JPS5867638A - Preparation of 2-(2'-chloroethoxy)ethanol - Google Patents

Abstract

PURPOSE:To prepare the titled compound useful as an intermediate of pharmaceuticals, etc., economically, in high yield, by reacting diethylene glycol with easily and industrially available hydrogen chloride, thereby converting one of the OH groups of diethylene glycol to Cl. CONSTITUTION:2-(2'-Chloroethoxy)ethanol is prepared easily by reacting diethylene glycol with hydrogen chloride at 50-150 deg.C, preferably keeping the amount of water in the reaction system to <=35wt% of the diethylene glycol. The amount of water existing in the reaction system plays an important role in the reaction, and it is controlled by controlling the water content in the raw material or by distilling out the water under reduced or atmospheric pressure during the reaction. USE:Raw material of polyoxyethylene ether having uniform polymerization degree distribution, raw material of diglycolamine which is a solvent for scrubbing acidic gas, or an intermediate of pesticides, dyes, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved process for producing 2-(2'-chloroethoxy)ethanol.

2-(2'-Chloroethoxy)ethanol is useful as a raw material for polyoxyethylene ether with a constant market distribution, and is also useful as a raw material for di(licol amines), which have recently been attracting attention as a cleaning solvent for acidic gases. , and is also useful as an intermediate for other medicines, agricultural chemicals, dyes, etc.
A method for producing 2-(2'-10 loethoxy)ethanol,
Alternatively, (2) a method of reacting diethylene glycol with thionyl chloride is known. Regarding method (1), for example, Industrial Chemistry Magazine, Vol. 64, No. 7 (1961
2003), on page 1192, for ethylene oxide, 3,
2-(2'-chloroethoxy)ethanol was obtained with a yield of 5@O~36.2 mo1%. However, in this method, the selectivity for 2-(2'-chloroethoxy)ethanol is low and many by-products with a high degree of polymerization are produced. Furthermore, the yield is low and the recycling of unreacted ethylene chlorohydrin requires a large amount of energy.

For method (2), for example, J, Qrg,
Qhem.

40, 1207 (1975), using pyridine as the solvent, 2-
(2'-chloroethoxy)ethanol is obtained. This method produces many by-products such as both hydroxyl groups on both sides of diethylene glycol being replaced with chlorine atoms, and also has industrial limitations such as the use of expensive thiochloride and the need to distill off the solvent pyridine. It has some disadvantages.

The inventors of the present invention have conducted intensive studies on an industrially advantageous method for producing 2-(2'-chloroethoxy)ethanol, and have surprisingly found that hydrogen chloride, which is industrially easy to use, is used.
2-(2'-chloroethoxy) easily and in high yield
We have discovered that ethanol can be obtained, and have arrived at the present invention.

That is, the present invention is a method for producing 2-(2'-chloroethoxy)ethanol, which is characterized by reacting diethylene glycol with hydrogen chloride and converting one hydroxyl group of diethylene glycol to a chlorine atom.

Conventionally, several methods have been known in which alkylene glycols such as ethylene glycol and propylene glycol are reacted with hydrogen chloride in the presence or absence of a catalyst such as zinc chloride to convert hydroxyl groups into chlorine atoms. Unlike these alkylene glycols, there is no example of application to diethylene glycol having an ether bond in the molecule.

Diethylene glycol, which is the raw material of the present invention, may be synthesized by any method, and the higher the purity, the better, but diethylene glycol obtained from the reaction of water with ethylene oxide containing a small amount of ethylene glycol, triethylene glycol, etc. It is advantageous.

As the hydrogen chloride, any of concentrated hydrochloric acid, synthetic hydrogen chloride gas, and by-product hydrogen chloride from various manufacturing processes can be used.
Note that the reaction of the present invention is greatly influenced by the amount of water present in the reaction system.

In other words, when using hydrogen chloride containing 35% by weight or less of water, the reaction proceeds much faster than when using concentrated hydrochloric acid, and the yield and selectivity of 2-(2'-chloroethoxy)ethanol are lower. Both give excellent results.

Adjustment of moisture in the reaction system involves controlling moisture in raw materials as well as
The reaction can be carried out as appropriate by a method such as reacting while distilling off water under reduced pressure or normal pressure.

Although a smaller amount of water in the reaction system gives relatively better results, it may be determined in consideration of other reaction conditions, equipment problems, operating conditions, etc.

The reaction temperature is preferably in the range of 50°C to 150°C. That is, at a reaction temperature of 50° C. or lower, the reaction progresses slowly and the reaction time is too long. If the temperature exceeds 15oC, the reaction rate will increase and the reaction time will be shortened, but side reactions will increase and as a result, the inside of the car will not be measurable.

There are no particular limitations on the reaction method. In other words, there is a batch method in which diethylene glycol and concentrated hydrochloric acid are charged in advance in a reaction vessel and the temperature is raised; a semi-continuous method in which diethylene glycol is previously charged in a reaction vessel and concentrated hydrochloric acid or hydrogen chloride gas is continuously or intermittently supplied; A continuous method may be used in which the mixture is mixed with hydrochloric acid or hydrogen chloride gas and supplied to the reactor.

According to the method of the present invention, in which diethylene glycol and hydrogen chloride are reacted in the absence of a catalyst under appropriate reaction conditions, there are extremely few side reactions due to the presence of ether bonds, and only one of the two hydroxyl groups of diethylene glycol is reacted. can be efficiently replaced with chlorine atoms.

In addition to solving the problem of the production of by-products with a high degree of polymerization due to the addition of ethylene oxide, which was a drawback of the conventional method of synthesizing 2-(2'-chloroethoxy)ethanol using ethylene chlorohydrin and ethylene oxide, It facilitates product separation and recycling of raw materials.
In addition, it is economically advantageous to use inexpensive hydrogen chloride, which is easily available industrially, as a raw material, without using expensive chlorinating reagents such as thionyl chloride, which were conventionally used for chlorinating diethylene glycol. It was possible to increase the selectivity of 2-(2'-10 loethoxy)ethanol.

Hereinafter, the features of the present invention will be illustrated in Examples, where "chi" in these examples means "morti" unless otherwise specified. Further, the composition analysis was performed by gas chromatographic analysis using an internal standard method.

Example 1 In a 500° glass flask equipped with a thermometer, a stirrer, and a reflux tube, 106F diethyl Vf + Mecol,
104f of 35% by weight hydrochloric acid was added, the temperature was raised to 100°C, and the mixture was reacted at 100°C for 5 hours.

After cooling, the reaction product was taken out and analyzed, resulting in a diethylene glycol conversion rate of 19.4% and a 2-(2'-chloroethoxy)ethanol selectivity of 51.6%.

Example 2 The reaction and analysis were conducted in the same manner as in Example 1 except that the reaction was carried out at 100° C. for 10 hours. Diethylene glycol conversion rate is 27.8 excellent, 2-(2'-chloroethoxy) ethanol selectivity is 50.44, and by-products include ethylene chlorohydrin, ethylene glycol, dioxane,
1-chloro-2(2'-chloroethoxy)ethane was detected.

Example 3 A 1ρ glass flask having a thermometer, a stirrer, a gas inlet, and a gas outlet via a reflux tube was charged with 106f diethylene glycol and set in an oil bath.

Diethylene glycol was heated to 100° C. while supplying nitrogen gas from the gas inlet.

9. Switch from nitrogen gas to hydrogen chloride gas while keeping the liquid temperature at 100°C. Hydrogen chloride gas was supplied at a rate of Ig/llr for 5 hours. The supply of hydrogen chloride gas was stopped, and after cooling, the reaction product was taken out and analyzed, resulting in a diethylene glycol conversion rate of 45.1% and a 2-(2'-10 loethoxy) ethanol selectivity of 52.2%. Ta.

Examples 4 to 9 Reactions were carried out in the same manner as in Example 1 except that the reaction temperature and reaction time were changed, and the results shown in Table 1 were obtained.

Table 1 Example 10 The reaction was carried out in the same manner as in Example 3, except that 36F of water was added to 106F of diethylene glycol in order to examine the effect of water, and analysis revealed that the conversion rate of diethylene glycol was 3.
1.2%, 2-(2'-chloroethoxy)ethanol selectivity 51.7m+7) results were obtained.

Claims (1)

[Claims] (1) A method for producing 2-(2'-chloroethoxy)ethanol, which comprises reacting diethylene glycol with hydrogen chloride and converting one hydroxyl group of diethylene glycol to a chlorine atom. 2. The method according to claim 1, wherein the reaction between diethylene glycol and hydrogen chloride is carried out while maintaining water in the reaction system at 35% by weight or less based on diethylene glycol.