Preparation method of 5-methyl-2-mercapto-1,3,4-thiadiazole

A thiadiazole and sulfhydryl technology, applied in the field of preparation of MMTD, can solve problems such as troublesome reaction operation, waste of energy, and multiple wastes, and achieve the effects of preventing toxic and harmful use, saving energy, and reducing production costs.

Inactive Publication Date: 2012-09-12
HEILONGJIANG HAOYUN FINE CHEM
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Problems solved by technology

[0003] The purpose of the present invention is in order to solve the preparation method of existing 5-methyl-2-mercapto-1,3,4-thiadiazole, usually all adds ethanol as solvent in synthetic step, because reactant concentration is lower, does not need Conducive to the reaction, the reaction operation is more troublesome, wastes energy, and easily generates more waste

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Embodiment Construction

[0016] The present invention will be described in further detail below: the present embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation is provided, but the protection scope of the present invention is not limited to the following examples.

[0017] A kind of preparation method of 5-methyl-2-mercapto-1,3,4-thiadiazole involved in the present embodiment, its steps are:

[0018] 1. Synthesis

[0019] 1. Add ethyl acetate and hydrazine hydrate into a 500ml reaction bottle, the mass ratio of ethyl acetate and hydrazine hydrate is 1:1~1.4:1, heat up to 60~70°C under stirring condition, keep reflux for 2 hours, Cooling obtains the solution of acetylhydrazine;

[0020] 2. Cool the solution of acetylhydrazide to below 5°C with an ice bath, then add carbon disulfide dropwise, the mass ratio of carbon disulfide and acetylhydrazide is 1:1~1.4:1;

[0021] 3. After the dropwise addition, remove the ice bath and feed NH ...

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Abstract

The invention provides a preparation method of 5-methyl-2-mercapto-1,3,4-thiadiazole. The preparation method comprises the following steps of adding ethyl acetate and hydrazine hydrate into a reaction flask having a volume of 500ml, keeping backflow for 2 hours, cooling to obtain an acethydrazide solution, dropwisely adding carbon disulfide into the acethydrazide solution, then feeding NH3 into the acethydrazide solution containing carbon disulfide at a temperature of 40 DEG C, adding a crude thiadiazole product into deionized water, carrying out elution of filter cake several times by distilled water, and carrying out vacuum-drying to obtain a thiadiazole finished product. The preparation method has that advantages that ethanol is not used in synthesis so that solvent-free reactions are realized; under solvent-free conditions, high reactant concentration is conducive to reaction development; solvent-free reactions are easy to operate, saves energy and prevents waste production; and NH3 replaces potassium hydroxide and thus it is avoided that potassium N-acetylhydrazinodithioformate produced in synthesis is dissolved in methanol and dissolution of potassium hydroxide needs a large amount of methanol and thus the part of potassium N-acetylhydrazinodithioformate dissolved in methanol is lost.

Description

technical field [0001] The invention relates to a preparation method of 5-methyl-2-mercapto-1,3,4-thiadiazole (MMTD), which belongs to the technical field of MMTD preparation. Background technique [0002] In the preparation method of existing 5-methyl-2-mercapto-1,3,4-thiadiazole, ethanol is usually added as a solvent in the synthesis step, because the reactant concentration is low, it is unfavorable for the carrying out of the reaction, and the reaction operation It is more troublesome, wastes energy, and easily generates more waste, which is not conducive to the environmental protection and cleaning of industrial production. During the synthesis process, because the N-acetylhydrazinodithioformate potassium that generates is dissolved in methanol, and potassium hydroxide needs a large amount of methanol to dissolve, causing a part of N-acetylhydrazinodithioformate potassium to be lost due to being dissolved in methanol, resulting in The production cost is high, and the di...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D285/125
Inventor 李雪李晴孙晓凤朱云波龚真固梁园园
Owner HEILONGJIANG HAOYUN FINE CHEM
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