Method for regenerating and recycling catalyst

Abstract

The invention discloses a method for regenerating and recycling a catalyst, which comprises the following steps: preparing metal tin fragments and / or chippings, pretreating tin-containing MOCA wastewater, pretreating tin-containing MOCA waste, preparing a tin-containing hydrochloric acid solution, preparing a regenerated catalyst stannous chloride and the like. The method comprises the following steps: separating tin elements in MOCA production wastewater and MOCA production wastes through hydrochloric acid to obtain a tin-containing hydrochloric acid solution, then reacting the tin-containing hydrochloric acid solution with metal tin fragments and / or fragments to synthesize a standard stannous chloride solution required by MOCA production, and continuously returning the prepared regenerated catalyst stannous chloride to an MOCA production process. According to the method, the catalyst stannous chloride is regenerated and recycled, and the MOCA waste after stannous chloride separation can be returned to a production line for use due to no tetravalent tin, so that the utilization rate of the catalyst stannous chloride and the MOCA raw material is effectively increased, the generation of hazardous wastes is reduced, and good economic and environmental benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical industry, in particular to a catalyst regeneration and recycling method. Background Art

[0002] The product name of MOCA is 3,3'-dichloro-4,4'-diaminodiphenylmethane, commonly known as Moca, which belongs to the diamine chain extender. When MOCA is used as a vulcanizing agent for cast polyurethane wear-resistant rubber, it can be widely used in the machinery industry, automobile and aircraft manufacturing, mining industry, sports facilities (such as plastic tracks, plastic floors) and light manufacturing industry. It can also be used as a cross-linking agent for polyurethane coatings and adhesives, and a curing agent for epoxy resins to prepare products with extremely high electrical resistance.

[0003] The preparation method of commercial finished product MOCA often uses o-chloroaniline as raw material, first reacts with hydrochloric acid to form o-chloroaniline hydrochloride, then condenses with formaldehyde in the presence of stannous chloride as a catalyst to form 4,4'-methanedi(2-chloroaniline) hydrochloride, then neutralizes with sodium hydroxide to form MOCA, and then adopts multi-stage cleaning, oil-water separation, stripping deamination, dehydration, and granulation to obtain it. The synthetic catalyst stannous chloride not only remains in the synthetic mother liquor but also in the wastewater of the cleaning process and the by-product MOCA waste. The wastewater is evaporated and concentrated, and the recovered distilled water is discharged after meeting the standards, while the catalyst stannous chloride continues to be mixed in the distillation residue and MOCA waste and is safely landfilled as hazardous waste.

[0004] This treatment method is a huge waste of precious metallic tin resources and a large economic loss for MOCA manufacturers. In addition, MOCA manufacturers need to purchase additional catalyst stannous chloride during the production of MOCA, which directly increases production costs. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a catalyst regeneration and recycling method, comprising the following steps:

[0006] Preparation of metallic tin fragments and / or debris: washing the surface of a metallic tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating the metallic tin ingot to melt it into metallic tin liquid, pouring the liquid metallic tin into a container containing deionized water in batches, causing the metallic tin liquid to explode when cooled to obtain metallic tin fragments and / or debris, which are fished out, dried, and set aside; the metallic tin fragments and / or debris have a larger specific surface area, which is conducive to expanding the contact area of ​​the reaction;

[0007] Pretreatment of tin-containing MOCA wastewater: adding 40-60wt% hydrogen peroxide to MOCA production process wastewater, stirring until all the residual stannous substance in the MOCA production process wastewater is converted into tetravalent tin, then adding sodium hydroxide to adjust the pH to 6-7, filtering and recovering the tin mud;

[0008] Pretreatment of tin-containing MOCA waste: mixing waste materials (such as MOCA, stannous chloride, tin oxychloride, and dichloroaniline) generated in the MOCA production process with tin mud, adding 25-35wt% hydrochloric acid solution to adjust the pH to 3-5 to obtain a mixture a, adding 3-5L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing 2-5 times to remove soluble salts (such as sodium chloride, etc.) in the tin-containing waste to obtain pretreated tin-containing MOCA waste;

[0009] Preparation of tin-containing hydrochloric acid solution: Detect the tin content in the pretreated tin-containing MOCA waste, add 25-35wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride (1:4-8) mol, heat to react for 4-6 hours, cool, and separate the solid and liquid to obtain the tin-containing hydrochloric acid solution;

[0010] Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred to a reactor equipped with a condensation reflux device, and then 0.8 to 1.2 times the mass of tin in the tin-containing hydrochloric acid solution is added with metal tin fragments and / or debris, and the reaction is heated until the content of tetravalent tin ions in the reactor is less than 0.5 g / L, and then 25 to 35 wt% of hydrochloric acid solution and metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin (1 to 5:1) mol to evaporate and concentrate until the stannous ions are 150 to 160 g / L and the free hydrochloric acid (calculated as hydrogen chloride) is 5 to 15 g / L, and then the concentration is stopped, cooled, and filtered to obtain the regenerated catalyst stannous chloride, and the MOCA waste after the stannous chloride is separated can be returned to the production line for use because it does not contain tetravalent tin.

[0011] Preferably, in the process of preparing the metallic tin fragments and / or scraps, the heating temperature for melting the metallic tin ingot into metallic tin liquid is controlled at 270-300°C.

[0012] Preferably, in the process of pretreating tin-containing MOCA wastewater, the ratio of MOCA production process wastewater to 40-60wt% hydrogen peroxide is 1000L:(1-5)L. Excessive hydrogen peroxide will lead to excessively high cost of treating wastewater on the one hand, and on the other hand, excessive hydrogen peroxide will also cause secondary environmental pollution.

[0013] More preferably, in the process of pretreating tin-containing MOCA wastewater, the ratio of MOCA production process wastewater to 50-55wt% hydrogen peroxide is 1000L:(2-3)L.

[0014] Preferably, in the process of pretreating tin-containing MOCA wastewater, the stirring time is 2 to 4 hours and the stirring speed is 500 to 1500 r / min.

[0015] Preferably, the heating temperature during the preparation of the tin-containing hydrochloric acid solution is 90-120° C. Reasonable heating temperature can ensure that the hydrochloric acid fully reacts with the tin compounds in the waste material while avoiding unnecessary side reactions or volatilization losses caused by excessively high temperature.

[0016] More preferably, the heating temperature during the preparation of the tin-containing hydrochloric acid solution is 95-110°C.

[0017] Preferably, in the process of preparing the regenerated catalyst stannous chloride, the amount of metal tin fragments and / or debris added is 0.8 to 1.2 times the mass of tin in the tin-containing hydrochloric acid solution. Adding an appropriate amount of metal tin fragments and / or debris can promote the reaction balance and make the reaction more thorough, reduce the unreacted tin remaining in the solution, and thus improve the total recovery rate of tin.

[0018] Preferably, in the process of preparing the regenerated catalyst stannous chloride, the heating temperature is 90-120°C.

[0019] More preferably, in the process of preparing the regenerated catalyst stannous chloride, the heating temperature is 95-105°C.

[0020] The beneficial effect is that the present application first pre-treats MOCA wastewater and waste materials, and then uses hydrochloric acid to separate the tin element in MOCA production wastewater and MOCA production waste to obtain a tin-containing hydrochloric acid solution, and then reacts the tin-containing hydrochloric acid solution with metallic tin fragments and / or debris to synthesize a standard stannous chloride solution required for MOCA production. At this time, the prepared regenerated catalyst stannous chloride can be continuously returned to the MOCA production process, thereby realizing the regeneration and recycling of the catalyst stannous chloride. The MOCA waste after separation of stannous chloride can also be returned to the production line for use because it does not contain tetravalent tin. This effectively improves the utilization rate of the catalyst stannous chloride and MOCA raw materials, reduces the generation of hazardous waste, and has good economic and environmental benefits. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0022] The following embodiments are only used to illustrate the present invention, but are not limited to the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the protection scope of the present invention.

[0023] In the examples of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0024] Source of raw materials:

[0025] MOCA wastewater waste was purchased from Huaibei Xingguang New Material Technology Co., Ltd.;

[0026] Tin ingots with a tin content greater than 99.9% were purchased from Shenzhen Yunshen Tin Industry Co., Ltd.

[0027] The remaining reagents are commercially available.

[0028] Example 1

[0029] This embodiment provides a catalyst regeneration and recycling method, comprising the following steps:

[0030] Preparation of metal tin fragments and / or debris: washing the surface of a metal tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating it to 270° C. to melt the metal tin ingot into a metal tin liquid, pouring the liquid metal tin into a container filled with deionized water in batches, and causing the metal tin liquid to explode when cooled to obtain metal tin fragments and / or debris, which are fished out, dried, and set aside;

[0031] Pretreatment of tin-containing MOCA wastewater: adding 40wt% hydrogen peroxide to MOCA production process wastewater at a volume ratio of 1000L:1L, stirring until all the residual stannous substance in the MOCA production process wastewater is converted into tetravalent tin, stirring and then adding sodium hydroxide to adjust the pH to 6-7, stirring for 2h, stirring at a speed of 500r / min, filtering and recovering the tin mud;

[0032] Pretreatment of tin-containing MOCA waste: mixing the waste generated in the MOCA production process with tin mud, adding 30wt% hydrochloric acid solution to adjust the pH to 3-5 to obtain a mixture a, adding 3L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing twice to obtain the pretreated tin-containing MOCA waste;

[0033] Preparation of tin-containing hydrochloric acid solution: Detect the tin content in the pretreated tin-containing MOCA waste, add 25wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride of 1mol:4mol, heat to 90°C for 4h, cool, and separate the solid and liquid to obtain a tin-containing hydrochloric acid solution;

[0034] Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred to a reactor equipped with a condensation reflux device, and then 0.8 times the mass of tin in the tin-containing hydrochloric acid solution is added with metal tin fragments and / or debris, and the reaction is heated to 90° C. until the content of tetravalent tin ions in the reactor is less than 0.5 g / L, and then 25wt% hydrochloric acid solution and metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin of 1mol:1mol for evaporation and concentration, cooling, and filtering to obtain the regenerated catalyst stannous chloride, and the MOCA waste after separation of the stannous chloride can be returned to the production line for use because it does not contain tetravalent tin.

[0035] Example 2

[0036] This embodiment provides a catalyst regeneration and recycling method, comprising the following steps:

[0037] Preparation of metal tin fragments and / or debris: washing the surface of a metal tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating it to 280° C. to melt the metal tin ingot into a metal tin liquid, pouring the liquid metal tin into a container containing deionized water in batches, and causing the metal tin liquid to explode when cooled to obtain metal tin fragments and / or debris, which are fished out, dried, and set aside;

[0038] Pretreatment of tin-containing MOCA wastewater: adding 50wt% hydrogen peroxide to the MOCA production process wastewater in a volume ratio of 1000L:2L, stirring until all the residual stannous substance in the MOCA production process wastewater is converted into tetravalent tin, stirring and then adding sodium hydroxide to adjust the pH to 6-7, stirring time is 3h, stirring speed is 800r / min, filtering and recovering the tin mud;

[0039] Pretreatment of tin-containing MOCA waste: mixing the waste generated in the MOCA production process with tin mud, adding 25wt% hydrochloric acid solution to adjust the pH to 4 to obtain a mixture a, adding 4L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing 3 times to obtain the pretreated tin-containing MOCA waste;

[0040] Preparation of tin-containing hydrochloric acid solution: Detect the tin content in the pretreated tin-containing MOCA waste, add 25-35wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride of 1mol:6mol, heat to 95°C for reaction for 5h, cool, and separate the solid and liquid to obtain the tin-containing hydrochloric acid solution;

[0041] Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred into a reactor equipped with a condensation reflux device, and then metal tin fragments and / or debris are added according to 1 times the mass of tin in the tin-containing hydrochloric acid solution, and heated to 95° C. for reaction until the tetravalent tin ion content in the reactor is less than 0.5 g / L, and then 30wt% hydrochloric acid solution and metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin of 2.5 mol:1 mol for evaporation and concentration, cooling, and filtering to obtain the regenerated catalyst stannous chloride, and the MOCA waste after separation of the stannous chloride can be returned to the production line for use because it does not contain tetravalent tin.

[0042] Example 3

[0043] This embodiment provides a catalyst regeneration and recycling method, comprising the following steps:

[0044] Preparation of metal tin fragments and / or debris: washing the surface of a metal tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating it to 290° C. to melt the metal tin ingot into a metal tin liquid, pouring the liquid metal tin into a container containing deionized water in batches, and causing the metal tin liquid to explode when cooled to obtain metal tin fragments and / or debris, which are fished out, dried, and set aside;

[0045] Pretreatment of tin-containing MOCA wastewater: adding 55wt% hydrogen peroxide to MOCA production process wastewater in a volume ratio of 1000L:3L, stirring until all the residual stannous substance in the MOCA production process wastewater is converted into tetravalent tin, stirring and then adding sodium hydroxide to adjust the pH to 6-7, stirring time is 3.5h, stirring speed is 1000r / min, filtering and recovering to obtain tin mud;

[0046] Pretreatment of tin-containing MOCA waste: mixing the waste generated in the MOCA production process with tin mud, adding 32wt% hydrochloric acid solution to adjust the pH to 3-5 to obtain a mixture a, adding 4.5L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing 4 times to obtain the pretreated tin-containing MOCA waste;

[0047] Preparation of tin-containing hydrochloric acid solution: Detect the tin content in the pretreated tin-containing MOCA waste, add 32wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride of 1mol:7mol, heat to 110°C for reaction for 5.5h, cool, and separate the solid and liquid to obtain a tin-containing hydrochloric acid solution;

[0048] Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred to a reactor equipped with a condensation reflux device, and then metal tin fragments and / or debris are added according to 1.05 times the mass of tin in the tin-containing hydrochloric acid solution, and heated to 105° C. for reaction until the tetravalent tin ion content in the reactor is less than 0.5 g / L, and then 32wt% hydrochloric acid solution and metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin of 4mol:1mol for evaporation and concentration, cooling, and filtering to obtain the regenerated catalyst stannous chloride, and the MOCA waste after separation of the stannous chloride can be returned to the production line for use because it does not contain tetravalent tin.

[0049] Example 4

[0050] This embodiment provides a catalyst regeneration and recycling method, comprising the following steps:

[0051] Preparation of metal tin fragments and / or debris: washing the surface of a metal tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating it to 300° C. to melt the metal tin ingot into a metal tin liquid, pouring the liquid metal tin into a container containing deionized water in batches, and causing the metal tin liquid to explode when cooled to obtain metal tin fragments and / or debris, which are fished out, dried, and set aside;

[0052] Pretreatment of tin-containing MOCA wastewater: adding 60wt% hydrogen peroxide to the MOCA production process wastewater in a volume ratio of 1000L:5L, stirring until all the residual stannous substance in the MOCA production process wastewater is converted into tetravalent tin, stirring and then adding sodium hydroxide to adjust the pH to 6-7, stirring time is 4h, stirring speed is 1500r / min, filtering and recovering the tin mud;

[0053] Pretreatment of tin-containing MOCA waste: mixing the waste generated in the MOCA production process with tin mud, adding 35wt% hydrochloric acid solution to adjust the pH to 3-5 to obtain a mixture a, adding 5L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing 5 times to obtain the pretreated tin-containing MOCA waste;

[0054] Preparation of tin-containing hydrochloric acid solution: Detect the tin content in the pretreated tin-containing MOCA waste, add 35wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride of 1mol:8mol, heat to 120°C for reaction for 6h, cool, and separate the solid and liquid to obtain the tin-containing hydrochloric acid solution;

[0055] Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred into a reactor equipped with a condensation reflux device, and then metal tin fragments and / or debris are added according to 1.2 times the mass of tin in the tin-containing hydrochloric acid solution, and heated to 120° C. for reaction until the tetravalent tin ion content in the reactor is less than 0.5 g / L, and then 35wt% hydrochloric acid solution and metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin of 5mol:1mol for evaporation and concentration, cooling, and filtering to obtain the regenerated catalyst stannous chloride, and the MOCA waste after separation of the stannous chloride can be returned to the production line for use because it does not contain tetravalent tin.

[0056] Test method:

[0057] The regenerated catalyst stannous chloride was tested according to the Chinese national standard "GB / T 638-2018 Chemical Reagent Stannous Chloride Dihydrate (Stannic Chloride)";

[0058] According to the industry standard "HG / T 3711-2012", MOCA synthesized using regenerated catalyst stannous chloride was tested;

[0059] The test results are shown in Table 1, which shows the test results of the regenerated catalyst stannous chloride and MOCA synthesized using the regenerated catalyst stannous chloride.

[0060] Table 1 Test results of regenerated catalyst stannous chloride and MOCA synthesized using regenerated catalyst stannous chloride

[0061]

[0062] From the data in the above table, it can be seen that the content of tetravalent tin in the regenerated stannous chloride is small, and the content of divalent tin is high, which can reflect that the regeneration process of stannous chloride is relatively successful. The present technical scheme can effectively reduce the tetravalent tin in MOCA wastewater to divalent tin, and the MOCA prepared by using the regenerated catalyst stannous chloride has high purity.

[0063] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A catalyst regeneration and recycling method, characterized in that: The following steps are involved: Preparation of metal tin fragments and / or debris: washing the surface of a metal tin ingot with a tin content greater than 99.9% with deionized water, drying it, and then putting it into a stainless steel pot, heating the metal tin ingot to melt it into a metal tin liquid, pouring the liquid metal tin into a container containing deionized water in batches, and the metal tin liquid explodes when cooled to obtain metal tin fragments and / or debris, which are fished out, dried, and set aside; Pretreatment of tin-containing MOCA wastewater: adding 40-60 wt% hydrogen peroxide to MOCA production process wastewater, stirring until all the residual stannous acid in the MOCA production process wastewater is converted into tetravalent tin, then adding sodium hydroxide to adjust the pH to 6-7, filtering and recovering the tin sludge; Pretreatment of tin-containing MOCA waste: mixing the waste generated in the MOCA production process with the tin mud, adding 25-35wt% hydrochloric acid solution to adjust the pH to 3-5 to obtain a mixture a, adding 3-5L of deionized water to each 1kg of the mixture a, mixing and stirring into a slurry, separating the solid and the liquid, and repeatedly washing 2-5 times to obtain the pretreated tin-containing MOCA waste; Preparation of tin-containing hydrochloric acid solution: detecting the tin content in the pretreated tin-containing MOCA waste, adding 25-35wt% hydrochloric acid solution to the pretreated tin-containing MOCA waste according to the stoichiometric ratio of tin to hydrogen chloride (1:4-8) mol, heating to react for 4-6 hours, cooling, and solid-liquid separation to obtain the tin-containing hydrochloric acid solution; Preparation of regenerated catalyst stannous chloride: after detecting the tin content in the tin-containing hydrochloric acid solution, the tin-containing hydrochloric acid solution is transferred to a reactor equipped with a condensation reflux device, and the metal tin fragments and / or debris are added to the reactor, and heated to react until the content of tetravalent tin ions in the reactor is less than 0.5 g / L, and then 25-35 wt% hydrochloric acid solution and the metal tin fragments and / or debris are continuously added to the reactor according to the stoichiometric ratio of hydrogen chloride to tin (1-5:1) mol for evaporation and concentration until the stannous ions are 150-160 g / L and the free hydrochloric acid (calculated as hydrogen chloride) is 5-15 g / L, and the concentration is stopped, cooled, and filtered to obtain the regenerated catalyst stannous chloride. The MOCA waste after separation of the stannous chloride can be returned to the production line for use because it does not contain tetravalent tin.

2. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of preparing the metal tin fragments and / or scraps, the heating temperature for melting the metal tin ingot into metal tin liquid is controlled at 270-300°C.

3. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of pretreating the tin-containing MOCA wastewater, the ratio of the MOCA production process wastewater to the 40-60wt% hydrogen peroxide is 1000L:(1-5)L.

4. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of pre-treating the tin-containing MOCA wastewater, the ratio of the MOCA production process wastewater to the 40-60wt% hydrogen peroxide is 1000L:(2-3)L.

5. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of pre-treating the tin-containing MOCA wastewater, the stirring time is 2 to 4 hours and the stirring speed is 500 to 1500 r / min.

6. The catalyst regeneration and recycling method according to claim 1, characterized in that: The heating temperature during the preparation of the tin-containing hydrochloric acid solution is 90-120°C.

7. The catalyst regeneration and recycling method according to claim 1, characterized in that: The heating temperature during the preparation of the tin-containing hydrochloric acid solution is 95-110°C.

8. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of preparing the regenerated catalyst stannous chloride, the amount of the metallic tin fragments and / or scraps added is 0.8 to 1.2 times the mass of tin in the tin-containing hydrochloric acid solution.

9. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of preparing the regenerated catalyst stannous chloride, the heating temperature is 90-120°C.

10. The catalyst regeneration and recycling method according to claim 1, characterized in that: In the process of preparing the regenerated catalyst stannous chloride, the heating temperature is 95-105°C.

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