CN110845378A

CN110845378A - Thiocarboxamide, preparation method and application thereof

Info

Publication number: CN110845378A
Application number: CN201911164883.9A
Authority: CN
Inventors: 孟宪锋
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-02-28

Abstract

The invention discloses a thioformamide, and a preparation method and application thereof. The preparation method comprises the steps of taking carbon disulfide, liquid ammonia and carbon monoxide as raw materials, reacting under the catalysis of organic base and under the pressure of 4-6 MPa to generate thiocarbamide, and rectifying and collecting the thiocarbamide after the reaction is finished. The prepared thiocarbamide can be used as a thiabendazole intermediate, is used for synthesizing thiabendazole, and is applied to the fields of sterilization, anticorrosion, fresh-keeping and the like. The invention adopts a one-step method to prepare the thiocarboxamide, has the advantages of simple preparation method, mild reaction conditions, easy realization, safety, controllability, low production cost, high yield, no generation of wastewater and toxic gas and environmental pollution reduction.

Description

Thiocarboxamide, preparation method and application thereof

Technical Field

The invention relates to the field of chemical material synthesis, and particularly relates to a preparation method of thiocarboxamide and application of thiocarboxamide as a thiabendazole intermediate.

Background

The thiocarbamide is a key intermediate of thiabendazole and is also an important fine chemical product.

At present, the synthesis process of the thiocarboxamide takes formamide and phosphorus pentasulfide as raw materials for reaction generation, impurities such as phosphorus pentoxide and the like are easy to generate in the reaction process and adhere to the wall to form inclusion, which is not beneficial to the reaction; in addition, Tetrahydrofuran (THF) is usually used as a solvent in the reaction system, and on one hand, the THF is expensive and has higher cost; on the other hand, the completely anhydrous environment needs to be ensured, and the THF drying process is complex and difficult. In a word, the synthesis process has the advantages of low yield, high production cost, large raw material consumption, production of a large amount of phosphorus-containing wastewater and toxic hydrogen sulfide gas, unsafe production process, environmental friendliness and extremely high disposal cost.

Therefore, there is still a need for a process for the preparation of thiocarboxamides which is simple and environmentally friendly.

Disclosure of Invention

In order to solve at least part of technical problems in the prior art, the invention carries out intensive research, and finds that the thiocarbamide is synthesized by taking carbon disulfide, liquid ammonia and carbon monoxide as raw materials in one step, the preparation method is simple, the yield can reach more than 95 percent in terms of ammonia, the synthesis process is safe and controllable, the production cost is low, no wastewater and toxic gas are generated, and the environmental pollution is reduced. The present invention has been accomplished, at least in part, based on this. Specifically, the present invention includes the following.

In a first aspect of the present invention, there is provided a process for the preparation of a thiocarboxamide, comprising the steps of: the method comprises the steps of taking carbon disulfide, liquid ammonia and carbon monoxide as raw materials, reacting under the catalysis of organic base and under the pressure of 4-6 MPa to generate thiocarbamide, and rectifying and collecting the thiocarbamide after the reaction is finished.

In certain exemplary embodiments, the molar ratio of the carbon disulfide, the liquid ammonia, and the carbon monoxide is 3:1: 1.2.

In certain exemplary embodiments, the organic base is sodium methoxide.

In certain exemplary embodiments, the reaction temperature is 180 to 200 ℃ and the reaction time is 6 to 8 hours.

In certain exemplary embodiments, the step of rectifying the collected thiocarboxamide comprises: after the reaction is finished, rectifying the reaction liquid at normal pressure, collecting carbon disulfide at a first temperature, and collecting distillate thiocarbamide at a second temperature.

In certain exemplary embodiments, the temperature is increased after the collection of the thiocarboxamide is complete and the distillate formamide is collected at a third temperature.

In certain exemplary embodiments, the first temperature is 45 to 50 ℃, the second temperature is 103 to 105 ℃, and the third temperature is 209 to 211 ℃.

In a second aspect of the invention, there is provided a thiocarboxamide obtained by the process of the first aspect of the invention.

In a third aspect of the present invention, there is provided the use of a thiocarboxamide obtained by the process of the first aspect of the present invention or a thiocarboxamide according to the second aspect of the present invention as an intermediate in the preparation of thiabendazole.

The thiocarboxamide disclosed by the invention can be particularly used as a key intermediate of thiabendazole for synthesizing thiabendazole, and the thiabendazole is widely applied to the fields of sterilization, corrosion prevention, fresh keeping and the like. The method takes the carbon disulfide, the liquid ammonia and the carbon monoxide as raw materials and the organic base as the catalyst to synthesize the thiocarbamide by adopting a one-step method, has the advantages of simple preparation method, mild reaction condition, easy realization of pressure and temperature condition, lower requirement on equipment, safe and controllable preparation process and improvement on production efficiency; the raw materials are all domestic, the price is low, and the production cost is low; the yield can reach more than 95 percent in terms of ammonia, and the yield is high; and no wastewater and toxic gas are generated, so that the environmental pollution is greatly reduced.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that the upper and lower limits of the range, and each intervening value therebetween, is specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

In a first aspect of the present invention, there is provided a process for the preparation of a thiocarboxamide, comprising the steps of: carbon disulfide, liquid ammonia and carbon monoxide are used as raw materials, and are reacted for 6-8 hours under the catalysis of organic base under the conditions of the pressure of 4-6 MPa and the temperature of 180-200 ℃ to generate the thiocarbamide. Preferably, the reaction process is carried out in an autoclave, the reaction pressure is 4-6 MPa, the reaction is carried out under the low-pressure condition, expensive high-pressure equipment is not needed, and the reaction process is safe and controllable.

The invention has simple post-treatment and easy product separation, and specifically comprises the following steps: after the reaction is finished, cooling the high-pressure kettle to below 20 ℃, discharging generated carbon dioxide gas, and then transferring the reaction liquid into a rectifying kettle for rectification and collecting the thiocarbamide. In an exemplary embodiment, the step of rectifying the collected thiocarboxamide comprises: rectifying the reaction liquid in a rectifying still at normal pressure, and recovering excessive carbon disulfide at a first temperature, preferably, the first temperature is 45-50 ℃, and more preferably, 46-47 ℃; collecting the distillate thiocarboxamide at a second temperature, preferably the second temperature is from 103 to 105 ℃. And (3) generating a byproduct formamide in the reaction process, so that the temperature is continuously increased after the thiocarbamide is collected, and the distillate formamide is collected at a third temperature, wherein the third temperature is preferably 209-211 ℃. The collected formamide can be used for further generation of thiocarboxamide.

The traditional formamide synthesis method is characterized in that carbon monoxide and ammonia are directly synthesized into formamide under the catalysis of sodium methoxide at the high pressure of 10-30 MPa and the temperature of 80-100 ℃, the method can be realized at 4-6 MPa, the requirement on equipment is obviously reduced, the reaction process is safe, and the production cost is reduced.

In addition, only carbon dioxide gas, formamide and thiocarbamide are generated in the whole reaction process, no wastewater and toxic gas are generated, no pollution is caused to the environment, and products are easy to separate.

Preferably, the molar ratio of the carbon disulfide, the liquid ammonia and the carbon monoxide is 3:1:1.2, so that excessive carbon disulfide is convenient for aftertreatment and product separation while the three raw materials are fully reacted to generate the thiocarbamide and the formamide.

In the present invention, the organic base is preferably sodium methoxide.

In a third aspect of the present invention, there is provided the use of a thiocarboxamide obtained by the process of the first aspect of the present invention or a thiocarboxamide according to the second aspect of the present invention as an intermediate in the preparation of thiabendazole. For example, thiabendazole is synthesized from thiocarboxamide and 2-dibromoacetylbenzimidazole hydrobromide, and the synthesized thiabendazole can be used as a bactericide, a preservative, an antistaling agent and the like, and is widely used for preventing and treating fungal diseases and root rot of various crops, preventing and preserving fruits and vegetables, preventing and killing paper, leather, paint and the like, and repelling insects in human and livestock intestinal tracts.

Example 1

A certain amount of organic base is added into a 2000ml autoclave (the design pressure is 10MPa) provided with a stirrer, an inner coil condenser, a pressure gauge and a thermometer, and the autoclave is covered with a kettle cover to carry out safety inspection according to the specification. After displacement with nitrogen 684g of carbon disulphide, 51g of liquid nitrogen and 100.8g of carbon monoxide are added. And after the raw materials are added, filling nitrogen to increase the pressure of the autoclave to 4MPa, closing a nitrogen inlet valve, uniformly heating to 180 ℃ within 1 hour for reaction, and keeping the pressure of the autoclave to be 4-6 MPa and the temperature of 180-200 ℃ for heat preservation reaction for 6-8 hours. Stopping heating, introducing cooling water into the inner coil pipe, cooling to below 20 ℃, opening the evacuation pipe to release pressure to normal pressure, discharging generated carbon dioxide gas, closing the evacuation pipe, and pressing the reaction liquid to the rectifying still from the liquid discharge pipe by using nitrogen.

And transferring the reaction solution into a 2000mL four-neck flask provided with a rectifying column, an oil bath and a reflux condensing device, heating to 50 ℃, and recovering carbon disulfide, wherein the recovered carbon disulfide can be used for continuously synthesizing the thiocarboxamide. And after the carbon disulfide recovery is finished, continuously heating to 120 ℃. Collecting about 137.25g of distillate with the overhead temperature of 103-105 ℃, wherein the yield is 75% by ammonia, continuing to heat to 220 ℃ after no distillate exists, and collecting about 27g of distillate with the overhead temperature of 209-211 ℃, wherein the yield is 20% by ammonia.

Only carbon dioxide gas is generated in the whole reaction process, no waste water is generated, and no harm is caused to the environment.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Many modifications and variations may be made to the exemplary embodiments of the present description without departing from the scope or spirit of the present invention. The scope of the claims is to be accorded the broadest interpretation so as to encompass all modifications and equivalent structures and functions.

Claims

1. A preparation method of thiocarboxamide is characterized by comprising the following steps: the method comprises the steps of taking carbon disulfide, liquid ammonia and carbon monoxide as raw materials, reacting under the catalysis of organic base and under the pressure of 4-6 MPa to generate thiocarbamide, and rectifying and collecting the thiocarbamide after the reaction is finished.

2. The process of claim 1, wherein the molar ratio of carbon disulfide, liquid ammonia, and carbon monoxide is 3:1: 1.2.

3. The process for the preparation of thiocarboxamide according to claim 1 wherein the organic base is sodium methoxide.

4. The method for preparing thiocarboxamide according to claim 1, wherein the reaction temperature is 180 to 200 ℃ and the reaction time is 6 to 8 hours.

5. The method for preparing thiocarboxamide according to claim 1, wherein the step of rectifying collection of the thiocarboxamide comprises: after the reaction is finished, rectifying the reaction liquid at normal pressure, collecting carbon disulfide at a first temperature, and collecting distillate thiocarbamide at a second temperature.

6. The process according to claim 5, wherein the temperature is further raised after collecting the thiocarboxamide, and the distillate formamide is collected at a third temperature.

7. The method according to claim 6, wherein the first temperature is 45 to 50 ℃, the second temperature is 103 to 105 ℃, and the third temperature is 209 to 211 ℃.

8. A thiocarboxamide obtainable by the process according to any one of claims 1 to 7.

9. Use of a thiocarboxamide as an intermediate in the preparation of thiabendazole, characterized in that it is obtained by a process according to any one of claims 1 to 7, or is a thiocarboxamide according to claim 8.