A method for preparing 1,1,2,3-tetrachloropropene

Abstract

The invention discloses a method for preparing 1,1,2,3-tetrachloropropylene, which belongs to the field of fine chemicals. 3-chloropropyne is used as a starting material, 3-chloropropyne is reacted with N-chlorosuccinimide ( NCS) is chlorinated under alkaline conditions to obtain 1,3-dichloropropyne; then chlorine is introduced under the action of a catalyst to prepare 1,1,2,3-tetrachloropropylene. The overall two-step process of the present invention is simple, the raw material market source is abundant, and after the step-by-step reaction, chlorine is finally added with a specific catalyst, which has the advantages of easy product purification, relatively high yield and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for preparing 1,1,2,3-tetrachloropropene. Background Art

[0002] 1,1,2,3-Tetrachloropropene (HCC-1230xa), referred to as TMA, is the main intermediate for synthesizing the new generation of environmentally friendly refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) and preparing chemical herbicide wheat flavor emulsion. HFO-1234yf has the characteristics of a greenhouse effect potential of about 4 and an ODP of 0.

[0003] At present, the main methods for synthesizing 1,1,2,3-tetrachloropropene are: synthesizing 1,1,2,3-tetrachloropropene with carbon tetrachloride / ethylene / chlorine as raw materials, synthesizing 1,1,2,3-tetrachloropropene with 1,2,3-trichloropropane as raw material / isomerization, synthesizing 1,1,2,3-tetrachloropropene with pentachloropropane as raw material, etc. From the current preparation methods, there are generally problems such as long synthesis route, low production efficiency, many by-products and three wastes, high cost, high requirements for equipment, high energy consumption, complex process route and post-treatment.

[0004] In summary, it is necessary to seek a more effective, simple and economical method for synthesizing 1,1,2,3-tetrachloropropene. Therefore, in view of the above problems, the present invention provides a new method for preparing 1,1,2,3-tetrachloropropene with high production efficiency, less by-products and three wastes, low cost, simple process route and post-treatment. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a method for preparing 1,1,2,3-tetrachloropropene, using 3-chloropropyne as a starting material, chlorinating 3-chloropropyne with NCS under alkaline conditions to obtain 1,3-dichloropropyne; then introducing chlorine gas under the action of a catalyst to prepare 1,1,2,3-tetrachloropropene. The present invention has the advantages of simple process, easy purification, GC purity of more than 98.5%, relatively high yield and low cost.

[0006] The method for preparing 1,1,2,3-tetrachloropropene described in the present invention has a reaction equation as follows:

[0007]

[0008] The steps include:

[0009] Step 1: After mixing 3-chloropropyne with an organic solvent, NCS is added under reduced temperature, followed by adding a base, the reaction is terminated, and 1,3-dichloropropyne is obtained by vacuum distillation;

[0010] Step 2: Mix 1,3-dichloropropyne, a catalyst and an organic solvent, cool down and slowly introduce chlorine gas, then heat up to react. After the reaction is completed, 1,1,2,3-tetrachloropropene is obtained by vacuum distillation.

[0011] Furthermore, the organic solvent in the first step is selected from one or more of tetrahydrofuran, sulfolane or dimethyl sulfoxide, preferably a mixed solvent, i.e. a mixed solvent composed of tetrahydrofuran / sulfolane or tetrahydrofuran / dimethyl sulfoxide.

[0012] Furthermore, the base in the first step is selected from 60% NaH or 38% sodium tert-amylate toluene solution. In actual feeding, it is found that 60% NaH has the best reaction effect, but considering the actual safety, 38% sodium tert-amylate toluene solution is preferred.

[0013] Furthermore, in the first step, the molar ratio of 3-chloropropyne, base and NCS is 1:1.05-1.10:1.05-1.10.

[0014] Furthermore, the catalyst in the second step is selected from a mixture of bismuth trifluoromethanesulfonate and tungsten trichloride, wherein the molar ratio of the two is 2:1.

[0015] Furthermore, the organic solvent in the second step is selected from chloroform or 1,2-dichloroethane; preferably chloroform.

[0016] Furthermore, in the second step, the molar ratio of 1,3-dichloropropyne, catalyst and chlorine is 1:0.02-0.05:2.5-3.5.

[0017] Furthermore, in the second step, the liquid chlorine bottle is heated and gasified in advance, 1,3-dichloropropyne, a catalyst and an organic solvent are mixed, the temperature is lowered and chlorine gas is slowly introduced, and then the temperature is raised to react, and the catalyst is filtered out after post-treatment, washed with water, dried, and 1,1,2,3-tetrachloropropene is obtained by vacuum distillation.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The process is simple, and the target product can be obtained through two-step reaction. 2. The raw materials are easily available and the cost is relatively low. 3. The yield is relatively high, and the purity can reach more than 98.5%. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to the embodiments.

[0020] Example 1

[0021]

[0022] 74.5g (1.0mol) of 3-chloropropyne, 900mL of tetrahydrofuran and 90mL of cyclopentane were put into a four-necked reaction bottle and mixed, cooled to 0-10°C, 140.2g (1.05mol) of NCS was added in batches, 324.6g (1.1mol) of 38% sodium tert-amyl alcohol toluene solution was added dropwise and the system temperature was kept at 15-20°C, reacted at this temperature for 5 hours, quenched by adding a mixed solution of acetic acid and water, pH was adjusted to 6.8-7.0, allowed to stand for stratification, the aqueous phase was extracted with 300mL*2 of dichloromethane, the organic phase was washed with 200g*2 of water, anhydrous magnesium sulfate was added to the organic phase for drying, filtered, the filtrate was first concentrated under reduced pressure at low temperature, and then distilled under reduced pressure at 50-60°C to obtain 95.4g of 1,3-dichloropropyne, with a yield of 87.6%. GC97.4%, GC-MS=108.95.

[0023] Example 2

[0024]

[0025] 74.5 g (1.0 mol) of 3-chloropropyne, 900 mL of tetrahydrofuran and 80 mL of dimethyl sulfoxide were put into a four-necked reaction bottle and mixed, and the temperature was lowered to 0-10°C. 140.2 g (1.05 mol) of NCS was added in batches, and 40 g (1.1 mol) of 60% NaH was added in batches while maintaining the system temperature at 10-15°C. The reaction was carried out at this temperature for 2 hours, and a mixed solution of acetic acid and water was added to quench the reaction. The pH was adjusted to 6.5-7.0, and the reaction was allowed to stand for stratification. The aqueous phase was extracted with 300 mL*2 of dichloromethane, and the organic phase was washed with 200 g*2 of water. Anhydrous magnesium sulfate was added to the organic phase for drying, and the organic phase was filtered. The filtrate was first concentrated under reduced pressure at low temperature, and then distilled under reduced pressure at 50-60°C to obtain 98.3 g of 1,3-dichloropropyne with a yield of 90.2% and a GC of 97.8%.

[0026] Example 3

[0027]

[0028] 87.2g (0.8mol) of 1,3-dichloropropyne, 13.1g (0.02mol) of bismuth trifluoromethanesulfonate, 11.6g (0.04mol) of tungsten trichloride and 800mL of chloroform were put into a four-necked reaction bottle with a tail gas absorption device and mixed. The liquid chlorine cylinder was preheated and opened, and first introduced into the buffer tank and then into the reaction bottle. The temperature was controlled at 18-25°C, and a total of 163.1g (2.3mol) of chlorine gas was introduced. The temperature was raised to 35-40°C for reaction for 8 hours, and then cooled to 10-15°C, filtered, and a 3% sodium bicarbonate aqueous solution was added to the filtrate to adjust the pH to 6.5-6.8. The organic phase was washed with 300g*3 water, and the organic phase was concentrated under reduced pressure to remove the chloroform. 119g of 1,1,2,3-tetrachloropropene was distilled out under reduced pressure at 90-95°C, with a GC of 99.1% and a yield of 82.7%, which was consistent with the GC peak of the standard product. 1 H NMR (400MHz, CDCl3): 4.47 (s, 2H).

[0029] Example 4

[0030]

[0031] 87.2 g (0.8 mol) of 1,3-dichloropropyne, 16.4 g (0.025 mol) of bismuth trifluoromethanesulfonate, 14.5 g (0.05 mol) of tungsten trichloride and 800 mL of 1,2-dichloroethane were put into a four-necked reaction bottle with a tail gas absorption device and mixed. The liquid chlorine cylinder was preheated and opened, and first introduced into the buffer tank and then into the reaction bottle. The temperature was controlled at 18-25° C., and a total of 170.2 g (2.4 mol) of chlorine gas was introduced. The temperature was raised to 35-40° C. for reaction for 8 hours, and then the temperature was lowered to 10-15° C., and the mixture was filtered. A 3% aqueous sodium bicarbonate solution was added to the filtrate to adjust the pH to 6.5-6.8. The organic phase was washed with 300 g*3 water, and the organic phase was concentrated under reduced pressure to remove 1,2-dichloroethane. 112.8 g of 1,1,2,3-tetrachloropropene was distilled out under reduced pressure at 90-95° C., with a GC of 98.8% and a yield of 78.4%.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing 1,1,2,3-tetrachloropropene, characterized in that: The steps include: The first step: after mixing 3-chloropropyne with an organic solvent, NCS is added under reduced temperature, and then a base is added. After the reaction is completed, 1,3-dichloropropyne is obtained by vacuum distillation; the base is selected from 60% NaH or 38% sodium tert-amyl alcohol / toluene solution; The second step: 1,3-dichloropropyne, a catalyst and an organic solvent are mixed, chlorine is slowly introduced while the temperature is reduced, and then the temperature is increased for reaction. After the reaction is completed, 1,1,2,3-tetrachloropropene is obtained by vacuum distillation; the catalyst is selected from a mixture of bismuth trifluoromethanesulfonate and tungsten trichloride; the molar ratio of bismuth trifluoromethanesulfonate to tungsten trichloride is 2:1; the molar ratio of 1,3-dichloropropyne, catalyst and chlorine is 1:0.02-0.5:2.5-3.

5.

2. The method for preparing 1,1,2,3-tetrachloropropene according to claim 1, characterized in that: In the first step, the organic solvent is selected from one or more of tetrahydrofuran, sulfolane or dimethyl sulfoxide.

3. The method for preparing 1,1,2,3-tetrachloropropene according to claim 1, characterized in that: In the first step, the molar ratio of 3-chloropropyne, base and NCS is 1:1.05-1.10:1.05-1.

10.

4. The method for preparing 1,1,2,3-tetrachloropropene according to claim 1, characterized in that: In the second step, the organic solvent is selected from chloroform or 1,2-dichloroethane.

Images