CN113735806B

CN113735806B - Method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation

Info

Publication number: CN113735806B
Application number: CN202110888516.4A
Authority: CN
Inventors: 高昌录; 孙秀花; 李大龙
Original assignee: Harbin Institute of Technology Weihai
Current assignee: Harbin Institute of Technology Weihai
Priority date: 2021-08-03
Filing date: 2021-08-03
Publication date: 2023-07-28
Anticipated expiration: 2041-08-03
Also published as: CN113735806A

Abstract

The invention discloses a method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation, which takes chloro-o-xylene as raw material, cobalt, manganese and bromine as composite catalyst, atomic oxygen as oxidant and chlorophthalic acid as additive.

Description

Method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation

Technical Field

The invention relates to a method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation, belonging to the category of synthetic chemistry.

Background

The chlorophthalic anhydride is a key raw material for preparing biphenyl dianhydride and various ether anhydrides at present, and the existing preparation method mainly comprises the following steps: 1) The method of introducing chlorine into phthalic anhydride mainly uses 4-chlorophthalic anhydride, and the obtained product has a large amount of unreacted phthalic anhydride raw materials, so that the separation and purification are difficult; 2) The gas-phase oxidation method of chloro-o-xylene has high reaction temperature, serious carbonization corrosion, about 70 percent of yield, low atom economy and failure in industrialization for several times; 3) The method adopts a high-price titanium kettle, takes acetic acid as a solvent, takes manganese cobalt nickel bromine and the like as a catalyst, and has higher reaction yield, but the high-pressure oxidation of the reaction and the massive use of acetic acid with low boiling point as the solvent can initiate and maintain the reaction under the pressure of 2.0-2.4 megapascals at the temperature of more than 200 ℃, thus belonging to dangerous processes, the industrialization of the method is more and more difficult, and the high-boiling point normal pressure reaction greatly improves the index of safe production.

Disclosure of Invention

In order to overcome the defects in the preparation of the chlorophthalic anhydride, the invention provides a new scheme for preparing the chlorophthalic anhydride by solvent-free catalytic oxidation of chloro-o-xylene, which utilizes the characteristic of the boiling point of chloro-o-xylene to 200 ℃, takes chlorophthalic acid with the boiling point of 300 ℃ (the melting point of which is more than 130 ℃) as a solvent-free reaction system of an additive, and a high-boiling organic system meets the condition that a cobalt-manganese-bromine composite catalyst forms oxygen free radicals under normal pressure, and by-product water generated by the reaction can be timely shunted and removed without affecting the activity of the catalyst; the reaction vessel can realize catalytic oxidation reaction by using ceramic or glass reaction kettles without sealing, and avoids using expensive titanium kettles, so that the investment in fixed assets can be greatly reduced.

In order to realize the task of the invention, the invention adopts the following technical scheme:

a method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation is implemented according to the following steps:

the catalyst is a compound of cobalt salt, manganese salt and bromide;

the additive is 3-chlorophthalic acid, 4-chlorophthalic acid or a mixture of the 3-chlorophthalic acid and the 4-chlorophthalic acid, and the mass percentage concentration is 1-30%;

the preparation and separation processes are as follows: mixing chloro-o-xylene, a catalyst and an additive into a reactor, introducing oxygen or air, reacting for 2-24 hours at 130-240 ℃, stopping the reaction when the concentration of oxygen in the tail gas reaches 95% of the concentration of a gas inlet sample, and then distilling and dehydrating to obtain the chlorophthalic anhydride.

Further, the cobalt salt is one of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt oxalate, cobalt chloride or cobalt bromide salt; the manganese salt is one of manganese acetate, manganese carbonate, manganese nitrate, manganese oxalate, manganese chloride, manganese sulfate or manganese bromide; the bromide is sodium bromide or tetrabromoethane; wherein, cobalt: manganese: bromine element molar ratio=1 to 10: 2-8:2-10, the mass percentage concentration of the catalyst in the reaction system is 0.01-0.5%.

Further, the chloro-o-xylene comprises 3-chloro-o-xylene, 4-chloro-o-xylene or a mixture of the two; the content of the oxidant is 20-100% of oxygen.

The invention has the advantages that the normal pressure solvent-free liquid phase oxidation reaction is realized, the problem of using a large amount of acetic acid solvent in the prior art is avoided, the product separation is easy, the catalyst is easy to recycle, and the invention is suitable for the industrialized process.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The present invention will be specifically described with reference to examples, but the present invention is not limited to the scope of the examples.

Example 1

140g of 4-chloro-o-xylene (1 moL), 0.3g of catalyst cobalt acetate and 0.1g of manganese acetate are added into a 500mL glass reaction tube, mixed, stirred and heated to 150 ℃ and then fed with 100% pure oxygen, the flow rate is 360mL/min, the temperature is controlled at 200 ℃ for 10 hours, the reaction is stopped when the concentration of oxygen in the tail gas is detected to be 95%, then 182.3g of 4-chlorophthalic anhydride is obtained through distillation and dehydration, the yield is 94%, and the melting point is 96 ℃.

Example 2

140g of 3-chloro-o-xylene (1 moL), 0.4g of catalyst cobalt acetate and 0.15g of manganese acetate are added into a 500mL glass reaction tube, 1.5g of tetrabromoethane and 13g of 3-chlorophthalic acid are mixed, stirred and heated to 150 ℃, oxygen with the purity of 100% is introduced, the flow rate is 240mL/min, the temperature is started, the temperature is controlled to react for 15 hours at 210 ℃, the reaction is stopped when the concentration of tail gas oxygen is detected to be 95%, then the 3-chlorophthalic anhydride is obtained by distillation dehydration, the yield is 93%, and the melting point is 125 ℃.

Example 3

In a 500mL glass reaction tube, 14g of a mixed 3-, 4-chloro-o-xylene mixture (0.1 mOl, 0.45/0.55), 0.04g of cobalt acetate as a catalyst, 0.015g of manganese acetate, 0.3g of sodium bromide and 1.3g of 3-chlorophthalic acid were added, and mixed, stirred and heated to 150 ℃, air was introduced at a flow rate of 240mL/min, the temperature was gradually increased to 210 ℃, the reaction was carried out for 8 hours, the reaction was stopped when the concentration of oxygen in the tail gas was detected to 20%, and then 180.3g of a 3-and 4-chlorophthalic anhydride mixture was obtained by distillation dehydration, the yield was 92%, and the melting point was 98 ℃.

The method for preparing the chlorophthalic anhydride by solvent-free catalytic oxidation provided by the invention is described in detail, and specific examples are used for illustrating the principle and the implementation mode of the invention, and the above examples are only used for helping to understand the method and the core idea of the invention, so that a person skilled in the art can carry out several improvements and modifications without departing from the scope of the full protection of the invention.

Claims

1. A method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation is characterized in that the preparation process is as follows in formula 1:

wherein the catalyst is a compound of cobalt salt, manganese salt and bromide;

2. The method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation according to claim 1, wherein the cobalt salt is one of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt oxalate, cobalt chloride or cobalt bromide salt; the manganese salt is one of manganese acetate, manganese carbonate, manganese nitrate, manganese oxalate, manganese chloride, manganese sulfate or manganese bromide; the bromide is sodium bromide or tetrabromoethane; wherein, cobalt: manganese: bromine element molar ratio=1 to 10: 2-8:2-10, the mass percentage concentration of the catalyst in the reaction system is 0.01-0.5%.

3. The process for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation according to claim 1, characterized in that the chloro-ortho-xylene comprises 3-chloro-ortho-xylene, 4-chloro-ortho-xylene or a mixture of both; the content of the oxidant is 20-100% of oxygen.