A process for the preparation of 4,4'-dichlorodiphenyl ether

Abstract

The application provides a preparation method of 4,4'-dichloride diphenyl ether, comprising the following steps: S1: 4,4'-diphenyl ether dicarboxylic acid is added into a solvent, carbon tetrachloride and a catalyst are dissolved in the same solvent to obtain a mixed solution A, S2: the mixed solution A is added dropwise into a 4,4'-diphenyl ether dicarboxylic acid solution at low temperature, and after the dropwise addition is completed, reaction is carried out at a certain temperature; S3: after the reaction is completed, the solvent is distilled off, and high-quality 4,4'-dichloride diphenyl ether is obtained after post-treatment. The application has the beneficial effects that: the preparation method uses a new process system, is simple to prepare, safe to operate, small in environmental pollution, high in product yield and high in product purity, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, and in particular relates to a method for preparing 4,4'-diacyl chloride diphenyl ether. Background Technology

[0002] Polyamides are polymeric materials whose main chain contains amide bonds. They are renowned for their high toughness, high modulus, and excellent thermal stability, and are located at the forefront of polymeric materials. 4,4'-diphenyl chloride ether is an important polyamide monomer, and polyamides synthesized using it have broad application prospects.

[0003] Currently, the common synthesis method mainly uses 4,4'-diphenyl ether dicarboxylic acid as a raw material and thionyl chloride to synthesize 4,4'-diacyl chloride diphenyl ether. This preparation method has several major challenges: the reaction requires high temperatures, resulting in high energy consumption; the reaction is vigorous, easily accumulating heat at the beginning, posing a risk of material spraying; and the product obtained at high temperatures has unstable and generally poor color, which affects the optical properties of the prepared polyamide. Summary of the Invention

[0004] In view of this, the present invention aims to provide a preparation method for 4,4'-diacyl chloride diphenyl ether that is simple in process, low in production cost, environmentally friendly, produces high quality and yield of product, and is suitable for large-scale production.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A method for preparing 4,4'-diacyl chloride diphenyl ether includes the following steps:

[0007] S1: Add 4,4'-diphenyl ether dicarboxylic acid to the solvent, and dissolve carbon tetrachloride and the catalyst in the same solvent to obtain mixed solution A.

[0008] S2: Add mixed solution A dropwise to 4,4'-diphenyl ether dicarboxylic acid solution at low temperature. After the addition is complete, react at a certain temperature.

[0009] S3: After the reaction is complete, the solvent is evaporated, and after post-treatment, high-quality 4,4'-diacyl chloride diphenyl ether is obtained.

[0010] Furthermore, the solvent in step S1 is one or more of tetrahydrofuran, dichloromethane, acetonitrile, diethyl ether, and methyl tert-butyl ether.

[0011] Preferably, the solvent is tetrahydrofuran.

[0012] Furthermore, the catalyst in step S1 is one or more of triphenylphosphine, tricyclohexylphosphine, and phenyldicyclohexylphosphine;

[0013] Preferably, the catalyst is tricyclohexylphosphine.

[0014] Furthermore, after the addition in step S2 is completed, the molar ratio of solvent, carbon tetrachloride, catalyst, and 4,4'-diphenyl ether dicarboxylic acid is 30-50:2.5-4:3-5:1.

[0015] The reaction temperature in step S2 is 30-50℃.

[0016] Furthermore, in step S3, the solvent is evaporated, a mixed solvent is added to the remaining residue, the mixture is heated to dissolve, activated carbon is added for decolorization, the mixture is filtered, the filtrate is cooled to precipitate white crystals, the crystals are filtered and vacuum dried to obtain high-quality 4,4'-diacyl chloride diphenyl ether.

[0017] Furthermore, the mixed solvent in step S2 is one of n-hexane / acetonitrile, n-hexane / ethyl acetate, or n-hexane / isopropyl ether;

[0018] Preferably, the mixed solvent is n-hexane / acetonitrile;

[0019] Furthermore, the molar ratio of n-hexane to other solvents is 1-3:1.

[0020] Furthermore, the molar ratio of the mixed solvent to 4,4'-diphenyl ether dicarboxylic acid is 10-20:1.

[0021] Furthermore, a mixed solvent is added and the temperature is raised to 50-60℃.

[0022] Furthermore, the mass ratio of activated carbon to 4,4'-diphenyl ether dicarboxylic acid is 0.05-0.2:1.

[0023] Compared with the prior art, the preparation method of 4,4'-diacyl chloride diphenyl ether described in this invention has the following advantages:

[0024] The preparation method described in this invention uses a novel process system, which is simple to prepare, safe to operate, has low environmental pollution, and produces high-yield and high-purity synthetic products, making it suitable for large-scale production. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a synthetic route diagram of 4,4'-diacyl chloride diphenyl ether obtained in Example 1 of the present invention;

[0027] Figure 2 This is an HPLC chromatogram of 4,4'-diacyl chloride diphenyl ether prepared in Example 1 of the present invention. Detailed Implementation

[0028] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] Example 1

[0031] 50g of 4,4'-diphenyl ether dicarboxylic acid was added to 420g of tetrahydrofuran and stirred until homogeneous; this solution is designated as solution A. 89.35g of carbon tetrachloride and 190.03g of tricyclohexylphosphine were added to 140g of tetrahydrofuran; this solution is designated as solution B. Solution A was cooled to 0℃, and solution B was slowly added dropwise to it. After the addition was complete, the temperature was slowly raised to 35℃, and the reaction was maintained at this temperature for 5 hours. Liquid chromatography analysis confirmed the reaction was complete. The solvent was evaporated under reduced pressure at 50°C. The remaining residue was added to a mixed solution of 40g acetonitrile and 87g n-hexane. The temperature was raised to 55°C, and the system gradually dissolved until transparent. 5g activated carbon was added and stirred for 20min. The mixture was then hot-filtered, and the filtrate was slowly cooled to 0°C, resulting in the precipitation of a large amount of white crystals. After filtration, the solid was dried under vacuum at 80°C for 12h to obtain 56.38g of 4,4'-diacyl chloride diphenyl ether, with a molar yield of 98.67%, a purity of 99.95%, and YI = 0.34.

[0032] Example 2

[0033] 50g of 4,4'-diphenyl ether dicarboxylic acid was added to 400g of methyl tert-butyl ether and stirred until homogeneous; this solution is designated as solution A. 80.41g of carbon tetrachloride and 217.17g of tricyclohexylphosphine were added to 200g of methyl tert-butyl ether; this solution is designated as solution B. Solution A was cooled to 5℃, and solution B was slowly added dropwise to it. After the addition was complete, the temperature was slowly raised to 35℃, and the reaction was maintained at this temperature for 7 hours. Liquid chromatography analysis confirmed the reaction was complete. The solvent was evaporated under reduced pressure at 50°C. The remaining residue was added to a mixed solution of 57.24 g ethyl acetate and 143.96 g n-hexane. The temperature was raised to 60°C, and the system gradually dissolved until transparent. 20 g activated carbon was added and stirred for 20 min. The mixture was then hot-filtered, and the filtrate was slowly cooled to 0°C, resulting in the precipitation of a large amount of white crystals. After filtration, the solid was dried under vacuum at 80°C for 12 h to obtain 55.74 g of 4,4'-diacyl chloride diphenyl ether, with a molar yield of 97.54%, a purity of 99.87%, and YI = 0.47.

[0034] Example 3

[0035] 50g of 4,4'-diphenyl ether dicarboxylic acid was added to 300g of tetrahydrofuran and stirred until homogeneous; this solution is designated as solution A. 104.24g of carbon tetrachloride and 187.88g of triphenylphosphine were added to 120g of tetrahydrofuran; this solution is designated as solution B. Solution A was cooled to 0℃, and solution B was slowly added dropwise to it. After the addition was complete, the temperature was slowly raised to 40℃, and the reaction was maintained at this temperature for 5 hours. Liquid chromatography analysis confirmed the reaction was complete. The solvent was evaporated under reduced pressure at 50°C. The remaining residue was added to a mixed solution of 177.67 g isopropyl ether and 150 g n-hexane. The mixture was heated to 50°C, and the system gradually dissolved until transparent. 15 g activated carbon was added and stirred for 20 min. The mixture was then hot-filtered, and the filtrate was slowly cooled to 0°C, resulting in the precipitation of a large amount of white crystals. The solid was then dried under vacuum at 80°C for 12 h to obtain 54.76 g of 4,4'-diacyl chloride diphenyl ether, with a molar yield of 95.83%, a purity of 99.82%, and YI = 0.49.

[0036] Comparative Example 1

[0037] 50 g of 4,4'-diphenyl ether dicarboxylic acid was added to a mixed solvent of 500 g toluene and 5 g dimethylformamide. The mixture was heated to 80 °C, and 15 mL of thionyl chloride was slowly added dropwise. After the addition was complete, the mixture was kept at 80 °C for 12 h. The reaction was confirmed to be complete by liquid chromatography. The solvent was evaporated under reduced pressure at 50 °C. The remaining residue was added to a mixed solution of 177.67 g isopropyl ether and 150 g n-hexane. The mixture was heated to 50 °C, and the system gradually dissolved until transparent. 15 g of activated carbon was added and stirred for 20 min. The mixture was then hot-filtered, and the filtrate was slowly cooled to 0 °C. A large amount of pale yellow solid precipitated out. After filtration, the solid was dried under vacuum at 80 °C for 12 h to obtain 48.98 g of 4,4'-diphenyl chloride dicarboxylic acid, with a molar yield of 85.73%, a purity of 99.12%, and YI = 8.6.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the preparation of 4,4'-dichloro diphenyl ether, characterized in that: It comprises the following steps: S1: 4,4'-diphenyl ether dicarboxylic acid is added to a solvent, carbon tetrachloride, a catalyst is dissolved in the same solvent to obtain a mixed solution A, The catalyst in step S1 is one or more of triphenylphosphine, tricyclohexylphosphine, and phenyl dicyclohexylphosphine; S2: The mixed solution A is added dropwise to a 4,4'-diphenyl ether dicarboxylic acid solution at low temperature, and after the dropwise addition is completed, the reaction is carried out at a certain temperature; The reaction temperature in step S2 is 30-50℃; S3: After the reaction is completed, the solvent is evaporated, and after post-treatment, high-quality 4,4'-dichloroformyl diphenyl ether is obtained.

2. The process for the preparation of 4,4'-dichloro diphenyl ether according to claim 1, characterized in that: The solvent in step S1 is one or more of tetrahydrofuran, dichloromethane, acetonitrile, diethyl ether, and methyl tert-butyl ether.

3. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 1, characterized in that: The solvent is tetrahydrofuran.

4. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 1, characterized in that: The catalyst is tricyclohexylphosphine.

5. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 1, characterized in that: After the dropwise addition is completed in step S2, the molar ratio of the solvent, carbon tetrachloride, the catalyst, and 4,4'-diphenyl ether dicarboxylic acid is 30-50:2.5-4:3-5:

1.

6. The process for the preparation of 4,4'-dichloro diphenyl ether as claimed in claim 1, wherein: In step S3, the solvent is evaporated, a mixed solvent is added to the remaining residue, and after warming and dissolving, activated carbon is added for decolorization, then it is filtered, the filtrate is cooled to precipitate white crystals, and the crystals are filtered and vacuum dried to obtain high-quality 4,4'-dichloroformyl diphenyl ether.

7. The process for the preparation of 4,4'-dichloro diphenyl ether according to claim 6, wherein: The mixed solvent in step S2 is one of n-hexane / acetonitrile, n-hexane / ethyl acetate, and n-hexane / isopropyl ether.

8. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 6, characterized in that: The mixed solvent is n-hexane / acetonitrile.

9. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 7, characterized in that: The molar ratio of n-hexane to other solvents is 1-3:

1.

10. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 6, characterized in that: The molar ratio of the mixed solvent to 4,4'-diphenyl ether dicarboxylic acid is 10-20:

1.

11. The process for the preparation of 4,4'-dichloro diphenyl ether as claimed in claim 6, wherein: The mixed solvent is added and warmed to 50-60℃.

12. The method for preparing a 4,4'-diacyl chloride diphenyl ether according to claim 6, characterized in that: The mass ratio of activated carbon to 4,4'-diphenyl ether dicarboxylic acid is 0.05-0.2:1.

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