CN113735806A

CN113735806A - Method for preparing chlorophthalic anhydride by solvent-free liquid phase catalytic oxidation

Info

Publication number: CN113735806A
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: 2021-12-03
Anticipated expiration: 2041-08-03
Also published as: CN113735806B

Abstract

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

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 the biphenyl dianhydride and various ether anhydrides at present, and the existing preparation method mainly comprises the following steps: 1) the method of introducing chlorine gas into phthalic anhydride, but the product mainly comprises 4-chlorophthalic anhydride, and the obtained product contains a large amount of unreacted phthalic anhydride raw materials, and is difficult to separate and purify; 2) the method adopts a chloro-o-xylene gas-phase oxidation method, but the method has high reaction temperature, serious carbonization corrosion, yield of about 70 percent, low atom economy and failure of several industrialization; 3) the method adopts a chlorinated o-xylene liquid phase oxidation method, which needs to adopt a titanium kettle with high price, acetic acid as a solvent, manganese, cobalt, nickel, bromine and the like as a catalyst, although the reaction yield is high, the reaction high pressure oxidation and a large amount of low boiling point acetic acid as a solvent need to be initiated and maintained at a pressure of 2.0-2.4 MPa and a temperature of more than 200 ℃, and belongs to a dangerous process, the industrialization of the process 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 novel scheme for preparing the chlorophthalic anhydride by the solvent-free catalytic oxidation of chloro-o-xylene, the invention utilizes the characteristic of the boiling point of the chloro-o-xylene to 200 ℃, takes the chloro-o-phthalic acid with the boiling point of more than 300 ℃ (the melting point is more than 130 ℃) as a solvent-free reaction system of an additive, a high-boiling-point organic matter system meets the condition that oxygen free radicals are formed by a cobalt-manganese-bromine composite catalyst under normal pressure, and the byproduct water generated by the reaction can be timely shunted and removed without influencing the activity of the catalyst; the reaction vessel does not need to be sealed, the catalytic oxidation reaction can be realized by using a ceramic or glass reaction kettle, and the use of a titanium kettle with high price is avoided, so that the investment of fixed assets can be greatly reduced.

In order to realize the invention task, 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 two, and the mass percentage concentration is 1-30%;

the preparation and separation process is as follows: mixing chloro-o-xylene, a catalyst and an additive into a reactor, introducing oxygen or air, reacting at 130-240 ℃ for 2-24 hours, stopping the reaction when the concentration of oxygen in tail gas reaches 95% of that of an air inlet sample, and then distilling and dehydrating to obtain chloro-phthalic 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, the ratio of cobalt: manganese: the molar ratio of the elements of bromine is 1-10: 2-8: 2-10, and 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 solvent-free liquid phase oxidation reaction is carried out under normal pressure, 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 recover, and the method is suitable for the industrial process.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The present invention will be described in detail 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 (1moL), 0.3g of catalyst cobalt acetate, 0.1g of manganese acetate and 1g of tetrabromoethane, 10g of 4-chlorophthalic acid are added into a 500mL glass reaction tube to be mixed, the mixture is stirred and heated to 150 ℃, oxygen with the purity of 100% is introduced, the flow rate is 360mL/min, the temperature is controlled at 200 ℃ for reaction for 10 hours, the reaction is stopped when the concentration of oxygen in tail gas is detected to be 95%, and then the 4-chloro-phthalic anhydride is obtained by distillation and dehydration, the yield is 94%, and the melting point is 96 ℃.

Example 2

140g of 3-chloro-o-xylene (1moL), 0.4g of catalyst cobalt acetate, 0.15g of manganese acetate, 1.5g of tetrabromoethane and 13g of 3-chloro phthalic acid are added into a 500mL glass reaction tube to be mixed, the mixture is 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 be 210 ℃ for reaction for 15 hours, the reaction is stopped when the concentration of oxygen in tail gas is detected to be 95%, and then the 3-chloro phthalic anhydride 181.3g, the yield is 93% and the melting point is 125 ℃ are obtained by distillation and dehydration.

Example 3

14g of a mixture of 3-, 4-chloro-o-xylene (0.1moL, 0.45/0.55), a catalyst of cobalt acetate 0.04g, manganese acetate 0.015g, sodium bromide 0.3g and 3-chloro-phthalic acid 1.3g are added into a 500mL glass reaction tube to be mixed, the mixture is stirred and heated to 150 ℃, air is introduced, the flow rate is 240mL/min, the temperature is gradually increased to 210 ℃ and the reaction is stopped when the concentration of tail gas oxygen is detected to be 20%, and then the mixture of 3-and 4-chloro-phthalic anhydride 180.3g is obtained by distillation and dehydration, the yield is 92% and the melting point is 98 ℃.

The present invention provides a solvent-free catalytic oxidation process for preparing chlorophthalic anhydride, which is described in detail above, and the principle and embodiments of the present invention are illustrated herein by using specific examples, and the description of the examples is only for the purpose of helping understanding the process of the present invention and the core concept thereof, and it should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and the improvements and modifications also fall within the full protection scope of the present 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 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; 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, the ratio of cobalt: manganese: the molar ratio of the elements of bromine is 1-10: 2-8: 2-10, and the mass percentage concentration of the catalyst in the reaction system is 0.01-0.5%.

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