阅读说明：本技术 一种连续合成橡胶硫化促进剂二硫化二苯并噻唑的反应系统及其方法 (Reaction system and method for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide ) 是由 章娟 何为盛 尹跃宁 刘勇贵 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种连续合成橡胶硫化促进剂二硫化二苯并噻唑的反应系统及其方法。反应系统包括加料器、氨水溶解釜、萃取釜、分相罐、多级氧化反应釜和压滤机,各设备之间通过管道串联连接；氨水溶解釜上部设有氨水加料器,萃取釜上部设有萃取剂加料器,各级氧化反应釜上部设有氧化剂加料器。首先将氨水加入氨水溶解釜中,然后加入粗M进行充分混合,得到M-NH<Sub>4</Sub>溶液；M-NH<Sub>4</Sub>溶液导入萃取釜中,加入萃取剂进行萃取、分相,得到精M-NH<Sub>4</Sub>溶液；所得精M-NH<Sub>4</Sub>溶液导入多级氧化反应釜中加入双氧水进行充分氧化混合反应；所得反应液过滤、烘干,得到产品二硫化二苯并噻唑DM。本发明反应系统为水系统,安全、无废盐,废水量少,有利于环保。(The invention discloses a reaction system and a method for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide. The reaction system comprises a feeder, an ammonia water dissolving kettle, an extraction kettle, a phase splitting tank, a multistage oxidation reaction kettle and a filter press, and all the devices are connected in series through pipelines; the upper part of the ammonia water dissolving kettle is provided with an ammonia water feeder, the upper part of the extraction kettle is provided with an extractant feeder, and the upper parts of all stages of oxidation reaction kettles are provided with oxidant feeders. Firstly, adding ammonia water into an ammonia water dissolving kettle, then adding coarse M, and fully mixing to obtain M-NH 4 A solution; M-NH 4 Introducing the solution into an extraction kettle, adding an extracting agent for extraction and phase splitting to obtain refined M-NH 4 A solution; obtaining the refined M-NH 4 Introducing the solution into a multistage oxidation reaction kettle, adding hydrogen peroxide, and carrying out full oxidation mixing reaction; and filtering and drying the obtained reaction liquid to obtain the product dibenzothiazyl disulfide DM. The reaction system is a water system, is safe, has no waste salt and little waste water, and is beneficial to environmental protection.)

1. A reaction system for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide is characterized in that: the reaction system comprises a feeder, an ammonia water dissolving kettle, an extraction kettle, a phase splitting tank, a multistage oxidation reaction kettle and a filter press, wherein all the devices are connected in series through pipelines; the ammonia water dissolving kettle is provided with an ammonia water feeder at the upper part, the extraction kettle is provided with an extractant feeder at the upper part, and the oxidation reaction kettles at different levels are provided with oxidant feeders at the upper parts.

2. The reaction system for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 1, wherein: the multi-stage oxidation reaction kettle is 3-8 stages.

3. A method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide by using the reaction system of claim 1, wherein the method comprises the following steps:

a. firstly, adding prepared ammonia water into an ammonia water dissolving kettle, then adding a crude product of 2-mercaptobenzothiazole prepared according to a conventional method, namely crude M, fully mixing the crude product under the condition of stirring after adding, and mixing to obtain M-NH₄A solution;

b. the M-NH obtained in the step a₄Introducing the solution into an extraction kettle, adding an extracting agent for extraction reaction, and performing phase separation after the extraction reaction to obtain refined M-NH₄A solution;

c. c, refining M-NH obtained in the step b₄Introducing the solution into a multistage oxidation reaction kettle, and adding hydrogen peroxide to perform full oxidation mixing reaction;

d. and c, continuously filtering the reaction liquid obtained in the step c through a filter press, drying the filtered product, and drying to obtain the product dibenzothiazole disulfide DM.

4. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: in the step a, the mass percentage concentration of the ammonia water is 1-5%, and the mass ratio of the crude M to the ammonia water is 1: 1-30.

5. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: and c, fully mixing the coarse M in the ammonia water in the step a, controlling the temperature to be 30-80 ℃ and the time to be 20-80 min.

6. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: the extractant in the step b is toluene, xylene, glycol or acetone, M-NH₄The mass ratio of the solution to the extracting agent is 1: 1-4;

the temperature is controlled to be 30-80 ℃ during the extraction reaction, and the extraction time is 1-30 min.

7. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: and c, the multi-stage oxidation reaction kettle is 3-8 stages.

8. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: and c, controlling the oxidation reaction temperature to be 20-80 ℃ and the oxidation reaction time to be 10-30 min during the oxidation mixing reaction.

9. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: fine M-NH in step c₄The molar ratio of the solution to the hydrogen peroxide is 1: 0.4-0.6; the mass percentage concentration of the hydrogen peroxide is 3-12%.

10. The method for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to claim 3, wherein: and d, drying by using an oven at the drying temperature of 100-120 ℃ for 10-30 min.

The technical field is as follows:

the invention relates to the technical field of chemistry and chemical engineering, and particularly relates to a reaction system and a method for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide.

Secondly, background art:

dibenzothiazyl disulfide (also known as accelerator DM) is a commonly used thiazole accelerator at present. The thiazole accelerator is an acidic accelerator, commonly used are M, DM and MZ, wherein DM is used in the largest amount, DM can be used for natural rubber, synthetic rubber and reclaimed rubber, and the application is similar to the accelerator M, but the vulcanization critical temperature is higher (130 ℃), and the thiazole accelerator is widely used for manufacturing tires, inner tubes, rubber shoes, adhesive tapes and general industrial products.

At present, the method for industrially producing the accelerator DM at home and abroad is mainly an oxidation method, and the used oxidants are sodium hypochlorite, chlorine, sodium nitrite, hydrogen peroxide, oxygen and the like. There are many reports on accelerator DM, for example: 1. the invention patent of CN200810183218.X discloses that sodium salt is used as a raw material, oxydol and sulfuric acid are used for preparing an oxidant according to a certain proportion, and M-Na is directly oxidized to obtain a product DM, the process is simple to operate, the amount of wastewater per ton of the product is 15t, and the amount of waste salt is 424 Kg. 2. CN 101215273A, which discloses a method for preparing M-NH₄A method for synthesizing MBTS by salt. At M-NH₄Dropwise addition of H to the salt₂O₂/H₂SO₄Reacting the mixed solution under certain conditions until the pH value reaches a certain value, and stopping the reaction to obtain the MBTS product. The process is simple, the product yield is high, and ammonium sulfate produced by refining can be treated as a byproduct. However, the method uses acid and alkali, the ammonia is only used once, the cyclic utilization cannot be realized, the material consumption and the cost are increased, and more waste water and waste gas are still discharged in the process to cause pollution.

At present, a great deal of research and study finds that the DM is not industrially continuously produced. The previous reaction device for synthesizing dibenzothiazyl disulfide mainly adopts an intermittent reaction tank to produce the dibenzothiazyl disulfide, and a large amount of waste water and waste salt are produced in the reaction, so that the production efficiency is very low, the equipment investment cost is high, the better yield of dibenzothiazyl disulfide is difficult to obtain, and the stability of the product batch is poor. The oxygen oxidation yield is high, the reaction speed is slow, and the requirement on equipment is high. At present, the process does not realize a continuous production device. In the reaction oxidation process, M is over-oxidized due to uneven dispersion of hydrogen peroxide, so that the quality of DM in the process of mother liquor sleeving is influenced. Thus, the apparatus and process of the oxidation reaction is at the heart of the process.

Thirdly, the invention content:

the technical problem to be solved by the invention is as follows: according to the development condition and the defects of the prior art of the current synthetic method of the rubber vulcanization accelerator dibenzothiazyl disulfide, the invention provides a reaction system and a method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide. According to the technical scheme, the crude M is dissolved by ammonia water, the M is further purified by extraction of an extracting agent, and then the reaction is further carried out by adopting a multi-stage oxidation reaction kettle, so that the generation of byproducts in the oxidation process is reduced, the back mixing amount is reduced, and the reaction yield is improved.

In order to solve the problems, the invention adopts the technical scheme that:

the invention provides a reaction system for continuously synthesizing rubber vulcanization accelerator dibenzothiazyl disulfide, which comprises a feeder, an ammonia water dissolving kettle, an extraction kettle, a phase separation tank, a multistage oxidation reaction kettle and a filter press, wherein all the devices are connected in series through pipelines; the ammonia water dissolving kettle is provided with an ammonia water feeder at the upper part, the extraction kettle is provided with an extractant feeder at the upper part, and the oxidation reaction kettles at different levels are provided with oxidant feeders at the upper parts.

According to the reaction system for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the multistage oxidation reaction kettle is 3-8 stages.

In addition, the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide by using the reaction system comprises the following steps:

a. firstly, adding prepared ammonia water into an ammonia water dissolving kettle, then adding a crude product of 2-mercaptobenzothiazole prepared according to a conventional method, namely crude M, fully mixing the crude product under the condition of stirring after adding, and mixing to obtain M-NH₄A solution;

b. the M-NH obtained in the step a₄Introducing the solution into an extraction kettle, adding an extracting agent for extraction reaction, and performing phase separation after the extraction reaction to obtain refined M-NH₄A solution;

c. c, refining M-NH obtained in the step b₄Introducing the solution into a multistage oxidation reaction kettle, and adding hydrogen peroxide to perform full oxidation mixing reaction;

d. and c, continuously filtering the reaction liquid obtained in the step c through a filter press, drying the filtered product, and drying to obtain the product dibenzothiazole disulfide DM.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the mass percentage concentration of the ammonia water in the step a is 1-5%, and the mass ratio of the crude M to the ammonia water is 1: 1-30.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the temperature of the crude M in the step a is controlled to be 30-80 ℃ when the crude M is fully mixed in ammonia water, and the time is 20-80 min.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the extracting agent in the step b is toluene, xylene, ethylene glycol or acetone, M-NH₄The mass ratio of the solution to the extracting agent is 1: 1-4;

the temperature is controlled to be 30-80 ℃ during the extraction reaction, and the extraction time is 1-30 min.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the multistage oxidation reaction kettle in the step c is 3-8 stages.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, in the step c, the oxidation reaction temperature is controlled to be 20-80 ℃ during the oxidation mixing reaction, and the oxidation reaction time is 10-30 min;

the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide according to the above, wherein the fine M-NH is used in step c₄The molar ratio of the solution to the hydrogen peroxide is 1: 0.4-0.6; the mass percentage concentration of the hydrogen peroxide is 3-12%.

According to the method for continuously synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide, the drying oven is adopted for drying in the step d, the drying temperature is 100-120 ℃, and the drying time is 10-30 min.

The invention dissolves coarse M in ammonia water to form ammonia salt, and the ammonia salt is oxidized into DM by hydrogen peroxide, and the reaction equation is as follows:

the invention has the following positive beneficial effects:

1. according to the technical scheme, the crude M is dissolved by ammonia water, the M is further purified by extraction of an extracting agent, and then the reaction is further carried out by adopting a multi-stage oxidation reaction kettle, so that the generation of byproducts in the oxidation process is reduced, the back mixing amount is reduced, and the reaction yield is improved.

2. According to the technical scheme, a multi-stage oxidation kettle is adopted for continuous reaction, the yield of the obtained product 2-mercaptobenzothiazole is higher than 97%, and the product is stable; the reaction system is a water system, is safe, has no waste salt and little waste water, and is beneficial to environmental protection.

3. The technical scheme of the invention has the advantages that the mother liquor is completely used, the cost is low by using hydrogen peroxide as an oxidant, and the drying is directly carried out without water washing during spin-drying. The industrial production of the invention has no waste salt and little waste water.

4. The technical scheme of the invention realizes the continuous process for synthesizing the rubber vulcanization accelerator dibenzothiazyl disulfide.

Fourthly, explanation of the attached drawings:

FIG. 1 is a schematic view of a reaction system for continuously synthesizing a rubber vulcanization accelerator dibenzothiazyl disulfide according to the present invention.

In fig. 1:1 is a coarse M feeder, 2 is an ammonia water dissolving kettle, 2-1 is an ammonia water feeder, 3 is an extraction kettle, 3-1 is an extractant feeder, 4 is a phase separation tank, 5 is an oxidation reaction kettle, 5-1 is an oxidant feeder, and 6 is a filter press.

FIG. 2 is a liquid chromatogram of the product obtained in example 6 of the present invention.

FIG. 3 is a liquid chromatogram of the product obtained in example 7 of the present invention.

FIG. 4 is a liquid chromatogram of the product obtained in example 8 of the present invention.

FIG. 5 is a liquid chromatogram of the product obtained in example 9 of the present invention.

FIG. 6 is a liquid chromatogram of the product obtained in example 10 of the present invention.

The fifth embodiment is as follows:

the invention is further illustrated by the following examples, which do not limit the scope of the invention.