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CN-122010804-A - Method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene

CN122010804ACN 122010804 ACN122010804 ACN 122010804ACN-122010804-A

Abstract

The invention relates to the technical field of synthesis and provides a method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene, which comprises the following steps of S1, reacting 2, 3-dichloropropene and thiocyanate compounds in a first-stage reaction kettle to obtain a reaction solution; S2, the water phase of the reaction liquid is discharged upwards from the first-stage reaction kettle, the oil phase of the reaction liquid and undissolved sodium chloride solids are operated downwards until the oil phase separated by the oil-solid separator enters the second-stage reaction kettle, sodium chloride solids are discharged from the system, S3, the mixed liquid is obtained after the rearrangement reaction of the oil phase in the second-stage reaction kettle, S4, water is added into the mixed liquid after the cooling of the mixed liquid, the mixed liquid is mixed, the first oil phase and the first water phase are formed after standing and layering, and the first oil phase is subjected to reduced pressure rectification to obtain 1-isothiocyanate-2-chloro-2-propylene. By the technical scheme, the problems of complex reaction steps and low production efficiency of the 1-isothiocyanate-2-chloro-2-propylene in the related technology are solved.

Inventors

  • BI YANBIAO
  • WANG SHOUQIANG
  • GUO JUNHUI
  • CAO XIAODONG
  • MA DONGXING

Assignees

  • 河北野田农用化学有限公司

Dates

Publication Date
20260512
Application Date
20260128

Claims (10)

  1. 1. A method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene is characterized by comprising the following steps: s1, reacting 2, 3-dichloropropene and thiocyanate compounds in a first-stage reaction kettle to obtain a reaction solution; s2, the water phase of the reaction liquid is discharged upwards from the first-stage reaction kettle, the oil phase of the reaction liquid and undissolved sodium chloride solids run downwards until the oil phase separated by the oil-solid separator enters the second-stage reaction kettle, and the sodium chloride solids are discharged from the system; S3, in the secondary reaction kettle, carrying out rearrangement reaction on the oil phase to obtain a mixed solution; s4, cooling the mixed solution, adding water, mixing, standing and layering to form a first oil phase and a first water phase, and performing reduced pressure rectification on the first oil phase to obtain 1-isothiocyanate-2-chloro-2-propylene.
  2. 2. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 1, wherein in the step S4, water is added after the mixed solution is cooled, the mixed solution is mixed, the mixture is kept stand and layered to form a first oil phase and a first water phase, the first water phase is extracted by a solvent, the first water phase is kept stand and layered to form a second oil phase and a second water phase, the first oil phase and the second oil phase are mixed and then are subjected to reduced pressure rectification to obtain the 1-isothiocyanate-2-chloro-2-propene, and the extracted solvent comprises ethyl acetate and methyl tertiary butyl ether.
  3. 3. The method for efficient and continuous synthesis of 1-isothiocyanato-2-chloro-2-propene according to claim 1, wherein the thiocyanate compound comprises sodium thiocyanate.
  4. 4. A method for the efficient and continuous synthesis of 1-isothiocyanate-2-chloro-2-propene according to claim 3, wherein the thiocyanate compound is reacted in the form of an aqueous solution of the thiocyanate compound in a primary reaction vessel.
  5. 5. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 4, wherein the mass fraction of the thiocyanate compound aqueous solution is 27% -30%.
  6. 6. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 5, wherein the molar ratio of sodium thiocyanate fed in the aqueous solution of 2, 3-chloropropene and thiocyanate is 1:1.01-1.1.
  7. 7. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 1, wherein in the step S1, the reaction temperature is 84-90 ℃ and the reaction time is 20-40 min.
  8. 8. The method for efficient and continuous synthesis of 1-isothiocyanato-2-chloro-2-propene according to claim 1, wherein in the step S3, the rearrangement reaction consists of a first stage reaction and a second stage reaction, and the temperatures and times of the first stage reaction and the second stage reaction are different.
  9. 9. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 8, wherein the temperature of the first stage reaction is 90-95 ℃, the reaction time is 20-40 min, the temperature of the second stage reaction is 100-105 ℃, and the reaction time is 100-160 min.
  10. 10. The method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propene according to claim 2, wherein the volume ratio of ethyl acetate to methyl tert-butyl ether is 4:5-6.

Description

Method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene Technical Field The invention relates to the technical field of synthesis, in particular to a method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene. Background 1-Isothiocyanate-2-chloro-2-propylene is an important chemical intermediate and has irreplaceable application value in the fields of medicine and agriculture. In the field of agriculture, the intermediate is a core raw material for synthesizing key precursor substances of anabasine pesticide, and the anabasine pesticide has the advantages of strong systemic property, high insecticidal efficiency, no interactive resistance with the traditional medicament and the like, thus becoming an important agricultural resource for guaranteeing grain crops and economic crops to avoid insect damage threat and having great significance for global agricultural safety production. However, at present, the synthesis of the compound generally adopts an intermittent kettle type reaction process, namely, 1, 3-dichloropropene is used as a raw material, and is reacted with thiocyanate ions to generate an intermediate, and then the intermediate is further functionalized to obtain a target product. The traditional method has obvious defects, complicated reaction steps, the need of transferring and separating materials for many times, low production efficiency, poor stability among batches and the like, and is difficult to meet the requirement of large-scale production. Therefore, a continuous synthesis process which is efficient, stable and easy to amplify is developed, and has important significance and industrial value for improving the yield and purity of the key intermediate, reducing the production cost and enhancing the process safety. Disclosure of Invention The invention provides a method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene, which solves the problems of complex reaction steps and low production efficiency of 1-isothiocyanate-2-chloro-2-propylene in the related art. The technical scheme of the invention is as follows: the invention provides a method for efficiently and continuously synthesizing 1-isothiocyanate-2-chloro-2-propylene, which comprises the following steps: s1, reacting 2, 3-dichloropropene and thiocyanate compounds in a first-stage reaction kettle to obtain a reaction solution; s2, the water phase of the reaction liquid is discharged upwards from the first-stage reaction kettle, the oil phase of the reaction liquid and undissolved sodium chloride solids run downwards until the oil phase separated by the oil-solid separator enters the second-stage reaction kettle, and the sodium chloride solids are discharged from the system; S3, in the secondary reaction kettle, carrying out rearrangement reaction on the oil phase to obtain a mixed solution; s4, cooling the mixed solution, adding water, mixing, standing and layering to form a first oil phase and a first water phase, and performing reduced pressure rectification on the first oil phase to obtain 1-isothiocyanate-2-chloro-2-propylene. According to a further technical scheme, in the step S4, after the mixed solution is cooled, water is added, the mixed solution is mixed, standing and layering are carried out, a first oil phase and a first water phase are formed, the first water phase is extracted by a solvent, standing and layering are carried out, a second oil phase and a second water phase are formed, the first oil phase and the second oil phase are mixed, and then reduced pressure rectification is carried out, so that 1-isothiocyanate-2-chloro-2-propylene is obtained, wherein the extracted solvent comprises ethyl acetate and methyl tertiary butyl ether. According to the invention, in the post-treatment stage, the ethyl acetate and the methyl tertiary butyl ether are compounded to serve as the extraction solvent, so that the yield and the purity are further improved, and the polarity of the mixed solvent formed by compounding the ethyl acetate and the methyl tertiary butyl ether is close to that of the target product 1-isothiocyanate-2-chloro-2-propylene, so that the compatibility between the extraction solvent and 1-isothiocyanate-2-chloro-2-propylene molecules is optimized, and the extraction efficiency is further improved. In the step S4, the extraction solution can be removed after the vacuum rectification and can be directly recycled for the extraction operation in the subsequent batch of product water washing process, so that the production cost caused by solvent consumption is reduced, the waste emission is reduced, and the process is unified in greenness and economy. As a further technical scheme, the thiocyanate compound comprises sodium thiocyanate. As a further technical scheme, the thiocyanate compound reacts in the primary reaction kettle in the form of an aqueous solution of the thiocyanate compound. As a further technica