Process for preparing halo-substituted diarylsulfones

Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur containing

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568 28, 568 33, 568 35, C07C14706

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active

045581614

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to an improved process for preparing diarylsulfones or more specifically, diarylsulfones having halogen on the aromatic ring, such as 4,4'-dichlorodiphenylsulfone and the like.
Diarylsulfones are industrially useful compounds as intermediates for synthesizing pharmaceuticals, dyes and the like or as materials for preparing various types of synthetic resins, epoxy resin-curing agents, etc.
A variety of processes as given below are known for producing diarylsulfones.
(1) A process in which benzene, chlorobenzene, toluene or like aromatic hydrocarbon is reacted with a mixture of sulfuric anhydride and dimethyl pyrosulfate (Japanese Pat. Nos. 301684; 305463; and 312809).
(2) A process in which aromatic hydrocarbon such as those mentioned above and p-toluenesulfochloride, p-chlorobenzenesulfochloride or like aromatic sulfochloride are subjected to Friedel-Crafts reaction in the presence of anhydrous iron chloride, anhydrous aluminum chloride or the like (German Pat. No. 701954).
(3) A process in which aromatic hydrocarbon such as those exemplified above is reacted with aromatic sulfochloride such as above in the presence of benzenesulfonic acid, 4-chlorobenzenesulfonic acid, or like aromatic sulfonic acid (Japanese Examined Patent Publication No. 5707/1975).
(4) A process in which aromatic hydrocarbon such as above and aromatic sulfonic acid such as above are subjected to condensation reaction using phosphorus pentoxide or like phosphorus oxide-type dehydrating agent (Japanese Examined Patent Publication No. 24662/1968).
(5) A process in which reaction is conducted between aromatic hydrocarbon such as above and aromatic sulfonic acid such as above at a high temperature of more than 200.degree. C. (Japanese Unexamined Patent Publication No. 76834/1974 and U.S. Pat. No. 2593001).
(6) A process in which specific amounts of halobenzene compound and chlorosulfonic acid are subjected to reaction at less than 10.degree. C. and thereafter a specific amount of halobenzene compound is further added to the resulting reaction mixture, followed by heating of the mixture at 40.degree. to 60.degree. C. (U.S. Pat. No. 2860168).
However, all of these processes have drawbacks to be remedied and remain unsatisfactory from commercial viewpoints. More specifically stated, the process (1) uses dimethyl sulfate having high toxicity and thus is impractical because of the problems on operators' sanitation and disposal of waste water. The processes (2) and (3) employ aromatic sulfochloride as the starting material which is difficult to obtain and which is prone to hydrolysis in handling and during storage, requires reaction at a high temperature of more than 100.degree. C. and gives product with low purities. The process (4) entails reaction which continues over a period of about 24 hours at a high temperature of over 80.degree. C., usually 130.degree. to 180.degree. C. and results in the production of a product with low purities. The process (5) requires reaction at a high temperature of more than 200.degree. C. and produces a product having low purities in low yields. The process (6) needs a low-temperature reaction, provides a product, although with high purities, in yields as low as about 30%, necessitates a cooling device to maintain the reaction system at a low temperature of less than 10.degree. C., usually -5.degree. to 5.degree. C. and involves a cumbersome procedure due to the two-step reaction. In short, these conventional processes suffer from the disadvantages with respect to starting materials to be used, procedures involved, reaction efficiency, equipment, etc. and generally entail reaction at high temperatures, fail to give a desired product with high purities in high yields and require purification of the reaction product using a solvent or the like to obtain a commercially acceptable end product.


DISCLOSURE OF THE INVENTION

An object of the present invention is to provide an improved process for preparing diarylsulfones, the process giving a desired product with high purities

REFERENCES:
patent: 2593001 (1952-04-01), Bender et al.
patent: 2860168 (1958-11-01), Erickson
patent: 2999883 (1961-09-01), Schoot et al.
patent: 3057925 (1962-10-01), Schoot et al.
patent: 3579590 (1971-05-01), Davis
patent: 3632642 (1972-01-01), Rosin et al.
patent: 3855312 (1974-12-01), Horner
patent: 4012451 (1977-03-01), Enoki et al.

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