JPH0229057B2 - MMARUKIRUHIDOROKISHIBENZENNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing m-alkylhydroxybenzenes that is rational and economical and particularly advantageous for industrial scale production. As a method for obtaining substantially pure m-alkylhydroxybenzene from alkylbenzene via alkylbenzene sulfonic acid, for example,
-33192, Japanese Patent Publication No. 49-33193, Japanese Patent Application Laid-Open No. 49-110638, etc. Their content consists of the following steps: (A) The alkylbenzene sulfonic acid mixture obtained by sulfonating alkylbenzene with sulfuric acid at low temperature is heated in the presence of sulfuric acid at a temperature in the range of 150 to 210°C, or the alkylbenzene is sulfonated with sulfuric acid to a temperature in the range of 150 to 210°C. (B) By maintaining the alkylbenzenesulfonic acid mixture at a temperature of
Preferably, alkylbenzene sulfonic acids other than the m-form are selectively hydrolyzed by contact with water vapor to produce 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) it is melted in a caustic manner to obtain m-alkylhydroxybenzene. Such known methods have several problems. First of all, in step A of the reaction between alkylbenzene and sulfuric acid, that is, sulfonation and isomerization, the higher the reaction temperature, the more m-isomers there are. As the reaction progresses, 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 hydrolysis of the m-isomer itself and side reactions are likely to occur in parallel or sequentially, resulting in a decrease in the purity and quality of the final product, or A decrease in yield is inevitable. The second problem is the presence of inorganic salts in steps C and D, that is, the alkaline salting of the hydrolyzed product and the caustic melting. Add sodium hydroxide to the reaction product of alkylbenzene and sulfuric acid until it becomes basic, convert the sulfonic acid into an alkaline salt, and at the same time neutralize the excess sulfuric acid. The viscosity becomes so high that stirring becomes impossible, and a large amount of Glauber's salt is mixed into the by-product sodium sulfite obtained during post-treatment, resulting in loss of utility value. In this method, there is a method in which the precipitated sodium sulfate is separated before melting, but the loss of adhesion of sulfonic acid is large and the process is complicated, involving steps such as washing with water, concentration, and refiltration. For this purpose, excess sulfuric acid during the sulfonation reaction is removed by an appropriate method. A commonly used method for separating sulfuric acid is the liming sodation method, in which sulfuric acid is removed as gypsum. However, this method is industrially disadvantageous in terms of process and energy consumption, such as disposal of waste gypsum and concentration of sulfonate aqueous solution. In recent years, a method has been proposed in which alkylbenzenesulfonic acid is extracted with a mixture of a primary to quaternary amine and a water-insoluble organic solvent. (Japanese Patent Application Laid-Open No. 55-154935) Although this method is advantageous when recovering dilute organic acids, it requires a large amount of amine and solvent to produce alkylhydroxybenzene, and is expensive in terms of equipment costs. , cannot be said to be an advantageous method. As a result of repeated detailed research in order to improve the drawbacks of the conventional method, the present inventors discovered that from the beginning of sulfonation, by adding 1 to 15 mol% of Glauber's salt to the sulfuric acid used, the isomerization Also, if the side reactions mentioned above during hydrolysis can be suppressed, and if 5 mol% or more of Glauber's salt is added to the sulfuric acid from the beginning of the sulfonation, the hydrolyzed product can be left standing at a high temperature of 80°C or higher. When we learned that this would separate the sulfonic acid layer and the sulfuric acid layer, and that the excess sulfuric acid could be easily separated and removed, we applied for a patent. (Special application 1984-210285, patent application 1987-
1503) In the course of further research into this advantageous method for producing m-alkylhydroxybenzene, the present inventors found that when the scale of the experiment was increased, especially when produced in an industrial production scale plant, the hydrolysis reaction was not completed. It was confirmed that when a high-purity m-isomer content composition confirmed in the genus was post-treated to become a corresponding hydroxyl composition, the m-isomer purity decreased.
As a result of the study, it was found that the longer the reaction solution was retained at a high temperature after hydrolysis, the more partial hydrolysis of the m-isomer progressed and the alkylbenzene dissolved in the reaction mass was sulfonated by sulfuric acid again to form the p-isomer. I found out that it was for the purpose of Therefore, we investigated ways to prevent the formation of p-isomers, and found that after the hydrolysis reaction, we immediately added water to the reaction mass and rapidly lowered the temperature and sulfuric acid concentration to prevent resulfonation and achieve a high-purity m-isomer composition. succeeded in getting something. In the present invention, a mixture of alkylbenzene and sulfuric acid or a mixture of alkylbenzenesulfonic acid and sulfuric acid is heated at 150 to 210°C in the presence of sodium sulfate (Granite) or acidic sodium sulfate (Granite) in an amount of 1 to 15 mol% based on the mole of sulfuric acid charged. After heating at a temperature within a range to obtain an alkylbenzenesulfonic acid with a high m-form content and selectively hydrolyzing alkylbenzenesulfonic acids other than the m-form, water is immediately poured to bring the temperature of the reactant to below 150°C. The alkylbenzenesulfonic acid that has not undergone hydrolysis after rapid cooling is melted in a caustic manner, or after hydrolysis, the hydrolysis reaction solution is allowed to stand still and separated into layers, and the separated alkylbenzenesulfonic acid layer is separated and dissolved in caustic solution. This is a method for producing m-alkylhydroxybenzene, which is characterized by melting the m-alkylhydroxybenzene. Examples of alkylbenzenes suitable for use in the present invention include toluene, ethylbenzene, isopropylbenzene, xylene, etc., and alkylbenzene sulfonic acids with a high content of m-isomer can be obtained by isomerization or hydrolysis. It is an alkylbenzene that can be produced. The reaction of alkylbenzene and sulfuric acid in the present invention is carried out under conditions well known in this type of technology.
This can be carried out by adding an inorganic salt. For example, when sodium sulfate (Granite) or acidic sodium sulfate (Acidic sodium sulfate) is added to alkylbenzene and the mixture is reacted with sulfuric acid at a temperature of 50 to 150°C, an alkylbenzene sulfonic acid with a high p-isomer content can be obtained. The alkylbenzenesulfonic acid is added in the presence of sulfuric acid, preferably at a molar ratio of sulfonic acid to sulfuric acid of about 2:1, to
When heat treated at a temperature in the range of 210°C, preferably at a temperature of 180 to 210°C, the alkylbenzenesulfonic acid is isomerized, and the p-form and m-form are equimolar or the content of the m-form is increased. . Alternatively, inorganic salts can be added to alkylbenzenes and reacted with excess sulfuric acid at temperatures ranging from 150 to 210°C.
A sulfonic acid mixture containing equimolar amounts of - and m-isomers or a large m-isomer content is produced. The resulting sulfonation or isomerization reaction mixture is then heated to a temperature in the range of 120 to 180°C, preferably 150 to 170°C.
When water is added or steam distilled at a temperature in the range of reused as feedstock for
or used as a starting material. The temperature of the hydrolyzed reaction mass containing alkylbenzenesulfonic acid with high m-isomer purity as the main component obtained in this way is usually 160 to 180°C, but immediately after the reaction, water is added as soon as possible to bring the temperature of the mass to 150°C. Cool to below °C. In order to rapidly lower the temperature of the mass by pouring water, it is effective to use water with a low temperature, and it is desirable to cool the mass with ice, ice water, or from the outside of the reaction vessel. By doing so, the amount of water does not increase more than necessary, and it is also possible to prevent a decrease in productivity. The injection rate should be as short as possible, and the injection should be performed so that the temperature drops to 150°C or less within one hour, preferably within 30 minutes. In this way, the effect of preventing the hydrolysis of the m-isomer and the formation of the p-isomer by rapidly lowering the temperature by pouring water into the mass that has completed hydrolysis is that the sulfuric acid concentration in the mass is moderately reduced by water injection. The reciprocal effects of this are also contributing. Therefore, in the present invention, water injection after hydrolysis rapidly lowers the temperature of the mass and simultaneously lowers the sulfuric acid concentration in the mass. Next, the obtained hydrolysis reaction solution is preferably 80 to 80%
Leave to stand at a temperature in the range of 150°C for about 30 minutes to 1 hour to separate the layers. Separate the separated sulfonic acid layer and sulfuric acid layer. In this case, the difficulty of layer separation and separation efficiency are as follows:
It depends on the amount of inorganic salt added at the beginning of sulfonation, the m-isomer content of the reaction solution after hydrolysis, the temperature, etc. The first objective of the present invention is to stabilize sulfonic acid during the high-temperature reaction between alkylbenzene and sulfuric acid, and for this purpose, sodium sulfate (sodium sulfate)
Alternatively, the amount of acidic sodium sulfate (acidic sodium sulfate) added is 1 to 15 mol% based on the charged sulfuric acid. 1
If the amount is less than mol%, side reactions such as oxidation and decomposition cannot be suppressed. When the amount exceeds 15 mol%, the hydrolysis reaction is also suppressed and the content of p-isomer increases. The amount of Glauber's salt added, which has the effect of suppressing such side reactions, must be further restricted for the static separation of the hydrolyzed solution, which is the second objective of the present invention. In other words, if the sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) is less than 4 mol%, the sulfuric acid layer cannot be separated because the layers do not separate at temperatures above 80°C. If it is lowered to a temperature of 80°C or lower and allowed to stand still, it will separate into layers, but the boundaries will be unclear and there will be industrial disadvantages in terms of cooling time, etc. Therefore, when the amount of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) added is 4 mol% or less, it is advantageous to immediately proceed to caustic melting without separating the sulfuric acid after hydrolysis, and even in this case, conventional methods cannot be used. In comparison, it is still an advantageous method for producing m-alkylbenzenesulfonic acid. When the addition rate of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) is 5 mol % or more, if the hydrolysis reaction solution is allowed to stand still, it will separate into a sulfuric acid layer and a sulfonic acid layer at a temperature of 80 to 170°C. The sulfonic acid dissolved in the separated sulfuric acid layer is less than 1% by weight, and the inorganic salt dissolved in the same layer precipitates at room temperature, so it can be easily separated.
Reused next time. The liquid obtained by separately separating sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) can be used for other purposes as highly concentrated sulfuric acid. In addition, the effects of adding sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) can be obtained not only by adding sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) from the beginning of sulfonation. It may be added after sulfonation and before isomerization, and if the only objective is stability during hydrolysis, the effect will not change even if it is added immediately before hydrolysis. Also, sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate)
The layer separation effect of the sulfonic acid layer and the sulfuric acid layer due to addition exhibits an excellent effect on the liquid after the hydrolysis reaction, but it does not separate into the liquid after the sulfonation or isomerization, and therefore the sulfuric acid is separated. I can't even do that. This suggests that the layer-separating effect caused by the addition of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) is recognized in relation to the isomer composition in the reaction solution. That is,
In a mixture of o- and p-alkylbenzenesulfonic acid or a mixed sulfonic acid with a high ratio of these and sulfuric acid, even if sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) is added, layer separation does not occur, and the m-isomer content When it exceeds a certain ratio, a layer-splitting effect occurs due to the addition of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate). After hydrolysis, the obtained alkylbenzene sulfonic acid, or after hydrolysis, stand at a temperature of 80-150℃,
The alkylbenzene sulfonic acid from which the sulfuric acid has been separated is alkali salified with, for example, sodium hydroxide and caustic melted with sodium hydroxide to give the desired m-alkylhydroxybenzene. obtain. The sulfonic acid layer separated from the hydrolysis reaction solution in the method of the present invention has a free sulfuric acid amount of
Since the amount is reduced to less than half, the amount of alkali used is reduced when used as an alkali salt, which is economically advantageous. In addition, the neutralized sulfonate can be directly melted with caustic material without removing the formed inorganic salt, and even when the sulfonate and the formed inorganic salt are separated, the amount of inorganic salt is small. It does not require concentration and can be separated very easily, which is advantageous compared to other previously known methods. The production method of the present invention significantly suppresses the oxidative decomposition of alkylbenzenesulfonic acids even at high temperatures of 200°C or higher, making it possible to carry out sulfonation, isomerization, and hydrolysis reactions at high temperatures and over long periods of time. The m-isomer obtained advantageously can be maintained stably in both quantity and quality until the decomposition reaction, and the m-isomer content is 98%.
% of hydroxybenzene can now be obtained in good yield and economically. 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 3600 kg of 98% sulfuric acid was charged into a 6000 reaction vessel, 60 kg of anhydrous sodium sulfate (1.16 mol % based on the charged sulfuric acid) was added with stirring, and then 2544 kg of ethylbenzene was added dropwise over a period of 1 hour. Gradually raise the temperature to 200°C over a period of 2 hours while removing distilled water. Heat and stir at the same temperature for 4 hours to isomerize.
Next, the internal temperature was lowered to 170℃, and the mixture was stirred at the same temperature.
Hydrolysis was carried out by continuously blowing steam equivalent to 7,800 g of water over a period of 12 hours. 1260Kg of ethylbenzene was recovered. m- and p in the reaction mass immediately after completion of hydrolysis
-The amount of ethylbenzenesulfonic acid was determined, and the relative ratio m/p was found to be 97.0/30. The sulfuric acid concentration in the water-sulfuric acid system from which ethylbenzenesulfonic acid was removed in the same reaction mass was 63%. After the hydrolysis reaction product has completed the reaction and samples necessary for analysis and small experiments are taken, cooling is immediately started from the outside, and 500 g of water is injected every 30 minutes to lower the temperature and simultaneously reduce the sulfuric acid concentration. At the end of water injection, the temperature had fallen to 130℃. The isomer ratio m/p of sulfonic acid in the obtained reaction mass was 95.9/4.1
It was hot. The sulfuric acid concentration in the trout was 56%. Add 47% caustic soda to the reaction solution to neutralize the pH to 80.
When heated at ℃, the mirabilite is separated, and the mother liquor is dropped into a mixture of 1700 kg of caustic soda and 250 kg of caustic potash, which is heated and melted in a 6000 solution pot at a temperature of 330 ℃. After the dropwise addition, the temperature was raised from 330°C to 340°C, and stirred and maintained at 340°C for 1 hour. The resulting melt reaction is dissolved in 6000 ml of water and neutralized to PH7.2 with 35% hydrochloric acid. The produced phenols are separated into layers, separated, and distilled to achieve a purity of 94.1.
% of crude m-ethylphenol was obtained. by fractional distillation
m-ethylphenol with a purity of 97.9% was obtained. The yield of ethylphenol was 70% based on the consumed ethylbenzene. Comparative Example 1 Immediately after the hydrolysis in Example 1, 1/2
A sample was taken on a 1000 scale, and the temperature was lowered to 130°C over a period of 4 hours using only external cooling without water injection. The isomer ratio of sulfonic acid in the obtained reaction mass was m/p=91.5/8.5. Thereafter, crude m-ethylphenol with a purity of 90.5% was obtained in the same manner as in Example 1. By fractional distillation, m-ethylphenol with a purity of 94.1% was obtained. Examples 2 to 4 The sulfuric acid concentration shown in the table (concentration in the water-sulfuric acid system in the mass) was applied to samples collected on a 1/1000 scale from the reaction mass immediately after the hydrolysis in Example 1 was completed.
Water was added so that the temperature was as shown in the table, and the temperature was adjusted externally and maintained for 4 hours. Among the sulfonic acid compositions in the reaction mass, the values of m- and p-ethylbenzenesulfonic acid were measured, and the relative ratio of m-form and p-form was determined as m/p ratio and shown in the table. Further, the purity of m-ethylphenol obtained by post-treatment according to Example 1 is shown in the table. Comparative Examples 2 to 4 From the reaction mass immediately after the completion of hydrolysis in Example 1,
Each sample was taken on a 1/1000 scale and was maintained at the temperature shown in the table for 4 hours without adding water, while adjusting it from the outside of the reactor. The m/p ratio in the reaction mass was determined according to Examples 2 to 4 and shown in the table. Further, the purity of m-ethylphenol obtained by post-treatment according to Example 1 is shown in the table.

[Table] From the results of Examples 1 to 4 and Comparative Examples 1 to 4,
It can be seen that after hydrolysis is completed, if the temperature is maintained at the same or slightly lower temperature during the hydrolysis reaction, the hydrolysis of the m-isomer progresses further, while the p-isomer increases. It is also shown that side reactions can be suppressed by simply lowering the temperature suddenly without adding water.
(Comparative Example 4). However, as in Comparative Example 1, it took a long time to lower the temperature to 130°C, or it was not effective at all. On the other hand, it is clear that if water is added and quenched after hydrolysis is completed, sufficient effects will be exhibited even at a temperature of 150°C. Example 5 1050 kg of m-ethylphenol was obtained from ethylbenzene in the same manner as in Example 1 except that 153 kg of anhydrous sodium sulfate (3 mol % based on the charged sulfuric acid) was added instead of 60 kg of anhydrous sodium sulfate in Example 1. The purity was 98.2%, and the yield based on the consumed ethylbenzene was 72.2%. Example 6 3,600 kg of 98% sulfuric acid was charged into a 6,000 reaction vessel, and 306 kg of anhydrous sodium sulfate (addition rate: 6 mol %) was added while stirring. Next, 2544 kg of ethylbenzene was added over 60 minutes, and the temperature was gradually increased. It takes 2 hours to heat to 200℃ while removing distilled water. The mixture is heated and stirred at the same temperature for 4 hours for isomerization. The temperature of the reaction mixture was lowered to 170°C, and the mixture was stirred at the same temperature.
Steam equivalent to 6,000 ml of water was blown in at a constant rate over a period of 10 hours to complete the hydrolysis. At the same time as cooling was restarted, 500ml of water was poured over 30 minutes to lower the temperature and simultaneously lower the sulfuric acid concentration. At the end of water injection, the temperature had dropped to 130℃. Analysis of the sulfonic acid composition in the resulting reaction mass revealed that the m/p ratio was 96.6/3.4. 130
When the mixture was allowed to stand at ℃ for 30 minutes, it separated into a sulfonic acid layer and a sulfuric acid layer, and the sulfuric acid layer was separated and removed. The separated sulfonic acid layer was neutralized to pH 7.8 with 50% caustic potassium and
Kg of caustic soda and 250 Kg of caustic potash were dropped into the melt heated and melted at a temperature of 330°C in a 6000 melting pot. After dropping, raise the temperature of the contents to 340℃,
The mixture was stirred and maintained at the same temperature for 60 minutes. Then melt the reactant
Dissolved in 6000 water and neutralized to PH7.2 with 35% hydrochloric acid,
The oil was separated and distilled to obtain 1044 kg of crude m-ethylphenol. Yield of ethylbenzene based on consumption 71
%, the purity of fractional distillation purified m-ethylphenol is 98.0
It was %. Comparative Example 5 When ethylbenzene was treated in accordance with Example 6 without adding anhydrous sodium sulfate, the yield of m-ethylphenol was 48.7% based on the consumed ethylbenzene, and the purity was 83.2%. It was hot. Example 7 1509 kg of toluene was charged into a reaction vessel, and while stirring, 3270 kg of 98% sulfuric acid was added dropwise over 1 hour.
Kg (2 mol % based on the charged sulfuric acid) is added, and the temperature is raised to 190°C over 2 hours. Isomerization is carried out by stirring at 185-190°C for 4 hours. Next, while maintaining the temperature at 160 to 165°C, water vapor equivalent to 3,000 ml of water is continuously dropped at a constant rate over a period of 10 hours. The hydrolyzed p-toluenesulfonic acid returns to toluene and sulfuric acid, and toluene is distilled out of the system by azeotropy with water. The amount of toluene recovered was 741Kg. After hydrolysis, start cooling and add 250 ml of water.
was injected over 30 minutes, and the sulfuric acid concentration was lowered at the same time as the temperature was lowered. At the end of water injection, the temperature had dropped to 120℃. The reaction mass will not separate into layers even if it is left standing, so it will remain as it is.
Neutralize with 47% caustic soda, melt at 350℃ using caustic potash and caustic soda, and process the melted reaction product according to conventional methods to obtain 594 kg of m-cresol with a purity of 98.1%.
I got it. Comparative Example 6 425 kg of m-cresol with a purity of 85% was obtained from toluene using the same procedure as in Example 7 except that anhydrous sodium sulfate was not added. Example 8 1700 kg of 98% sulfuric acid was charged into a 3000 reaction vessel, and while stirring, 144 kg of anhydrous sodium sulfate (addition rate 6%) was added.
Next, 1100 kg of meta-xylene was added dropwise, and the temperature was raised to 180°C over a period of 2.5 hours. Thereafter, the mixture is kept at 175-180°C for 3 hours to perform isomerization. Temperature drops to 150℃, water 700℃
Hydrolysis was carried out by continuously adding water vapor corresponding to 100 ml dropwise at the same temperature over 3 hours. Meta-xylene, which was distilled out along with water vapor through hydrolysis, was separated from water and recovered in an amount of 270 kg. After hydrolysis, cooling was started and 200 g of water was injected over 30 minutes. After injection the temperature dropped to 120°C. When the mixture was allowed to stand at 120°C for 30 minutes, it was separated into a sulfonic acid layer and a sulfuric acid layer. 47 sulfonic acid layer
% caustic soda, followed by alkaline melting and post-treatment according to Example 1 to obtain 707 kg of 3.5-xylenol with a purity of 97%. Example 9 3,600 kg of 98% sulfuric acid was placed in a 6,000 inverted reactor, and while stirring, 102 g of acidic sodium sulfate (addition rate: 2.3 mol%) was added, and 2,544 kg of ethylbenzene was added dropwise over 1 hour. Gradually raise the temperature to 200°C over 2 hours while removing distilled water. The temperature was maintained at 200°C and the mixture was stirred for 4 hours for isomerization. Then 170℃
At the same temperature, while stirring, steam equivalent to 7,800 g of water was injected over a period of 12 hours to carry out hydrolysis. Inject 500ml of water into the resulting reaction mass over 30 minutes to lower the temperature and simultaneously lower the sulfuric acid concentration. At the end of water injection, the temperature had reached 130℃. Add 47% caustic soda to the reaction solution to neutralize it to pH 8, filter the mirabilite when heated at 80°C, and melt the mother liquor with an alkali according to Example 1.
After work-up, crude metaethylphenol was obtained. Next, fractional distillation is performed to extract phenol, cresol, o-
By cutting off the initial distillation of the main component of ethylphenol, 97.9% m-ethylphenol was obtained.

Claims (1)

[Claims] 1. In a mixture of alkylbenzene and sulfuric acid or a mixture of alkylbenzenesulfonic acid and sulfuric acid, in the presence of sodium sulfate or acidic sodium sulfate in an amount of 1 to 15 mol% based on the mol of sulfuric acid charged, 150 to 210
℃ to obtain an alkylbenzenesulfonic acid with a high content of m-isomer, selectively hydrolyzing the alkylbenzenesulfonic acid other than the m-isomer, and immediately add water to bring the temperature of the reaction product to 150℃. A method for producing m-alkylhydroxybenzene, which comprises rapidly cooling and causticly melting the alkylbenzenesulfonic acid layer that has not undergone a hydrolysis reaction. 2. The production method according to claim 1, wherein the alkylbenzenesulfonic acid that has not undergone the hydrolysis reaction is obtained by separating the reaction solution into layers after the selective hydrolysis reaction is completed. 3. The step of allowing the hydrolysis reaction solution to stand still, separating the layers, and separating the separated alkylbenzenesulfonic acid layer.
The manufacturing method according to claim 2, characterized in that the manufacturing method is carried out at a temperature in the range of 80 to 150°C.