Synthesis method of propargyl chloride

Abstract

The invention relates to the technical field of synthesis of propargyl chloride, in particular to a synthesis method of propargyl chloride. When 3-chloropropyne is synthesized by a conventional method, the yield is difficult to reach 90% or above. In order to solve the technical problems, the invention provides the synthesis method of the propargyl chloride, and propargyl alcohol and hydrogen chloride are subjected to substitution reaction in an organic solvent to generate the 3-propargyl chloride under the action of a closed reactor and a catalyst. According to the method for synthesizing the 3-chloropropyne, the yield of the 3-chloropropyne is larger than or equal to 90%, and the generation amount of by-products is smaller than 5%. The by-product hydrogen chloride is directly used as a synthesis raw material, so that the raw material cost is remarkably reduced. The method is mild in reaction condition, low in equipment investment and suitable for industrial amplification.

Description

Technical Field

[0001] The present invention relates to the technical field of chloropropyne synthesis, and in particular to a method for synthesizing chloropropyne. Background Art

[0002] As an important organic synthesis intermediate, 3-chloropropyne has a wide range of applications in pharmaceuticals, pesticides, industrial additives, and other fields. For example, in the pharmaceutical field, it is used to synthesize the antihypertensive drug pargyline, as well as synthetic steroids and growth hormones. In the pesticide field, it is used as a raw material for the synthesis of pyrethroid pesticides such as prallethrin. It can also be used as a soil fumigant, metal protective agent, and electroplating additive.

[0003] The main method for synthesizing 3-chloropropyne is to react propargyl alcohol with phosphorus trichloride under the catalysis of pyridine, using kerosene as the reaction solvent, and undergoing a reflux reaction at low temperature (below 15°C). The yield of 3-chloropropyne obtained can only reach about 83%, and it is difficult to reach more than 90%. This synthesis process also produces a large amount of hydrogen chloride or hydrochloric acid as byproducts. Summary of the Invention

[0004] A problem with the existing technology is that conventional methods for synthesizing 3-chloropropyne rarely achieve yields exceeding 90%. To address this technical issue, the present invention provides a method for synthesizing chloropropyne. In this method, propargyl alcohol and hydrogen chloride undergo a substitution reaction in an organic solvent in a closed reactor using a catalyst to produce 3-chloropropyne.

[0005] Preferably, the catalyst comprises one of zinc chloride, phosphorus pentachloride (expensive), 1-chloro-N,N,2-trimethyl-1-propenamine (expensive), benzoyl chloride, and oxalyl chloride.

[0006] Preferably, the catalyst is a complex formed by zinc chloride as a carrier and phosphorus pentachloride or 1-chloro-N,N,2-trimethyl-1-propenamine.

[0007] Preferably, the method for forming a complex with phosphorus pentachloride using zinc chloride as a carrier comprises the following steps:

[0008] Add PCl5 into the sublimator and slowly raise the temperature to 170℃. Maintain the temperature to allow PCl5 to completely sublime. The sublimated gas enters the receiving container through the conduit and deposits on the surface of the ZnCl2 solid powder to obtain a composite. The deposition temperature in the receiving container does not exceed room temperature.

[0009] Preferably, the method for forming a complex with 1-chloro-N,N,2-trimethyl-1-propenamine using zinc chloride as a carrier comprises the following steps:

[0010] The dichloromethane solution of 1-chloro-N,N,2-trimethyl-1-propenamine was impregnated on a zinc chloride support by an impregnation method, and the dichloromethane was removed by rotary evaporation to obtain a composite.

[0011] Preferably, the organic solvent comprises dichloromethane or toluene.

[0012] Preferably, the temperature of the substitution reaction is 0-60°C.

[0013] Preferably, the temperature of the substitution reaction is 30-50°C.

[0014] Preferably, the reaction time of the substitution reaction is 2-5 h.

[0015] Preferably, during the substitution reaction, the pressure in the closed reactor is maintained at 0.2-0.4 MPa by introducing hydrogen chloride.

[0016] The present invention has the following beneficial effects:

[0017] (1) High yield and selectivity: The method of the present invention is used to synthesize 3-chloropropyne with a yield of ≥90% and a by-product content of <5%;

[0018] (2) Resource recycling: Directly using by-product hydrogen chloride as a synthetic raw material significantly reduces the cost of raw materials;

[0019] (3) Environmental advantages: reducing waste acid emissions and meeting green chemistry requirements;

[0020] (4) Easy operation: mild reaction conditions, low equipment investment, and suitable for industrial scale-up. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the following examples. However, it should be understood that the following examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention.

[0022] Example 1

[0023] In a 1L glass-lined reactor, 100g of propargyl alcohol, 300g of dichloromethane, and 4g of phosphorus pentachloride catalyst were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.2MPa. Stirring was started and the temperature was slowly raised to 40°C. The reaction was then stirred at a constant temperature for 3h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 124g of 3-chloropropyne with a purity of 99.3% and a yield of 92.7%.

[0024] Example 2

[0025] In a 1L glass-lined reactor, 100g of propargyl alcohol, 300g of dichloromethane, and 1g of 1-chloro-N,N,2-trimethyl-1-propenamine catalyst were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.2MPa. Stirring was started and the temperature was slowly raised to 30°C. The reaction was then stirred at a constant temperature for 2h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, the organic phase was separated, and the fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 125g of 3-chloropropyne with a purity of 99.4% and a yield of 93.6%.

[0026] Example 3

[0027] In a 1L glass-lined reactor, 100g of propargyl alcohol, 500g of toluene, and 3g of benzoyl chloride catalyst were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.5MPa. Stirring was started and the temperature was slowly raised to 40°C. The reaction was then stirred at this constant temperature for 3h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 120g of 3-chloropropyne with a purity of 99.1% and a yield of 89.5%.

[0028] Example 4

[0029] In a 1L glass-lined reactor, 100g of propargyl alcohol, 400g of dichloromethane, and 2g of oxalyl chloride catalyst were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.3MPa. Stirring was started and the temperature was slowly raised to 40°C. The reaction was then stirred at a constant temperature for 3h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 121g of 3-chloropropyne with a purity of 99.1% and a yield of 90.3%.

[0030] Example 5

[0031] 2g of PCl5 was added to the sublimator and the temperature was slowly raised to 170°C. The temperature was maintained to allow the PCl5 to completely sublime. The sublimated gas entered the receiving container through a conduit and deposited on the surface of 3g of ZnCl2 solid powder to obtain a phosphorus pentachloride / zinc chloride complex. The deposition temperature in the receiving container was room temperature.

[0032] In a 1L glass-lined reactor, 100g of propargyl alcohol, 500g of dichloromethane, and 5g of a phosphorus pentachloride / zinc chloride complex were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.3MPa. Stirring was started and the temperature was slowly raised to 40°C. The reaction was then stirred at this constant temperature for 5h. The pressure was then slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 121g of 3-chloropropyne with a purity of 99.3% and a yield of 90.5%.

[0033] Example 6

[0034] 0.4 g of 1-chloro-N,N,2-trimethyl-1-propenamine was dissolved in 3.6 mL of dichloromethane to form a solution. 4.6 g of zinc chloride solid powder was then added to the solution. After stirring and dispersing evenly, the dichloromethane was removed by rotary evaporation to obtain a 1-chloro-N,N,2-trimethyl-1-propenamine / zinc chloride complex.

[0035] In a 1L glass-lined reactor, 100g of propargyl alcohol, 400g of dichloromethane, and 5g of 1-chloro-N,N,2-trimethyl-1-propenylamine / zinc chloride complex were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.3MPa. Stirring was started and the temperature was slowly raised to 30°C. The reaction was then stirred at a constant temperature for 4h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, the organic phase was separated, and the fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 123g of 3-chloropropyne with a purity of 99.4% and a yield of 92.1%.

[0036] Comparative Example 1

[0037] In a 1L glass-lined reactor, 100g of propargyl alcohol, 300g of dichloromethane, and 5g of zinc chloride catalyst were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.4MPa. Stirring was started and the temperature was slowly raised to 50°C. The reaction was then stirred at this constant temperature for 5h. After the reaction was completed, the pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed by water. After the pressure release was completed, the reaction solution was allowed to stand for stratification, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 112g of 3-chloropropyne with a purity of 99.2% and a yield of 83.7%.

[0038] Comparative Example 2

[0039] 2 g of PCl5 was added to the sublimator and the temperature was slowly raised to 170°C. The temperature was maintained to allow the PCl5 to completely sublime. The sublimated gas entered the receiving container through a conduit and deposited on the surface of 3 g of silica solid powder to obtain a phosphorus pentachloride / silicon dioxide composite. The deposition temperature in the receiving container was room temperature.

[0040] In a 1L glass-lined reactor, 100g of propargyl alcohol, 500g of dichloromethane, and 5g of phosphorus pentachloride / silicon dioxide composite were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.3MPa. Stirring was started and the temperature was slowly raised to 40°C. The reaction was then stirred at this constant temperature for 5h. The pressure was then slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 109g of 3-chloropropyne with a purity of 99.1% and a yield of 81.3%.

[0041] Comparative Example 3

[0042] 0.4 g of 1-chloro-N,N,2-trimethyl-1-propenamine was dissolved in 3.6 mL of dichloromethane to form a solution. 4.6 g of alumina powder was then added to the solution. After stirring and dispersing evenly, the dichloromethane was removed by rotary evaporation to obtain a 1-chloro-N,N,2-trimethyl-1-propenamine / alumina complex.

[0043] In a 1L glass-lined reactor, 100g of propargyl alcohol, 400g of dichloromethane, and 5g of 1-chloro-N,N,2-trimethyl-1-propenylamine / alumina complex were added. The reactor was closed and the temperature was controlled at 20°C. Hydrogen chloride was slowly introduced to maintain the pressure in the reactor at 0.3MPa. Stirring was started and the temperature was slowly raised to 30°C. The reaction was then stirred at this constant temperature for 4h. The pressure was slowly released to atmospheric pressure. The tail gas generated during the pressure release process was absorbed with water. After the pressure release was completed, the reaction solution was allowed to stand and stratify, and the organic phase was separated. The fraction within the boiling point range of 3-chloropropyne was collected by distillation to obtain 114g of 3-chloropropyne with a purity of 99.3% and a yield of 85.2%.

[0044] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for synthesizing chloropropyne, characterized in that: In a closed reactor and under the action of a catalyst, propargyl alcohol and hydrogen chloride undergo a substitution reaction in an organic solvent to produce 3-chloropropyne.

2. The method for synthesizing chloropropyne according to claim 1, wherein: The catalyst comprises one of zinc chloride, phosphorus pentachloride, 1-chloro-N,N,2-trimethyl-1-propenamine, benzoyl chloride and oxalyl chloride.

3. The method for synthesizing chloropropyne according to claim 1, wherein: The catalyst is a complex formed by zinc chloride as a carrier and phosphorus pentachloride or 1-chloro-N,N,2-trimethyl-1-propyleneamine.

4. The method for synthesizing chloropropyne according to claim 3, wherein: The method for forming a complex with phosphorus pentachloride as a carrier comprises the following steps: Add PCl5 into the sublimator and slowly raise the temperature to 170℃. Maintain the temperature to allow PCl5 to completely sublime. The sublimated gas enters the receiving container through the conduit and deposits on the surface of the ZnCl2 solid powder to obtain a composite. The deposition temperature in the receiving container does not exceed room temperature.

5. The method for synthesizing chloropropyne according to claim 3, wherein: The method for forming a complex with 1-chloro-N,N,2-trimethyl-1-propenamine as a carrier comprises the following steps: The dichloromethane solution of 1-chloro-N,N,2-trimethyl-1-propenamine was impregnated on a zinc chloride support by an impregnation method, and the dichloromethane was removed by rotary evaporation to obtain a composite.

6. The method for synthesizing chloropropyne according to claim 1, wherein: The organic solvent includes dichloromethane or toluene.

7. The method for synthesizing chloropropyne according to claim 1, wherein: The temperature of the substitution reaction is 0-60°C.

8. The method for synthesizing chloropropyne according to claim 5, characterized in that: The temperature of the substitution reaction is 30-50°C.

9. The method for synthesizing chloropropyne according to claim 1, wherein: The reaction time of the substitution reaction is 2-5h.

10. The method for synthesizing chloropropyne according to claim 1, characterized in that: During the substitution reaction, the pressure in the closed reactor is maintained at 0.2-0.4 MPa by introducing hydrogen chloride.