Method for preparing rubber accelerator DM (2,2'-dithiobis(benzothiazole)) from 2-mercaptobenzothiazole coarse product as raw material

A technology of rubber accelerator and benzothiazole, which is applied in the production field of preparing DM (dibenzothiazole disulfide), can solve problems such as residue and unqualified product quality, and achieve the effect of reducing waste water discharge and energy consumption.

Inactive Publication Date: 2012-12-26
KEMAI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the crude product M containing impurities is used to synthesize DM, the impurities will remain in the finished product, resulting in unqualified product quality

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Add 100g of crude product M and 100g of water into the reactor (the weight ratio of the crude product M is 1:1), add 24g of sodium hydroxide solid (the weight ratio of the crude product M is 100:24), and the M sodium salt liquid generated by the reaction is passed through Set aside to settle, add the supernatant to the oxidation kettle, and add 1% hydrogen peroxide and 1% dilute sulfuric acid dropwise to the oxidation kettle at a temperature of 20°C and a stirring speed of 50 rpm Mix the solution, the flow rate is controlled at 8m 3 / h, until the pH value of the solution reaches 4, stop adding the oxidant solution dropwise, the molar ratio of hydrogen peroxide to sulfuric acid is 1:1; the product is washed with 1% ethanol solution of 500g (500:100 by weight with crude M) DM material , filtered, washed with water, and dried to obtain DM. The product DM84g was obtained, with a melting point of 170.6°C.

Embodiment 2

[0016] Add 100g of crude product M and 1000g of water into the reactor (the weight ratio of the crude product M is 10:1), add 24g of sodium hydroxide solid (the weight ratio of the crude product M is 100:24), and the M sodium salt liquid generated by the reaction is passed through Set aside to settle, add the supernatant to the oxidation kettle, and add 1% hydrogen peroxide and 1% dilute sulfuric acid dropwise to the oxidation kettle at a temperature of 20°C and a stirring speed of 50 rpm Mixed solution (the molar ratio of hydrogen peroxide to sulfuric acid is 1.6:1), the flow rate is controlled at 8m 3 / h, until the pH value of the solution reaches 4, stop adding the oxidant solution dropwise, wash the DM material with 50g (50:100 by weight of the crude product M) solution of DM, filter, wash with water, and dry to obtain DM. The product DM83.1g was obtained with a melting point of 170.1°C.

Embodiment 3

[0018] Add 100g of crude product M and 2000g of water into the reactor (the weight ratio to crude product M is 20:1), add 200g of sodium hydroxide solution with a mass percentage concentration of 30% (the weight ratio of pure sodium hydroxide to crude product M is 100: 60), the M sodium salt liquid produced by the reaction was left to settle, and the supernatant was added to the oxidation kettle. Under the condition of 60°C and the stirring speed was 1000 rpm, the concentration of 27.5 % hydrogen peroxide and 30% dilute sulfuric acid mixed solution (the molar ratio of hydrogen peroxide to sulfuric acid is 1.2:1), the flow rate is controlled at 1m 3 / h, until the pH value of the solution reaches 9, stop adding the oxidant solution dropwise, wash the DM material with 50g (50:100 by weight of the crude product M) solution of DM, filter, wash with water, and dry to obtain DM. The product DM83g was obtained with a melting point of 170.2°C.

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Abstract

A method for preparing a rubber accelerator DM (2,2'-dithiobis(benzothiazole)) from 2-mercaptobenzothiazole coarse product as a raw material is provided and is characterized by comprising the steps of adding water and rubber accelerator coarse product M (2-mercaptobenzothiazole) into a reaction kettle with weight ratio of (1-20) to 1, and adding sodium hydroxide with weight ratio of sodium hydroxide to rubber accelerator coarse product M of 100 to (24-60), and reacting to generate M sodium salt liquid; standing solution, collecting supernatant and adding into an oxidation pot, dripping a mixed solution containing hydrogen peroxide with concentration of 1% to 27.5% and dilute sulphuric acid with concentration of 1% to 30% into the oxidation pot with the flow velocity of 1 to 8 m<3> / h under the condition that the temperature is 20 to 60 DEG C and the mixing speed is 50 to 1000rpm, and stopping dripping oxidant solution till the pH value of the solution reaches 4 to 9; and filtrating and washing DM material with the solution, and removing impurities in DM. The process is simple in process, the solvent can be recovered and recycled for use and the loss is small; and the method is nontoxic and harmless to the people, free from the waste gas and high in environmental protection property.

Description

technical field [0001] The invention belongs to the technical field of preparing rubber accelerators, and in particular relates to a production technology for preparing DM (dibenzothiazole disulfide) by using crude product 2-mercaptobenzothiazole (M) as a raw material. Background technique [0002] Rubber accelerator DM (dibenzothiazole disulfide) is an accelerator for natural rubber and various synthetic rubbers. Vulcanization, safe operation, easy to disperse, no pollution, vulcanized rubber is resistant to aging. It is mainly used in the manufacture of general industrial products such as tires, rubber hoses, rubber shoes, and tapes. [0003] At present, the commonly used preparation method is to use the alkali metal salt of 2-mercaptobenzothiazole (M) as the raw material, and add an oxidant to polymerize it into DM. The literature (Advances in Fine Petrochemical Industry, 2006, 7:35) reported the method of synthesizing DM by molecular oxidation reaction. The M alkali m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/78
Inventor 尹红伟
Owner KEMAI CHEM
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