JPH04316550A - Production of cyanoacetic acid ester - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high reactivity and easily handleable state without using highly toxic substance as a raw material by reacting monochloroacetonitrile with a formic acid ester in the presence of a basic substance and a cobalt carbonyl. CONSTITUTION:The objective cyanoacetic acid ester can be produced by reacting monochloronitrile with a formic acid ester of formula HCOOR (R is 1-6C alkyl, cyclohexyl, 2-alkoxyethyl, 1-6C chloroalkyl, allyl, phenyl, 1-6C alkylphenyl or benzyl) (e.g. ethyl formate) in the presence of a basic substance (e.g. triethylamine, pyridine or lithium carbonate) and a cobalt carbonyl (e.g. dicobalt octacarbonyl). Since a formic acid ester is used as a raw material, the process has decreased danger of highly toxic substance used as a raw material, the operation of the process becomes easy, the reactivity is high and the reaction can be performed under normal pressure.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing cyanoacetic esters. More specifically, the present invention relates to a method for producing cyanoacetate from monochloroacetonitrile and formate in the presence of a basic substance and cobalt carbonyl. Cyanoacetic acid ester is an industrially useful substance as a raw material for adhesives, a raw material for organic synthesis, a raw material for medicines and agrochemicals, etc.

0002

BACKGROUND OF THE INVENTION Hitherto, several methods have been known for producing cyanoacetic esters. For example, US Pat. No. 2,553,065 describes a method for producing it using monochloroacetic acid and sodium cyanide as raw materials. In this method, first, a sodium monochloroacetate aqueous solution is prepared from monochloroacetic acid and caustic soda, and a sodium cyanide aqueous solution is added thereto to obtain a sodium cyanoacetate aqueous solution. The mixture is then acidified with sulfuric acid, water is distilled off, and alcohol is added to synthesize cyanoacetic acid ester. However, this method cannot be called a practical production method because it uses highly toxic sodium cyanide and requires many reaction steps.

Furthermore, West German Patent No. 2,403,483 describes a method for synthesizing cyanoacetic ester by reacting monochloroacetonitrile with carbon monoxide and alcohol in the presence of a metal carbonyl and a basic substance. There is. However, although this method is a one-step reaction to obtain cyanoacetate, it requires the use of highly toxic carbon monoxide under high pressure, and is not necessarily an easy method to implement industrially.

0004

OBJECTS OF THE INVENTION The present invention has been made to solve the problems of the conventional methods as described above, and its purpose is to eliminate the use of highly toxic substances as raw materials. The object of the present invention is to provide a novel method for producing cyanoacetic ester that is easy to handle and has excellent reactivity.

[0005]

[Means for Solving the Problems] As a result of intensive studies to achieve the above object, the present inventors have found that if monochloroacetonitrile is reacted with formic acid ester in the presence of a basic substance and cobalt carbonyl, The present inventors have discovered that cyanoacetic acid ester can be easily produced without requiring a reaction at high pressure, and have accomplished the present invention.

That is, the method for producing cyanoacetic ester according to the present invention consists of monochloroacetonitrile and the general formula HC.
OOR (in the formula, R is a C1 to C6 alkyl group, a cyclohexyl group, a 2-alkoxyethyl group, a C1 to C6
It is characterized by reacting a formic acid ester represented by a chloroalkyl group, an allyl group, a phenyl group, or a benzyl group) in the presence of a basic substance and cobalt carbonyl.

Specific examples of the formic acid ester represented by the above general formula used in the method of the present invention include methyl formate, ethyl formate, propyl formate, butyl formate, amyl formate, cyclohexyl formate, 2-methoxyethyl formate, Formic acid-2
-(2-methoxyethoxy)ethyl, 2-chloroethyl formate, 3-chloropropyl formate, allyl formate, phenyl formate, methylphenyl formate, ethylphenyl formate,
Examples include propylphenyl formate, butylphenyl formate, benzyl formate, and the like. The amount of formic acid ester used is in the range of 1 to 5 mol per 1 mol of monochloroacetonitrile,
Preferably, the amount is in the range of 1 to 2 moles.

Examples of the basic substances used in the method of the present invention include triethylamine, N-methylpiperidine,
Tertiary amines such as N,N-dimethylaniline, pyridines such as pyridine, picoline, lutidine, and collidine;
Lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, sodium bicarbonate, potassium bicarbonate, lithium acetate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, barium acetate, trilithium phosphate, phosphorus Alkali metal or alkaline earth carbonates, bicarbonates, acetates, phosphates or borates such as trisodium acid, tripotassium phosphate, sodium metaborate and potassium metaborate; One type or a mixture of two or more types can be used.

The amount of the basic substance to be used is 1 mol or more for monoacid bases, particularly in the range of 1.0 to 3.0, and 0.5 mol or more for diacid bases, per 1 mol of monochloroacetonitrile. In particular, it is preferable to select from the range of 0.5 to 2.0.

[0010] As the cobalt carbonyl used in the method of the present invention, dicobalt octacarbonyl is usually mentioned, but tetracobalt decacarbonyl, cobalt hydrotetracarbonyl, cobalt tetracarbonyl anion, etc. can also be used, and one of these may be used. There is no problem in using one type or two or more types.

The amount of cobalt carbonyl used is preferably in the range of 1/500 to 1/2 mole, preferably in the range of 1/200 to 1/5 mole, per mole of monochloroacetonitrile. Note that in order to maintain the catalytic activity of cobalt carbonyl, carbon monoxide can also be present.

The method of the invention can be carried out using a solvent. Examples of solvents include aliphatic hydrocarbons such as hexane and octane, aromatic hydrocarbons such as benzene, toluene, and xylene, and ethers such as diethyl ether, dipropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, and dioxane. , acetone, methyl ethyl ketone, methyl isobutyl ketone, and other ketones, and esters of acetic acid and C1 to C3 alcohols. Note that when an inorganic base is used as the basic substance, a small amount of water can be added in order to increase the solubility of the inorganic salt in the reaction system.

[0013] The reaction temperature can be carried out in the range of 10 to 150°C, preferably in the range of 30 to 120°C. Although the reaction time depends on the catalyst activity, stirring speed, and reaction temperature, it is preferably carried out within a range of 1 to 6 hours.

[0014] After the reaction, unreacted raw materials, solvent, etc. are recovered from the reaction solution by distillation under normal pressure or reduced pressure, and then the catalyst and the produced salt are separated by a known method to obtain the cyanoacetic ester. The separated catalyst and the recovered unreacted raw material or solvent can be purified and used again in the reaction.

[0015]

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 150 ml of ethyl formate in a 500 ml flask equipped with a stirrer, reflux condenser, addition funnel, nitrogen inlet and thermometer.
g, 121 g of triethylamine and 17.1 g of dicobalt octacarbonyl, and the reaction temperature was set at 55-60°C.
76 g of monochloroacetonitrile was added dropwise from the dropping funnel under a nitrogen atmosphere over a period of 2 hours. After the dropwise addition was completed, the mixture was aged for 2 hours while maintaining the same temperature. Then, unreacted ethyl formate, monochloroacetonitrile and triethylamine were distilled off. After cooling, the residual liquid was acidified by adding 5% by weight of sulfuric acid, and then ether was added to separate it into an organic layer and an aqueous layer. After distilling off the ether, the organic layer was distilled to isolate ethyl cyanoacetate. As a result, 59.3 g of ethyl cyanoacetate with a purity of 99% or higher and a yield of 52.4% (based on monochloroacetonitrile) were obtained.

Example 2 In a 300 ml autoclave equipped with a stirrer, a thermometer and a pressure gauge, 30 g of methyl formate and 30 g of triethylamine were added.
After charging 19 g of chloroacetonitrile and 4.3 g of dicobalt octacarbonyl, replacing the inside of the autoclave with carbon monoxide, the pressure was increased to 3 kg/cm2 with carbon monoxide.
It was adjusted to The reaction temperature was raised to 55 to 60°C and aged for 3 hours while maintaining the same temperature. The pressure at this time is 5-6 kg
/cm2. After the reaction was completed, the temperature was returned to room temperature, carbon monoxide was replaced with nitrogen gas, and unreacted methyl formate, chloroacetonitrile, and triethylamine were distilled off. After cooling to room temperature, 5% by weight of sulfuric acid and ether were added to the residual liquid, and the mixture was separated into an organic layer and an aqueous layer. After removing the ether, the organic layer was distilled to isolate methyl cyanoacetate. As a result, purity is 99%
23.5 g of methyl cyanoacetate, yield 47.5% (
for monochloroacetonitrile).

Examples 3 to 5 Cyanoacetic acid esters were produced in the same manner as in Example 1 using n-propyl formate, isobutyl formate, and cyclohexyl formate in place of ethyl formate in Example 1, respectively. The results are shown in Table 1.

[0018]

[Table 1]

Examples 6 to 8 Cyanoacetate was prepared in the same manner as in Example 1 except that sodium carbonate, trisodium phosphate, and collidine were each used in an amount equivalent to 1.2 times that of chloroacetonitrile in place of triethylamine in Example 1. Manufactured. Note that in the reaction using sodium carbonate, 7.5 g of water was added, and in the reaction using trisodium phosphate, 6.0 g of water was added. The results are shown in Table 2.

[0020]

[Table 2]

[0021]

[Effects of the Invention] Cyanoacetate production by the method of the present invention uses formic acid ester as a raw material, reducing the risk of using highly toxic substances as a raw material, making it easy to handle, and having high reactivity and being able to be used at normal pressure. reactions can be carried out.

Claims (1)

[Claims] [Claim 1] Monochloroacetonitrile and general formula H
COOR (in the formula, R is a C1 to C6 alkyl group, a cyclohexyl group, a 2-alkoxyethyl group, a C1 to C6
Chloroalkyl group, allyl group, phenyl group, C1
A method for producing a cyanoacetic acid ester, which comprises reacting a formic acid ester represented by C6 alkylphenyl group or benzyl group in the presence of a basic substance and cobalt carbonyl.