JPH06329571A - Production of ethylene glycol monoalkyl ethers - Google Patents

Abstract

PURPOSE:To obtain an ethylene glycol monoalkyl ether useful as a high-holding solvent in excellent selectivity at a low cost by subjecting ethylene oxide to addition reaction with an alcohol by using a specific amount of an alkali (alkaline earth) metal oxide (hydroxide) as a catalyst while suppressing formation of impurities. CONSTITUTION:Ethylene oxide is subjected to addition reaction with an alcohol by using 0.3-20(wt.) ppm, preferably 0.5-10 ppm based on the raw material of an alkali (alkaline earth) metal oxide (hydroxide) as a catalyst to give the objective compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing ethylene glycol monoalkyl ethers. More specifically, the present invention relates to a method for producing ethylene glycol monoalkyl ethers by addition-reacting enelen oxide with alcohols in the presence of a minimal amount of a basic catalyst.
Since ethylene glycol monoalkyl ethers have very good dissolving power and appropriate volatility, they are useful as high boiling water-soluble solvents.

[0002]

2. Description of the Related Art Ethylene glycol monoalkyl ethers are produced by addition reaction of ethylene oxide with alcohols in the presence or absence of an acid catalyst or a basic catalyst. This reaction is a sequential reaction according to the following reaction formula. Ethylene oxide + alcohol → monoethylene glycol monoalkyl ether ethylene oxide + monoethylene glycol monoalkyl ether → diethylene glycol monoalkyl ether ethylene oxide + diethylene glycol monoalkyl ether → triethylene glycol monoalkyl ether Therefore, depending on the reaction between ethylene oxide and alcohols When producing monoethylene glycol monoalkyl ether, the by-product of diethylene glycol monoalkyl ether or triethylene glycol monoalkyl ether cannot be avoided. However, diethylene glycol monoalkyl ether and triethylene glycol monoalkyl ether have remarkably limited applications as compared with monoethylene glycol monoalkyl ether, so ethylene glycol monoalkyl ether is reacted with ethylene oxide monoalcohol. When producing ethers, it is important to produce monoethylene glycol monoalkyl ether with good selectivity.

On the other hand, in the case of producing ethylene glycol monoalkyl ethers by reacting ethylene oxide with alcohols, various impurities such as aldehydes, other ethers, organic acids and organic acid esters are produced during the reaction. Generate at the same time. If these impurities are mixed in the ethylene glycol monoalkyl ethers of the product, the quality of the product, that is, the acidity, the hue, the odor, the purity and the like are deteriorated, which is not preferable from the viewpoint of the use of the ethylene glycol monoalkyl ethers. Furthermore, since many of these impurities have boiling points close to those of ethylene glycol monoalkyl ethers as products, it is very difficult to remove them by rectification after the reaction. Therefore, when producing ethylene glycol monoalkyl ethers, it is important to suppress the production of the above impurities during the reaction, as well as to produce monoethylene glycol monoalkyl ether with good selectivity.

When ethylene glycol monoalkyl ethers are produced in the presence or absence of an acid catalyst,
It is possible to produce monoethylene glycol monoalkyl ether with high selectivity to the extent that it is satisfied. However, in this case, the above-mentioned impurities such as aldehydes are produced at a relatively high concentration during the reaction, and these impurities are mixed into the ethylene glycol monoalkyl ethers of the product, and the quality of the product, that is, acidity, hue, etc. , Odor, purity, etc. deteriorate.

On the other hand, in the case of a basic catalyst, the above-mentioned impurities such as aldehydes are generated very little, but they are not generated. However, the basic catalyst reacts with the active hydrogen atom of the raw material alcohol to produce water, and further ethylene oxide is added to the water to produce mono (di, tri) ethylene glycol. Moreover, since the boiling points of these impurities are close to the boiling points of the product ethylene glycol monoalkyl ethers, it is difficult to remove them from the product.

In JP-A-52-156807, alkylene oxide and alcohol are mixed in the presence of a catalyst containing an alkali or alkaline earth cation,
Catalytically active anhydrous high-boiling liquid residue prepared by concentrating the liquid residue after catalytically reacting under specific conditions and separating the desired mono- or polyglycol ether from the liquid reaction product effluent. Is disclosed as a catalyst for the next step, and a method for producing mono- and polyglycol ethers is disclosed.

Also, Czechoslovak Patent No. 206,0
No. 05 specification, 60-250 ℃, 0.05-6MP
temperature the composition of C ₁ ~ product of hydroxyethyl of alcohol ₆ using a basic catalyst in a, amount of catalyst, are set forth as being controlled by the recycling ratio of product to reactants, basic A method for controlling the ratio of the obtained mono (di, tri) ethylene glycol monoalkyl ethers by changing the catalyst supply amount within the range of 37 to 1235 ppm with respect to the raw material alcohol is disclosed.

[0008]

However, JP-A-52-156807 and Czechoslovak Patent No. 20.
The invention of No. 6,005 has the main object of the invention to increase the reaction rate of the addition reaction of ethylene oxide to alcohols by adding an alkali catalyst, and the recycled amount of unreacted alcohol, product distribution, There is an unsolved problem in product quality as described below. JP-A-52-1568
About 5 based on the alcohol reactant used in the method of No. 07.
With conventionally known catalyst amounts in the range of 00 to 5000 ppm by weight, a considerable amount of mono (di, tri) is present in the product.
Since ethylene glycol is mixed, it is not always possible to obtain high quality products. Further, when the catalyst concentration is in this range, the selectivity of monoethylene glycol monoalkyl ether is significantly deteriorated. Further, if the supply amount of alcohol is increased to avoid this, the cost for separating unreacted alcohol increases, which is economically disadvantageous.

Further, the method of the Czechoslovak patent is not satisfactory in the production ratio of mono (di, tri) ethylene glycol monoalkyl ethers and the recycled amount of alcohols, and the impurities are not clear.

An object of the present invention is to provide a novel method for producing monoethylene glycol monoalkyl ether with high selectivity while suppressing the production of the above-mentioned undesirable impurities which deteriorate the quality of products.

[0011]

Means for Solving the Problems The present inventors have focused their attention on oxide and hydroxide catalysts of alkali metals and alkaline earth metals, and as a result of earnest research, as a result, they are far more than conventional catalyst concentration ranges. When the above-mentioned catalysts are used alone or in combination in a low concentration range, ethylene glycols are produced only in such a small amount that does not cause a problem, and further, aldehydes, which are peculiar to acid catalysts and non-catalysts, etc. Ethers, organic acids,
It has been found that almost no impurities such as organic acid esters are produced, and in this case, monoethylene glycol monoalkyl ether is produced with good selectivity, and the present invention has been completed.

That is, the present invention provides "1. When ethylene glycol monoalkyl ethers are produced by addition-reacting ethylene oxide with alcohols in the presence of a basic catalyst, 0.3% of the starting material is used as a catalyst. To 20 ppm by weight of an alkali metal and / or alkaline earth metal oxide and / or hydroxide are used. The production method according to claim 1, wherein the oxide and / or the hydroxide of the alkaline earth metal is in the range of 0.5 to 10 ppm by weight based on the raw material. Hereinafter, the method of the present invention will be specifically described.

(Alkali Metal or Alkaline Earth Metal Oxide or Hydroxide Catalyst) Examples of the alkali metal or alkaline earth metal oxide or hydroxide used in the present invention include lithium hydroxide and sodium hydroxide. , Rubidium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, potassium oxide, barium oxide and the like. These may be used alone or in combination of two or more. The amount of the catalyst used is 0.3 to 20, preferably 0.5 to 1 with respect to the total weight of the raw materials including ethylene oxide and alcohols.
0, more preferably 1 to 5 ppm by weight.

(Ethylene Oxide) The ethylene oxide used in the present invention does not have to be particularly highly pure, and ordinary commercial grade ethylene oxide is sufficient.

(Alcohols) Examples of alcohols used in the present invention include alcohols having 1 to 8 carbon atoms, such as methanol, ethanol, propanol and butanol.

(Ethylene glycol monoalkyl ethers) The ethylene glycol monoalkyl ethers in the present invention refer to compounds formed by adding 1, 2 or 3 molecules of ethylene oxide to 1 molecule of the above alcohols, and the following general formula It is represented by. _{R- (OC 2 H 4) 1} , 2 OR 3 -OH ( wherein R represents an alkyl group having 1 to 8 carbon atoms.) Specifically, mono (di, tri) ethylene glycol monomethyl ether, mono Examples thereof include (di, tri) ethylene glycol monoethyl ether and mono (di, tri) ethylene glycol monobutyl ether.

(Reaction) The hydroxyethylation reaction of alcohols in the present invention proceeds as a uniform liquid phase reaction in a tank type batch reactor or a tubular flow type reactor. There is no particular limitation on the quantitative relationship between ethylene oxide and alcohols to be fed to the reactor. However, in view of the selectivity of monoethylene glycol monoalkyl ether and the cost of separating alcohols, the molar ratio of ethylene oxide and alcohols is 0.1: 1 to 0.5: 1, preferably 0.2: 1. A feed rate in the range of 0.4: 1 is used. The reaction temperature is 100 to 250 ° C., preferably 150.
Is in the range of up to 250 ° C. The reaction pressure is usually 10
The reaction time is usually 5 in the range of 60 kg · w / cm ^2.
~ 20 hours range.

[0018]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 150 g of ethylene oxide and 6 of butanol were placed in an autoclave made of stainless steel and having an internal capacity of 1500 ml and equipped with a magnetic stirrer.
70 g and 0.0012 g of sodium hydroxide (1.5 ppm relative to the total weight of the reaction raw materials) were charged, and 20 kg of nitrogen was charged.
After pressurizing to / cm ² -G, the autoclave was heated and reacted at 170 ° C. for 2 hours, 200 ° C. for 3 hours, and 240 ° C. for 3 hours for a total of 8 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities.
The analysis results are shown in Table 1.

Example 2 150 g of ethylene oxide and 6 parts of butanol were placed in an autoclave made of stainless steel with an electromagnetic rotary stirrer having an internal capacity of 1500 ml.
70 g and 0.0012 g of potassium oxide (1.5 ppm based on the total weight of the reaction raw materials) were charged, and 20 kg / c of nitrogen was charged.
After pressurizing the m ² -G, and the autoclave heated 17
The reaction was carried out at 0 ° C. for 2 hours, 200 ° C. for 3 hours, and 240 ° C. for 3 hours, for a total of 8 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1.

Example 3 150 g of ethylene oxide and 6 parts of butanol were placed in an autoclave made of stainless steel and having an internal capacity of 1500 ml and equipped with a magnetic rotary stirrer.
70 g and 0.0012 g of strontium hydroxide (1.5 ppm based on the total weight of the reaction raw materials) were charged, and nitrogen was added to 20
After pressurizing to Kg / cm ² -G, the autoclave was heated and reacted at 170 ° C. for 2 hours, 200 ° C. for 3 hours, and 240 ° C. for 3 hours for a total of 8 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1.

Example 4 150 g of ethylene oxide and 6 parts of butanol were placed in an autoclave made of stainless steel and having an internal capacity of 1500 ml and equipped with a magnetic rotary stirrer.
70 g, 0.0082 g of barium oxide (10 ppm relative to the total weight of the reaction raw materials) were charged, and nitrogen was used at 20 kg / cm.
After pressurizing to ^2- G, heat the autoclave to 170
The reaction was conducted at 8 ° C. for 2 hours, 200 ° C. for 3 hours, and 240 ° C. for 3 hours, for a total of 8 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1.

COMPARATIVE EXAMPLE 1 An autoclave with an internal capacity of 1500 ml made of stainless steel and equipped with an electromagnetic rotary stirrer was added with 15 parts of ethylene oxide without adding a catalyst.
Charge 0 g and butanol 670 g, and nitrogen to 20 kg
/ Cm ² -G, then heat the autoclave to 17
The reaction was carried out at 0 ° C. for 2 hours, 200 ° C. for 3 hours, and 240 ° C. for 6 hours, for a total of 11 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1 below.

Comparative Example 2 150 g of ethylene oxide, 670 g of butanol and 0.082 g of sodium hydroxide (100 ppm based on the total weight of the reaction raw materials) were charged into an autoclave made of stainless steel with an electromagnetic rotary stirrer having an internal capacity of 1500 ml, and 20 kg of nitrogen was charged.
/ Cm ² -G, then heat the autoclave to 15
The reaction was carried out at 0 ° C for 4 hours. The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1.

Comparative Example 3 150 g of ethylene oxide, 670 g of butanol and 0.082 g of barium oxide (100 ppm based on the total weight of the reaction raw materials) were charged into an autoclave made of stainless steel and equipped with an electromagnetic rotary stirrer having an internal capacity of 1500 ml, and nitrogen was supplied at 20 kg / c.
After the m ² -G, and the autoclave heated 170 ° C.
For 2 hours and at 200 ° C. for 3 hours for a total of 5 hours.
The reaction product solution was analyzed by gas chromatography to determine the composition and the concentration of impurities. The analysis results are shown in Table 1.

[0026]

[Table 1]

[0027]

EFFECTS OF THE INVENTION According to the present invention, in the reaction, an alkali metal and / or alkaline earth metal oxide and hydroxide catalyst is used in an extremely low concentration range which has hitherto been unknown. The remarkable effect of producing monoethylene glycol monoalkyl ether with high selectivity can be achieved while suppressing the production of undesired impurities that deteriorate the quality of the product.

Claims (2)

[Claims] 1. When an ethylene glycol monoalkyl ether is produced by addition reaction of ethylene oxide with an alcohol in the presence of a basic catalyst, the amount of the catalyst is 0.3 to 20 ppm by weight based on the raw material. A method for producing ethylene glycol monoalkyl ethers, which comprises using an oxide and / or hydroxide of an alkali metal and / or an alkaline earth metal. 2. The alkali metal and / or alkaline earth metal oxide and / or hydroxide used as a catalyst is in the range of 0.5 to 10 ppm by weight based on the raw material.
The manufacturing method described.