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Production method of thiocarbazide

A technology for thiocarbazide and a production method, which is applied in directions such as organic chemistry and chemical recovery, can solve problems such as low conversion rate of hydrazine hydrate, and achieve the effects of increasing yield, improving yield and improving conversion rate.

Pending Publication Date: 2022-06-07
宁夏彩源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Based on this, the present invention provides a kind of thiocarbazide production method, to solve the technical problem that the hydrazine hydrate conversion ratio is low in the thiocarbazide production process existing in the prior art

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  • Production method of thiocarbazide
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Experimental program
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Effect test

Embodiment 1

[0057] 3t of hydrazine hydrate with a mass concentration of 80% was added into the reactor, and 150kg of mercaptoethanol was added, and chilled water was introduced into the jacket to reduce the temperature in the reactor to 15°C. First, a total of 1000L of CS was slowly added dropwise to the reactor at a flow rate of 50L / h. 2 (CS 2 and the molar ratio of hydrazine hydrate was 1:2.9), and kept for 1 h. After the heat preservation, the temperature was raised to 65° C., and the temperature was maintained for 8 h to decompose the HDTC. Then the temperature was lowered to 15°C, and a total of 520L of CS was slowly added dropwise to the reactor at a flow rate of 50L / h. 2 (CS 2 and the molar ratio of hydrazine hydrate is 1:5.6, the current theoretical CS 2 The molar ratio of hydrazine hydrate is 1:1.7), and the temperature is kept for 2h. After the heat preservation, the temperature was raised to 65° C., and the temperature was maintained for 20 h to decompose HDTC. It was coo...

Embodiment 2

[0059] 3t of hydrazine hydrate with a mass concentration of 80% was added into the reactor, and 300kg of mercaptoethanol was added, and chilled water was introduced into the jacket to reduce the temperature in the reactor to 20°C. First, a total of 828L of CS was slowly added dropwise to the reactor at a flow rate of 55L / h. 2 (CS 2 and hydrazine hydrate in a molar ratio of 1:3.5), and incubated for 1 h. After the heat preservation, the temperature was raised to 70 °C, and the temperature was maintained for 8 h to decompose the HDTC. Then the temperature was lowered to 15°C, and a total of 520L of CS was slowly added dropwise to the reactor at a flow rate of 55L / h. 2 (CS 2 and the molar ratio of hydrazine hydrate is 1:5.6, the current theoretical CS 2 The molar ratio of hydrazine hydrate is 1:2.4), and the temperature is kept for 2h. After the heat preservation, the temperature was raised to 70° C., and the temperature was maintained for 20 h to decompose the HDTC. It was...

Embodiment 3

[0061] 3t of hydrazine hydrate with a mass concentration of 80% was added into the reactor, and 300kg of mercaptoethanol was added, and chilled water was introduced into the jacket to reduce the temperature in the reactor to 15°C. First, a total of 1000L of CS was slowly added dropwise to the reactor at a flow rate of 40L / h. 2 (CS 2 and the molar ratio of hydrazine hydrate was 1:2.9), and kept for 1 h. After the heat preservation, the temperature was raised to 70 °C, and the temperature was maintained for 8 h to decompose the HDTC. Then the temperature was lowered to 15°C, and a total of 415L of CS was slowly added dropwise to the reactor at a flow rate of 40L / h. 2 (CS 2 and the molar ratio of hydrazine hydrate is 1:7, the current theoretical CS 2 The molar ratio of hydrazine hydrate is 1:2.2), and the temperature is kept for 2h. After the heat preservation, the temperature was raised to 70° C., and the temperature was maintained for 20 h to decompose the HDTC. It was co...

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Abstract

The invention provides a thiocarbazide production method, and belongs to the technical field of organic synthesis processes. The method comprises the following steps: slowly dropwise adding CS2 into hydrazine hydrate at a low temperature, controlling the ratio of the total molar weight of CS2 to the molar weight of hydrazine hydrate to be 1: (2.9-3.5), and keeping the hydrazine hydrate to be excessive in the whole reaction process; and after the first reaction is finished, heating to the second reaction temperature to decompose the reaction product HDTC. Then cooling to 25-35 DEG C, adding liquid caustic soda, and adjusting the pH value of the system; then, CS2 is slowly dropwise added into the reaction system again at low temperature, the ratio of the total dropwise-added molar weight of CS2 to the molar weight of hydrazine hydrate is controlled to be 1: (5.6-7), due to the fact that reaction products in the system are removed, conversion of CS2 into HDTC is facilitated, the conversion rate of CS2 is effectively increased, and the yield of thiocarbazide is increased. Practice shows that under the same condition, the yield of the thiocarbazide is increased to 83%-85% (based on CS2) by adopting the thiocarbazide production method provided by the invention.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis technology, in particular to a method for producing thiocarbazide. Background technique [0002] Thiocarbazide, English name: Thiocarbazide, CAS.No.:2231-57-4, molecular formula: CH 6 N 4 S, molecular weight: 106.17, widely used in organic synthesis, is an important raw material for the production of high-efficiency broad-spectrum herbicide mezatrione. One of the main production methods of thiocarbazide uses carbon disulfide and hydrazine hydrate as raw materials, and is prepared by two-step reaction. Specifically, under the action of a catalyst (mercaptoethanol), carbon disulfide and hydrazine hydrate react at a lower temperature to generate dithiocarbazamic acid (HDTC), the reaction solution is heated and decomposed to release hydrogen sulfide, and the obtained liquid is cooled After filtration, thiocarbazide (TCH) can be isolated. [0003] The synthetic method of above-mentioned t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C337/06
CPCC07C337/06Y02P20/584
Inventor 张得国范卫卫王海东
Owner 宁夏彩源科技有限公司