Method for deep reduction of phenazine waste residue

Abstract

This invention provides a method for the deep reduction of phenazine waste residue. The phenazine waste residue generated during RT-PS production is hydrogenated and reduced to cyclohexylamine using a supported nickel catalyst. This invention, through deep reduction, converts phenazine, azobenzene, aniline, and other components in the phenazine waste residue into cyclohexylamine, solving the problem of difficult disposal of phenazine waste residue and realizing its resource utilization. This significantly reduces waste residue emissions during RT-PS production.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals, specifically relating to a method for the deep reduction of phenazine waste residue. Background Technology

[0002] RT-Pyrate, chemically known as p-aminodiphenylamine, can be used in rubber additives, dyes, textiles, printing and pharmaceutical industries, etc. It is mainly used to produce p-phenylenediamine rubber antioxidants such as 6PPD and 4010NA. The global production capacity of RT-Pyrate is approximately 225kt / a.

[0003] The nitrobenzene process is currently the latest industrialized process for synthesizing p-aminodiphenylamine internationally, and it is a clean and green process. In the nitrobenzene process for producing RT (p-aminodiphenylamine), the condensation step uses a batch reactor. Aniline, nitrobenzene, and the catalyst quaternary ammonium base react under vacuum conditions to yield 4-nitrodiphenylamine and 4-nitrosodiphenylamine. The reaction process is as follows:

[0004] (1) Aniline reacts with an organic base to dehydrate and generate aniline anions.

[0005]

[0006] The dehydration of aniline with organic bases to produce aniline anions is a prerequisite for the condensation of aniline with nitrobenzene to produce 4-(nitroso)nitrate.

[0007] (2) The aniline anion reacts with nitrobenzene to form a complex.

[0008]

[0009] The formation of the complex is key to the overall selectivity of the target products 4-nitrosodiphenylamine and 4-nitrodiphenylamine.

[0010] (3) Rearrangement, hydrolysis

[0011]

[0012] The complex undergoes molecular rearrangement and hydrolysis to yield 4-nitrosodiphenylamine, or reacts with nitrobenzene followed by rearrangement and hydrolysis to yield 4-nitrosodiphenylamine. During rearrangement, one molecule of water is released, and during hydrolysis, one molecule of water is consumed, releasing tetramethylammonium hydroxide. From step (1) to step (3), tetramethylammonium hydroxide completes the catalytic condensation process.

[0013] (4) 4-(nitrosodiphenylamine) is hydrogenated and reduced to RT-pes, and azobenzene is reduced to aniline.

[0014]

[0015] During the reaction of aniline anions with nitrobenzene, the aniline anions attack the ortho-position of the nitro group in nitrobenzene, producing phenazine. The phenazine produced is separated during the RT-process die distillation, yielding phenazine waste residue. The phenazine content in the waste residue can be as high as 80%. Currently, in the production of RT-process die distillation using the nitrobenzene method, 2-10 kg of phenazine waste residue is generated for every ton of RT-process die distillation.

[0016] Currently, phenazine waste is typically disposed of by direct incineration as hazardous waste. Some studies have explored refining the phenazine from the waste to obtain high-purity phenazine. However, due to market constraints, the amount of phenazine generated in RT-process RT-process production far exceeds market demand. Therefore, the phenazine waste generated in RT-process RT-process RT-process is primarily treated as hazardous waste, resulting in resource waste. Summary of the Invention

[0017] The phenazine molecules produced during RT product manufacturing have a conjugated structure, exhibiting relatively stable chemical properties and being difficult to decompose, add to, or substitute. Through extensive research and implementation, the applicant has discovered that phenazine and other substances in the phenazine waste residue can be reduced to cyclohexylamine under high temperature and pressure, catalyzed by a highly active hydrogenation catalyst, thus achieving the resource utilization of the phenazine waste residue.

[0018] Based on the above research, in order to solve the problem that the phenazine waste residue generated in the current RT production process is mainly treated as hazardous waste, resulting in resource waste, this invention provides a method for deep reduction of phenazine waste residue.

[0019] The method for deep reduction of phenazine waste residue described in this invention uses phenazine waste residue generated during RT product manufacturing as raw material and a nickel-supported catalyst as a hydrogenation catalyst for hydrogenation reduction to reduce phenazine in the phenazine waste residue to cyclohexylamine. Specifically, it includes the following steps:

[0020] 1) Heat the phenazine waste residue until it is completely melted;

[0021] 2) Add the molten phenazine waste to the reactor and add a supported nickel catalyst for deep reduction.

[0022] Furthermore, the support for the nickel catalyst is alumina, and the nickel content is 5%-40%.

[0023] Furthermore, the mass ratio of the added nickel catalyst to the phenazine waste residue is 0.05-0.20:1.

[0024] Furthermore, the hydrogenation reduction temperature is 240-340℃, the hydrogenation reduction pressure is 2.0-8.0MPa, and the hydrogenation reduction residence time is 1-8h.

[0025] This invention has the following advantages and technological advancements:

[0026] This invention utilizes a deep reduction method to convert phenazine, azobenzene, aniline, and other components in phenazine waste residue into cyclohexylamine, solving the problem of difficult disposal of phenazine waste residue and realizing its resource utilization. This significantly reduces waste emissions during RT product production. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the embodiments.

[0028] Example 1

[0029] 200g of 99.9% phenazine was added to a high-pressure reactor, followed by 20g of a nickel-supported catalyst with a nickel content of 28%. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 300℃ and the reaction pressure at 8.0MPa. Hydrogen was continuously introduced for reduction. After 5 hours of reduction, the reactor was opened, and 217.1g of the reduced solution was obtained. A sample was taken for analysis.

[0030] HPLC analysis results: cyclohexylamine 83.9%, phenazine 1.4%, 2-aminodicyclohexylamine 9.7%. The calculated yield of cyclohexylamine was 82.7%.

[0031] Example 2

[0032] 200g of 99.9% phenazine was added to a high-pressure reactor, followed by 40g of a nickel-supported catalyst with a nickel content of 40%. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 320℃ and the reaction pressure at 8.0MPa. Hydrogen was continuously introduced for reduction. After 8 hours of reduction, the reactor was opened, and 218.5g of the reduced solution was obtained. A sample was taken for analysis.

[0033] HPLC analysis results: cyclohexylamine 86.4%, phenazine 0.4%, 2-aminodicyclohexylamine 6.7%. The calculated yield of cyclohexylamine was 85.0%.

[0034] Example 3

[0035] 200g of 99.9% phenazine was added to a high-pressure reactor, followed by 10g of a nickel-supported catalyst with a nickel content of 28%. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 240℃ and the reaction pressure at 2.0MPa. Hydrogen was continuously introduced for reduction. After 1 hour of reduction, the reactor was opened, and 208.9g of the reduced solution was obtained. A sample was taken for analysis.

[0036] HPLC analysis results: cyclohexylamine 27.8%, phenazine 22.4%, 2-aminodicyclohexylamine 47.9%. The calculated yield of cyclohexylamine was 26.4%.

[0037] Example 4

[0038] 200g of phenazine waste containing 72.3% phenazine, 10.9% RT-pes, 13.1% 2-aminodiphenylamine, 1.4% aniline, and 2.3% azobenzene was added to a high-pressure reactor. Then, 40g of a supported nickel catalyst with a nickel content of 40% was added. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 320℃ and the reaction pressure at 8.0MPa. Hydrogen was continuously introduced for reduction. After 8 hours of reduction, the reactor was opened, and 219.7g of reduced solution was obtained. A sample was taken for analysis.

[0039] HPLC analysis results: cyclohexylamine 87.6%, phenazine 1.6%, 2-aminodicyclohexylamine 7.5%. The calculated yield of cyclohexylamine was 88.8%.

[0040] Example 5

[0041] 200g of phenazine waste containing 72.3% phenazine, 10.9% RT-pes, 13.1% 2-aminodiphenylamine, 1.4% aniline, and 2.3% azobenzene was added to a high-pressure reactor. Then, 40g of a nickel-supported catalyst with a nickel content of 40% was added. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 340℃ and the reaction pressure at 8.0MPa. Hydrogen was continuously introduced for reduction. After 8 hours of reduction, the reactor was opened, and 219.3g of reduced solution was obtained. A sample was taken for analysis.

[0042] HPLC analysis results: cyclohexylamine 82.6%, phenazine 0.3%, 2-aminodicyclohexylamine 4.8%. The calculated yield of cyclohexylamine was 83.6%.

[0043] Example 6

[0044] 200g of phenazine waste containing 72.3% phenazine, 10.9% RT-pes, 13.1% 2-aminodiphenylamine, 1.4% aniline, and 2.3% azobenzene was added to a high-pressure reactor. Then, 20g of a supported nickel catalyst with a nickel content of 28% was added. After purging with nitrogen and hydrogen, the reaction temperature was controlled at 310℃ and the reaction pressure at 5.0MPa. Hydrogen was continuously introduced for reduction. After 8 hours of reduction, the reactor was opened, and 213.7g of reduced solution was obtained. A sample was taken for analysis.

[0045] HPLC analysis results: cyclohexylamine 74.2%, phenazine 2.9%, 2-aminodicyclohexylamine 14.8%. The calculated yield of cyclohexylamine was 73.1%.

Claims

1. A method for deep reduction of phenazine waste residue, characterized in that: The phenazine waste generated during the production of RT-based cyclohexylamine was hydrogenated and reduced using a supported nickel catalyst.

2. The method for deep reduction of phenazine waste residue according to claim 1, characterized in that... Includes the following steps: 1) Heat the phenazine waste residue until it is completely melted; 2) Add the molten phenazine waste to the reactor and then add a supported nickel catalyst for deep reduction.

3. The method for deep reduction of phenazine waste residue according to claim 1 or 2, characterized in that: The support for the nickel catalyst is alumina, and the nickel content is 5%-40%.

4. The method for deep reduction of phenazine waste residue according to claim 1 or 2, characterized in that: The mass ratio of the added supported nickel catalyst to the phenazine waste residue is 0.05-0.20:

1.

5. The method for deep reduction of phenazine waste residue according to claim 1, characterized in that: The temperature for hydrogenation reduction is 240-340℃.

6. The method for deep reduction of phenazine waste residue according to claim 1 or 2, characterized in that: The hydrogenation reduction pressure is 2.0-8.0 MPa.

7. The method for deep reduction of phenazine waste residue according to claim 1 or 2, characterized in that: The residence time for hydrogenation reduction is 1-8 hours.

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