Process for preparing thiocarbamate

A technology of thiocarbamate and thiocyanate, which is applied in organic chemistry and other fields, and can solve problems such as high toxicity, strong corrosion, and easy exposure of isothiocyanate

Inactive Publication Date: 2009-02-18
北京天任瑞创科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this technology also has some fatal shortcomings: oil-water separation makes the production process more complicated, the process is complicated, the highly toxic isothiocyanate is easily exposed, and the waste water is difficult to treat, etc. Especially with the improvement of environmental protection requirements and the development of green chemical industry, this Technology is on the verge of becoming obsolete
[0003] However, in the above methods, allyl chloride is used as a raw material, and the boiling point of allyl chloride is 45°C, which is extremely volatile, and at the same time is flammable, highly corrosive and highly toxic, so it is not conducive to storage, transportation and use.

Method used

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Examples

Experimental program
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preparation example Construction

[0006] A preparation method of thiocarbamate, comprising reacting ammonium thiocyanate with allyl alcohol to generate thiocyanate, then raising the temperature to isomerize thiocyanate into isothiocyanate and distill off excess unreacted Propyl alcohol, and then add another alcohol with a higher boiling point to react with isothiocyanate to generate thiocarbamate. It is characterized in that: thiocyanate is NH 4 SCN; the alcohol reacting with thiocyanate is the alcohol R`OH of propenyl structure, wherein R` is a C3-5 hydrocarbon group; the R of the higher boiling alcohol ROH reacting with isothiocyanate is C3-C8 Alkyl; in the synthesis process, propenyl alcohol R`OH or higher boiling point alcohol ROH or a mixture of the two is used as the solvent medium, and the process is as follows:

[0007] 1. Disperse and dissolve thiocyanate in the mixture of the above-mentioned propenyl alcohol R`OH or R`OH and ROH, and heat up to prepare thiocyanate. The process conditions are:

[00...

Embodiment

[0018] Example 1. Add 2 moles of propenyl alcohol and 0.2 moles of ammonium thiocyanate into the reactor, stir and gradually raise the temperature to reflux the feed solution, and react at 90-100° C. for 3 hours. Then change the reflux to distillation, steam out and recover excess propenyl alcohol. When the temperature rises to 105°C, add 1 mole of isobutanol to the feed liquid, continue distillation, and then add 0.02 mole of catalyst (RO)mTi(Cl)n when the temperature rises to 110°C, (m+n)=4 , react at 110-120°C for 4 hours. Cool and filter, distill off excess alcohol from the filtrate under reduced pressure, and the remaining liquid is 28 grams of thiocarbamate product.

[0019] Example 2, add 1.2 moles of isobutanol, 0.6 moles of propenol, and 0.2 moles of ammonium thiocyanate into the reactor, stir and gradually raise the temperature, make the feed liquid reflux, and react at 90-100° C. for 3 hours. Then change the reflux to distillation, steam out and recover excess prop...

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Abstract

The present invention provides a preparation method of thiocarbamate, which is used for preparing benefication reagent of the category of thiocarbamate. The preparation method is characterized in that secure, lowly toxic and non-corrosive allyl alcohol is used as a raw material to substitute flammable, easily volatilizing, highly toxic and corrosive chloropropene, reacts with ammonium thiocyanide to prepare thiocyanate ester and isothiocyanate, and then reacts with alcohol with higher boiling point after simple distillation to prepare the thiocarbamate, so that the production process is safer and conducive to the environmental protection.

Description

technical field [0001] The invention relates to a method for preparing thiocarbamate as a mineral dressing agent for mines, and belongs to the technical field of mine chemicals preparation. Background technique [0002] Thiocarbamate is a kind of important mine beneficiation agent, and its industrial production methods mainly include aqueous system liquid-liquid phase transfer catalytic synthesis method and anhydrous solid-liquid phase transfer catalytic synthesis method. Wherein U.S. Patent No. 4479903 adopted a liquid-liquid phase transfer catalytic synthesis method, that is, using allyl chloride and thiocyanate aqueous solution as raw materials, generating thiocyanate under the catalysis of a phase transfer catalyst and then converting it into isothiocyanate, Water and unreacted allyl chloride are removed by phase separation and distillation, and then isobutanol is added to react with the obtained isothiocyanate to form thiocarbamate. This technique is an efficient metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C333/04
Inventor 武荣成咸建良
Owner 北京天任瑞创科技发展有限公司
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