JPS59163331A - Production of xylylene glycol - Google Patents

Abstract

PURPOSE:To prepare the titled compound useful as a raw material or a modifying agent of polyurethane resin, etc., in high yield, in one step, suppressing the production of tarry material, by reacting xylylenediamine with a nitrous acid salt in the presence of a specific amount of water and a specific amount of a mineral acid. CONSTITUTION:High-purity xylylene glycol can be produced easily, by (1) mixinig 1mol of xylylenediamine, e.g. m- or p-xylylenediamine and a nitrous acid salt with 2.04-2.50 g-equivalent of hydrochloric acid or sulfuric acid at 0-100 deg.C under agitation, (2) adding >=8pts.wt. of water, based on 1pt.wt. of the xylylenediamine, to the system, (3) reacting the components at >=70 deg.C for 20min -5hr under normal pressure, (4) neutralizing the reaction mixture with an alkali after the completion of the reaction, and (5) separating the xylylene glycol from the product by conventional method. The molar ratio of the nitrous acid group/ xylylenediamine is preferably 2.0-2.5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing xylylene glycol by reacting xylylene diamine and nitrite.

Xylylene glycol has different characteristics from aliphatic glycols as a raw material for polyurethane, polyester resins, etc. and as a modifier, and its importance is recognized.

Conventionally, the following method is known as a method for producing xylylene glycol.

(1) A method of producing xylylene glycol by using xylylene dichloride as a raw material and directly hydrolyzing it in the presence of an alkali compound, or by once converting xylylene dichloride into diacetoxymethylbenzene and then hydrolyzing it. .

The method (1) itself requires a pressurizing device and requires a long time for the reaction. In addition to problems such as a long and complicated process, there are the following essential drawbacks. That is, xylylene dichloride, which is a raw material in method 11, is usually produced by chlorinating xylene, but in this case, it is not possible to selectively monochlorinate each of the two methyl groups attached to the aromatic nucleus. In the reaction, polychlorination of methyl groups and nuclear chlorination occur simultaneously, producing unnecessary chlorinated products as by-products, which not only lowers the yield of the target product but also makes it difficult to separate and purify it from the mixture.

Method (2), for example, is found in Japanese Patent Publication No. 47-22814, but it requires a high-pressure device and the conversion rate is kept low to suppress side reactions. The xylylene glycol is obtained as a mixture with the compound, and it is necessary to separate the xylylene glycol from the mixture and to circulate the separated raw materials and intermediates to the reaction system.

Furthermore, this separation operation is not easy and the yield per pass is low, so it cannot be said to be an industrially advantageous method.

In order to overcome the drawbacks of such conventional methods and establish an industrially advantageous method for producing xylylene glycol, the present inventors reacted xylylene diamine and nitrite in the presence of a mineral acid to produce xylylene glycol. We examined the method for producing lene glycol.

When a primary amine and nitrite are reacted in an acidic aqueous solution,
It is well known that reazonium compounds are produced.
This reaction is generally called diazotization reaction. It is also known that diazonium compounds produced by the diazotization reaction of aliphatic primary amines are unstable and decompose in water to produce alcohols and olefins.

The method for producing alcohol derivatives by subjecting benzylamine or its derivatives to a diazotization reaction and decomposing the diazonium compound involves adding a special substituent such as synthesizing p-diethylaminomethylbenzyl alcohol from p-diethylaminomethylbenzylamine. However, there are only a few reported examples of producing ginlylene glycol from xylylene diamino.

“When producing alcohol derivatives by diazotizing benzylamine derivatives, especially xylylene diamine, and decomposing the resulting diazonium compound, tar-like substances are extremely likely to be produced, and for this reason, the desired alcohol derivatives can be produced in extremely low yields. For example, 2.5 to 6.0 mol per -NH2 group (5.0 to 6.0 mol per mol of xylylene diamine), which is usually used in the diazotization reaction of aromatic primary amines. When xylylene diamine is diazotized by adding 1 mol of hydrochloric acid, most of the product is a tar-like substance, and the yield of quinrylene glycol is only 110-2096.

As described above, when benzylamine derivatives are diazotized and diazonium salts are decomposed, tar-like substances are extremely likely to be produced, and this makes it difficult to produce benzyl alcohol derivatives by diazotizing benzylamine type compounds. It is thought that a major cause of this is uncontrolled force.

The present inventor reacted xylylenediamine and nitrite in the presence of mineral acid, decomposed the resulting diazonium compound, and
As a result of intensive research on the reaction to produce xylylene glycol, we found that the production of tar-like substances is greatly affected by the amount of acid used in the reaction and the amount of water present in the system. The present inventors have also discovered that quinrylene glycol can be produced in a surprisingly high yield by suppressing the formation of tar-like substances by carrying out the reaction under a specific amount of acid, and have thus arrived at the present invention.

That is, the present invention combines xylylene diamine and nitrite with JJX
This is a method for producing xylylene glycol by adding hydrochloric acid or sulfuric acid equivalent to 14 to 2.50 g of the material and 8 parts by weight or more of water per 1 part by weight of xylylene diamine to cause a reaction.

In the present invention, xylylene diamine means 1n-xylylene diamine, p-xylylene diamino and mixtures thereof, and xylylene glycol means the corresponding m-xylylene glycol, p-xylylene glycol and these ' means a mixture of glycols. Furthermore, nitrites are inorganic salts of nitrous acid such as sodium nitrite, potassium nitrite, and barium nitrite.

In carrying out the present invention, the reaction is carried out by adding a predetermined amount of xylylenediamine, water, and mineral acid to a reactor, and gradually adding an aqueous solution of nitrite to this stirred mixture at a temperature of 0 to 100°C. It will be done.

The mineral acid to be added is hydrochloric acid or sulfuric acid in an amount of 2.04 to 2.50 g equivalent per 1 mole of xylylene diamine used as a raw material, and at the same time 1 mole of xylylene diamine used as a raw material.
At least 8 parts by weight, preferably from 10 to 20 parts by weight, of water are added per part by weight. If the amount of mineral acid is 2.50 equivalents or more, or if the amount of water is 8 parts by weight or less, more tar-like substances will be produced and the yield of xylylene glycol will decrease. Although there is no problem in the reaction even if the amount of water is too large, adding too much water is disadvantageous because it deteriorates the volumetric efficiency.

For diazotization reactions and decomposition reactions of diazonium compounds;
is carried out at 0 to 100°C, preferably 40 to 100°C, more preferably 70 to 100°C. Reaction temperature 40°C
As mentioned above, when the reaction temperature is 70°C or higher, in particular, the diazotization reaction while adding nitrite occurs, and when the reaction temperature is 70°C or lower, especially 40'C or lower, the decomposition of the diazonium compound is slow, and therefore the diazotization reaction After the completion of the reaction, it is necessary to raise the temperature again to completely decompose the diazonium compound into xylylene glycol.

The amount of nitrite used in the reaction is not particularly limited, but in order to carry out the reaction efficiently, it is desirable to use a slight excess of nitrite groups relative to the amino groups of xylylenediamine; /xylylenediamine is preferably used in a molar ratio of 2.0 to 2.5.

As described above, the reaction is carried out by gradually adding an aqueous solution of nitrite to an aqueous solution of xylylene diamine and mineral acid under stirring at a predetermined temperature. The addition of nitrite to the reaction system was
It is carried out for a period of minutes to 5 hours, preferably 30 minutes to 6 hours.

The reaction is exothermic and involves the generation of nitrogen gas, so
Heat removal and nitrogen gas discharge are performed appropriately according to the capacity of the reactor 1. Addition of nitrite can be carried out at such a rate that the

When a predetermined amount of nitrite has been added, stirring is continued for a while at a temperature of 70 to 100°C, and the reaction is terminated when gas generation becomes less or almost no longer observed.

Since the mixture after completion of the reaction is acidic, it is neutralized by adding an alkali, and then treated by a conventional method to separate and recover xylylene glycol.

According to the present invention, high-purity xylylene glycol can be easily produced in good yield from xylylene diamine by reaction under normal pressure.

Example-1 594 g of water was placed in a fourth flask equipped with a stirrer, a thermometer, a dropping funnel, and a condenser that also served as a gas outlet.
- Take 54.5 g (0.40 mol) of xylylenediamine and 962 g (0.92 mol) of 6696 hydrochloric acid,
After stirring and mixing, the contents are heated to raise the temperature of the contents to 95°C.

Next, from the dripping port 1, 98.5% pure sodium nitrite
An aqueous solution of 61.7 g (0.88 mol) dissolved in 87 g of water is added dropwise over 2 hours at such a rate that the entire amount is added.

When a sodium nitrite aqueous solution is added dropwise, a reaction occurs, producing heat and nitrogen gas. Adjust the heating to bring the internal temperature to 95°
The aqueous solution of sodium nitrite was continuously added dropwise while stirring, and the entire amount was added in about 2 hours. After dropping the entire amount of sodium nitrite, continue stirring at 95°C for another 60 minutes.
The reaction has ended.

The amount of reaction liquid was 866 g, and the xylylene glycol concentration in the reaction liquid was 498 wt% by GC analysis. This corresponds to a m-xylylene glycol yield of 78.0% based on the charged m-xylylene diamine.

Next, a small amount of caustic soda aqueous solution was added to this reaction solution to neutralize the acid, and water in the reaction solution was partially distilled off and concentrated using a rotary evaporator to obtain 295 g of a concentrated solution.

, r was extracted six times by adding 600 g of methyl isobutyl ketoso per extraction.

The six extracts were combined and methyl isobutyl ketone was distilled off to obtain 53.1 g of a residual liquid. Add this solution to 5 son H
Distillation under vacuum of 40.5 g of distillate was obtained. The yield of distillate as m-xylylene glycol based on n]-xylylene diamine was 73.6%.
According to GC analysis, the purity was 99.496.

Example-2 485 g of water was added to the same reactor as in Example-1.

p-xylylenediamine 54.5g (0.40 mol)
and 97.3 g (0°96 mol) of 66% hydrochloric acid, stirred and mixed, and then heated to bring the temperature of the contents to 80°C.

Next, an aqueous solution prepared by dissolving 7 g (0.88 mol) of sodium nitrite 6+ with a purity of 1398.596 in 90 g of water was added dropwise over 2 hours through a dropping funnel, while a reaction was carried out at 80° C. with stirring. After dropping the entire amount of sodium nitrite, the reaction was terminated by stirring at 80°C for another 50 minutes.
)is.

Next, a small amount of alkali was added to neutralize the reaction solution.

The amount of reaction solution was 759 g, and the xylylene glycol concentration in the reaction solution as determined by GCC analysis was 5.96 wt%. This corresponds to a p-xylylene glycol yield of 8+,0964 based on the charged p-xylylene diamine. When the liquid was concentrated using a rotary evaporator, precipitation of crystals was observed in the middle.

It was concentrated to 290 g, and after cooling, the crystals were separated. P
Extraction was performed six times by adding 500 g of methyl isobutyl ketone to the solution each time.

The extracts were combined, and the crystals previously separated from P were added thereto, dissolved by heating, and after oil removal, distillation was carried out under a vacuum of 51IIIHg. 421g of fraction corresponding to p-xylylene glycol
was gotten. This corresponded to a p-xylylene glycol yield of 76.+96 based on the charged p-xylylene diamine, and the purity as determined by GC analysis was 99.69V).

Example-3 In the same reactor as Example-1, 658 g of water, 47.7 g (0,350 mol) of m-xylylenediamine, and 6
Take 88.6 g (0°87 mol) of 696 hydrochloric acid and mix.

This mixture and sodium nitrite of 98,596 purity 56-
Example-1 using an aqueous solution in which 4g was dissolved in 79g of water.
In the same manner as above, the reaction was carried out by dropping a sodium nitrite aqueous solution over 4.5 hours at a reaction temperature of 55°C. After dropping the entire amount of sodium nitrite, the reaction mixture was further stirred at 55° C. for 30 minutes, and then the reaction was completed.

The amount of reaction liquid was 904 g, and the m-xylylene glycol concentration in the reaction liquid was 6.7 wt % as determined by GC analysis. This corresponds to a m-xylylene glycol yield of 69% based on the charged m-xylylene diamine.

Example-4 650 g of water was added to the same reactor as in Example-1.

96% sulfuric acid 49.0 g (0.48 mol) and p-
Take 54.5 g (0°40 mol) of xylylene diamine and mix.

This mixture and sodium nitrite with a purity of 98.596 61
．． A reaction was carried out in the same manner as in Example 1 using an aqueous solution in which 7 g (0.88 mol) was dissolved in 87 g of water.

The reaction temperature was 80°C, and the sodium nitrite aqueous solution was added dropwise to
The reaction was completed by continuing stirring for another 60 minutes.

The amount of the reaction solution was 876 g, and the concentration of p-xylylene glycol in the reaction solution as determined by GC analysis was 5.2% by weight. This corresponds to a p-xylylene glycol yield of 82.496 based on the charged p-xylylene diamine.

Comparative Example-1 Using the same reactor as used in Example-1, % I
The charging ratio was exactly the same as in Example-1, except that 54-5 g of n-xylylene diamine was used and the reaction temperature was 20°C.
The reactions were carried out under the same reaction operating conditions.

The gas emitted by the reaction was observed to turn brown when it came into contact with air.

The amount of reaction liquid after the reaction was completed was 862 g, and the m-xylylene glycol concentration in the reaction liquid was 0.97 g by GC analysis.
It was wt%. This corresponds to 1596 m-xylylene glycol yield based on the charged m-xylylene diamine.

Comparative Example-2 Using the same reactor as used in Example-1, water was
186g1m-xylylenediamine 54.5g (0,4
0 mol) and 95-2 g of 3696 hydrochloric acid are taken and mixed. That is, the reaction was carried out at exactly the same charging ratio and under the same conditions as in Example 1, except that the amount of water was reduced to 4.5 parts based on the xylylene diamine starting material.

The amount of reaction liquid after the reaction was completed was 454 g, and the concentration of m-xylylene glycol in the reaction liquid was determined by GC analysis to be s, iow.
It was t%. This corresponds to a m-quinrylene glycol yield of 25.5% based on the charged m-xylylene diamine.

A tar-like substance was observed in the reaction solution.

patent applicant Mitsubishi Gas Chemical Co., Ltd. Representative Kazuyoshi Nagano

Claims (1)

[Claims] Xylylene diamine and nitrite are reacted by adding 2.04 to 2.50 g equivalent of hydrochloric acid or sulfuric acid per mole of raw material xylylene diamine, and 8 parts by weight or more of water per 1 part by weight of xylylene diamine. Characteristic production method of xylylene glycol