JPS58109435A - Preparation of m-alkylhydroxybenzene - Google Patents

Abstract

PURPOSE:To suppress the side reactions such as disulfonation, dealkylation, etc. in the preparation of substantially pure m-alkylhydroxybenzene from alkylbenzene through alkylbenzenesulfonic acid, by carrying out the reaction in the presence of a specific amount of inorganic salt such as Glauber salt. CONSTITUTION:Alkylbenzene or alkylbenzenesulfonic acid mixture is heated at 150-210 deg.C in the presence of sulfuric acid. The above reaction is carried out in the presence of 1-5mol% inorganic salt (preferably Glauber salt) based on charged sulfuric acid to obtain alkylbenzene-sulfonic acid having high m-isomer content. The alkylbenzene sulfonic acids other than m-isomer are selectively hydrolyzed, and the unhydrolyzed alkylbenzenesulfonic acid is subjected to caustic alkali fusion to obtain m-alkylhydroxybenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rational and economical method for producing m-alkylhydroxybenzenes.

Substantially pure m-alkylbenzene 3-7837 from alkylbenzene via alkylbenzene sulfonic acid,
This is known as a technique described in Japanese Patent Publication No. 43-9713, Japanese Patent Application Laid-open No. 49-110638, etc. Their content consists of the following steps:

(A) An alkylbenzene sulfonic acid mixture obtained by sulfonating alkylbenzene with sulfuric acid at low temperature is heated at a temperature in the range of 150 to 210°C in the presence of sulfuric acid, or the alkylbenzene is heated to 150 to 210°C with sulfuric acid.
By keeping the alkylbenzenesulfonic acid compound a having a high content of m at a temperature in the range of m, (B) contacting the 6-flukylbenzenesulfonic acid mixture with water, preferably water vapor, to form an alkylbenzenesulfone other than m. The acid is selectively hydrolyzed into alkylbenzene and sulfuric acid, and the alkylbenzene is azeotroped with water and removed from the system.

(C) The m-alkylbenzenesulfonic acid that has not undergone hydrolysis is converted into an alkali salt, and then (D) the m-alkylhydroxybenzene is dissolved in a caustic solution.

In step A1, ie, sulfonation and isomerization, the higher the reaction temperature, the more m-integrity increases. However, oxidation and decomposition proceed rapidly especially from around 190° C., dealkylation and tarring appear, and the sulfonated product becomes black tar-like and becomes unusable.

Hydrolysis in step B is also carried out at high temperatures and over a long period of time, so side reactions are likely to occur. As a result, a decrease in the purity and quality of the final product or a decrease in yield is unavoidable.

As a result of repeated research to improve the drawbacks of the conventional method, the inventors of the present invention discovered that 150 to 2
It is effective to have a specific amount of Glauber's salt present in order to suppress side reactions such as disulfonation, dealkylation, and sulfonic acid decomposition that occur during isomerization when heated to 10°C and hydrolysis when the sulfuric acid molar ratio increases. They found that this is the case and completed the present invention.

That is, the present invention prepares an alkylbenzene or an alkylbenzene sulfonic acid mixture in the presence of sulfuric acid and an inorganic salt of 1 to 5% of the mol of sulfuric acid charged to obtain an alkylbenzene sulfonic acid with a high body content. This is a method for producing m-alkylhydroxybenzene, which comprises selectively hydrolyzing and then causticly melting the alkylhensene sulfonic acid that has not undergone hydrolysis.

Alkylbenzenes suitable for use in the present invention include:
Examples include toluene, ethylbenzene, isopropylbenzene, xylene, etc., which are alkylbenzenes whose m-isomer can be obtained by isomerization, hydrolysis, or the like.

The reaction of alkylbenzene and sulfuric acid in the present invention can be carried out under the conditions known in the art and as described above. The present invention will be explained in detail below using ethylbenzene as an example. When ethylbenzene was sulfonated and isomerized with MIIJ sulfuric acid according to the method of Example 1 described later, the composition of the reaction product with and without the addition of Glauber's salt was measured, and the percentages are shown in Table 1. Next, each reaction composition was hydrolyzed according to Example 1, and the composition ratios of the resulting compositions are shown in Table 3. Further, each hydrolyzed composition was subjected to caustic melting, neutralization, and distillation according to the method of Example 1, and the compositions and composition ratios of the obtained compositions are shown in Table 2.

Table 1 Composition and ratio (%) at the end of isomerization Table ■Table ■1 a) Yield 1 shows the yield of ethylbenzene relative to the consumption of ethylphenol.

From the composition ratios of the compositions in Tables 1 to ■, it can be seen that without the addition of Glauber's salt, there are many benzenesulfonic acids, toluenesulfonic acids, and unknown components due to unfavorable side reactions, the purity and yield of ethylphenol is low, and the concentration of Glauber's salt increases. It is clear that as the process progresses, these side reactions are suppressed and the purity and yield are also increased. The amount of Glauber's salt to be added is preferably 1 to 5% based on the mole of sulfuric acid charged. If it is less than 1%, the effect is poor, and if it is less than 5%, it is sufficient, and if it is more than 5%, it is unnecessary. Furthermore, the effect of adding mirabilite can be achieved not only by adding mirabilite from the beginning of sulfonation, but also by adding mirabilite after sulfonation and before isomerization. Even if it is added just before decomposition, the effect remains the same. In either case, the obtained m-alkylbenzenesulfonic acid can be purified much more efficiently than the conventional method, and after undergoing an alkaline melting process, it can be purified to a highly pure m-alkylbenzenesulfonic acid.
-Can be made into alkylhydroxybenzenes.

By the production method of the present invention, the oxidative decomposition of alkylbenzenesulfonic acid is significantly suppressed even at high temperatures of 20oC or higher,
As a result, high-temperature and long-term sulfonation, isomerization, and hydrolysis reactions became possible, and when the m-rod exceeded 98%, droxybenzene could be obtained in good yield.

The method of the present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 98% i acid 1200y 21! Pour into a Yotsuro flask, add 20p of anhydrous sodium sulfate with stirring, and then
Add y of ethylbenzene dropwise over a period of 1 hour. Gradually raise the temperature to 200℃ while removing distilled water for 2 hours.
Make it. Heat and stir at the same temperature for 4 hours to isomerize. Next, the internal temperature was lowered to 170℃, and at the same temperature it was heated to 2600℃ with stirring.
Me water was continuously added dropwise over a period of 12 hours to carry out hydrolysis.

420p of ethylbenzene was recovered. 47 to the reaction solution
% caustic soda to neutralize it to pH 8, heat it at 80°C, pour the mother liquor into a mixture of 563y of caustic soda and 83y of caustic potash, which is heated and melted in a 21 melting pot at a temperature of 330°C.

After the dropwise addition, the temperature of the contents was raised from 330°C to 340°C, and stirred and held at 340°C for 60 minutes. The obtained molten reaction product was dissolved in 2000me water, and the pH was adjusted to 7.2 with 35% hydrochloric acid.
to neutralize.

The produced phenols were extracted with ether and distilled to obtain crude m-ethylphenol with a purity of 92.8%. 335 g of m-ethylphenol with a purity of 98% was obtained by fractional distillation. The yield was 68% based on consumed ethylbenzene.

Example 2 600 y of 98% sulfuric acid is charged into a flask No. 11, and 34 y of anhydrous sodium sulfate (addition rate: 4%) is added while stirring. Next, ethylbenzene 424y was added to the mixture for 30 minutes, and the temperature was gradually increased. It took 2 hours and 200 yen while draining the distillate water.
℃. The mixture is heated and stirred at the same temperature for 4 hours for isomerization. Thereafter, post-treatment was carried out in the same manner as in Example-1 to obtain 93.8% crude m-ethylphenol. Fractional distillation yielded 1789 with a purity of 98.2%. Yield of ethylbenzene based on consumption is 7
It was 2%.

Example 3 98% sulfuric acid 1090y 21! Charge the mixture into a flask, and add anhydrous Glauber's Salt 317;' (addition rate: 2%) while stirring.

Next, 503y of toluene was added dropwise, and 19g was added over 2 hours.
Raise the temperature to 5℃. Isomerization is carried out by heating and stirring at 195° C. for 4 hours. Next, after the temperature was lowered to 165°C, 1000+++e of water was continuously added dropwise at a constant rate over a period of 10 hours while maintaining the same temperature. The hydrolyzed p-)luenesulfonic acid returns to toluene and sulfuric acid, and toluene is distilled out of the system by azeotropy with water. Recovered toluene //''1216y
Met.

The toluenesulfonic acid after hydrolysis was neutralized with caustic soda, followed by caustic melting, extraction, and fractional distillation to obtain m-cresol 242y with a purity of 98%.

Example 4 Pour 1700y of 98% sulfuric acid into a 317 lasco, and add 75g of anhydrous sodium sulfate while stirring! (addition rate: 3%) and then meta-xylene 1100? li! It takes 2.5 hours to raise the temperature to 180° C. under fi. Thereafter, the mixture is kept at 175 to 180°C for 3 hours to perform isomerization. The temperature drops to 150℃, water 7
Hydrolysis was carried out by continuously dropping 00me at the same temperature over 3 hours. Meta-xylene distilled out together with water vapor due to hydrolysis was separated from water and recovered for 270y. Xylene sulfonic acid contained in the residual liquid 3100y after hydrolysis was neutralized by a conventional method and caustic melting was performed to obtain 3,5-xylenol 707y. The purity was 97%.

Patent applicant: Taoka Chemical Industry Co., Ltd. -11 completed- 228-

Claims (1)

[Claims] 1. An alkylbenzene or alkylbenzene sulfonic acid mixture is heated in the presence of sulfuric acid and an inorganic salt of 1 to 5% of the mol of sulfuric acid charged at a temperature in the range of 150 to 210°C to produce an alkylbenzene sulfonic acid with a high monomer content. A method for producing m-alkylhydroxybenzene, which comprises selectively hydrolyzing alkylbenzene sulfonic acids other than m-monomers, and then causticly melting alkylbenzene sulfonic acids that have not undergone hydrolysis.