Method for resource utilization of m-phenylenediamine rectification waste residue

Abstract

The present application relates to the technical field of catalyst, and particularly discloses a method for resource utilization of m-phenylenediamine rectification waste residue. The waste residue is stabilized by a stabilizer, and then the stabilized precursor is carbonized and activated directly under a CO2 atmosphere. The method has the advantages of simplicity, high efficiency, environmental friendliness, low cost, etc. The method can treat the m-phenylenediamine rectification waste residue, and simultaneously prepare porous carbon material with high nitrogen doping and high specific surface area in a simple and low-cost manner.

Description

(I) TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst, in particular to a resource utilization method of chemical waste residue. (II) BACKGROUND

[0002] M-phenylenediamine is an important fine chemical intermediate, which is widely used in the synthesis of various dyes and the preparation of high-performance new materials such as aramid 1313.

[0003] At present, the main production method of m-phenylenediamine is to prepare mixed dinitrobenzene from benzene as raw material under mixed acid conditions through nitration reaction; then to prepare mixed phenylenediamine under the condition of hydrogenation catalyst through catalytic hydrogenation reaction; and then to obtain m-phenylenediamine, p-phenylenediamine and o-phenylenediamine products by distillation separation of the mixed phenylenediamine.

[0004] Due to the characteristics of m-phenylenediamine that it is easily oxidized and polymerized, and coked, under the influence of high temperature in the m-phenylenediamine distillation purification process, it is inevitable that side reactions such as oxidation, polymerization and coking will occur in the tower, generating complex tar impurities, which are gradually enriched in the tower kettle. Because such waste is highly toxic and difficult to handle, it is defined as hazardous waste, and the treatment cost is extremely high. The tar has high nitrogen content and is viscous, and there is no good treatment method at present, and most of them are still treated by direct incineration. The disadvantage of this treatment method is that a large amount of toxic and harmful gas is generated during the incineration process, polluting the environment, which does not meet the current trend of environmental protection and clean production. In addition, a large amount of aromatic amine structure in the waste residue is not reused, causing great waste of resources. Therefore, it is of great significance to develop a clean, simple and low-cost treatment method for the effective resource utilization of m-phenylenediamine distillation residue tar. (III)SUMMARY

[0005] In order to make up for the shortcomings of the prior art, the present application provides a clean, simple and low-cost method for treating m-phenylenediamine distillation residue tar.

[0006] The present application is realized by the following technical scheme:

[0007] A resource utilization method of m-phenylenediamine distillation waste residue, taking the impurity tar enriched in the m-phenylenediamine distillation column kettle as the treatment object, comprising the following steps: (1) mixing the residue tar and a stabilizer A in a certain proportion, heating and stirring for stabilization pretreatment to obtain a uniformly mixed precursor; (2) directly transferring the precursor obtained in step (1) to a rotary furnace, replacing the air with CO2, and then carbonizing and activating under CO2 atmosphere according to the programmed temperature rise, without subsequent washing, to obtain a porous carbon material.

[0008] The more preferred technical scheme of the present application is:

[0009] In step 1, the stabilizer A is one or more of p-phthalaldehyde, m-phthalaldehyde or o-phthalaldehyde. The mass ratio of the coking tar to the stabilizer A is 100:1-10:1, the stabilization temperature is 80-120℃, and the stabilization time is 0.5-5 hours.

[0010] In step 2, the heating rate of the carbonization process is 0.2-20℃ / min, the highest carbonization temperature is 800-1000℃, and the maintaining time at the highest carbonization temperature is 1-10 hours. The CO2 flow rate is 100-2000 mL / min.

[0011] The carbonization yield of the prepared porous carbon material is 30-50%. The specific surface area of the prepared porous carbon material is greater than 1500 m 2 / g, and the N doping amount is greater than 5%.

[0012] The method of the present application has the advantages of simplicity, high efficiency, environmental friendliness, mild conditions, etc. No corrosive acid or base chemical activator or pore-forming agent is used. Only greenhouse gas CO2 is consumed, which is friendly to equipment and can significantly reduce the preparation cost of carbon materials. (IV) DETAILED DESCRIPTION

[0013] The present application will be further described below in combination with examples.

[0014] Example 1 includes the following steps:

[0015] (1) 1000 g of coking tar and 50 g of p-phthalaldehyde are mixed, heated to 100℃, and stirred for stabilization pretreatment for 1 hour to obtain a uniformly mixed precursor; (2) the precursor obtained in step (1) is directly transferred to a rotary furnace, the air is replaced with CO2, and then heated at a heating rate of 5℃ / min under a CO2 atmosphere of 500 mL / min to perform carbonization-activation, the highest temperature is 900℃, and the maintaining time is 2 hours. The obtained carbon material weighs about 350 g.

[0016] The obtained carbon material is sampled for elemental analysis and nitrogen physical adsorption-desorption analysis. The analysis results are as follows: the N content in the obtained carbon material is 7.4%, the S BET = 1720 m 2 / g.

[0017] Example 2 includes the following steps:

[0018] (1) 1500 g of coking residue tar and 150 g of isophthalaldehyde were mixed, and the mixture was heated to 120°C and stirred for 2 hours for stabilization pretreatment to obtain a uniformly mixed precursor; (2) the precursor obtained in step (1) was directly transferred into a rotary furnace, and after replacement of air with CO2, the precursor was heated at a heating rate of 8°C / min under a CO2 atmosphere of 300 mL / min to perform carbonization-activation, and the highest temperature was 850°C for 3 hours. The carbon material obtained after carbonization-activation was weighed to be about 570 g.

[0019] The carbon material obtained above was sampled for elemental analysis and nitrogen physical adsorption-desorption analysis. The analysis results were: the N content in the obtained carbon material was 6.8%, the S content was 0.1%, and the specific surface area was 1670 m2 / g. BET 2 / g.​

Claims

1. A method for resource utilization of m-phenylenediamine rectification waste residue, taking the impurity tar enriched in the m-phenylenediamine rectification column as the processing object, characterized in that, The method comprises the following steps: 1) mixing the coking residue tar and stabilizer A according to a certain proportion, and performing a stabilization pretreatment by stirring and heating to obtain a precursor with uniform mixture; 2) directly transferring the precursor obtained in step 1) into a rotary furnace, replacing the air with CO2, and then performing carbonization-activation under a CO2 atmosphere according to a programmed temperature rise to directly obtain a porous carbon material without subsequent washing; in step 1), the stabilizer A is one or more of p-phthalaldehyde, m-phthalaldehyde or o-phthalaldehyde.

2. The method for resource utilization of m-phenylenediamine rectification waste residue according to claim 1, characterized in that: In step 1), the mass ratio of the coking residue tar to the stabilizer A is 100:1-10:1, the stabilization temperature is 80-120℃, and the stabilization time is 0.5-5 hours.

3. The method for resource utilization of m-phenylenediamine rectification waste residue according to claim 1, characterized in that: In step 2), the heating rate of the carbonization process is 0.2-20℃ / min.

4. The method for resource utilization of m-phenylenediamine rectification waste residue according to claim 1, characterized in that: In step 2), the CO2 flow rate is 100-2000 mL / min.

5. The method for resource utilization of m-phenylenediamine rectification waste residue according to claim 1, characterized in that: The carbonization rate of the prepared porous carbon material is 30%-50%.

6. The method for resource utilization of m-phenylenediamine rectification waste residue according to claim 1, characterized in that: The specific surface area of the porous carbon material prepared is greater than 1500 m 2 / g, and the N doping amount is greater than 5%.