Process for the preparation of 1,4-bis(4-hydroxybenzoyl)-benzene

Details Process for the preparation of 1,4-bis(4-hydroxybenzoyl)-benzene Process for the preparation of 1,4-bis(4-hydroxybenzoyl)-benzene

1992-02-24

1993-10-05

Reamer, James H.

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

568796, C07C 4564

Patent

active

052507386

DESCRIPTION:

BRIEF SUMMARY
DESCRIPTION

The present invention relates to an improved process for the preparation of 1,4-bis(4-hydroxybenzoyl)benzene by reaction of 1,4-bis(4-halobenzoyl)benzene with alkali metal hydroxides or alkaline earth metal hydroxides in various solvents at elevated temperatures.
1,4-Bis(4-hydroxybenzoyl)benzene is an important monomer compound for the preparation of industrial plastics and can be converted by reaction with 1,4-haloaromatics to give polyether ketones. Previous preparation methods are the Fries rearrangement of diphenyl terephthalate (J.A.C.S. 1938, 2284; EP 75,390), the dealkylation of 1,4-bis(4-methoxybenzoyl)benzene with HBr (Doroshenko, Vysokomol, Soedin 8(10), 1787-92, 1966) and the nucleophilic substitution reaction of 1,4-bis(4-chlorobenzoyl)-benzene with sodium hydroxide solution in water in the presence of copper salts (SU 405,859). It is common to these known preparation methods that they proceed with heavy environmental pollution using compounds which are hazardous to health and moreover expensive.
It has now been found that the nucleophilic replacement of the hydroxyl group by a halogen atom, in contrast to the process of SU-PS 405,859, is possible without copper in the presence of a solvent and that this solvent can be separated off by distillation after reaction is complete and recycled to the next reaction.
The invention thus relates to an improved process compared to the prior art for the preparation of 1,4-bis-(4-hydroxybenzoyl)benzene of the formula (I) ##STR3## by reacting a 1,4-bis(4-halobenzoyl)benzene of the formula (II) ##STR4## in which X is a fluorine, chlorine or bromine atom, with an alkali metal hydroxide, preferably lithium hydroxide, sodium hydroxide or potassium hydroxide, or with an alkaline earth metal hydroxide, preferably magnesium hydroxide or calcium hydroxide, or with mixtures of the abovementioned hydroxides, in a solvent which is inert to the reaction components under the reaction conditions or in a two-phase system of water and an inert organic solvent at temperatures from about 100.degree. C. to about 250.degree. C., preferably about 150.degree. C. to about 220.degree. C., if appropriate in the presence of a phase transfer catalyst.
As far as the amount of hydroxide used is concerned, advantageously about 200 to about 500 mol percent, preferably about 200 to about 250 mol percent, of hydroxide are employed per halogen atom to be replaced. The hydroxide can be added both as an aqueous solution and in anhydrous form, the use of aqueous hydroxide solutions being preferred because of their good meterability.
The phase transfer catalysts optionally employed are, for example, added in an amount from about 0.5 to about 30% by weight, relative to the hydroxide. Phase transfer catalysts of this type are described, for example, in Dehmlow/Dehmlow "Phase Transfer Catalysis", Verlag Chemie, Weinheim 1983 and are as a rule quaternary ammonium or phosphonium compounds, and also crown ethers or pyridinium compounds. Examples of these which may be mentioned are tetraalkylammonium chloride or bromide, tetraalkylphosphonium chloride or bromide, tetraphenylphosphonium chloride or bromide, distearyldimethylammonium choloride (sic) or bromide, hexadecyltributylphosphonium chloride or bromide, pyridinium chloride or bromide or 18-crown-6. In addition to an individual phase transfer catalyst, mixtures of various phase transfer catalysts can also be employed.
Examples of suitable inert solvents for the process according to the invention are chlorobenzene, dichlorobenzene, trichlorobenzene, xylene, toluene or chlorotoluene. In addition to organic inert solvents, two-phase systems composed of water and an organic inert solvent can also be used. Customarily, the reaction is carried out in a water/solvent mixture, the weight ratios of water:solvent being 50:1 to 1:20. After reaction is complete, the solvent is separated off by azeotropic distillation, if necessary with the addition of water. It can be recycled to the next reaction without loss.
The reaction can be carried out with

REFERENCES:
patent: 4022795 (1977-05-01), Bamfield et al.
patent: 4504689 (1985-03-01), Veracini
patent: 4691058 (1987-09-01), Stegmann
Chemical Abstracts vol. 80, 1974, (Columbus, Ohio, see p. 348 abstract 82351d.

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