A method for continuous synthesis of 1,1,1,3-tetrachloropropane

Abstract

This invention discloses a method for the continuous synthesis of 1,1,1,3-tetrachloropropane. Specifically, the method includes: feeding carbon tetrachloride and ethylene feedstocks into a tubular reactor containing an iron catalyst in a specific ratio and feeding manner; collecting the crude reaction product after cooling it in a cold trap; obtaining the final product through distillation and rectification; and reusing unreacted materials in the reactor. Compared with existing batch or continuous reaction processes, this invention features high catalytic activity, short reaction time, low by-products, no need for subsequent catalyst separation, and simple reaction process and equipment, making it suitable for continuous industrial production.

Description

Technical Field

[0001] This invention relates to a method for preparing 1,1,1,3-tetrachloropropane, and particularly to a method for continuously preparing 1,1,1,3-tetrachloropropane from carbon tetrachloride and ethylene via a telomerization reaction under the action of a catalyst. Background Technology

[0002] 1,1,1,3-Tetrachloropropane (TCP) is a raw material for the synthesis of 3,3,3-trifluoropropylene (TFP). 3,3,3-Trifluoropropylene is a basic raw material for the synthesis of high-performance polymer materials such as fluorosilicone oil, fluorosilicone rubber, and fluorosilicone coatings. In particular, fluorosilicone rubber not only has the high and low temperature resistance (-55~205℃) of silicone rubber, but also the fuel oil resistance and chemical media resistance of fluororubber. It is now widely used in modern industries such as aerospace, aircraft, automobiles, and artificial organs, as well as in defense, transportation, and medicine. 1,1,1,3-Tetrachloropropane is also a raw material for the synthesis of the new generation refrigerant HFO-1234yf. HFO1234yf, as a fourth-generation refrigerant, has an ODP of 0, a GWP of 4, and an atmospheric lifetime of only 11 days. It is considered a direct replacement for HFC-134a and has already been used in the European automotive market. It is expected that there will be a very large market value increase globally after 2021.

[0003] In existing technologies, 1,1,1,3-tetrachloropropane is generally synthesized by telomerization of carbon tetrachloride and ethylene. The main production method for carbon tetrachloride is the co-production of methane chloride. Domestic demand for methane chloride is increasing year by year, and the capacity of related equipment is also continuously increasing. As a byproduct of methane chloride production, the output of carbon tetrachloride will also show an upward trend. According to the Montreal Protocol on Substances that Deplete the Ozone Layer, as an ODS (Ozone Depleting Substance), carbon tetrachloride will be restricted from sale and prohibited from use as a solvent by 2010. Carbon tetrachloride will face a severe oversupply situation. The production of 1,1,1,3-tetrachloropropane not only realizes the high-value utilization of carbon tetrachloride but also reduces the ozone layer depletion caused by carbon tetrachloride emissions and alleviates the production pressure on methane chlorination enterprises.

[0004] Domestic research papers on the telomerization of carbon tetrachloride and ethylene to synthesize 1,1,1,3-tetrachloropropane all use single-reactor intermittent reactions, with transition metals such as copper chloride, ferric chloride, and iron powder as the main catalysts and phosphate esters or amines as co-catalysts. The disadvantages of this process are: (1) Telomerization is a pressurized reaction, and it is difficult to design a single-reactor output for such intermittent or semi-continuous reactions, resulting in high operational risks; (2) The reaction cycle is usually 5-10 hours, resulting in low production efficiency, high by-product content, and difficulty in separating iron powder catalyst, which affects product quality and increases separation costs; (3) The reaction uses mechanical stirring, which consumes a lot of electricity. Sinochem Modern Environmental Protection and Sinochem Blue Sky Group disclosed a continuous method for preparing 1,1,1,3-tetrachloropropane in patent CN201510130347.2. This continuous method uses a reactor for continuous feeding and continuous discharging, but it still cannot solve many of the disadvantages of reactor reactions, such as long residence time, serious backmixing of reactants, mechanical stirring, and separation of iron powder catalyst. Existing technologies for the chemipolymerization of 1,1,1,3-tetrachloropropane from carbon tetrachloride and ethylene primarily rely on batch reactors, which can only operate with limited market demand. However, the future market demand for 1,1,1,3-tetrachloropropane is expected to be strong, which will inevitably place high demands on the industrialization technology of 1,1,1,3-tetrachloropropane. This will require large single-unit production capacity and a high degree of continuous operation, which batch reactors clearly cannot meet the needs of large-scale industrial production.

[0005] In summary, there is an urgent need in the field to develop a method for the continuous reaction production of 1,1,1,3-tetrachloropropane. Summary of the Invention

[0006] The purpose of this invention is to develop a method for the continuous reaction production of 1,1,1,3-tetrachloropropane.

[0007] A first aspect of the present invention provides a method for the continuous synthesis of 1,1,1,3-tetrachloropropane, the method comprising the steps of:

[0008] The carbon tetrachloride feedstock solution containing the co-catalyst and ethylene is continuously fed into a reactor containing an iron catalyst for reaction, and then continuously discharged into a cold trap to collect 1,1,1,3-tetrachloropropane.

[0009] In another preferred embodiment, the reactor is a tubular fixed-bed reactor, and the amount of iron catalyst packed in the reactor is 60-90 (v / v)% of the reactor volume, preferably 65-75 (v / v)%.

[0010] In another preferred embodiment, during the reaction process, the feeding method is selected from the group consisting of: gas-liquid co-flow upward through the catalyst bed, gas-liquid co-flow downward through the reactor bed, or gas-liquid cross-flow.

[0011] In another preferred embodiment, the molar ratio of carbon tetrachloride to ethylene in the feed liquid is carbon tetrachloride:ethylene = (1-10):1, preferably (1-5):1.

[0012] In another preferred embodiment, the reaction is a plug flow continuous reaction.

[0013] In another preferred embodiment, the reaction is a gas-liquid-solid three-phase reaction.

[0014] In another preferred embodiment, the volume hourly space velocity (VHSV) of the feed liquid is 10-100 h⁻¹ (based on ethylene). -1 .

[0015] In another preferred embodiment, the reaction temperature is 60-150°C, preferably 90-120°C; and / or

[0016] The reaction pressure is 0.1-2.0 MPa, preferably 0.8-1.1 MPa; and / or

[0017] The reaction time is 1-60 minutes, preferably 5-30 minutes.

[0018] In another preferred embodiment, the iron catalyst is selected from the group consisting of iron particles, iron sand, iron balls, Raschig rings, Pall rings, iron wire mesh, or by-products from iron processing, or an iron catalyst supported on a porous carrier material.

[0019] In another preferred embodiment, the iron catalyst is an iron catalyst supported on a porous support material, and the iron catalyst is obtained by the following means:

[0020] Ferric nitrate is directly loaded onto a porous support material, or other soluble iron salts are precipitated to generate ferric hydroxide, which is then loaded onto a porous material and calcined at high temperature to obtain iron oxide. The iron catalyst is then obtained by online reduction with hydrogen.

[0021] In another preferred embodiment, the porous carrier material is selected from the group consisting of silica gel, activated carbon, alumina, silicon dioxide, or combinations thereof.

[0022] In another preferred embodiment, the calcination temperature is 500-1000℃, preferably 600-800℃.

[0023] In another preferred embodiment, the hydrogen reduction time is 1-8 hours, preferably 3-5 hours.

[0024] In another preferred embodiment, the hydrogen reduction temperature is 100-800°C, preferably 400-600°C.

[0025] In another preferred embodiment, the cocatalyst is selected from the group consisting of phosphate ester cocatalysts, or amine or lactam cocatalysts; preferably, the cocatalyst is selected from the group consisting of triethyl phosphate, trimethyl phosphate, tributyl phosphate, triethyl phosphite, trimethyl phosphite, tributyl phosphite, N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone; and / or

[0026] The amount of the co-catalyst is 0.01-15 wt% (based on carbon tetrachloride), preferably 0.1-10 wt%, more preferably 0.1-5 wt%.

[0027] In another preferred embodiment, the method further includes: recycling the ethylene gas in the tail gas into the feed line for reaction; and / or

[0028] The crude product was separated into 1,1,1,3-tetrachloropropane by distillation, and the unreacted carbon tetrachloride obtained from the separation was added into the feed line for further reaction.

[0029] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0030] Figure 1 This is a line graph showing the running time, tetrachloropropane concentration, and carbon tetrachloride conversion rate in Example 8 of the present invention. Detailed Implementation

[0031] Through long-term and in-depth research, the inventors have designed a flow cytometry method for preparing 1,1,1,3-tetrachloropropane. This method prepares 1,1,1,3-tetrachloropropane via a continuous reaction process. The method of this invention has a large single-unit production capacity and a high degree of continuity, making it suitable for the industrial-scale continuous production of 1,1,1,3-tetrachloropropane. Based on the above findings, the inventors completed this invention.

[0032] Flow Cytometry Preparation Method of 1,1,1,3-Tetrachloropropane

[0033] In this invention, the method includes using iron-based materials as the main catalyst, phosphate esters and amines as co-catalysts, dissolving a certain amount of co-catalysts in carbon tetrachloride feedstock, and continuously feeding ethylene into the reactor at a certain flow rate, ratio, and feeding method. Under a certain reaction temperature and pressure, the feedstock is continuously discharged into a cold trap to collect crude 1,1,1,3-tetrachloropropane. Ethylene gas is recycled and incorporated into the ethylene feed pipeline to continue the reaction. The crude product is separated into 1,1,1,3-tetrachloropropane product by distillation, and unreacted carbon tetrachloride is incorporated into the feed pipeline to continue the reaction.

[0034] As one implementation scheme, the main catalyst described in this method is an iron-based material, which can be pure iron, including but not limited to iron particles, iron sand, iron balls, Raschig rings, Pall rings, iron wire mesh, and byproducts from iron processing. Alternatively, ferric nitrate can be loaded onto a porous support material, calcined at high temperature to obtain iron oxide, and then reduced online with hydrogen to obtain an iron catalyst loaded on the porous support material. The porous support material includes, but is not limited to, silica gel, activated carbon, alumina, and silicon dioxide; the calcination temperature is 500-1000℃, preferably 600-800℃; the hydrogen reduction time is 1-8 hours, preferably 3-5 hours; and the hydrogen reduction temperature is 100-800℃, preferably 400-600℃.

[0035] The iron catalyst is loaded into a tubular reactor and reacted in a fixed-bed configuration. In a preferred embodiment, the catalyst loading is 60-90% (v / v)% of the reactor volume, preferably 65-75% (v / v)%.

[0036] An appropriate amount of co-catalyst is added to the carbon tetrachloride feedstock. The amount of co-catalyst is 0.01-10 wt% (based on the amount of carbon tetrachloride), preferably 0.1-5 wt%. If the amount of co-catalyst is too low, the conversion rate of the reaction will be too low. If the amount of co-catalyst is too high, a large amount of substances insoluble in the reactants will be formed during the reaction, causing rapid corrosion of the iron catalyst and making subsequent separation difficult.

[0037] As one embodiment, the cocatalyst described in this method includes, but is not limited to, triethyl phosphate, trimethyl phosphate, tributyl phosphate, triethyl phosphite, trimethyl phosphite, tributyl phosphite, N,N-dimethylformamide, N-methylpyrrolidone, and N-ethylpyrrolidone.

[0038] During the reaction, carbon tetrachloride is pumped into the reactor, and ethylene is introduced into the reactor through a flow meter. Both materials can enter the reactor according to a suitable feeding method, such as gas-liquid co-flow upwards through the catalyst bed, gas-liquid co-flow downwards through the reactor bed, or gas-liquid cross-flow. The reaction is carried out at 60-150℃, preferably 90-120℃, at a reaction pressure of 0.1-2.0 MPa, preferably 0.8-1.1 MPa, and at a residence time of 1-60 minutes, preferably 5-30 minutes.

[0039] The mixture after the reaction was distilled to recover unreacted carbon tetrachloride and co-catalyst, and then distilled under reduced pressure to obtain 1,1,1,3-tetrachloropropane product.

[0040] As one implementation scheme, the reactor described in this method is a tubular fixed-bed reactor with a plug flow continuous reaction. The iron catalyst is loaded at 70-90% of the reactor volume, and the reaction is a gas-liquid-solid three-phase reaction.

[0041] Typically, at least one of carbon tetrachloride and ethylene is in excess. In this case, the ratio of carbon tetrachloride to ethylene is selected with carbon tetrachloride in excess, and the molar ratio of carbon tetrachloride to ethylene is (1-10):1, preferably (1-5):1.

[0042] As one implementation scheme, the reaction temperature of this method is 60-150℃, preferably 90-120℃, the reaction pressure is 0.1-2.0MPa, preferably 0.8-1.1MPa, and the reaction residence time is 1-60 minutes, preferably 5-30 minutes.

[0043] Compared with the prior art, the present invention has at least the following advantages and outstanding effects:

[0044] This invention uses pure iron and supported iron materials as the main catalysts, and phosphate esters or nitrogen-containing compounds as co-catalysts. The co-catalysts and main catalysts form complexes that dissolve in the reactants and exert their catalytic effect. A tubular fixed-bed reactor is used to achieve continuous reaction, resulting in simple equipment. The iron catalyst not only acts as a catalyst in the reaction but also enhances heat transfer. The advantages of this invention are high catalytic efficiency, short reaction residence time, low by-product levels, no need for catalyst separation in subsequent processes, simple process equipment, and suitability for continuous industrial production. In particular, the porous material-supported iron-based catalyst prepared in this invention has a larger specific surface area, more catalytic active sites, and higher catalytic efficiency compared to pure iron materials, while also reducing reactor weight and improving operating efficiency.

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Percentages and parts are by weight unless otherwise stated.

[0046] Example 1:

[0047] Weigh 500g of carbon tetrachloride raw material, add 2% ethyl phosphate, mix thoroughly, and set aside. The reaction tube is a quartz tube with an inner diameter of 20mm, filled with small iron balls to 70% of the reactor volume. When the center temperature of the reaction tube reaches 70℃, the carbon tetrachloride raw material and ethylene are introduced into the reaction tube at a molar ratio of 5:1, flowing upwards. The ethylene volume hourly space velocity is 100 h⁻¹. -1 The reaction temperature was controlled at 90℃, the reaction pressure at 0.8 MPa, and the reaction time at 30 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. Gas chromatography analysis of the crude product showed 1,1,1,3-tetrachloropropane with an ethylene conversion of 48.5% and a selectivity of 92.5% for 1,1,1,3-tetrachloropropane.

[0048] Example 2:

[0049] Weigh 500g of carbon tetrachloride raw material, add 4% butyl phosphate, mix thoroughly and set aside. The reaction tube is a quartz tube with an inner diameter of 20mm, and filled with fine iron filings to 70% of the reactor volume. When the center temperature of the reaction tube is heated to 70℃, the carbon tetrachloride raw material and ethylene are added at a molar ratio of 2:1, and the ethylene volume hourly space velocity is 80h⁻¹. -1 The crude product was collected in a cold trap and flowed upwards through the reaction tube. The reaction temperature was controlled at 110℃, the reaction pressure at 1.0 MPa, and the reaction time at 20 minutes. The separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. Gas chromatography analysis of the crude product showed that 1,1,1,3-tetrachloropropane was present, with an ethylene conversion rate of 62.5% and a selectivity of 93.5% for 1,1,1,3-tetrachloropropane.

[0050] Example 3:

[0051] Weigh 500g of carbon tetrachloride feedstock, add 0.5% butyl phosphite, mix thoroughly, and set aside. Use a quartz tube with an inner diameter of 20mm, and fill the reactor with Raschig rings to 70% of its volume. When the center temperature of the reactor tube reaches 70℃, the carbon tetrachloride feedstock and ethylene are introduced into the reactor tube at a molar ratio of 8:1, with the flow direction being upwards and a volume hourly space velocity (VHSV) of 40 h⁻¹. -1 The reaction temperature was controlled at 60℃, the reaction pressure at 1.5 MPa, and the reaction time at 40 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. Gas chromatography analysis of the crude product showed a 1,1,1,3-tetrachloropropane conversion of 68.5% and a 1,1,1,3-tetrachloropropane selectivity of 92.5%.

[0052] Example 4:

[0053] Weigh 500g of carbon tetrachloride feedstock, add 1.0% N,N-dimethylformamide, mix thoroughly, and set aside. The reaction tube is a quartz tube with an inner diameter of 20mm, filled with Pall rings to 70% of the reactor volume. When the center temperature of the reaction tube reaches 70℃, the carbon tetrachloride feedstock and ethylene are introduced into a flow path of 5:1 downwards through the reaction tube at a volume hourly space velocity (VHSV) of 60 h⁻¹. -1 The reaction temperature was controlled at 130℃, the reaction pressure at 2.0 MPa, and the reaction time at 60 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. The crude product was analyzed by gas chromatography for 1,1,1,3-tetrachloropropane, with a selectivity of 91.4%. The ethylene conversion rate was calculated to be 80.5% based on the amount of unreacted ethylene collected by water displacement and the ethylene feed rate.

[0054] Example 5:

[0055] Weigh 500g of carbon tetrachloride feedstock, add 1.0% trimethyl phosphate, mix thoroughly, and set aside. The reaction tube is a quartz tube with an inner diameter of 20mm, filled with Pall rings to 70% of the reactor volume. When the center temperature of the reaction tube reaches 70℃, the carbon tetrachloride feedstock and ethylene are introduced into a 2:1 molar ratio and flow downwards through the reaction tube at a volume hourly space velocity (VHSV) of 80 h⁻¹. -1 The reaction temperature was controlled at 150℃, the reaction pressure at 0.6 MPa, and the reaction time at 50 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. The crude product was analyzed by gas chromatography for 1,1,1,3-tetrachloropropane, with a selectivity of 93.4%. The ethylene conversion rate was calculated to be 70.5% based on the amount of unreacted ethylene collected by water displacement and the ethylene feed rate.

[0056] Example 6:

[0057] Preparation of Fe@SiO2 catalyst:

[0058] 30g of ferric nitrate was dissolved in a beaker to obtain a yellow solution. 100g of dried SiO2 support was accurately weighed into the solution. After ultrasonic impregnation under vacuum for 1 hour, the solution was impregnated under pressure at 60℃ for 12 hours. The crude sample after impregnation was dried at 120℃ for 8 hours to obtain Fe(NO3)3@SiO2.

[0059] Fe(NO3)3@SiO2 was activated in a tube furnace at 800℃ for 5 hours to obtain Fe2O3@SiO2, which was then reduced in a tube furnace at 500℃ with hydrogen for 4 hours to obtain Fe@SiO2 catalyst.

[0060] Evaluation of telomerization reaction:

[0061] Weigh 500g of carbon tetrachloride feedstock, add 10% N-methylpyrrolidone, mix thoroughly, and set aside. The reaction tube is a quartz tube with an inner diameter of 20mm, and filled with a supported iron catalyst Fe@SiO2 to 70% of the reactor volume. When the center temperature of the reaction tube reaches 70℃, the carbon tetrachloride feedstock and ethylene are introduced into the reaction tube at a molar ratio of 10:1, flowing downwards at a volume hourly space velocity (VHSV) of 50 h⁻¹. -1 The reaction temperature was controlled at 100℃, the reaction pressure at 0.7MPa, and the reaction time at 30 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. The crude product was analyzed by gas chromatography for 1,1,1,3-tetrachloropropane, with a selectivity of 94.4%. The ethylene conversion rate was calculated to be 90.5% based on the amount of unreacted ethylene collected by water displacement and the ethylene feed rate.

[0062] Example 7:

[0063] Preparation of Fe@AC catalyst:

[0064] 30g of ferric chloride was dissolved in a beaker, and 100g of dried activated carbon AC carrier was accurately weighed in. The pH value was adjusted with ammonia water to induce precipitation. The addition time was controlled at 30 minutes. Then, the sample was aged at 60℃ for 12 hours. After filtration, the wet sample was dried at 120℃ for 8 hours to obtain Fe(OH)3@AC.

[0065] Fe(OH)3@AC was activated in a tube furnace at 600℃ for 4 hours to obtain Fe2O3@AC, which was then reduced with hydrogen at 400℃ for 5 hours to obtain the Fe@AC catalyst.

[0066] Evaluation of telomerization reaction:

[0067] Weigh 500g of carbon tetrachloride feedstock, add 3% N-ethylpyrrolidone, mix thoroughly, and set aside. Use a 20mm inner diameter quartz tube as the reaction tube, and fill 70% of the reactor volume with a supported iron catalyst, Fe@AC. When the center temperature of the reaction tube reaches 70℃, the carbon tetrachloride feedstock and ethylene are cross-flowed through the reaction tube at a molar ratio of 1:1, with a volume hourly space velocity (VHSV) of 45 h⁻¹. -1 The reaction temperature was controlled at 120℃, the reaction pressure at 0.5 MPa, and the reaction time at 60 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. The crude product was analyzed by gas chromatography for 1,1,1,3-tetrachloropropane, with a selectivity of 95.4% and a carbon tetrachloride conversion rate of 85.5%.

[0068] When using the supported iron catalysts in Examples 6 and 7, the feed conversion rate was significantly improved, and the tubular reactor was lightweight and easy to operate. The catalyst loading, disassembly and recovery were easy, the reactor weight was reduced, the cost was lowered, and it was safer.

[0069] Example 8:

[0070] Using Fe@AC prepared in Example 7 as a catalyst, 2000g of carbon tetrachloride feedstock was weighed, and 3% of N-ethylpyrrolidone was added to it. The mixture was thoroughly mixed and set aside. A quartz tube with an inner diameter of 20mm was used as the reaction tube, and the supported iron catalyst Fe@AC was packed into the reactor to fill 70% of the reactor volume. When the center temperature of the reaction tube was heated to 70°C, the carbon tetrachloride feedstock and ethylene were cross-flowed through the reaction tube at a molar ratio of 1:1, with a volume hourly space velocity of 50 h⁻¹. -1The reaction temperature was controlled at 100℃, the reaction pressure at 0.5MPa, and the reaction time at 20 minutes. The crude product was collected in a cold trap, and the separated carbon tetrachloride was refluxed back into the reaction solution to continue the reaction. Gas chromatography analysis of the crude product showed a selectivity of over 90% for 1,1,1,3-tetrachloropropane, and a carbon tetrachloride conversion rate of 75-80%. Even after 200 hours of reaction, the catalyst maintained high activity and stability, meeting the requirements for industrial production. (See attached image) Figure 1 As described in [the text].

[0071] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A continuous synthesis method for 1,1,1,3-tetrachloropropane, characterized in that, The method includes the following steps: The carbon tetrachloride feedstock solution containing the catalyst and ethylene is continuously fed into a reactor containing an iron catalyst for reaction, and then continuously discharged into a cold trap to collect 1,1,1,3-tetrachloropropane. The iron catalyst is an iron catalyst supported on a porous support material, and the iron catalyst is obtained through the following method: Ferric nitrate is directly loaded onto a porous support material, or other soluble iron salts are precipitated to generate ferric hydroxide, which is then loaded onto a porous material and calcined at high temperature to obtain iron oxide. The iron catalyst is then obtained by online reduction with hydrogen. The porous carrier material is silicon dioxide or activated carbon; The cocatalyst is N-methylpyrrolidone or N-ethylpyrrolidone; The reaction temperature is 90-120℃; The reaction pressure is 0.1-2.0 MPa; The reaction time is 1-60 minutes.

2. The synthesis method according to claim 1, characterized in that, The reactor is a tubular fixed-bed reactor, and the amount of iron catalyst loaded in the reactor is 70-90% of the reactor volume.

3. The synthesis method as described in claim 1, characterized in that, In the aforementioned liquid, the molar ratio of carbon tetrachloride to ethylene is carbon tetrachloride:ethylene = (1-10):

1.

4. The synthesis method according to claim 1, characterized in that, In the aforementioned liquid, the molar ratio of carbon tetrachloride to ethylene is carbon tetrachloride:ethylene = (1-5):

1.

5. The synthesis method according to claim 1, characterized in that, The volume hourly space velocity (VHSV) of the feed liquid is 10-100 h⁻¹ (based on ethylene). -1 .

6. The synthesis method according to claim 1, characterized in that, The reaction pressure is 0.8-1.1 MPa; and / or The reaction time is 5-30 minutes.

7. The synthesis method according to claim 1, characterized in that, The amount of the co-catalyst is 0.01-15 wt% based on the amount of carbon tetrachloride.

8. The synthesis method according to claim 1, characterized in that, The amount of the co-catalyst is 0.1-10 wt% based on the amount of carbon tetrachloride.

9. The synthesis method according to claim 1, characterized in that, The amount of the co-catalyst is 0.1-5 wt% based on the amount of carbon tetrachloride.

10. The synthesis method according to claim 1, characterized in that, The method further includes: recycling the ethylene gas in the tail gas into the feed line for reaction; and / or The crude product was separated into 1,1,1,3-tetrachloropropane by distillation, and the unreacted carbon tetrachloride obtained from the separation was added into the feed line for further reaction.

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