DD272295A1 - PROCESS FOR PREPARING 1,4-BIS (4-METHOXYBENZOYL) BENZENE - Google Patents

Abstract

The invention relates to a simple process for the preparation of 1,4-bis (4-methoxybenzoyl) benzene, which is a key compound for the preparation of conjugated specialty polymers. The aim of the invention is a solvent-free process that manages with non-molar amounts of catalysts, has a favorable space-time yield and allows an environmentally friendly workup. The novel process is characterized in that anisole and terephthaloyl chloride in a molar ratio of 2: 1 to 4: 1 solvent-free and with the addition of 2 mol% to 12 mol% zinc powder or 2 mol% to 12 mol% iron powder (based on terephthaloyl chloride ) are reacted at 110C to 180C, the reaction product 1,4-bis (4-methoxybenzoyl) benzene is subsequently precipitated from the reaction mixture with methanol and recrystallized from dimethylformamide (DMF). From anisole and terephthaloyl chloride in a molar ratio 4: 1 with the addition of about 10 mol% zinc powder is obtained in 4.5 hours about 55 percent. 1,4-bis (4-methoxybenzoyl) benzene.

Description

The invention relates to "a simple process" for the preparation of 1,4-Bls (4-methoxybdatehone), since an intermediate product was of importance for chemical syntheses, in particular, it represents a key interlocking for the production of the industrially important poly | 1, 4 |) henylen * 1,2-bli (4> metho) iyphenylWinyleni | is why koitengünittge and simple procedures tu Miner Heritellung are needed.

Characteristic of the well-known technical solutions

The synthesis of 1,4-bis (4-methoxybenzoyl) benzene has heretofore been carried out by Friedel-Cra'ts ketone synthesis from terephthaloylchloride and anisole in the presence of molar amounts of aluminum chloride, with the recommended solvent carbon disulfide (J.ehem. Soc. London 1W7.39M).

A disadvantage of this method is the Einsati a large amount of aluminum chloride, through which a cumbersome, umwehbelastende adverse workup is due, which is hindering for an application of the method on a larger scale Itßerst. This fundamental disadvantage is also not eliminated by the recent procedures for Friedel-Crafts acylation with aluminum chloride in the presence of halogenated carbon dioxide or in an excess of anisole.

Aim of the invention

The aim of the invention is therefore a simple solvent-free process for the preparation of 1,4-Bls (4-methoxybenzoyl) benzene, daa manages with non-molar amounts of inexpensive catalysts, has a favorable space-time yield and environmentally friendly processing allowed.

Explanation of the essence of the invention

The present process for the preparation of 1,4-bis (4-methoxybenzoyl) benzene on teiophthaloyl chloride and anisole is characterized by the presence of anisole and terephthaloyl chloride in the molar range. 1 \ m 4; 1 solvents and unier addition of 2 MoI-H to 12 mol% zinc powder or 2 mol% to 12 mol% iron powder (teflon on terephthaloyl chloride) are reacted at 110'C to 180'C, the reaction product 1,4-bis (4-methoxybenzoyl) bηften η successively from the Präparektiontgemiseh with methanol deposited and from dimethylformamide (DMF) is recrystallized.

The process is preferably carried out in such a way that anisole and terephthaloyl chloride in a molar ratio> 2: 1 are initially charged and the mixture, after addition of the zinc powder or iron powder *, is heated under reflux until the completion of the hydrogen chloride reforming. The progress of the reaction can be monitored by hydrogen chloride evolution.

The reaction time is influenced by various factors, in particular the type and amount of catalyst, the molar ratio of the reaction couplers, the addition mode and the temperature program. The reaction has been carried out under atmospheric pressure, anisole and terephthaloyl chloride in the molar ratio 4: '<are presented and the mixture after addition of about 10 mol% Zunkpulver, based on terephthaloyl chloride, heated rapidly, the internal temperature of 110'C to 166 * C increases. In this particular case, the reaction is already complete after about 4.5 hours. Thereafter, the Roaming Gomic is terminated after about 4.5 hours. Thereafter, the reaction mixture to obtain the 1,4-bis (4-methoxybenzoyl) benzene is mixed with Moihanol, stirred, the separating solid substance separated and recrystallized from dimethylformamide (DMF).

Daa process according to the invention can also be carried out with significantly smaller amounts of zinc powder or iron powder than 2 mol%, based on terephthaloyl chloride, but significant shifts in the reaction time or reductions in the yield result. Advantageously, the process is carried out with terephthaloyl chloride, based on 2 to 12 mol% of elven powder or zinc powder.

The essential Voriell the erfindungsgcmlßen method is that the proposed catalyst is very cheap and that in contrast to the usual Friedel-Crafts ketone synthesis, in which molar amounts of aluminum chloride are used, is not worked up here with water. Because it works without additional solvents, the expenditure on equipment is reduced, and a molar reaction of the reaction products can be carried out, for example. B. already be carried out in a reaction volume of about 11. Furthermore, the accumulation of waste products is low, which pollution of the environment are largely avoided, and as eliminates the separation of water and solvent residues from the otherwise incurred η voluminous crude. t.

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The work-up can also be carried out in a simple manner by dissolving off the excess of anisole and then reacting the residue with dimethylformamide.

Since the process is hardly influenced by small amounts of water, it is not dead-walled, dried anisole elniusetien. The target product is very difficult to lyophilize in most organic solvents such as toluene, tetrachloromethane, dioxane, chlorobenzene, butyl acetate, etc., and only with good amounts of solvent. The proposed Krltll tion of DMF therefore also represents an optimal Relnlgv ngsvarlante.

AusfOhrungsbettplele example 1

101.0g of terephthalatoyl chloride (0.6 mol) and 216g of anisole I2.0mol) and 3.6g of zinc dust (0.064 -nol) are added until the end of

Hydrogen chloride evolution (about 4.6 h) with stirring until boiling erhiedert. Dunach is cooled and methanol is added. The mixture is stirred through, filtered off with suction and dried. The crude product is recrystallized from dimethylformamide containing 1.4Bls (4X).

MethoxybenioyObenten washed with methanol and dried.

Msn receives 83.6g (64S of Th.) Of colorless crystal powder Ci ₁ HuO ₄ calc. C76.28 H 5,24 018.48

(346,4) gef. C 76.46 H 4.98

Example 2

170g of terephtalloylchloride (0.64mol) are cycled with 363g anisole (3.36mol) and 6.0g iron powder (0.089mol) for 24 hours

Simmer. After cooling, methanol is tugegeben, the mixture stirred and filtered with suction. After drying

is umkrlstallislert from dimethylformamide, washed with methanol and dried.

ManerhMt 170g colorless crystal powder (59% of theory)

1.4Bis (4methoxybentoyl) benzene "" ^^ -j-uu-t - * - ι.ΐ7-ν · * - «ι, π.

Claims (1)

-ι- 2722OS Invention Attention: A process for the preparation of 1,4-bis (4-mothoxybenzoyl) boniums on anisole and terephthaloyl chloride, characterized in that anisole and terephthaloylchloride in molar ratio 2: 1 to 4: 1 solvent and 2 mol% to 12 Mol% of zinc powder or 2 mol% to 12 mol% of iron powder (based on terephthaloylchlorld) at 110'C to 18O ⁰ C umgesetit, the reaction product 1,4-Bls [4-methoxybenioyl) benien subsequently from the reaction mixture with methanol separated and dimethylformamide (DMP) is recrystallized.