JPS63218653A - Production of diaryl sulfones - Google Patents

Abstract

PURPOSE:To efficiently, industrially and advantageously obtain a compound useful as a raw material for polyesters in high yield and purity, by reacting an aromatic compound with an aromatic sulfonic acid in the presence or absence of a catalyst under specific reaction condition. CONSTITUTION:A aromatic compound is reacted with an aromatic sulfonic acid (e.g. benzenesulfonic acid) in the presence or absence of a catalyst to afford diaryl sulfones. In the process, a phosphoric acid compound or condensed phosphoric acid or both as a dehydrating agent in a molar amount of 0.025-0.5 expressed in terms of phosphoric acid based on the raw material aromatic sulfonic acid are added when the conversion rate of the aromatic sulfonic acid attains 40-95% or 70-95% in the presence of the catalyst. Since the dehydrating agent is not added from the initial reaction period by the above-mentioned method, the amount of the dehydrating agent can be remarkably reduced. Waste water treatment can be drastically reduced, since waste phosphoric acid is discharged in a small amount. For example, tungstic acid or molybdic acid is used as the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improved method for producing diarylsulfones.

The diarylsulfones obtained by the present invention are useful compounds as raw materials or raw material intermediates for heat-resistant resins such as polyesters, polyamides, polyimides, and polysulfones.

[Prior art] As a method for producing diarylsulfones, aromatic sulfonic acid is synthesized from an aromatic compound and sulfuric acid, and the aromatic sulfonic acid and aromatic compound are mixed with a dehydrating agent such as phosphorus pentoxide. (U.S. Pat. No. 3,501゜532, U.S. Pat. No. 3,729,
No. 517, JP-A-60-92256@).

However, in this method, if the amount of dehydrating agent used is catalytic, the yield of diarylsulfones is as low as 30% at most, and in order to improve the yield, it is necessary to use a larger amount of dehydrating agent. Therefore, it is necessary to treat a large amount of wastewater containing phosphoric acid, which is unfavorable not only industrially but also environmentally.

Furthermore, since the above-mentioned dehydrating agents are generally expensive, they are economically disadvantageous.

On the other hand, while studying methods for producing diarylsulfones, the present inventors discovered that tungstic acid, molybdic acid, and their heteropolyacids have excellent catalytic effects, and have previously proposed this (patent application 61
-168597, Japanese Patent Application No. 61-213368).

This production method does not produce phosphorus-containing wastewater and is economically advantageous, but in subsequent studies, we found that it is difficult to use aromatic compounds that do not have alkyl substituents, such as benzene and chlorobenzene, as raw materials. However, there was still room for improvement, such as the fact that it took a long time for the reaction to complete.

[Problems to be Solved by the Invention] The present inventors have conducted intensive studies to establish a method for producing diarylsulfones at low cost and in high yield by reacting aromatic sulfonic acids with aromatic compounds. discovered that the amount of dehydrating agent required could be significantly reduced if the dehydrating agent was not added from the initial stage of the reaction, but was added at a stage when the reaction had progressed to a certain extent, and based on this knowledge, the present invention was completed. Ta.

That is, an object of the present invention is to provide an improved method for producing diarylsulfones.

[Means for Solving the Problems] The present invention provides a method for producing diarylsulfones by reacting an aromatic compound and an aromatic sulfonic acid in the presence or absence of a catalyst. When the conversion rate is 40 to 95%, 0.025 to 0.5 times the molar amount of phosphorus oxide and/or condensed phosphorus M (hereinafter referred to as "phosphorus-based It is characterized by the addition of a chemical compound (referred to as "compound").

Aromatic compounds used in the method of the present invention include:
Benzene, naphthalene, and substituted products thereof with alkyl groups (1 to 20 carbon atoms), phenyl groups, hydroxyl groups, alkoxy groups, phenoxy groups, or halogen atoms are exemplified, and specifically, benzene, toluene, ethylbenzene, dodecylbenzene, phenol, biphenyl,
Examples include anisole, diphenyl ether, xylene, trimethylbenzene, β-haloethylbenzene, naphthalene, methylnaphthalene, naphthol, fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene.

The aromatic sulfonic acid used in the method of the present invention is a monosulfonated product obtained by sulfonating the above-mentioned aromatic compound with a sulfonating agent such as sulfuric acid, and
Specifically, benzenesulfonic acid, toluenesulfonic acid, ethylbenzenesulfonic acid, β-haloethylbenzenesulfonic acid, dodecylbenzenesulfonic acid, hydroxybenzenesulfonic acid, phenylbenzenesulfonic acid, fluorobenzenesulfonic acid, chlorobenzenesulfonic acid, bromine Benzenesulfonic acid, iodobenzenesulfonic acid, nitrobenzenesulfonic acid, methoxybenzenesulfonic acid, phenoxybenzenesulfonic acid, xylene sulfonic acid, dichlorobenzenesulfonic acid, dibromobenzenesulfonic acid, trimedelbenzenesulfonic acid, naphthalenesulfonic acid, methylnaphthalene Examples include sulfonic acid, hydroxynaphthalenesulfonic acid, 4,4°-diphenyldisulfonic acid, and 4,4′-diphenyl ether disulfonic acid.

However, the aromatic compounds and aromatic sulfonic acids are not limited to the above examples.

When an aromatic compound is sulfonated with sulfuric acid or the like to obtain a monosulfonated product, followed by a dehydration reaction to produce diarylsulfones, symmetrical sulfones having the same aryl group at both ends of the sulfone group are obtained. In addition, in the method of dehydrating a pre-prepared aromatic sulfonic acid and an aromatic compound, asymmetric sulfones can be obtained by appropriately selecting the aromatic compound, and the present invention is applicable to any of the above methods. It can also be applied to methods.

Examples of phosphoric oxides include phosphorus pentoxide and phosphorus sesquioxide, and examples of condensed phosphoric acids include metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, and polyphosphoric acid.

Specifically, the amount of the phosphorus-based compound added in the method of the present invention is 0.02 in terms of phosphoric acid based on the raw material aromatic sulfonic acid.
5 to 0.5 times the mole is preferable. If it is less than this, the yield will be low, if it is more than this, the burden of treating wastewater will be large, and
It is also economically disadvantageous.

The addition of phosphorus compounds increases the conversion rate of aromatic sulfonic acids to 4.
Preferably, a time point between 0 and 95% is taken.

The above time points are appropriately selected depending on the reaction conditions, and specifically,
When the reaction proceeds in the presence of a catalyst, a predetermined amount of phosphorus is added when the conversion rate of aromatic sulfonic acid is 70 to 95%, and when the conversion rate is 40 to 70% when no catalyst is used. It is desirable to add compounds. When added at a conversion rate lower than this, the yield of the target product tends to be low, and at a higher conversion rate, the reaction time becomes longer, which is industrially disadvantageous.

Although the production method according to the present invention can be applied without a catalyst, the use of a catalyst can increase the yield and productivity, which is industrially advantageous.

Examples of catalysts include tungstic acid, molybdic acid,
Alternatively, these heteropolyacids can be mentioned. The heteropolyacid referred to herein is a condensed acid consisting of two or more types of oxyacids.

Examples of polyacid atoms include W and MO, and examples of heteroatoms in heteropolyacids such as tungstic acid include P and AS.

Si, Ti, Co, Fe, B, V, Be, ■, N's
Examples include G a and the like.

Further, examples of the heteroatom in the heteropolyacid of molybdic acid include PSAs, Si, Ge, and Ti.

Ce, Th, Mn, Ni, Te, I, Co, Cr
, Fe, Ga, etc.

The catalysts exemplified above may be used in East Germany or two or more thereof may be used in combination.

Examples of preferred heteropolyacids include 12-tunges 1-phosphoric acid, 12-tungstosilicic acid, and 12-molybdophosphoric acid.

The amount of catalyst used varies depending on the type of catalyst, but is not particularly limited as long as it is effective for exhibiting catalytic activity. However, from the viewpoint of reaction rate and economic efficiency, 0.01 to 3 parts per 100 parts of aromatic sulfonic acid as the raw material
It must be about 0 parts by weight or 0.1 to 10 parts by weight.

The manufacturing method according to the present invention is generally carried out as follows.

In a system in which an aromatic compound and a WIt acid, or an aromatic compound and an aromatic sulfonic acid, and preferably a catalyst are present in predetermined amounts, the reaction proceeds under predetermined temperature conditions while removing produced water.

When the aromatic sulfonic acid reaches a predetermined conversion rate, a predetermined amount of a phosphorus compound is added to complete the reaction.

Specifically, methods for removing the water produced by the reaction include a method of refluxing the aromatic compound and phase separation of the azeotropic water, a method of introducing a carrier gas such as nitrogen gas into the reaction solution, a method of introducing a carrier gas such as nitrogen gas into the reaction liquid, and a method of removing the water under reduced pressure. Examples include methods of reaction.

The amount of aromatic compound used is 2.0 to 40 times the molar amount of sulfuric acid when sulfuric acid is used as a raw material, and 1.0 times the molar amount of aromatic sulfonic acid when aromatic sulfonic acid is used as a raw material. ~
A 20-fold molar amount is suitable.

If the amount of the aromatic compound is below the above range, the yield of diarylsulfones will be low, and on the other hand, if it is used beyond the range, no particular advantage will be recognized and it will be economically disadvantageous.

The reaction temperature can be appropriately selected depending on the type of aromatic sulfonic acid and aromatic compound, the desired reaction time, etc.
The temperature is 0 to 280°C, preferably 100 to 230°C. If the reaction temperature is 60°C or lower, it is difficult to obtain a practical reaction rate, and if the reaction temperature is 280°C or higher, side reactions such as polymerization occur, and the yield of diarylsulfones tends to decrease.

Sulfonation is completed in 1 to 10 hours after adding the phosphorus compound.

The reaction solution thus obtained is diluted with an aromatic compound as a raw material for the reaction or an organic solvent such as a lower alcohol, ether, or cologne as necessary, and the catalyst is filtered off. The diarylsulfones are obtained either by cooling and crystallizing or by distilling off the diluting medium from the mother liquor. In the above steps, washing with water may be performed as necessary, and the order is not limited. The recovered catalyst, diluent medium, etc. can be reused as they are.

Moreover, even higher purity diarylsulfones can be obtained by recrystallizing with an aliphatic lower alcohol such as methanol or ethanol, or an aromatic compound such as toluene or xylene.

[Example] The present invention will be explained in detail below by giving Examples and Comparative Examples.

Example 1 98% sulfuric acid 10 (1 (1,0 mol) and benzene 187 g
(2.4 mol) was reacted for 10 hours under reflux with heating and stirring. At this point, no sulfuric acid was detected, and the reaction solution was analyzed using high-performance liquid chromatography, and the conversion rate of aromatic sulfonic acid was determined from the amount of unreacted aromatic sulfonic acid.6
It was 0%.

23 g of phosphorus pentoxide (0.32 times the mole of aromatic sulfonic acid as a raw material in terms of phosphoric acid, the same applies hereinafter) was added to the reaction solution, and the mixture was further refluxed for 3 hours. Next, add benzene 2 to the reaction solution.
00g was added to dilute the solution and washed with water. Benzene was then distilled off under reduced pressure to obtain 196 g of diphenylsulfone (yield 90%, melting point 124-128°C).

Example 2 158 g' (1.0 mol) of benzenesulfonic acid and 94 g (1.2 mol) of benzene were heated and stirred under reflux and reacted for 9 hours. When the reaction solution was analyzed by high performance liquid chromatography, the conversion rate of benzenesulfonic acid was 70%. 11 (0.24 times the mole) of phosphorus pentoxide was added to the reaction solution, and the mixture was further refluxed for 3 hours. Next, add benzene 2 to the reaction solution.
00g was added to dilute the solution and washed with water. Benzene was then distilled off from the reaction solution under reduced pressure, and the resulting solid was washed with water and dried to obtain 203 g of diphenylsulfone (yield 93%, melting point 124-128°C).

Example 3 190 g (1.0 mol) of p-toluenesulfonic acid-hydrate and 111 g (1.2 mol) of toluene were heated and stirred under reflux and reacted for 8 hours. When the reaction solution was analyzed by high performance liquid chromatography, the conversion rate of p-toluenesulfonic acid was 70%.

21 g (0.3 times the mole) of phosphorus pentoxide was added to the reaction solution, and the mixture was further refluxed for 3 hours. Next, add 300 g of toluene to the reaction solution.
was added to dilute it and washed with water.

Toluene was distilled off under reduced pressure to obtain 236 g of 4,4°-dimethyldiphenylsulfone (yield 96%, melting point 153-1
56℃) in one field.

Example 4 158 g (1.0 mol) of benzenesulfonic acid, 94 g (1.2 mol) of benzene and 12-tanxtrine M (
H3PW12040-29H20)5';t was heated and stirred under reflux and reacted for 4 hours. When the reaction solution was analyzed by high performance liquid chromatography, the conversion rate of benzenesulfonic acid was 85%. Add 110 g of polyphosphorus (0,
11 times the mole) and further refluxed for 2 hours. Thereafter, in the same manner as in Example 1, 210 g (yield 96%) of diphenyl sulfone was added to 191 g.

Example 5 98% sulfuric acid 100y (1.0 mol), O-xylene 1
27 g (1,2 mol) and 12-Tungstosilica M (
H4S i W18O49''24H20>5゜0g was heated and stirred under reflux, and 107g (1.0 mol) of O-xylene was gradually added dropwise.After reacting for 6 hours, the reaction solution was heated to high speed liquid in the same manner as in Example 1. When analyzed by chromatography, the conversion rate of 0-xylene sulfonic acid was 90%. 5.1 (0.08 times mole) of phosphorus pentoxide was added to the reaction solution, and the mixture was further refluxed for 2 hours. Next, The reaction solution was diluted with 300 ff of 0-xylene and washed with water.The xylene was distilled off under reduced pressure to obtain 3,3°,4,4-tetramethyldiphenylsulfone 26,1 (yield 96%, melting point 164
~165°C) was obtained.

Example 6 190 g (1.0 mol) of p-toluenesulfonic acid-hydrate, 127 g (1.2 mol) of 0-xylene and 12-
Tungstophosphoric acid (H3PW12040/30H20)
3 g was heated and stirred under reflux and reacted for 8 hours. When the reaction solution was analyzed by high performance liquid chromatography, the conversion rate of p-toluenesulfonic acid was 82%. 10 tj (0.14 times mole) of phosphorus pentoxide was added to the reaction solution, and the mixture was allowed to flow at high speed for an additional 3 hours. Next, 300 g of 0-xylene was added to the reaction solution to dilute it, and the solution was washed with water. 0-xylene was distilled off under reduced pressure to obtain 247 g of 3,4.4'-trimethyldiphenylsulfone (yield 95%, melting point 128-131°C).

Comparative Example 1 98% 5A acid 100g (1.0 mol), benzene 187
g (2.4 mol) was heated and stirred under reflux and reacted for 1 hour. When the reaction solution was analyzed by high performance liquid chromatography, the conversion rate of benzenesulfonic acid was 15%. The same amount of 23y (0,32
twice the molar amount) and further centrifuged for 12 hours. Next, 200 g of benzene was added to the reaction solution to dilute it, and the solution was washed with water.

Diphenylsulfone obtained by distilling off benzene under reduced pressure was 153 g (yield 70%).

Comparative example 2 98% sulfuric acid 100g (1.0 mol), benzene 187g
(2.4 mol) and 5 g of 12-tungstophosphoric acid were heated and stirred under reflux to react until the conversion rate of benzenesulfonic acid in the reaction solution reached 99%. The reaction time is 15
It was time. Add 2g of phosphorus pentoxide (0,028
2 times the mole) and the mixture was further allowed to flow at high speed for 3 hours. Next, when benzene 2009 was added to the reaction solution to dilute it, insoluble matter due to overreaction was found, so this was filtered off and washed with water.

Diphenylsulfone obtained by distilling off benzene under reduced pressure was 190 g (yield: 87%).

Comparative Example 3 In Example 3, phosphorus pentoxide was added at 1.49 (0°02
When the same procedure was repeated except that 4,4-dimethyldiphenylsulfone was used (2017 times the mole), 4,4-dimethyldiphenylsulfone was
Yield: 83%).

"Effects of the Invention" According to the present invention, diarylsulfones can be obtained efficiently and in high yield from sulfuric acid or aromatic sulfonic acid and an aromatic compound. Moreover, since the amount of expensive dehydrating agent used is small, it is inexpensive, and furthermore, since the amount of phosphoric acid is small, the amount of water treatment is significantly reduced. Therefore, it is possible to industrially produce diarylsulfones very advantageously by the method according to the present invention.

(Margin below)

Claims (4)

[Claims] (1) In a method for producing diarylsulfones by reacting an aromatic compound and an aromatic sulfonic acid in the presence or absence of a catalyst, the conversion rate of the aromatic sulfonic acid is 40%.
A diaryl sulfone characterized by adding 0.025 to 0.5 times the molar amount of phosphoric oxide and/or condensed phosphoric acid in terms of phosphoric acid to the aromatic sulfonic acid as a raw material at a point of ~95%. Methods of manufacturing products. (2) A patent claim characterized in that in producing diarylsulfones in the presence of a catalyst, phosphorus oxide and/or condensed phosphoric acid is added when the conversion rate of aromatic sulfonic acid is 70 to 95%. A method for producing diarylsulfones according to item 1. (3) The catalyst according to claim 1 or 2, wherein the catalyst is one or a mixture of two or more selected from the group consisting of tungstic acid, molybdic acid, and their heteropolyacids. Method for producing diarylsulfones. (4) When producing diarylsulfones in the absence of a catalyst, the conversion rate of aromatic sulfonic acid is 40 to 70%.
The method for producing diarylsulfones according to claim 1, characterized in that phosphoric oxide and/or condensed phosphoric acid are added at the point of .