A method for recycling a promoter m tar

Abstract

The present application belongs to the technical field of fine chemical industry, and relates to a recycling method of accelerator M tar. In the waste M tar produced in M production, a catalyst is added, high-temperature decomposition is carried out under nitrogen protection, and recycled raw materials aniline, carbon disulfide and intermediate benzothiazole and the like are obtained, most of which are recycled. The present application adopts common equipment and unit operations, the catalyst can be reused, and the treatment of production waste is easy to realize industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical production waste treatment, and particularly relates to a recycling method of accelerator M (chemical name: 2-mercaptobenzothiazole, abbreviated as MBT or M) resin tar. BACKGROUND

[0002] Rubber accelerator M is not only an important vulcanizing accelerator in the rubber industry, but also a parent material of most secondary sulfonamide accelerators. At present, the high-pressure synthesis method is generally used. The reaction product contains about 88-92% of MBT, the rest is by-product benzothiazole, intermediate anilino benzothiazole, and a large amount of resin tar with unknown structure.

[0003] The high-pressure synthesis reaction product is generally refined in two ways, acid-base method and solvent method. The acid-base method is to dissolve the reaction crude M into a NaOH solution and assist air oxidation to make the resin couple out of the solution. After filtration, the product is precipitated by H2SO4 acidification, dehydration and drying to obtain the finished product M. The solvent method is to add a solvent to the reaction product for dissolution, and then filter to obtain M resin / tar. After that, the solvent is separated to obtain the finished product M. Generally, 200-250 kg of resin-like waste (M tar) is produced per ton of product. The M process flow of the acid-base method is shown as follows:

[0004] .

[0005] CN 106967007A discloses a tar treatment method: the accelerator M tar is placed in a reaction kettle, heated to evaporate the water in the tar, and when the temperature rises to 140-160℃, steam is introduced to start stripping. The stripped benzothiazole is cooled by a condenser, and after standing and layering, it is collected and used in the M reaction. After extracting the benzothiazole, the waste residue is dried and ground, and then extracted with carbon disulfide to obtain a sulfur-containing extract, and the residual sulfur is separated out. Distillation obtains the recovered solvent carbon disulfide. The remaining residue is crushed and processed for waterproofing membrane production.

[0006] CN 109111410A discloses a treatment method for acid-base method M production waste: the acid-base method M production waste is dehydrated; a solvent is added and heated to dissolve; the temperature is lowered to precipitate crystals, which are filtered to obtain a crystallization mother liquor and a filter cake; the filter cake is washed with a solvent and then a dilute lye is added to dissolve the M, which is filtered and the filter cake is washed with water to recover the M; the filter cake after water washing is dried to obtain a material mainly composed of sulfur and benzothiazole; the crystallization mother liquor is reduced pressure distilled to obtain aromatic solvents, aniline, benzothiazole and a small amount of transition component fractions. This method recycles and utilizes resources of M, sulfur, aniline and benzothiazole in the waste.

[0007] The method is directed to the tar of M, and the treatment needs to go through many production steps such as stripping and solvent extraction, and the operation is complicated, and the promoter M is generally produced by a production device with a capacity of about 10,000 tons, and the annual output of the tar is about 1,000 tons, so the method has large equipment investment and low efficiency. More importantly, the method only recycles M, aniline and benzothiazole in the tar of M, and a large amount of high-boiling-point substances (about 130-150 kg of long-chain oligomer components of aniline and benzothiazole) still need to be treated. The remaining tar still contains a small amount of aniline, M, benzothiazole, sulfur, anilinobenzothiazole and a large amount of high-boiling-point substances. Since the waste tar contains toxic substances such as aniline and has a low softening point (lower than 40 DEG C), the tar is difficult to have a direct use. If the waste tar cannot be treated in time, the enterprise will inevitably have great safety risks and environmental risks. If the waste tar is treated and the components such as aniline, M and benzothiazole are recycled, the safety risks and environmental risks of the enterprise can be solved, the waste can be turned into treasure, and the economic benefits of the enterprise can be improved. SUMMARY

[0008] The purpose of the present application is to overcome the defects of the prior art, to crack and decompose the tar of the promoter M into low-molecular substances by adding a catalyst, and then to separate and recycle the substances, so that the materials in the tar of M are recycled, the difficulty of tar treatment is reduced, and the product consumption is reduced.

[0009] The recycling method of the present application is realized by the following way: the recycling method of the tar of the promoter M: the tar of M is subjected to catalytic cracking reaction under the protection of nitrogen gas, and the reaction material is divided into organic phase and inorganic phase, the organic phase is separated to obtain aniline, carbon disulfide, benzothiazole and sulfur, and the inorganic phase is the catalyst which is reused.

[0010] Generally, the tar of M is a tar-like substance in the production process of the promoter M, and contains 0.1wt%-2wt% of aniline, 0.1wt%-2wt% of sulfur, 1wt%-25wt% of M, 10wt%-15wt% of benzothiazole, 3wt%-25wt% of anilinobenzothiazole and long-chain oligomer components of aniline and benzothiazole.

[0011] The catalyst is a molecular sieve catalyst, and contains 10wt%-15wt% of Zr oxide, 15-20wt% of Ni oxide, 7-10wt% of Cr oxide, 15wt%-20wt% of molecular sieve, 25-35wt% of clay and 10wt%-20wt% of binder, based on the total weight of the catalyst.

[0012] The organic phase is separated, the carbon disulfide is separated under normal pressure, and the water is separated under normal pressure or negative pressure. The aniline is separated under a pressure of -0.06 MPa to -0.090 MPa, a liquid phase temperature of 150 to 170 DEG C, and a gas phase temperature of 85 to 140 DEG C.

[0013] The catalytic cracking reaction is carried out at a temperature of 400 to 600 DEG C and a pressure of 1 to 6 MPa for 2 to 10 hours.

[0014] The ratio of the total mass of the catalyst to the mass of the tar is 0.01 to 0.1:1, preferably 0.05 to 0.07:1.

[0015] The molecular sieve used in the catalyst is selected from one or more of REHSUY molecular sieve, HZSM-5 molecular sieve, REZSM-5 molecular sieve, and REHZSM-5 molecular sieve, the clay is selected from one or more of kaolin, montmorillonite, diatomite, saponite, hydrotalcite, and bentonite, and the binder is selected from one or more of boehmite, pseudo-boehmite, and aluminum sol.

[0016] The catalyst is prepared by mixing the raw materials in a certain proportion, aging, and aging, and then crystallizing in a crystallization kettle at 100 to 150 DEG C for 5 to 10 hours, recovering the product after crystallization, filtering and washing, and then drying at 90 to 110 DEG C for 2 to 5 hours, and then calcining at 500 to 600 DEG C for 3 to 10 hours to obtain the finished catalyst.

[0017] The catalyst is regenerated by calcining at 500 to 600 DEG C for 3 to 10 hours.

[0018] The application further provides the use of the above-mentioned complex molecular sieve catalyst and the tar in catalytic cracking treatment, wherein the catalyst comprises 12 to 14 wt% of Zr oxide, 18 to 20 wt% of Ni oxide, 8 wt% of Cr oxide, 18 wt% of molecular sieve, 25 to 30 wt% of clay, and 10 to 20 wt% of binder, based on the total weight of the complex molecular sieve catalyst.

[0019] The preparation method of the catalyst can for example include: mixing the catalyst raw materials (for example, Zr, Ni, Cr salts such as nitrate, molecular sieve, clay and oxide binder) in a certain proportion at 55-75°C, stirring uniformly, aging for 2h, aging for 3h, crystallizing in a constant temperature hydrothermal kettle at 100-130°C for 5-8h, recovering the product obtained after crystallization, filtering, washing, drying in an oven at 90-110°C for 2-5h, and roasting in a muffle furnace at 550-600°C for 3-5h to obtain the catalyst product.

[0020] The catalyst is used in the M-tar catalytic cracking method, which can for example include: promoting M-tar, the catalyst is put into a reaction kettle, replaced by nitrogen, heated and warmed, stirred and warmed, maintained, cooled to discharge the reaction product, the reaction material is filtered, the organic phase is distilled and separated to obtain carbon disulfide, water, aniline, benzothiazole and kettle liquid respectively. The inorganic phase is used as the catalyst and continuously used.

[0021] Beneficial effects:

[0022] The present application realizes the resource recycling and harmless treatment of the promoter M-tar: the waste M-tar produced in M production is added with a catalyst, high-temperature catalytic cracking is carried out to obtain recycled raw materials such as aniline, carbon disulfide and intermediate benzothiazole, and most of them are recycled. Compared with the traditional incineration method, the products of the present application are all raw materials or intermediate products of M, the catalyst can be reused, the whole process is relatively simple, the process conditions are easy to control, and environmental pollution is not caused, and the resource utilization of waste is truly realized. DETAILED DESCRIPTION

[0023] The present application will be further described in detail through specific examples, but should not be understood as a limitation on the present application. The examples in the present application and the features in the examples can be combined with each other without conflict. The present application will be described in detail below in combination with examples.

[0024] Example 1

[0025] Preparation of the catalyst: the catalyst raw materials (Zr, Ni, Cr nitrate, REHSUY molecular sieve, kaolin and boehmite) are mixed in a certain proportion at 75°C, stirred uniformly, aged for 2h, aged for 3h, crystallized in a constant temperature hydrothermal kettle at 100°C for 8h, the product obtained after crystallization is recovered, filtered, washed, dried in an oven at 110°C for 5h, roasted in a muffle furnace at 550°C for 3h to obtain the catalyst product. The content of Zr, Ni and Cr oxides in the catalyst product is 14wt%, 18wt% and 8wt% respectively.

[0026] M tar catalytic cracking: 1000 kg of promoter M tar and 50 kg of catalyst were put into a reaction kettle, replaced by nitrogen, heated and stirred to 400°C, the pressure was raised to 4.5 MPa and maintained for 5 h. The reaction product was discharged after cooling, filtered, and the organic phase was distilled to separate carbon disulfide, water, aniline (distilled at a gas phase temperature of 100-140°C under a pressure of -0.090 MPa), benzothiazole (distilled at a gas phase temperature of 141-180°C under a pressure of -0.095 MPa, containing a small amount of sulfur), and kettle liquid. The total weight of the recovered components, including carbon disulfide, aniline, benzothiazole, etc., was 972 kg, which was recycled to the M synthesis process. The inorganic phase was recycled as catalyst. The effective component yield of M tar was 97.2%. After 20 cycles, the inorganic phase was calcined at 500-600°C for 3-10 h and continued to be recycled.

[0027] Example 2

[0028] The catalyst preparation method was the same as in Example 1.

[0029] 1000 kg of promoter M tar and 70 kg of catalyst were put into a reaction kettle, replaced by nitrogen, heated and stirred to 450°C, the pressure was raised to 4.8 MPa and maintained for 3 h. The reaction product was discharged after cooling, filtered, and the organic phase was distilled to separate carbon disulfide, water, aniline (distilled at a gas phase temperature of 100-130°C under a pressure of -0.092 MPa), benzothiazole (distilled at a gas phase temperature of 145-175°C under a pressure of -0.094 MPa, containing a small amount of sulfur), and kettle liquid. The total weight of the recovered components, including carbon disulfide, aniline, benzothiazole, etc., was 984 kg, which was recycled to the M synthesis process. The inorganic phase was recycled as catalyst. The effective component yield of M tar was 98.4%. After 23 cycles, the inorganic phase was calcined at 600°C for 10 h and continued to be recycled.

[0030] Examples 3-7

[0031] The experimental method of Example 1 was used. Under the same conditions, the effective component yield was investigated by changing the catalyst preparation raw materials, reaction temperature, and time, etc. The results are shown in Table 1.

[0032] Table 1: Process condition data table of Examples 3-7

[0033] .

[0034] Note: *The recovered components refer to the sum of carbon disulfide, aniline, benzothiazole, and sulfur.

[0035] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application, such as the shape and structure of the reactor, etc. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for recovering and utilizing tar from accelerator M, characterized in that... Includes the following steps: M tar was subjected to catalytic cracking under nitrogen protection. The reaction product was divided into an organic phase and an inorganic phase. The organic phase was separated to obtain aniline, carbon disulfide, benzothiazole, and sulfur, respectively. The inorganic phase was used as the catalyst. The catalytic cracking reaction is carried out at a temperature of 400–600°C, a pressure of 1–6 MPa, and a time of 2–10 hours. The catalyst regeneration conditions are as follows: the catalyst is calcined at 500-600°C for 3-10 hours. The catalyst is a composite molecular sieve catalyst, comprising, based on the total weight of the catalyst: 10 wt% to 15 wt% Zr oxide, Ni oxides of 15 wt% to 20 wt%, 7 wt% to 10 wt% of Cr oxides, Molecular sieves of 15 wt% to 20 wt%, 25 wt% to 30 wt% clay, and 10 wt% to 20 wt% of binder; The M tar mainly comprises 0.1wt% to 2wt% aniline, 0.1wt% to 2wt% sulfur, 1wt% to 25wt% M, 10wt% to 15wt% benzothiazole, 3wt% to 25wt% aniline-benzothiazole, and long-chain oligomers of aniline and benzothiazole. The catalyst used is selected from one or more of REHSUY molecular sieve, HZSM-5 molecular sieve, REZSM-5 molecular sieve, and REHZSM-5 molecular sieve; the clay is selected from one or more of kaolin, montmorillonite, diatomite, soapstone, hydrotalcite, and bentonite; and the binder is selected from one or more of boehmite, pseudoboehmite, and alumina sol. The catalyst preparation method is as follows: after the catalyst raw materials are mixed evenly in proportion, they are aged and matured, and then crystallized in a crystallization kettle at 100℃~150℃ for 5~10 hours. The product obtained after crystallization is recovered, filtered, washed, and dried at 90℃~110℃ for 2~5 hours. Then, it is calcined at 500℃~600℃ for 3~10 hours to obtain the finished catalyst.

2. The recycling method according to claim 1, characterized in that: The aforementioned organic phase separation, carbon disulfide separation The separation conditions are: atmospheric pressure; water separation conditions are: atmospheric pressure or negative pressure; aniline separation conditions are: pressure of -0.06MPa to -0.090MPa, liquid phase temperature of 150℃ to 170℃, gas phase temperature of 85℃ to 140℃; benzothiazole separation conditions are: pressure of -0.091MPa to -0.098MPa, liquid phase temperature of 171℃ to 230℃, gas phase temperature of 141℃ to 180℃.

3. The recycling method according to claim 1, characterized in that: The ratio of the total mass of the catalytic cracking catalyst to the mass of the tar is 0.01 to 0.1:

1.

4. The recycling method according to claim 1 or 3, characterized in that: The ratio of the total mass of catalytic cracking catalyst to the mass of tar is 0.05~0.07:

1.

5. The recycling method according to claim 1, characterized in that: Catalyst preparation method: Mix the raw materials of the catalyst in proportion at 55℃~75℃, stir evenly, age for 2 hours and aging for 3 hours, crystallize in a constant temperature hydrothermal reactor at 100℃~130℃ for 5~8 hours, recover the product obtained after crystallization, filter and wash, dry in an oven at 90℃~110℃ for 2~5 hours, and calcine in a muffle furnace at 550℃~600℃ for 3~5 hours to obtain the finished catalyst.