Method for preparing 2-mercaptobenzothiazole

A technology of mercaptobenzothiazole and aniline, applied in the field of rubber vulcanization accelerator production, can solve problems such as low yield, and achieve the effect of reducing the generation of asphalt-like wastes

Active Publication Date: 2011-05-25
TIANJIN UNIV +1
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

The above two patents use the method of crystallization or extraction to purify the crude MBT obtained from the reaction to obtain the product MBT, which eliminates operations such as alkali dissolution, oxidation, and acidification, and does not generate waste water and waste gas. The yield is low, and the amount of bitumen-like waste generated accordingly has not been reduced, and the problems existing in the existing process have not been completely solved

Method used

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  • Method for preparing 2-mercaptobenzothiazole
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  • Method for preparing 2-mercaptobenzothiazole

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Embodiment 1

[0031](1) Add 400g aniline, 344g sulfur and 360g carbon disulfide to a total of 1106g in the reactor of 1.2L, (reactant ratio is aniline: sulfur: carbon disulfide is 1: 2.5: 1.1) at 250~260 ℃ and react 90min, this When the reaction is 9.1MPa, the reaction is terminated to obtain a crude product melt. Using the self pressure generated by the reaction, the crude MBT melt is pressed into a 3L crystallizer equipped with 1200g of 140°C carbon disulfide. The maximum temperature of the mixed solution after mixing is 165 ℃, lower the temperature at a cooling rate of 0.5°C / min, and start to discharge hydrogen sulfide when the crystallizer is 90°C, the discharge time of hydrogen sulfide is controlled at 30min, the temperature of the mixture is reduced to 18°C, and the MBT filter cake and carbon disulfide mother liquor are obtained by filtration, with 600g The filter cake was washed twice with carbon disulfide, and vacuum-dried at room temperature to obtain 542 g of MBT product with a pur...

Embodiment 2

[0039] (1) Add 212g of aniline, 117g of sulfur and 260g of carbon disulfide to a 0.6L reactor, a total of 589g, (the ratio of reactants is aniline: sulfur: carbon disulfide is 1: 1.6: 1.5) react at 240-250°C for 120min, terminate reaction, the reaction pressure is 6.9MPa. Using the self-pressure generated by the reaction, the crude MBT melt is pressed into a 2L crystallizer equipped with 1000g of 130°C carbon disulfide. The maximum temperature of the mixed liquid after mixing is 153.5°C, and the temperature is lowered at a cooling rate of 0.5°C to 1°C / min. When the temperature of the mixture in the crystallizer drops to 70°C, hydrogen sulfide starts to be discharged. The hydrogen sulfide discharge time is controlled at 30 minutes, and the temperature of the mixture drops to 20°C. Filter to obtain MBT filter cake and carbon disulfide mother liquor, wash the filter cake twice with 500g carbon disulfide, and keep Drying under vacuum gave 258 g of MBT product with a purity (HPLC) ...

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Abstract

The invention discloses a method for preparing 2-mercaptobenzothiazole, which comprises the steps of: adding carbon disulfide, aniline and sulfur into a reaction kettle; and heating the mixture, finishing a reaction under the reaction pressure of 6.8 to 9.5MPa to obtain a crude product, namely a melt, pressing the melt into a crystallizer loaded with carbon disulfide, controlling the initial temperature of the crystallization, reducing the temperature, beginning to discharge hydrogen sulfide when the material temperature in the crystallizer is reduced to be between 70 and 100 DEG C, controlling the discharge time of hydrogen sulfide to be between 20 and 60min, cooling the obtained product to be between 15 and 20 DEG C, filtering the obtained product to obtain a filter cake and carbon disulfide mother liquor, washing the filter cake for 2 to 5 times by using carbon disulfide in an amount which is 1 to 3 times mass of the filter cake, and drying the scrubbed filter cake to obtain the 2-mercaptobenzothiazole at the mass percentage concentration of over 98 percent. By the method, no 'waste water' and 'waste gas' are discharged, and asphalt-like wastes are greatly reduced. The circulation of crystallization mother liquor realizes the recycling of intermediate products, and the total yield of the process is improved to be over 94 percent.

Description

technical field [0001] The invention belongs to the technical field of rubber vulcanization accelerator production, and in particular relates to a preparation method of a rubber vulcanization accelerator 2-mercaptobenzothiazole. Background technique [0002] Rubber vulcanization accelerator 2-mercaptobenzothiazole (MBT) is a widely used rubber vulcanization accelerator precursor. In industry, the Kelly process is generally used to produce MBT. This method is to react aniline, carbon disulfide and sulfur under high temperature and high pressure, and then obtain the product MBT through alkali dissolution, oxidation and acidification. The advantage of this method is that it is simple and easy to operate. The disadvantage is that the process requires a large amount of acid and alkali solutions, and about 30 to 60 tons of waste water is produced per ton of product. The salt content and COD value of the waste water are high, and the treatment is very difficult; the product yield i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/72
Inventor 陈松李国兵王树华安静韩毅范江洋
Owner TIANJIN UNIV
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