommended when R 
in the formula RC(O)Hal represents a 2,2,3,3-tetramethylcyclopropyl group) 
and often by placing together the total amounts of the starting compounds 
and vigorous agitating, e.g. stirring, of the mixture thus formed, which 
is particularly recommended when R represents a 
1-(4-chlorophenyl)-2-methylpropyl, an isopropyl or a 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropyl group. 
The process is of particular interest to prepare pesticidally active 
esters, for example when the aromatic aldehyde is 3-phenoxybenzaldehyde 
and the acyl halide is an aralkyl halide such as 
2-(4-chlorophenyl)-3-methylbutanoyl chloride, or a 
substituted-cyclopropanecarbonyl halide such as 
2,2,3,3-tetramethylcyclopropanecarbonyl chloride or 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarbonyl chloride, because 
the esters then formed are .alpha.-cyano-3-phenoxybenzyl 
2-(4-chlorophenyl)-3-methylbutanoate, .alpha.-cyano-3-phenoxybenzyl 
2,2,3,3-tetramethylcyclopropanecarboxylate and 
.alpha.-cyano-3-phenoxybenzyl 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxylate, respectively, 
all of which are pesticidally active compounds disclosed in Belgian patent 
801,946, U.S. Pat. No. 3,835,176 and Netherlands publication No. 
7,307,130, respectively.

EXAMPLES 
The Examples further illustrate the invention. All experiments were 
conducted at a temperature of 23.degree. C. The sodium cyanide used 
consisted of particles having a largest dimension of 0.5 mm and contained 
0.44% by weight of water. The molar ratio of water to sodium cyanide has 
been calculated taking into account the water present in the sodium 
cyanide and the water added, if any. For comparison it may be stated that 
the molar ratio of water to sodium cyanide in a saturated aqueous solution 
of sodium cyanide having a temperature of 23.degree. C is 4.1. The 
reaction mixtures were stirred vigorously and analysed by gas-liquid 
chromatography to determine the yield of the ester formed. Reaction 
mixtures were filtered to remove precipitated sodium chloride and solid 
sodium cyanide, if any, and drying of solutions was carried out over 
anhydrous sodium sulphate. Flashing of the solvent took place in a film 
evaporator at a pressure of 15 mm Hg. All yields are calculated on 
starting aromatic aldehyde. 
EXAMPLE I 
Preparation of .alpha.-cyano-3-phenoxybenzyl 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxylate 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, an amount of 
2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarbonyl chloride, 12 mmol 
of sodium cyanide, water, a catalyst, if any and 20 ml of n-heptane. The 
mixture thus formed was stirred. Two experiments were carried out in this 
manner, see Table I. Column 3, 4 and 5 state the amounts of catalyst, 
water and acyl chloride added. The sodium cyanide was completely 
dissolved. The yield of the desired ester is presented in column 7. 
TABLE I 
______________________________________ 
1 2 3 4 5 6 7 
______________________________________ 
Catalyst Acyl 
amount Water chlor- 
Reaction 
Exp. %mol on added ide, time, Yield of 
no. name aldehyde m1 mmol h ester, % 
______________________________________ 
1.sup.1) 
-- -- 1.0 10.2 3 49 
21 94 
44 99 
2 Dobanol 2 1.0 10.0 1 62 
91-6.sup.2) 2 80 
18 99 
______________________________________ 
.sup.1) not according to the invention 
.sup.2) a registered trade name for a non-ionic surface-active agent 
formed from a C.sub.9 -C.sub.11 alcohol mixture and containing an average 
of 6 ethyleneoxy units; the alcohol mixture consists of 85% n-alkanols an 
15% 2-alkylakanols. 
EXAMPLE II 
Preparation of .alpha.-cyano-3-phenoxybenzyl 
2-(4-chlorophenyl)-3-methylbutanoate in the presence of toluene 
A 50 ml roundbottomed flask equipped with a magnetic stirrer was charged 
with 10 mmol of 3-phenoxybenzaldehyde, 10.5 mmol of 
2-(4-chlorophenyl)-3-methylbutanoyl chloride, 12, mmol of sodium cyanide 
and 20 ml of toluene. The mixture thus formed was stirred. The yields of 
the desired ester after 3 and 20 hours' stirring are presented in Table 
II, see experiment 1. 
Four other experiments were conducted in this manner, see Table III. 
Columns 2 and 3 in Table II state the catalyst and amount of water if any, 
respectively, added to the starting mixture, and column 4 states the molar 
ratio of water to sodium cyanide. The amount of catalyst added was 10%, 
calculated on 3-phenoxybenzaldehyde, in experiments 3 and 5. In experiment 
5, 10.0 mmol instead of 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl 
chloride was used. 
TABLE II 
______________________________________ 
1 2 3 4 5 6 
______________________________________ 
Water Molar ratio 
Exp. added, water to 
Reaction 
Yield of 
no. Catalyst ml NaCN time, h 
ester, % 
______________________________________ 
1.sup.1) 
none -- 0.012.sup.3) 
3 19 
20 18 
2.sup.1) 
none 0.02 0.105.sup.3) 
3 38 
24 98 
44 99 
3 Dabanol 91-6.sup.2) 
0.02 0.105.sup.3) 
1 82 
4 99 
4.sup.1) 
none 1.00 4.64 3 41 
24 87 
85 95 
5 Dobanol 91-6.sup.2) 
1.00 4.64 6 83 
20 88 
______________________________________ 
.sup.1) not according to the invention. 
.sup.2) for explanation of this word, see Table I. 
.sup.3) solid NaCN was present. 
EXAMPLE III 
Preparation of .alpha.cyano-3-phenoxybenzyl 
2,2,3,3-tetramethyl-cyclopropanecarboxylate in the presence of n-heptane 
Methods A and B were applied to prepare the ester wanted. 
Method A 
A 50 ml round-bottomed 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, 1.00 ml of water, a catalyst, if any, and 20 ml of n-heptane. The 
molar ratio of water to NaCN was 4.64, solid NaCN being absent. The 
catalyst was added in an amount of 0.20 mmol. The mixture thus formed was 
stirred for 1.5 hours and analysed. 
Method B 
The flask used for method A was charged with 10 mmol of 
3-phenoxybenzaldehyde, 12 mmol of sodium cyanide, 10 ml of n-heptane, 1.00 
ml of water and 0.20 mmol of a catalyst, if any, the molar ratio of water 
to NaCN being 4.64. An amount of 10 mmol of 
2,2,3,3-tetramethylcyclopropanecarbonyl chloride dissolved in 10 ml of 
n-heptane was introduced into the flask during a period of 70-75 min. The 
yield of the ester was determined at the end of this period. 
Two experiments were carried out in this manner. Table III states the 
catalysts used, if any. This Table also presents the yield of the desired 
ester. 
TABLE III 
______________________________________ 
Exp. Yield of ester, % 
no. Catalyst Method A Method B 
______________________________________ 
1.sup.*) 
none 17 40 
2 Dobanol 91-6.sup.**) 
44 98 
______________________________________ 
.sup.*) not according to the invention 
.sup.**) for explanation of this word, see Table I. 
The amount of the catalysts used was 10% m in experiment 2, calculated on 
3-phenoxybenzaldehyde. 
EXAMPLE IV 
Preparation of .alpha.-cyano-3-phenoxybenzyl 
2-(4-chlorophenyl)-3-methylbutanoate on an enlarged scale 
Methods A (not according to the invention), and B were compared for the 
preparation of the ester wanted. 
Method A, in the absence of a phase transfer catalyst. 
A 500 ml round-bottomed flask equipped with a paddle 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 (which dissolved all sodium cyanide) and 200 ml of 
n-heptane. After stirring for 45 hours the mixture was warmed to a 
temperature between 40.degree. and 50 .degree. C and filtered. The 
filtrate was washed twice with 50 ml of a 1 M aqueous sodium bicarbonate 
solution, once with 50 ml of water, dried and the n-heptane was flashed 
from the dried solution to give the desired ester in a yield of 99% and a 
purity of 96%. 
Method B, in the presence of a non-ionic surface-active agent. 
The experiment described in Section A of this Example was repeated in the 
presence of 10%m of "Dobanol 91-6" (for explanation of this word, see 
Table I), calculated on 3-phenoxybenzaldehyde. After three hours' stirring 
the reaction mixture was warmed to a temperature between 40.degree. and 
50.degree. C and filtered. An amount of 50 ml of ethanol was added (to 
break the emulsion formed) to the filtrate and the filtrate was washed 
twice with 50 ml of a 1 M aqueous solution of sodium bicarbonate, once 
with 50 ml of water, dried and the n-heptane was flashed from the dried 
solution to give the ester in a yield of 98% and a purity of 97%.