Synthetic method of 2,5-dimercapto-1,3,4,-thiadiazole

Abstract

The invention discloses a synthetic method of 2,5-dimercapto-1,3,4,-thiadiazole and mainly relates to the technical field of synthesis of fine chemicals. The synthetic method comprises the following steps: adding ethanol, a hydrazine hydrate, carbon disulfide and a solid base catalyst into a reaction vessel, stirring at a temperature of 20-100 DEG C to react for 1-10 hours, then cooling to room temperature, filtering, distilling filtrate under reduced pressure to remove a solvent to obtain a yellowish solid, and re-crystallizing with absolute ethyl alcohol to obtain a product DMTD. The synthetic method disclosed by the invention has the benefits that the solid base catalyst is adopted for catalysis, so that the problems that a traditional strong base catalyst corrodes equipment, and the product post-treatment is difficult are solved; the catalyst can be recycled and has the advantages of being mild in reaction conditions, low in production cost, low in equipment corrosion, easy in product separation, high in catalytic activity, low in environment pollution and the like; the synthetic method is a green synthetic technique.

Description

technical field

[0001] The invention mainly relates to the technical field of synthesis of fine chemicals, in particular to a synthesis method of 2,5-dimercapto-1,3,4-thiadiazole. Background technique

[0002] 2,5-Dimercapto-1,3,4,-Thiadiazole (2,5-Dimercapto-1,3,4-Thiadiazole, DMTD for short) is an important chemical intermediate. The -SH group in the molecule can undergo substitution reactions with halogen atoms, aldehydes, amines, etc., and can also undergo intermolecular polymerization reactions. The heterocyclic structure is tight, and heteroatoms are easy to form complexes with metal ions. These characteristics make It has important applications in many fields and has always been a research hotspot for organic chemists. As early as the 1960s, DMTD was used in photography, medicine, agriculture, dyes, chemical analysis and other fields. Such as DMTD is an effective stabilizer in photosensitive emulsions, and its salts are good developers, (1. Zheng Wei, Bi Li, the syn...

Examples

Embodiment 1

[0029] In the there-necked flask, add 100 g of ethanol, 30.6 g of hydrazine hydrate (0.5 mol, content 80%), 133.2 g (1.75 mol) of carbon disulfide, and 2.4 g of solid base, stir and react at 80° C. for 4 h, cool to room temperature, and filter. The solvent was distilled off from the filtrate under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 69.9 g of pure DMTD, with a yield of 93.0%, a melting point of 164-165.5°C, and a content of 98.54%.

Embodiment 2

[0031] In the there-necked flask, add ethanol 120g, hydrazine hydrate 30.6g (0.5mol, content 80%), carbon disulfide 114.2g (1.5mol), solid base 3.0g, stir and react at 80°C for 4h, cool to room temperature, filter, The filtrate was evaporated to remove the solvent under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 69.0 g of pure DMTD with a yield of 91.9%, a melting point of 164-165.5°C, and a content of 98.36%.

Embodiment 3

[0033]In the there-necked flask, add 100 g of ethanol, 30.6 g of hydrazine hydrate (0.5 mol, content 80%), 152.3 g (2.0 mol) of carbon disulfide, and 4.6 g of solid base, stir and react at 60° C. for 6 h, cool to room temperature, and filter. The solvent was distilled off from the filtrate under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 68.7 g of pure DMTD with a yield of 91.5%, a melting point of 164-165.5°C, and a content of 98.73%.

technical field

[0001] The invention mainly relates to the technical field of synthesis of fine chemicals, in particular to a synthesis method of 2,5-dimercapto-1,3,4-thiadiazole. Background technique

[0002] 2,5-Dimercapto-1,3,4,-Thiadiazole (2,5-Dimercapto-1,3,4-Thiadiazole, DMTD for short) is an important chemical intermediate. The -SH group in the molecule can undergo substitution reactions with halogen atoms, aldehydes, amines, etc., and can also undergo intermolecular polymerization reactions. The heterocyclic structure is tight, and heteroatoms are easy to form complexes with metal ions. These characteristics make It has important applications in many fields and has always been a research hotspot for organic chemists. As early as the 1960s, DMTD was used in photography, medicine, agriculture, dyes, chemical analysis and other fields. Such as DMTD is an effective stabilizer in photosensitive emulsions, and its salts are good developers, (1. Zheng Wei, Bi Li, the syn...

Examples

Embodiment 1

[0029] In the there-necked flask, add 100 g of ethanol, 30.6 g of hydrazine hydrate (0.5 mol, content 80%), 133.2 g (1.75 mol) of carbon disulfide, and 2.4 g of solid base, stir and react at 80° C. for 4 h, cool to room temperature, and filter. The solvent was distilled off from the filtrate under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 69.9 g of pure DMTD, with a yield of 93.0%, a melting point of 164-165.5°C, and a content of 98.54%.

Embodiment 2

[0031] In the there-necked flask, add ethanol 120g, hydrazine hydrate 30.6g (0.5mol, content 80%), carbon disulfide 114.2g (1.5mol), solid base 3.0g, stir and react at 80°C for 4h, cool to room temperature, filter, The filtrate was evaporated to remove the solvent under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 69.0 g of pure DMTD with a yield of 91.9%, a melting point of 164-165.5°C, and a content of 98.36%.

Embodiment 3

[0033]In the there-necked flask, add 100 g of ethanol, 30.6 g of hydrazine hydrate (0.5 mol, content 80%), 152.3 g (2.0 mol) of carbon disulfide, and 4.6 g of solid base, stir and react at 60° C. for 6 h, cool to room temperature, and filter. The solvent was distilled off from the filtrate under reduced pressure to obtain a light yellow solid, which was recrystallized from absolute ethanol to obtain 68.7 g of pure DMTD with a yield of 91.5%, a melting point of 164-165.5°C, and a content of 98.73%.