JPS6153243A - Production of alpha-chloroethylcycloalkyl carbonate - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a raw material of agricultural chemicals and pharmaceuticals, without producing byproducts, economically in an industrial scale, by using a chloro-formate and acetaldehyde as the starting raw materials, and reacting the reactants in a solvent in the presence of a tert-amine. CONSTITUTION:The compound of formula II can be produced by reacting (A) 1mol of a chloroformate of formula I (R is cycloalkyl) with (B) preferably 0.5- 10.0mol, especially 2.0-4.0mol of acetaldehyde, in an organic solvent such as dichloromethane, carbon tetrachloride, acetonitrile, etc., in the presence of a tert-amine such as pyridine, quinoline, etc., preferably at 0-30 deg.C. The amount of the tert-amine is 0.05-1.5mol, preferably 0.2-0.5mol per 1mol of the chloroformate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to a method for producing α-chloroethyl alkyl carbonates useful as agricultural and pharmaceutical raw materials.

[Conventional technology]

As a method for producing α-chloroethyl alkyl carbonates, ethyl chloroformate is reacted with chlorine gas in the presence of sunlight, and then the obtained α-chloroethyl chloroformate is reacted with ethanol.
Method for synthesizing α-chloroethyl ethyl carbonate (
HlMu-11er, Annalen der C
hemie, 3 standing 1.50 (1980)) is known.

However, this document does not mention the yield, and in addition, various chlorinated by-products are produced in the first step of chlorinating ethyl chloroformate, making it impossible to separate the target product, making it very difficult to industrially. It is not something that can be implemented. In addition, chlorine gas is introduced into diethyl carbonate under scattered light or in the presence of an organic peroxide, chlorination is carried out until the conversion rate of diethyl carbonate is 40 to 90%, the reaction product is distilled, and the desired α - A method for producing chloroethyl ethyl carbonate (JP 56-1213736) and directly reacting diethyl carbonate under ultraviolet irradiation, or
Method for obtaining the target α-chloroethyl ethyl carbonate by chlorination in a carbon tetrachloride solvent (Japanese Unexamined Patent Publication No. 57-1097
44) has been proposed.

[Problem that the invention seeks to solve]

However, it is very difficult to employ any of these methods industrially because many types of chlorinated products are produced as by-products due to the chlorination method.

[Means for solving problems]

In view of the above-mentioned problems, the present inventors have conducted intensive studies to overcome the drawbacks of such conventional methods and to industrially produce high-purity α-chloroethyl alkyl carbonates in an easy and efficient manner. As a result, they discovered a new method for producing α-chloroethyl alkyl carbonates from chloroformates and acetaldehyde, and completed the present invention.

That is, the present invention involves reacting a chloroformate represented by the general formula % (wherein R represents a cycloalkyl group) with acetaldehyde in the presence of a tertiary amine in an organic solvent. α represented by the general formula % (wherein R has the same meaning as above)
- A method for producing chloroethylcycloalkyl carbonates.

This reaction is shown by the following reaction formula.

ROCO(:f+cH, CHO-ROCOOCHCjI
CH.

That is, in the present invention, chloroformates, acetaldehyde, and a reaction solvent are charged into a reactor, mixed at 10°C or lower, a tertiary amine is added thereto to complete the reaction, and after the solvent is distilled off, cold water is added. In addition, the oil layer is distilled to produce α-chloroethylcycloalkyl carbonates.

Examples of the chloroformates that are raw materials of the present invention include cyclohexyl chloroformate, cyclopentyl chloroformate, cycloheptyl chloroformate,
-Methylcyclohexylchloroformate, '4-t
-butyl cyclohexyl chloroformate and the like.

Therefore, examples of R include cyclohexyl, cyclopentyl, cycloheptyl, 4-methylcyclohexyl,
Examples include 4-t-butylcyclohexyl group.

Examples of the tertiary amines used in the present invention include pyridine, picoline, quinoline, triethylamine, tributylamine, N,N-dimethylbenzylamine, and the like.

Examples of α-chloroethylcycloalkyl carbonates produced by the method of the present invention include α-chloroethylcyclohexyl carbonate, α-chloroethylcyclopentyl carbonate, α-chloroethylcyclopeptyl carbonate, α-chloroethyl-4 -methylcyclohexyl carbonate, α-chloroethyl-4-t-butylcyclohexyl carbonate, and the like.

In the present invention, the molar ratio of acetaldehyde to chloroformates is 0.5 to 10.0 times, preferably 2.0 to 4.0 times. As the organic solvent, for example, dichloromethane, chloroform, carbon tetrachloride, acetonitrile, etc., which are inert to the reaction, are used. The amount is not particularly limited and may be an amount necessary for good stirring.

The amount of the tertiary amine used in the reaction is 0.05 to 1.5 times the mole, preferably 0.2 to 0.5 times the mole of the chloroformate. The reaction temperature is carried out below the boiling point of the reaction system, preferably from 0 to 30°C. Although the reaction time is not particularly limited, it is usually completed in 1 to 20 hours.

After distilling off the solvent, cold water was added to the reaction solution, and the oil layer was separated.
By distillation, the desired α-chloroethylcycloalkyl carbonate can be produced.

〔Example〕

The present invention will be explained in detail below using examples.

Example 1 163 g of cyclohexyl chloroformate, 192 g of acetaldehyde (anhydrous), and 37 g of acetonitrile were mixed at 10°C or below, and 32 g of pyridine was mixed in the mixture at 10°C or lower.
was added over 10 hours while stirring and maintaining the temperature at 20-25°C.

After the addition was completed, the mixture was stirred at the same temperature for 1 hour, then the solvent acetonitrile was distilled off under reduced pressure, 30 g of dichloromethane and 100 g of cold water were added, and the oil layer was separated, washed with water, dehydrated with anhydrous nitric acid, and then distilled. 83 g of α-chloroethylcyclohexyl carbonate was obtained.

Boiling point (b, p) 92-95℃/5 mm H
g Gas chromatography purity (hereinafter abbreviated as GC purity) 98.1% Yield ao, o% (based on cyclohexyl chloroformate) Examples 2 and 3 Except for changing the type of chloroformate used in Example 1 , carried out in the same manner as in Example 1. These results are shown in Table 1.

Claims (1)

[Claims] The feature is that a chloroformate represented by the general formula ROCOCl (wherein R represents a cycloalkyl group) and acetaldehyde are reacted in the presence of a tertiary amine in an organic solvent. α represented by the general formula CH_3CHClOCOOR (wherein R has the same meaning as above)
- A method for producing chloroethylcycloalkyl carbonates.