JPS5929586B2 - Method for producing 4,4'-dichlorodiphenylsulnene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing 4.4'-dichlorodiphenyl sulfone.

Diarylsulfones are important and useful organic compounds.

For example, 4.4'-dichlorodiphenyl sulfone is a monomer in the production of polysulfone resins such as the polyarylene polyethers disclosed in Pelkey Patent No. 650,476. An industrially important process for the production of 4.4'-dichlorodiphenyl sulfone is described in Keogh et al., US Pat. No. 3,701,806.

In the process, a mixture of sulfonyl chloride and aromatic sulfone is prepared and 4,4'-dichlorodiphenyl sulfone is readily isolated from the mixture, or more importantly, as described in U.S. Pat. No. 2,224,964. Further reaction with chlorobenzene in the presence of ferric chloride according to the process disclosed herein can produce 4,4'-dichlorodiphenyl sulfone in high overall yield. In the method described in the patent specification of Keoff et al., the formula: (
A monosubstituted benzene having the formula (X is a H1 fluoro, bromo or methyl substituent) is reacted with sulfur trioxide (SO3) in the presence of at least a stoichiometric amount of thionyl chloride (SOCl2). The resulting mixture can be converted into FeCl3, AlCl3 without the need for further purification.
, SbCl3, Sncl4, etc., to substantially complete conversion to diarylsulfone. The method for producing 4,4'-dichlorodiphenyl sulfone disclosed by Keoff et al.
Although it represents a significant improvement over many methods of preparing dichlorodiphenyl sulfone and offers industrial advantages in that it does not require isolation of intermediate products, the overall chemical efficiency of the method is is only about 86% based on SO3 in the laboratory and SO3 during industrial operation.
It was found that the amount was approximately 82% on the basis of the amount of carbon dioxide, and was accompanied by the formation of undesirable residual by-products.

Although the chemical efficiency of this process is not impractically low and the undesirable by-products can be separated, the chemical efficiency suggests room for significant improvement. The present invention includes an improved method for producing a mixture of aromatic sulfonyl chloride and aromatic sulfone substantially free of the corresponding aromatic sulfonic acids and their anhydrides, which method comprises: (wherein X is a hydrogen, fluoro, chloro, bromo or methyl substituent) and at least about 15 mole % to about 50 mole %, based on the sulfur trioxide, of sulfur trioxide. thionyl chloride, and preferably between about 20 mol % and 40 mol % thionyl chloride; (b) reacting the reaction mixture of process a) above in the presence or absence of a catalyst; to which at least about 60 mole percent thionyl chloride, based on sulfur trioxide, and preferably a small catalytic amount of N-N-dimethylformamide are added, in which case the total thionyl chloride in the reaction mixture is At least about 110 based on sulfur oxide
(c) continuing the reaction to a temperature at which excess thionyl chloride is stripped from the reaction mixture, preferably at a temperature of about 160°C; includes.

This process produces a substantially pure mixture of aromatic sulfonyl chloride and diaryl sulfone from which the diaryl sulfone can be readily separated or, more importantly, purified further. diarylsulfones can be produced in high yields by reaction with monochlorobenzene in the presence of ferric chloride, for example, according to the method disclosed in the aforementioned U.S. Pat. No. 2,224,964, without It has been found that 4,4'-dichlorodiphenyl sulfone can be prepared using

The present invention provides an improved method for producing 4,4'-dichlorodiphenyl sulfone, which method comprises: (a) monochlorobenzene and sulfur trioxide; (b) reacting in the presence of from mol % to about 50 mol % of thionyl chloride, preferably between about 20 mol % and 40 mol %; (b) said step (a);
to the reaction mixture of, in the presence or absence of a catalyst, at least about 60 mole % thionyl chloride, based on sulfur trioxide, and preferably a small catalytic amount of N-N-dimethylformamide; in which the total thionyl chloride in the reaction mixture is at least about 110 mole percent based on sulfur trioxide, and the reaction mixture is maintained under heating during this time; (c) excess thionyl chloride is present in the reaction mixture; (d) reacting the product of c) with monochlorobenzene in the presence of a ferric chloride catalyst; - A step of producing 4'-dichlorodiphenyl sulfone.

Sulfur trioxide, about 15 mol% based on the sulfur trioxide
and 50 mol% of thionyl chloride, which is substantially less than the stoichiometric amount of thionyl chloride based on sulfur trioxide. It has now been found that the sulfonation reaction can be carried out easily.

by then adding at least 60 mol % thionyl chloride, based on SO3, to the reaction mixture to bring the thionyl chloride content of the reaction mixture to at least a stoichiometric excess of thionyl chloride, based on SO3. , a mixture of a diarylsulfone and an arylsulfonyl chloride is formed, which is particularly useful if the reaction temperature is relatively tightly controlled or if the reaction is carried out using small catalytic amounts of a catalyst such as N-N-dimethylformamide. substantially free of undesirable by-products when carried out in the presence of

If it is then desired to completely convert the mixture to a diarylsulfone, such as 4.l-dichlorodiphenylsulfone, the mixture and monochlorobenzene in the presence of a catalyst such as ferric chloride may be The reaction is quite facile and with high yields of the desired sulfone. The overall chemistry that occurs in this method is generally known.

For example, Wagner and ZOOk.
) are Jiyoung, Williichi, And, Songs (JOllnW
Published by ``Synthetic, Organ, Chemistry'' (SyntheticOrga)
(1953) No. 811
It was pointed out on page 1 that sulfur trioxide reacts with aromatic hydrocarbons to form the corresponding sulfonic acids, with some sulfones as by-products.

Keof et al. also disclose that when monosubstituted benzene and sulfur trioxide are reacted in the presence of at least a stoichiometric excess of thionyl chloride, a mixture of aromatic sulfonyl chloride and diarylsulfone is formed. are doing. The reaction of p-chlorobenzenesulfonic acid with thionyl chloride in the presence of at least a molar amount of dimethylformamide to produce p-chlorobenzenesulfonyl chloride is disclosed in U.S. Pat. No. 2,888,486 to Greg Ory. There is. The general reaction of an aromatic sulfonic acid with thionyl chloride to form the corresponding sulfonyl chloride in the presence of a catalytic amount of dimethylformamide has been described by Bosshard et al. [Helvetica, Himica, Acta]
himicaActa)” XLllll653 (195
9) and Kittila's "Dimethylformamide, Chemical, Uses"
Ormamide Chemical Uses)"I.
Ai. Dupond. Nemur (E”.DupOntde
Published by NemOurs, Chapter 16, pages 76-77. For the overall ferric chloride catalyzed reaction, see, for example, Keoff et al., supra, Lopins (RO
bbins U.S. Pat. No. 3,125,604 and Huismann U.S. Pat. No. 2,224.
It is described in the specification of No. 964. Although, as mentioned above, the overall chemical reaction that occurs in this method is known,
The particular combination of steps of the present invention results in a process with unexpectedly high efficacy, as evidenced in the examples below. In a preferred embodiment of the invention, in step a) of the method, at least about 15 mol% to about 50 mol%, based on sulfur trioxide (SO3);
Monochlorocabenzene (MCB) is reacted with sulfur trioxide in the presence of preferably between about 20 and 40 mole % thionyl chloride (SOCl2).

The amount of thionyl chloride present in the reaction medium of step (a) (during which monochlorobenzene reacts with sulfur trioxide) depends on the overall chemical efficiency of the reaction and on the desired 4.
It is very important for the efficiency with which the 41-dichlorodiphenylsulfone isomer is produced (isomer efficiency). The isomer efficiency is significantly reduced when less than about 15 mole % thionyl chloride is used, and the chemical efficiency of the process is significantly reduced when the amount of thionyl chloride exceeds about 50 mole %. There was found. In process a) it is preferred to use an excess of MCB as reaction medium.

A convenient ratio has been found to be in the range of about 2 to about 3 moles of MCB per mole of SO3. SO3 is commonly used in a stabilized form, for example in the cyclic trimeric form known as Sulfan. Molarly substituted benzenes (ArX) in which the substituents are hydrogen, fluoro, bromo or methyl are also suitable for use in the process of the invention.

The process is not critical as to the molar ratio or excess of monosubstituted benzene to sulfur trioxide that can be used. From a practical standpoint, the ratio of ArX to SO3 generally does not exceed 6:1. The process of the invention is most advantageously carried out in excess monosubstituted benzene.

The monosubstituted benzene can then act as a solvent. Other solvents useful in the method include nitrobenzene, SO2, and other liquids known to be relatively inert to SO3. The reaction of step (a) is rapid, exothermic and substantially quantitative.

The reaction temperature is not critical (e.g. the operating temperature range is about -
(e.g., 200 to +40°C), it is preferred to maintain the reaction mixture at a temperature of, for example, about 10°C to about 30°C during the course of the reaction. The temperature can be maintained by conventional means such as heat exchange means on the reactor and by adjusting the rate of addition of SO3 to the MCB. (Heat of reaction is 70,000 BTU/lb.mol or 875 BTU/lb. SO3). Although it is convenient to employ atmospheric pressure in step (a), other pressures may also be employed. For safety reasons, it is desirable to use an inert atmosphere (eg nitrogen) to cover the reaction mixture throughout the process. In step (b), at least 60 mol% thionyl chloride based on SO3 is added to the step (b).
Add to the reaction mixture of a).

The total amount of thionyl chloride in the reaction mixture is thereby at least in slight molar excess. SOCl2
The stoichiometric amount of SOCl2 added in step (a) and step (b) per mole of SO3 used in step (a) is
It is 1 mole. A minimum value of at least about 10% excess of the stoichiometric amount should be employed, and an excess of about 15 to 50% of the stoichiometric amount has been found to be advantageous. The chemical efficiency and overall efficiency of the method of the present invention are as small as practical.
．． Very pure SOCl, containing a tank of sulfur chloride,
It is even improved further by the use of .

Up to about 0.4% by weight, preferably about 0.2% by weight of S
The proportion of sulfur chloride in OCl2 is most advantageously employed.
When SOCl2 contains more than about 0.8 to 1.0 weight percent sulfur chloride, the chemical efficiency of the process is significantly reduced as sulfur chloride participates in undesirable side reactions. Thionyl bromide can be used interchangeably with thionyl chloride.

As used herein, the term "thionyl chloride" is intended to include thionyl bromide. Preferably a small catalytically effective amount of a catalyst such as dimethylformamide (DMF) is used in step (b).

The NF is removed prior to step (d) using a minimum amount, i.e. a catalytically effective amount of
It is preferable to avoid the need to use relatively more ferric chloride in ). The minimum catalytically effective amount of D is about 2 mol % based on the moles of SO3, but if the quality of thionyl chloride is that commonly available commercially, smaller amounts of D) (the exact amount required can be determined by routine experimentation).

Step (b) comprises thionyl chloride, preferably together with PW.
at a moderate temperature, such as from about 25°C to about 30°C, and then heating the reaction mixture at an incremental rate to about 70°C, preferably from about 55°C to 60°C. This can be done by:

The heating rate was found to be important. Also, generally
about 0.5°C/min, preferably about 0.25°C/min and 0.3
The chemical efficiency of the process is improved by adjusting the heating rate to give a temperature increase of between 0.degree. C./min. By adjusting the heating rate, more conversion of chlorobenzenesulfonic acid to chlorobenzenesulfonyl chloride occurs at lower temperatures, reducing decomposition of thionyl chloride and reducing by-product formation. Or alternatively, the process (
6) while maintaining the reaction temperature between about 25°C and 70°C,
It can be carried out by continuously adding thionyl chloride to the reaction mixture of step (a) in a stepwise manner. As soon as the addition of thionyl chloride and the incremental heating of the reaction mixture to a temperature of about 70° C. is completed, the reaction mixture of step (b) is heated incrementally to drive the reaction to completion and to eliminate excess unreacted thionyl chloride. Step (c) is carried out by influencing the temperature at which all is removed from the reaction mixture.

Preferably step (c) comprises heating the reaction mixture of step b) at a substantially constant rate to a temperature of about 155°C to 160°C over a period of 15 to 30 minutes or until the end of gas evolution is detected. This is done by maintaining the above temperature until the temperature is reached. During steps (b) and (c), the off-gas, SO2, is passed through a scrubber used to absorb the off-gases, maintaining a pressure of about 1.1 to 1.2 atmospheres on the reaction mixture. It is desirable to provide a driving force to push the HCl and HCl. In other respects the choice of pressure is not critical at all. Standard, glass-lined reactors with corrosion-resistant aids can be used for steps (a), (b) and (c). In industrial scale operations, steps (a), (b) and (c)
It is desirable to use a separate reactor for step (d) to avoid contamination of the reaction mixture with ferric chloride. A catalytic amount, e.g. about 3 to 4 based on SO3
The reaction mixture of step (c) is charged to the reaction vessel with a minimum amount of mol % ferric chloride, but greater than the number of moles of DMF that may have been charged during step (b).

There is no advantage to using more ferric chloride. Additional MCB is added with ferric chloride (which is added as a slurry in the MCB) until it flows out of the conduit.

MCB can also be added from time to time during step (d) to maintain the desired temperature by reflux. The total amount of MCB added is usually sufficient to provide a concentration of about 65 to 70% by weight of sulfone product in the MCB. Typically, a total amount of about 1 extra mole of MCB per 1 mole of SO charged to coffin a) is added during step (d). For step (d), a relatively narrow temperature range (1300-160°C) is proposed as a compromise between too slow reaction rate and the formation of color bodies (COlOrbOdy), but between 130°C and 140°C. Suggest a starting temperature between

At a temperature of about 155°C, the reaction of step (d) is about 1
It takes 2 hours. The progress of the reaction can be followed by off-gas titration (which is convenient on a laboratory scale) or by analysis of the reaction mixture by gas chromatography for residual sulfonyl chloride content. Conveniently, in step (d) a pressure of about 1.1 to 1.2 atmospheres is used.

Corrosion-resistant equipment should be used. Upon completion of the reaction,
Additional MCB is added to dilute the sulfone to a concentration of about 40% by weight based on the total solution weight (this is done by keeping the sulfone in solution during cooling and washing).

The reaction mixture is then cooled to a temperature of about 70°C, washed with water to remove the ferric chloride, and the 4,4'-dichlorodiphenylsulfone product is then recovered by standard means such as by crystallization. . Another advantage found with the method of the present invention is that it reduces corrosion problems commonly associated with recovery equipment. As pointed out herein, the general overall chemical reactions that occur in the process of the present invention are known and are disclosed in the Keoff et al.
Although No. 806 discloses a method for industrial use in the production of 4,4'-dichlorodiphenyl sulfone, as mentioned above, the particular combination of steps and conditions of the present invention This results in a process with a surprising and unexpectedly high efficiency both in the laboratory and during industrial operation.

Not only is there a high chemical efficiency in producing a substantially pure mixture of diarylsulfone and arylsulfonyl chloride, but also virtually complete conversion of the mixture to the diarylsulfone, particularly the 4,4'-dichlorodiphenylsulfone isomer. It was also found that the efficiency of the further reaction of the mixture to achieve the desired conversion was also quite good.
The process of the present invention provides a more effective and economical method for producing 4,4' dichlorodiphenyl sulfone when used under industrial production conditions, and the product is
There are fewer dye impurities compared to industrial operations using, for example, the method disclosed by Keoff et al., supra. The present invention will be further elucidated by the following examples, which are merely illustrative of the present invention and are not intended to limit the present invention in any manner.

All parts and percentages are by weight unless otherwise indicated. Example 1 Step (a) Monochlorobenzene 2437 (2.16 mol) and thionyl chloride (sulfur chloride 0.8% by weight) 43y (0.36 mol) were mixed with a thermometer, a drip load, a stirrer, and a backflow condenser. The mixture was charged into a 1/2 liter glass reactor.

Sulfur trioxide (sulfane) 81.7y (1.02 mol)
was added at a constant rate over approximately 50 minutes. During this time, the temperature is reduced by cooling from about 17°C to about 33°C.
It was kept at °C. Step (b) N-N-dimethylformamide (2.3y; 0.031
mol) and thionyl chloride (1257; 1.05 mol; 0.8% by weight sulfur chloride) in the same reaction vessel as used in step (a) at a temperature of about 30°C. was added to the reaction mixture.

The top of the backflow condenser was attached to an alkaline scrubber. Off gas began to be generated immediately. This off-gas was absorbed in the scrubber with an aqueous sodium hydroxide solution of known strength. The progress of the reaction was followed by incremental addition of sodium hydroxide to the aqueous solution. The reaction mixture was heated with a heating mantle using a "Variac" control.

the reaction mixture at a substantially constant rate of 0.23°C/min;
It was heated to a temperature of 70° C. for about 3 hours. Process (c
) The reaction mixture of step (b) is then heated to 155° C. at a substantially constant rate of 0.6° C./min for about 2-f hours.
heated to a temperature of °C.

After this time, off-gassing stopped. Excess thionyl chloride was then distilled off. Step (d) 9.7y (0.06 mol) of ferric chloride was added to the reaction mixture of step (c) above at a temperature of 29°C.

The mixture was heated to reflux at a temperature of 135°C.
Approximately 407 grams of additional monochlorobenzene was added to the reaction mixture to maintain reflux. following the reaction by measuring off-gas over a period of about 1 hour as in step (b) above;
The reaction was then allowed to proceed overnight. After 12 hours the reactor was cooled to ambient temperature.

The reaction mixture was then heated to a temperature of 155° C. for about 1 hour until the evolution of off-gas ceased. The reaction mixture was diluted with MCB to a concentration of 40% sulfone, cooled to a temperature of 70° C., washed with water to remove ferric chloride, and then dichlorodiphenyl sulfone was recovered. Total 265.3t
(0.924 mol) of sulfone was produced, of which 91.3
% is the desired 4,4' dichlorodiphenyl sulfone isomer, and the chemical efficiency based on sulfur trioxide is 90.6%
It was hot. Example 2 Chemical efficiency of the process for the preparation of 4,4'-dichlorodiphenyl sulfone isomer when the reaction of sulfur trioxide and monochlorobenzene is carried out in the presence of various amounts and qualities of thionyl chloride. and the difference in isomer efficiency.

In carrying out the method of this example, the apparatus described in Example 1 above was used. Method A: Step (a) Monochlorobenzene 2807 (2.49 mol) was charged into a reactor, and sulfur trioxide (sulfane) 93.47 (1.
17 mol) was added at a constant rate over about 60 minutes.

During this time, the temperature was maintained at about 30°C to about 40°C by cooling. Step (b) Thionyl chloride (sulfur chloride 0.8% by weight) 1857 (1.
55 mol) and N-N-dimethylformamide 1707 (
0.023 mol) was added to the reaction mixture of step (a) above at a temperature of about 30°C.

Off gas began to be generated immediately. The reaction mixture was reduced to about 0
．． 1 for 4 hours at a substantially constant rate of 5°C/min.
Heated to a temperature of 55°C.

After this time, off-gassing stopped. Excess thionyl chloride was then distilled off. Step (c) 9.97 (0.06 mol) of ferric chloride were added to the reaction mixture of step (b) above at a temperature of 135°C and the mixture was then heated to reflux at a temperature of 155°C.

Additional monochlorobenzene was added periodically to give 155
Reflux was maintained at a temperature of °C. After 12 hours, off gas generation stopped.

The reaction mixture was diluted with MCB to a concentration of 40% sulfone, cooled to a temperature of 70°C, washed with water to remove ferric chloride, and dichlorodiphenyl sulfone was recovered. A total amount of sulfone of 310.27 (1.08 mol) was produced, and 8
9.5% was the 4.4' monoisomer. The chemical efficiency of this method is summarized in Table 1. Method B This method was carried out using the procedure described in Keoff et al., US Pat. No. 3,701,806, supra.

Step (a) Monochlorobenzene 337.57 (3.0 mol) and thionyl chloride (sulfur chloride 0.8% by weight) 1937 (1.62
mol) was charged to the reactor and then 82.07 (1.02 mol) of sulfur trioxide was added at a constant rate over about 60 minutes.

During this time, the temperature was maintained at about 30° C. by cooling. After the sulfur trioxide addition was complete, heating was continued at a substantially constant rate for about 3 hours to a temperature of about 130°C and for an additional 30 minutes to a temperature of about 155°C. At this temperature, off-gas generation ceased. Excess thionyl chloride was then distilled off. Step (b) Adding 5.37 (0.032 mol) of ferric chloride to the reaction mixture of step (a) at a temperature of about 90°C and then heating the mixture to a temperature of 160°C to 165°C. It was refluxed at

Additional monochlorobenzene was added periodically to maintain reflux. After about 3-i hours, the reaction mixture was heated to 160'C for about 1 hour until off-gas evolution ceased.
It was heated to a temperature of 65°C. The reaction mixture was diluted with MCB to a concentration of 40% sulfone, cooled to a temperature of 70°C, washed with water to remove ferric chloride, and dichlorodiphenyl sulfone was recovered. Total amount 2797 (0.97 mol)
of sulfone was produced, 91.9% of which was the 4.4' monoisomer. The chemical efficiency of this method is summarized in Table 1 below. Method C: Step (a) 241.07 (2.14 mol) of monochlorobenzene and 42.17 (0.2% by weight of sulfur chloride) of thionyl chloride.
A mixture of sulfur trioxide (35 mol) and sulfur trioxide (
Sulfane) 80.17 (1.0 mol) was added at a constant rate while the temperature was maintained between 5°C and 25°C by cooling.

Step (b) Thionyl chloride (sulfur chloride 0.2% by weight) 1207 (1.
0 mol) and N-N-dimethylformamide 2.37 (0 mol)
．． 030 mol) was added to the reaction mixture of step (a) above at a temperature of about 30°C.

The mixture was heated to 69°C at a substantially constant rate of 0.27°C/min.
heated to a temperature of Step (c) The reaction mixture of step (b) above was then heated at a substantially constant rate to a temperature of 155° C. over a period of about 2 hours.

After this time, off-gassing stopped. Excess thionyl chloride was then distilled off. Step (d) Cool the reaction mixture of step (c) and add ferric chloride8.
87 (0.054 mol) was added.

The mixture was then heated to reflux at a temperature of 135°C and held for 12 hours, during which time additional monochlorobenzene was added periodically to maintain reflux. The reaction mixture was then diluted with MCB, cooled and washed with water to remove ferric chloride. A total of 274.8y of dichlorodiphenyl sulfone was produced, 91.2% of which was the desired 4.4' monoisomer. The chemical efficiency of this method is summarized in Table 1 below.
Method D: Using the procedure described in Method C above, 84.06y (0.71 mol) of thionyl chloride (0.8% by weight sulfur chloride),
Monochlorobenzene 242,71y (2.16 mol) and sulfur trioxide 80.927 (1.01 mol) were added to step (a).
); during step (b), thionyl chloride (
Sulfur chloride 0.8% by weight) 84.687 (0.71 mol)
and N-N-dimethylformamide 2.

387 (0.03 mol) was added to the reaction mixture and the reaction mixture was then heated at a constant rate of 0.32°C/min to 70°C.
heated to a temperature of °C.

Claims (1)

[Claims] 1 (a) monochlorobenzene and sulfur trioxide, at least about 15 mol % to about 5 mol % based on the sulfur trioxide;
(b) adding to the reaction mixture of step (a) at least about 60 moles, based on the sulfur trioxide, in the presence or absence of a catalyst; % of thionyl chloride, where the total thionyl chloride in the reaction mixture is at least about 110 mole % based on the sulfur trioxide, while maintaining the reaction mixture under heated conditions; c) continuing the reaction to a temperature at which excess thionyl chloride is stripped from the reaction mixture; (d) reacting the product of step (c) with monochlorobenzene in the presence of a ferric chloride catalyst; and producing 4,4'-dichlorodiphenylsulfone. 2. Step (b) of the method is carried out using a small catalytic amount of N as a catalyst.
- The method according to claim 1, which is carried out in the presence of N-dimethylformamide. 3. Step (b) of the process is carried out by adding thionyl chloride to the reaction mixture at a temperature of about 25°C to 30°C, and then heating the reaction mixture at a rate of up to about 0.5°C/min. The method described in Scope No. 2. 4 Approximately 20 mol% and 40 mol% based on sulfur trioxide
3. The method according to claim 2, wherein thionyl chloride between 5. The method of claim 1, wherein the thionyl chloride contains up to about 1.0% by weight sulfur chloride.