JPH0229056B2 - MMARUKIRUHIDOROKISHIBENZENNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rational and economical method for producing m-alkylhydroxybenzenes. 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) An alkylbenzene sulfonic acid mixture obtained by sulfonating an 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 an alkylbenzene is sulfonated with sulfuric acid to a temperature in the range of 150 to 210°C. (B) adding water to the alkylbenzenesulfonic acid mixture,
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 the m-isomer becomes. As decomposition progresses, dealkylation and tar formation appear, and the sulfonated product becomes a black tar, making it unusable. Hydrolysis in step B also takes a long time at high temperatures, so hydrolysis of the m-isomer itself is difficult. and side reactions are likely to occur in parallel or sequentially, which inevitably leads to a decrease in the purity and quality of the final product or a decrease in yield. 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 it cannot be stirred, and a large amount of Glauber's salt is mixed into the by-product sodium sulfite obtained during post-processing, thereby losing its 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 5 mol% of Glauber's salt to the sulfuric acid used, the isomerization process was improved. After discovering that the side reactions mentioned above during hydrolysis could be suppressed, he applied for a patent. Subsequently, as the inventors continued to conduct related research, they added sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) from 5 mol% to 15 mol% of sulfuric acid from the beginning of sulfonation of alkylbenzene. As for the things you kept, 1~
It should have the same side reaction suppressing effect as the case of 5 mol%, and the 5 mol% addition should be heated to 80℃ after hydrolysis.
It was discovered that when the product was allowed to stand still at the above-mentioned high temperature, it would separate into a sulfonic acid layer and a sulfuric acid layer, and the excess sulfuric acid could be easily separated and removed, and after studying the surrounding circumstances, the present invention was completed. 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 5 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, the hydrolysis reaction solution is allowed to stand, separated into layers, and separated. This is a method for producing m-alkylhydroxybenzene, which is characterized by separating the layered alkylbenzenesulfonic acid layer and causticly melting it. 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 sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate). That is, 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 heated in the presence of sulfuric acid, preferably at a molar ratio of sulfonic acid to sulfuric acid of about 2:1, at a temperature in the range of 150-210°C, preferably 180-210°C.
When heat treated at a temperature of 210°C, the alkylbenzenesulfonic acid is isomerized, resulting in p- and m-
The m-isomer content is about equimolar or the m-isomer content increases. Alternatively, sodium sulfate or acidic sodium sulfate (acidic sodium sulfate) is added to alkylbenzene, and the mixture is reacted with an excess amount of sulfuric acid at a temperature in the range of 150 to 210°C, so that the p- and m-isomers are equimolar or A sulfonic acid mixture with a high 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. Next, the obtained hydrolysis reaction solution is preferably 80 to 80%
Leave to stand at a temperature in the range of 170°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 ease of separating the layers and the separation efficiency are:
Addition amount of sodium sulfate (mirabilite) or acidic thorium (acidic mirabilite) present at the beginning of sulfonation,
It depends on the m-isomer content and temperature of the reaction solution after hydrolysis. 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, the amount of sodium sulfate (mirabilite) or acidic sodium (acidic sodium sulfate) added is 1 to 15 It is mole%. If the amount is less than 1 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 sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate), which has the effect of suppressing such side reactions, is also limited for the static separation of the hydrolyzed solution, which is the second objective of the present invention. Must be. 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, sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) in the present invention
The amount of addition should be 5 to 15 mol % to have a substantial effect. The amount of sulfonic acid dissolved in the separated sulfuric acid layer is 1% by weight or less, and the sodium sulfate (mirabilite) or acidic sodium (acidic sodium sulfate) dissolved in the same layer precipitates at room temperature, so it can be easily separated. can be used again next time. The liquid from which sodium sulfate (mirabilite) or acidic sodium (acidic sodium sulfate) is separated is treated as highly concentrated sulfuric acid.
Can be used for other purposes. 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,
The layer separation effect between the sulfonic acid layer and the sulfuric acid layer due to the addition of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate) has an excellent effect on the hydrolysis reaction finished liquid, but it is effective for the sulfonation or isomerization finished liquid. In this case, there is no layer separation, and therefore sulfuric acid cannot be separated. 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. In other words, in the case of a mixture of o- or p-alkylbenzenesulfonic acid or a mixed sulfonic acid with a high ratio of these and sulfuric acid, sodium sulfate (mirabilite) is used.
Or, even if acidic sodium sulfate (acidic sodium sulfate) is added, layer separation does not occur, and when the m-form content exceeds a certain ratio, a layering effect will occur due to the addition of sodium sulfate (mirabilite) or acidic sodium sulfate (acidic sodium sulfate). be. After hydrolysis, leave it at a temperature of 80 to 170℃, separate the layers,
The separated alkylbenzene sulfonic acid is alkali salified with, for example, sodium hydroxide and causticized with sodium hydroxide under conditions well known in the art to yield the desired m-alkylhydroxybenzene. In the method of the present invention, the amount of free sulfuric acid in the sulfonic acid layer separated from the hydrolysis reaction solution is less than half of that in the case of no separation, so when making it into an alkali salt, the amount of alkali used is reduced. , it 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. ―
Hydroxybenzene with a body content of over 98% 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. Examples 1 to 4 Comparative Examples 1 to 2 In the presence of anhydrous sodium sulfate, ethylbenzene was sulfonated with sulfuric acid, isomerized, and hydrolyzed, excess sulfuric acid was separated, neutralized, and melted with alkali to synthesize m-ethylphenol. Check the composition of reactants at each step,
The relationship with the amount of mirabilite added was investigated. Pour 600g of 98% sulfuric acid into a four-necked flask,
While stirring, add anhydrous sodium sulfate in an amount equivalent to the molar percentage of sulfuric acid shown in the table. Next, add 424g of ethylbenzene.
Pour over 30 minutes and gradually raise the temperature. 2
It takes time to remove the distilled water and raise the temperature to 200℃. The mixture is heated and stirred at the same temperature for 4 hours for isomerization. The composition of the sulfonated product was determined and shown in the table. The composition ratios in the table are expressed in weight %. BSA is benzenesulfonic acid,
TSA stands for toluenesulfonic acid and ESA stands for ethylbenzenesulfonic acid.

[Table] Next, lower the internal temperature of the isomerization reaction product to 170°C.
While maintaining the same temperature and stirring, 1100 ml of water was continuously added dropwise at the same rate over a period of 10 hours to carry out hydrolysis. The resulting reaction mass was heated at a temperature of 150 °C for 30
Leave to stand for a minute to separate the sulfonic acid layer and sulfuric acid layer. The sulfonic acid composition of the sulfonic acid layer and the sulfuric acid cut rate are shown in the table. The composition ratios in the table are expressed in weight %. The abbreviations of BSA, TSA, and ESA are the same as in the table. However, in the case of no addition of mirabilite and in the case of addition of 2 mol % of mirabilite, the sulfuric acid cut rate was set as 0 because no layer separation occurred even when the temperature of the hydrolyzed reaction solution was lowered to 80° C. and allowed to stand.

【table】

[Table] Next, 50% caustic potassium solution was added to the separated sulfonic acid layer to neutralize it to pH 8, and the resulting slurry was
Drop into a mixture of 282 g of caustic soda and 42 g of caustic potash melting at 330°C. After dropping, the temperature of the contents was raised from 330℃ to 340℃, and the temperature was increased to 60℃ at 340℃.
Stir for 1 minute. The resulting molten reaction product is dissolved in 1000 ml of water and neutralized to pH 7.2 with 35% hydrochloric acid. The produced phenols were extracted with ether, distilled and further fractionated, and the phenol composition and ethylphenol yield were determined and shown in the table. Yields were determined relative to ethylbenzene consumed. The composition ratio is expressed in weight %; PH indicates phenol, CR indicates cresol, and EP indicates ethylphenol.

[Table] As can be seen from these experimental results, when sulfonate is added to ethylbenzene, benzenesulfonic acid, toluenesulfonic acid, and unknown components are reduced compared to the case without addition, and the purity and yield of ethylphenol are reduced. It's also expensive. In other words, it is clear that in high-temperature sulfonation of ethylbenzene, when 2 to 15 mol% of Glauber's salt is present relative to the charged sulfuric acid, Glauber's sulfate contributes to the stability of ethylbenzenesulfonic acid and suppresses side reactions. It is. However, when the amount of Glauber's salt added was 2 mol %, although the effect of suppressing side reactions was observed, no layer separation occurred even if the mixture was allowed to stand at the end of hydrolysis, and sulfuric acid could not be separated. Glauber's salt is 4 mol% based on the sulfuric acid used.
From the time of use, phase separation and separation after hydrolysis become easier, and side reactions are also suppressed. But 15
If it exceeds mol %, the hydrolysis reaction will also be suppressed and the composition ratio of the p-isomer will increase, and the interface between the sulfonic acid layer and the sulfuric acid layer will become unclear and separation will become difficult. Example 5 1200 g of 98% sulfuric acid was placed in a 2-4 neck flask, 102 g of anhydrous sodium sulfate (addition rate: 6 mol %) was added while stirring, and 424 g of ethylbenzene was added over 30 minutes. The temperature was gradually increased to 200°C over a period of 2 hours while distilled water was removed. The mixture was kept at the same temperature for 4 hours for isomerization. The temperature of the reaction mixture was lowered to 170°C,
At the same temperature and with stirring, 2000 g of water was injected at a constant rate over 10 hours to complete the hydrolysis. When the obtained reaction mass was allowed to stand at around 150°C for 30 minutes, it was separated into a sulfonic acid layer and a sulfuric acid layer, and the sulfuric acid layer was separated and removed. 1074g of the separated sulfone layer (854g) was neutralized to pH 7.8 with 50% caustic potassium solution.
563 g of caustic soda and 83 g of caustic potash were dropped into two melting pots into a mixture heated and melted at a temperature of 330°C. 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 2000ml of water and neutralized to PH7.2 with 35% hydrochloric acid.
The produced phenols were extracted with ether and distilled to obtain 348 g of crude m-ethylphenol. Yield of ethylbenzene based on consumption: 71%. The purity of fractionated m-ethylphenol was 98.2%. Example 6 1090 g of 98% sulfuric acid was placed in flask 1, and 103 g of anhydrous sodium sulfate (addition rate 6.7%) was added while stirring. 503g of toluene was added over 30 minutes.
The temperature was gradually increased to 195℃ over 2 hours.
The mixture was heated and stirred at the same temperature for 4 hours to perform isomerization. Next, the temperature was raised to 165°C, and 1000 g of water was continuously added dropwise at a constant rate over a period of 10 hours while maintaining the same temperature. 216 g of recovered toluene was distilled out together with water vapor by hydrolysis. After hydrolysis, the reaction mass is left standing at 150℃ for 30 minutes, and it separates into two layers.
It was possible to separate 695g of sulfuric acid layer and 1040g of sulfonic acid layer. After neutralizing the sulfonic acid layer with 50% caustic potassium solution,
Following the method of Example 5, 242 g of m-cresol with a purity of 98% was obtained by caustic melting, post-treatment, and fractional distillation. Example 7 1700g of 98% sulfuric acid was placed in 3 flasks, 120g of anhydrous sodium sulfate (addition rate 5%) was added while stirring, and 1100g of m-xylene was added dropwise over a period of 2.5 hours.
The temperature was raised to 180°C and kept at 175-180°C for 3 hours to perform isomerization. The temperature was lowered to 150℃, 700g of water was continuously added dropwise over 3 hours at the same temperature, and the reaction product was allowed to stand for 1 hour to form a 2334g sulfonic acid layer and 760g of water.
A 60% concentrated sulfuric acid layer was separated. The amount of meta-xylene recovered was 270g. The sulfonic acid layer was neutralized in accordance with the method of Example 5, followed by caustic melting and post-treatment to obtain 707 g of 3,5-xylenol. The purity was 97%. Example 8 1200g of 98% sulfuric acid was charged into a 2-four neck flask, and while stirring, 102g of acidic sodium sulfate (addition rate
7.1 mol %) was added thereto, 424 g of ethylbenzene was added dropwise, and the temperature was raised 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. Next, the temperature was lowered to 170°C, and at the same temperature, 2000 ml of water was injected at a uniform rate over 10 hours while stirring to complete the hydrolysis. When the obtained reaction mass was allowed to stand at around 150°C for 30 minutes, it was separated into a sulfonic acid layer and a sulfuric acid layer, and the sulfuric acid layer was separated and removed. The separated 1074 g of sulfonic acid layer was neutralized to pH 7.8 with a 50% caustic potassium solution, and subjected to alkaline melting and post-treatment in accordance with Example 5 to obtain crude m-ethylphenol. Next, fractional distillation was performed to remove the initial distillation of phenol, cresol, and o-ethylphenol as main components, yielding 98.2% m-ethylphenol.

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 5 to 15 mol% based on the mol of sulfuric acid charged, 150 to 210
After heating at a temperature in the range of °C to obtain an alkylbenzenesulfonic acid with a high m-form content and selectively hydrolyzing alkylbenzenesulfonic acids other than the m-form, the hydrolysis reaction solution is allowed to stand still and separated into layers. A method for producing m-alkylhydroxybenzene, which comprises separating the separated alkylbenzenesulfonic acid layer and causticly melting the separated alkylbenzenesulfonic acid layer. 2. 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 1, characterized in that it is carried out at a temperature in the range of 80 to 170°C.