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A method for preparing high-purity 4,4'-difluorobenzophenone

A technology of difluorobenzophenone and p-fluorobenzoic acid is applied in the field of preparation of fluorine-containing intermediates, which can solve the problems of high temperature and pressure requirements, low yield, and difficulty in realizing cost control, and achieves synthesis process conditions. The effect of mildness, cheap and easy-to-obtain raw materials, broad application prospects and industrial value

Active Publication Date: 2016-10-12
RUYUAN YAO AUTONOMOUS COUNTY DONGYANGGUANG FORMED FOIL CO LTD
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  • Summary
  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are many routes for public reports on 4,4'-difluorobenzophenone, mainly as follows: (1) Patent EP 178184 reports that fluorobenzene and p-fluorobenzoyl chloride are used as raw materials in trichlorination Under the catalysis of aluminum, product is made, and this method yield is higher, and the purity of product is also relatively high, but the cost of the raw material p-fluorobenzoyl chloride of reaction is on the high side, is unfavorable for suitability for industrialized production; (2) China Pharmaceutical Industry Journal, 40(10), 737-738; 2009 Using fluorobenzene as raw material, the product was obtained under the direct catalysis of phosgene and aluminum trichloride, but the content of the isomer 2,4'-difluorobenzophenone in the product Higher, in addition phosgene is highly toxic, and the yield of this route is also low; (3) Journal of Hebei University of Science and Technology, 29 (1), 20-22; 2008 reported that fluorobenzene was used as raw material, carbon tetrachloride Under the catalysis of aluminum chloride, 4,4'-difluorodiphenyldichloromethane is generated, and then hydrolyzed under acidic conditions to obtain the product. This method is simple to operate, but the by-product isomer 2,4'-difluorobenzophenone More, not conducive to purification, and the yield is also low; (4) patent JP 61221146 uses fluorobenzene as raw material, in the presence of CO and air, with PdCl 2 and FeCl 3 The product is obtained by reacting the catalyst, which requires high temperature and pressure, and the catalysis of the reaction is relatively expensive, so it is not easy to realize the cost control of industrialization; (5) Patent US 4453009 reports the use of 4,4'-dichloro Benzophenone is used as the starting raw material, and 4,4'-difluorobenzophenone is obtained through KF fluorination. The raw material of this method is not easy to prepare, and the conversion is not complete, and it is difficult to obtain a product with a purity that meets the requirements; (6) Patent EP 0004710 reported 4,4'-diaminodiphenylmethane as starting material, and NaNO 2 4,4′-difluorodiphenylmethane is produced by Sandmeyer reaction with HF, and then oxidized by nitric acid at low temperature. This route has been industrialized, but the reaction time is long, the equipment is seriously corroded, and there are hidden dangers of explosion, etc. limitation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Preparation of p-fluorobenzoic acid:

[0028] In a round-bottomed flask equipped with stirring, a thermometer, and a reflux condenser, 220 g (2.0 mol) of p-fluorotoluene and 34 g (0.2 mol) of hydrobromic acid were added successively, and the temperature was slowly raised to 75 ° C, and the incandescent lamp was turned on to give Light source illumination. 680 g (6.0 mol) of 30% hydrogen peroxide was started dropwise addition, the dropwise addition was completed within 3 hours, and the temperature was maintained for 6 hours. After the bromine color in the reaction system has basically faded, the gas phase detection of p-fluorotoluene is completely converted, cooled to room temperature, the reaction product is poured into ice water, a large amount of white solid is precipitated, and about 266 g of p-fluorobenzoic acid is obtained by suction filtration. Yield 95.1%.

[0029] Preparation of p-fluorobenzoyl chloride:

[0030] Weigh solid phosgene (BTC) 89.1g (0.3mol) and ...

Embodiment 2

[0034] Preparation of p-fluorobenzoic acid:

[0035] In a round-bottomed flask equipped with stirring, a thermometer and a reflux condenser, 220 g (2.0 mol) of p-fluorotoluene and 34 g (0.2 mol) of hydrobromic acid were successively added, and the temperature was slowly raised to 100 ° C, and the reaction was transferred to sunlight under natural sunlight. 567 g (5.0 mol) of 30% hydrogen peroxide was started to be added dropwise, and the dropwise addition was completed within 3 hours, and the temperature was maintained for 6 hours. After the color of bromine in the reaction system has basically faded, the gas phase detection of p-fluorotoluene is completely converted, cooled to room temperature, the product of the reaction is poured into ice water, a large amount of white solid is precipitated, and about 261 g of p-fluorobenzoic acid is obtained by suction filtration. Yield 93.2%.

[0036] Preparation of p-fluorobenzoyl chloride:

[0037] Weigh solid phosgene (BTC) 89.1g (0...

Embodiment 3

[0041] Preparation of p-fluorobenzoyl chloride:

[0042] In a round-bottomed flask equipped with stirring, a thermometer and a reflux condenser, 220 g (2.0 mol) of p-fluorotoluene and 34 g (0.2 mol) of hydrobromic acid were successively added, and the temperature was slowly raised to 50°C, then the UV lamp was turned on, and the Illuminated with light source. 1134 g (10.0 mol) of 30% hydrogen peroxide was started to be added dropwise, and the dropwise addition was completed within 3 hours, and the reaction was maintained at the temperature for 6 hours. After the bromine color in the reaction system has basically faded, the gas phase detection of p-fluorotoluene is completely converted, cooled to room temperature, the reaction product is poured into ice water, a large amount of white solid is precipitated, and about 269 g of p-fluorobenzoic acid is obtained by suction filtration. Yield 96.8%.

[0043] Preparation of p-fluorobenzoyl chloride:

[0044] Weigh solid phosgene (BT...

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Abstract

The invention discloses a method for preparing high-purity 4,4'-difluorobenzophenone. p-fluorotoluene is used as an initial raw material and oxidation reaction, chloroformylation reaction and condensation reaction are carried out, so that the target product 4,4'-difluorobenzophenone is finally obtained; the melting point of the product is 107-109 DEG C; the purity of the product is greater than or equal to 99.9 percent and accords with the purity requirement for synthesis of polyether-ether-ketone (PEEK). Moreover, according to the preparation method disclosed by the invention, the used raw material is cheap and is easy to obtain, the synthetic process conditions are mild and in the synthesizing process, a used reagent is relatively green and environmental-friendly, and thus, the method has wide application prospect and high industrial value.

Description

technical field [0001] The invention relates to the field of preparation of fluorine-containing intermediates, in particular to a method for preparing high-purity 4,4'-difluorobenzophenone. Background technique [0002] 4,4'-Difluorobenzophenone is an important fluorine-containing intermediate, an important intermediate for the synthesis of fluorine-containing drugs flunarizine, lomerizine and amitriazine, and its special application lies in its It is a monomer of special high-performance engineering plastic polyetheretherketone (PEEK). In the field of chemical and military industry, polyetheretherketone (PEEK) is a special polymer material. It has physical and chemical properties such as high temperature resistance and chemical corrosion resistance. It can be used as a high temperature resistant structural material and electrical insulating material, and can be compounded with glass fiber or carbon fiber to prepare reinforcing materials. Generally, a type of polyarylene et...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C49/813C07C45/45
CPCC07C45/46C07C51/60C07C49/813C07C63/70
Inventor 李凯伍阳王发平方海亮曾水明刘新烁
Owner RUYUAN YAO AUTONOMOUS COUNTY DONGYANGGUANG FORMED FOIL CO LTD
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