1, 1, 1, 3-tetrachloropropane and synthesis method thereof

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to 1, 1, 1, 3-tetrachloropropane and a synthesis method thereof. The synthesis method comprises the following steps: adding a carbon-coated elemental iron catalyst, a cocatalyst and carbon tetrachloride into a reaction kettle, heating to a reaction temperature, introducing ethylene to a reaction pressure, carrying out a reaction while keeping the temperature and the pressure to obtain a crude tetrachloropropane product, and filtering and rectifying the crude tetrachloropropane product to obtain 1, 1, 1, 3-tetrachloropropane, the preparation method of the coated elemental iron catalyst comprises the following steps: dissolving ferric citrate in ethanol, uniformly stirring to obtain a precursor solution, drying in a vacuum drying oven at 50 DEG C to obtain precursor powder, and performing high-temperature pyrolysis on the precursor powder in an inert atmosphere to obtain the carbon coated elemental iron catalyst. The synthesis reaction of 1, 1, 1, 3-tetrachloropropane disclosed by the invention has the advantages of high carbon tetrachloride conversion rate, high tetrachloropropane selectivity, short reaction time and small by-product generation amount.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to 1,1,1,3-tetrachloropropane and a synthesis method thereof. Background Art

[0002] According to the Montreal Protocol, carbon tetrachloride is one of the ozone-depleting substances whose production and use are restricted. However, it can still be used as a chemical raw material. Converting carbon tetrachloride into other products is of great significance for protecting the ozone layer and has good prospects for development and utilization. 1,1,1,3-tetrachloropropane is an important raw material for preparing a new generation of refrigerants, hydrofluoroolefins (HFOs). Hydrofluoroolefin refrigerants have a low global warming potential (GWP) and a zero ozone depletion potential (ODP), and are considered ideal substitutes for traditional Freon refrigerants, being more environmentally friendly and meeting environmental protection requirements.

[0003] Regarding the synthesis of tetrachloropropane, there are many research methods at home and abroad. According to different reaction conditions, they can be divided into peroxide activation method, electromagnetic wave radiation method, metal and cocatalyst catalysis method. After years of technical accumulation, using carbon tetrachloride and ethylene as raw materials, with iron as the main catalyst and organophosphorus compounds as the cocatalyst has been widely used in industrial production.

[0004] CN106146247A discloses a synthesis process of 1,1,1,3-tetrachloropropane using ferrous chloride / ferric chloride as the main catalyst and phosphate esters as the cocatalyst. The yield of 1,1,1,3-tetrachloropropane in this process can reach 93%, but the high cost of the catalyst limits its industrial application.

[0005] US2004225166 discloses a synthesis process of 1,1,1,3-tetrachloropropane using reduced iron powder as the main catalyst and tributyl phosphate as the cocatalyst. The catalysts in this process are cheap and easily available, so this method is generally adopted in industrial production. However, this method mainly has the following problems in the synthesis process of tetrachloropropane: (1) Many polymers (tar): A large amount of polymers are easily generated during the reaction, resulting in difficult separation of products, reducing the product yield, and increasing the burden of equipment cleaning. (2) Low conversion rate and selectivity: The catalytic activity of the existing catalysts is limited, resulting in low ethylene conversion rate and low selectivity of tetrachloropropane (lower than 85%), and low raw material utilization rate. (3) Long reaction time: The reaction rate is slow, and a long reaction time (generally more than 5 hours) is required to achieve a high conversion rate, reducing the production efficiency.

[0006] Therefore, there is an urgent need for a synthesis process of tetrachloropropane with few by-products, high conversion rate, high selectivity and short reaction time. Summary of the Invention

[0007] To solve the drawbacks of the above-mentioned existing technologies, the present invention discloses a method for synthesizing 1,1,1,3-tetrachloropropane, and the following technical means are adopted: Add a carbon-coated elemental iron catalyst, a co-catalyst and carbon tetrachloride into a reaction kettle. After heating to the reaction temperature, introduce ethylene until the reaction pressure is reached, keep the temperature and pressure constant during the reaction, and then obtain a crude product of tetrachloropropane. After filtering and rectifying the crude product of tetrachloropropane, 1,1,1,3-tetrachloropropane is obtained; The preparation method of the carbon-coated elemental iron catalyst is as follows: dissolve ferric citrate in ethanol, stir evenly to obtain a precursor solution, dry it at 50°C in a vacuum drying oven to obtain a precursor powder, and pyrolyze the precursor powder at high temperature under an inert atmosphere to obtain a carbon-coated elemental iron catalyst.

[0008] Further, in the preparation method of the carbon-coated elemental iron catalyst, before the stirring step, glucose is further added to the ethanol. The ferric citrate selected in the present invention can be used as both an iron source and a carbon source. After high-temperature pyrolysis under an inert atmosphere, a carbon-coated elemental iron catalyst can be directly generated. However, during the high-temperature pyrolysis process, the iron in ferric citrate is easily reduced at high temperature and falls off from the carbon skeleton, thus affecting the activity of the catalyst. By adding glucose to the precursor solution in the present invention, a carbon layer can be coated again on the outermost layer during the pyrolysis process to prevent the reduced elemental iron from falling off and ensure the activity of the catalyst.

[0009] Further, the reaction temperature is 110 - 130°C, preferably 120°C; the reaction pressure is 0.9 - 1.1 MPa, preferably 1.0 MPa; the reaction time is 3 - 5 h, preferably 4 h.

[0010] Further, the addition amount of the carbon-coated elemental iron catalyst is 0.6 - 1.0 wt% of the total mass of carbon tetrachloride. Preferably, the addition amount of the carbon-coated elemental iron catalyst is 0.8 wt% of the total mass of carbon tetrachloride; the addition amount of the co-catalyst is 0.5 - 0.7 wt% of the total mass of carbon tetrachloride. Preferably, the addition amount of the co-catalyst is 0.6 wt% of the total mass of carbon tetrachloride.

[0011] Further, the co-catalyst is tributyl phosphate or triethyl phosphite.

[0012] Further, in the preparation method of the carbon-coated elemental iron catalyst, the ratio of ferric citrate to ethanol is 1:100 - 150, preferably 1:100, where ferric citrate is in g and ethanol is in mL.

[0013] Further, the mass ratio of ferric citrate to glucose is 1:0.4 - 0.6, preferably 1:0.5.

[0014] Furthermore, the temperature of the high-temperature pyrolysis is 500 - 900 °C, preferably 700 °C; the time is 4 - 6 h, preferably 5 h.

[0015] The present invention also discloses a 1,1,1,3 - tetrachloropropane prepared by using any one of the above - mentioned synthesis methods.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: When synthesizing 1,1,1,3 - tetrachloropropane, the present invention selects a carbon - coated iron catalyst as the main catalyst. When preparing the main catalyst, ferric citrate is selected as the iron source. The prepared main catalyst has a high specific surface area and rich active sites, effectively improving the catalytic activity and shortening the reaction time; the carbon - coated layer can effectively inhibit the occurrence of side reactions, improve the selectivity of tetrachloropropane, and reduce the generation of polymers (tar); the carbon - coated layer can also prevent the aggregation and oxidation of iron nanoparticles, improving the stability and service life of the catalyst. Therefore, the 1,1,1,3 - tetrachloropropane synthesis reaction of the present invention has the advantages of high carbon tetrachloride conversion rate, high tetrachloropropane selectivity, short reaction time, and low by - product generation. Description of the Drawings

[0017] Figure 1 SEM image of the carbon - coated iron catalyst prepared in Example 1; Figure 2 XRD diffraction pattern of the carbon - coated iron catalyst prepared in Example 1; Figure 3 Verification chromatogram of 1,1,1,3 - tetrachloropropane prepared in Example 1. Detailed Embodiments

[0018] The following further illustrates the present invention with reference to the drawings and examples. The reagents, equipment, and materials described in the following examples and comparative examples are all prior art and can be obtained from commercial channels without special instructions.

[0019] Example 1 Preparation of the carbon - coated iron catalyst: Dissolve 10.0 g of ferric citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder. Under a nitrogen atmosphere, heat the precursor powder to 700 °C at a heating rate of 10 °C / min, hold for 5 hours, and naturally cool to room temperature to obtain the carbon - coated iron catalyst; Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to the reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 599.8 g of the crude tetrachloropropane product was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0020] Example 2 Preparation of carbon - coated elemental iron catalyst: 10.0 g of iron citrate was dissolved in 1000.0 mL of ethanol, 5.0 g of glucose was added, and the mixture was stirred evenly to obtain a precursor solution. The precursor solution was dried at 50 °C in a vacuum drying oven to obtain a precursor powder. The precursor powder was heated to 500 °C at a heating rate of 10 °C / min in a nitrogen atmosphere, held for 4 hours, and then naturally cooled to room temperature to obtain the carbon - coated elemental iron catalyst; Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to the reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 599.8 g of the crude tetrachloropropane product was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0021] Example 3 Preparation of carbon - coated elemental iron catalyst: 10.0 g of iron citrate was dissolved in 1000.0 mL of ethanol, 4.0 g of glucose was added, and the mixture was stirred evenly to obtain a precursor solution. The precursor solution was dried at 50 °C in a vacuum drying oven to obtain a precursor powder. The precursor powder was heated to 900 °C at a heating rate of 10 °C / min in a nitrogen atmosphere, held for 5 hours, and then naturally cooled to room temperature to obtain the carbon - coated elemental iron catalyst.

[0022] Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to the reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 587.8 g of the crude tetrachloropropane product was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0023] Example 4 Preparation of carbon - coated elemental iron catalyst: 10.0 g of iron citrate was dissolved in 1000.0 mL of ethanol, 5.0 g of glucose was added, and the mixture was stirred evenly to obtain a precursor solution. The precursor solution was dried at 50 °C in a vacuum drying oven to obtain a precursor powder. The precursor powder was heated to 500 °C at a heating rate of 10 °C / min in a nitrogen atmosphere, held for 5 hours, and then naturally cooled to room temperature to obtain the carbon - coated elemental iron catalyst.

[0024] Synthesis of 1,1,1,3 - tetrachloropropane: Add 3.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride into the reaction kettle. After heating to 120 °C, introduce ethylene until the pressure reaches 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 585.3 g of the crude tetrachloropropane product is obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane is obtained.

[0025] Example 5 Preparation of carbon - coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution. Dry the precursor solution in a vacuum drying oven at 50 °C to obtain a precursor powder. Under a nitrogen atmosphere, heat the precursor powder to 500 °C at a heating rate of 10 °C / min, hold for 6 hours, and then cool naturally to room temperature to obtain the carbon - coated elemental iron catalyst.

[0026] Synthesis of 1,1,1,3 - tetrachloropropane: Add 5.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride into the reaction kettle. After heating to 120 °C, introduce ethylene until the pressure reaches 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 603.6 g of the crude tetrachloropropane product is obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane is obtained.

[0027] Example 6 Preparation of carbon - coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution. Dry the precursor solution in a vacuum drying oven at 50 °C to obtain a precursor powder. Under a nitrogen atmosphere, heat the precursor powder to 500 °C at a heating rate of 10 °C / min, hold for 5 hours, and then cool naturally to room temperature to obtain the carbon - coated elemental iron catalyst.

[0028] Synthesis of 1,1,1,3 - tetrachloropropane: Add 4.0 g of the carbon - coated elemental iron catalyst obtained above, 2.5 g of tributyl phosphate, and 500.0 g of carbon tetrachloride into the reaction kettle. After heating to 120 °C, introduce ethylene until the pressure reaches 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 590.2 g of the crude tetrachloropropane product is obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane is obtained.

[0029] Example 7 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder to 500 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, keep it warm for 5 hours, and naturally cool it to room temperature to obtain the carbon-coated elemental iron catalyst.

[0030] Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.5 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to the reaction kettle, heat it to 120 °C, then introduce ethylene until the pressure reaches 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 604.6 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane can be obtained.

[0031] Example 8 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 6.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder to 500 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, keep it warm for 5 hours, and naturally cool it to room temperature to obtain the carbon-coated elemental iron catalyst.

[0032] Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to the reaction kettle, heat it to 110 °C, then introduce ethylene until the pressure reaches 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 594.1 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane can be obtained.

[0033] Example 9 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, keep it warm for 5 hours, and naturally cool it to room temperature to obtain the carbon-coated elemental iron catalyst.

[0034] Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to the reaction kettle, heat it to 130 °C, then introduce ethylene until the pressure reaches 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 611.3 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane can be obtained.

[0035] Example 10 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder. Heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 5 hours, and naturally cool to room temperature to obtain the carbon-coated elemental iron catalyst.

[0036] Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to the reaction kettle. After heating to 120 °C, introduce ethylene until the pressure reaches 0.9 MPa. After holding the temperature and pressure for 4 hours, obtain 607.8 g of crude tetrachloropropane product. Filter and rectify it to obtain 1,1,1,3-tetrachloropropane.

[0037] Example 11 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder. Heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 5 hours, and naturally cool to room temperature to obtain the carbon-coated elemental iron catalyst.

[0038] Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to the reaction kettle. After heating to 120 °C, introduce ethylene until the pressure reaches 1.1 MPa. After holding the temperature and pressure for 4 hours, obtain 614.2 g of crude tetrachloropropane product. Filter and rectify it to obtain 1,1,1,3-tetrachloropropane.

[0039] Example 12 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder. Heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 5 hours, and naturally cool to room temperature to obtain the carbon-coated elemental iron catalyst.

[0040] Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After holding the temperature and pressure for 3 hours, 580.5 g of crude tetrachloropropane was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0041] Example 13 Preparation of carbon - coated elemental iron catalyst: 10.0 g of iron citrate was dissolved in 1000.0 mL of ethanol, and 5.0 g of glucose was added and stirred evenly to obtain a precursor solution. The precursor solution was dried in a vacuum drying oven at 50 °C to obtain a precursor powder. The precursor powder was heated to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, held for 5 hours, and then naturally cooled to room temperature to obtain the carbon - coated elemental iron catalyst.

[0042] Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After holding the temperature and pressure for 5 hours, 603.3 g of crude tetrachloropropane was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0043] Example 14 Preparation of carbon - coated elemental iron catalyst: 10.0 g of iron citrate was dissolved in 1000.0 mL of ethanol and stirred evenly to obtain a precursor solution. The precursor solution was dried in a vacuum drying oven at 50 °C to obtain a precursor powder. The precursor powder was heated to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, held for 5 hours, and then naturally cooled to room temperature to obtain the carbon - coated elemental iron catalyst; Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of the carbon - coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After holding the temperature and pressure for 4 hours, 589.7 g of crude tetrachloropropane was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0044] Comparative Example 1 Synthesis of 1,1,1,3 - tetrachloropropane: 4.0 g of 300 - mesh reduced iron powder as a traditional catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reaction kettle. After heating to 120 °C, ethylene was introduced until the pressure reached 1.0 MPa. After holding the temperature and pressure for 6 hours, 576.7 g of crude tetrachloropropane was obtained. After filtration and rectification, 1,1,1,3 - tetrachloropropane was obtained.

[0045] Comparative Example 2 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of ferrocene in 1000.0 mL of ethanol, add 5.0 g of thiophene, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder in a nitrogen atmosphere at a heating rate of 10 °C / min to 700 °C, keep it warm for 5 hours, and naturally cool to room temperature to obtain a carbon-coated elemental iron catalyst; Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to a reaction kettle, heat it to 120 °C, then introduce ethylene to 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 590.8 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane is obtained.

[0046] Comparative Example 3 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron nitrate in 1000.0 mL of ethanol, add 5.0 g of sucrose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder in a nitrogen atmosphere at a heating rate of 10 °C / min to 700 °C, keep it warm for 5 hours, and naturally cool to room temperature to obtain a carbon-coated elemental iron catalyst; Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to a reaction kettle, heat it to 120 °C, then introduce ethylene to 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 587.2 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane is obtained.

[0047] Comparative Example 4 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 5.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder in a nitrogen atmosphere at a heating rate of 10 °C / min to 700 °C, keep it warm for 5 hours, and naturally cool to room temperature to obtain a carbon-coated elemental iron catalyst; Synthesis of 1,1,1,3-tetrachloropropane: Add 2.0 g of the above-obtained carbon-coated elemental iron catalyst, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to a reaction kettle, heat it to 120 °C, then introduce ethylene to 1.0 MPa, keep it warm and under pressure for 4 hours, and obtain 582.5 g of crude tetrachloropropane product. After filtering and rectifying it, 1,1,1,3-tetrachloropropane is obtained.

[0048] Comparative Example 5 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 3.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 5 hours, and naturally cool to room temperature to obtain a carbon-coated elemental iron catalyst; Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the carbon-coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to a reaction kettle, heat to 120 °C, then introduce ethylene to 1.0 MPa, hold for 4 hours after heat preservation and pressure maintenance, obtain 595.0 g of crude tetrachloropropane product, and filter and rectify it to obtain 1,1,1,3-tetrachloropropane.

[0049] Comparative Example 6 Preparation of carbon-coated elemental iron catalyst: Dissolve 10.0 g of iron citrate in 1000.0 mL of ethanol, add 7.0 g of glucose, stir evenly to obtain a precursor solution, dry it in a vacuum drying oven at 50 °C to obtain a precursor powder, and heat the precursor powder to 700 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 5 hours, and naturally cool to room temperature to obtain a carbon-coated elemental iron catalyst; Synthesis of 1,1,1,3-tetrachloropropane: Add 4.0 g of the carbon-coated elemental iron catalyst obtained above, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride to a reaction kettle, heat to 120 °C, then introduce ethylene to 1.0 MPa, hold for 4 hours after heat preservation and pressure maintenance, obtain 592.8 g of crude tetrachloropropane product, and filter and rectify it to obtain 1,1,1,3-tetrachloropropane.

[0050] The carbon tetrachloride conversion rate, tetrachloropropane selectivity, reaction time, and tar generation amount obtained by the methods of each example and comparative example are shown in Table 1.

[0051] Table 1

[0052] From the experimental results of Examples 1-14 and Comparative Examples 1-6 in Table 1, it can be seen that the synthesis method of the present invention has the advantages of high carbon tetrachloride conversion rate, high tetrachloropropane selectivity, short reaction time, and low tar generation amount.

[0053] Figure 1 SEM image of the carbon-coated elemental iron catalyst prepared in this Example 1. From Figure 1 (A) and (B) in it, it can be seen that this material is a composite material of macropores and micropores, and the macropore diameter is between 10-20 μm. From Figure 1It can be seen from (C) that the surface of the material is rough and composed of closely packed particles. The synergistic effect of the multi-size pore structure helps to increase the reaction specific surface area and provide more active centers; Figure 2 XRD diffraction pattern of the carbon-coated elemental iron catalyst prepared in Example 1. It can be seen from Figure 2 that at 700 °C (pyrolysis temperature), the main components are Fe elemental and Fe 3 C. At 500 °C, Fe is not completely reduced and there is no obvious diffraction peak of Fe elemental. At 900 °C, the main component is Fe elemental; Figure 3 Chromatogram of the final product of the example, Figure 3 The peak table is shown in Table 2. It can be seen from Figure 3 and Table 2 that the final product of Example 1 is 1,1,1,3-tetrachloropropane.

[0054] Table 2

Claims

1. A method for synthesizing 1,1,1,3-tetrachloropropane, characterized in that: The steps include: Adding a carbon-coated elemental iron catalyst, a promoter and carbon tetrachloride into a reaction kettle, heating to a reaction temperature, introducing ethylene to a reaction pressure, maintaining the temperature and pressure for reaction, and obtaining a crude tetrachloropropane product, and filtering and rectifying the crude tetrachloropropane product to obtain 1,1,1,3-tetrachloropropane; The preparation method of the carbon-coated elemental iron catalyst is as follows: dissolving ferric citrate in ethanol, stirring evenly to obtain a precursor solution, drying in a vacuum drying oven at 50° C. to obtain a precursor powder, and performing high-temperature pyrolysis of the precursor powder in an inert atmosphere to obtain a carbon-coated elemental iron catalyst.

2. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: In the method for preparing the carbon-coated elemental iron catalyst, glucose is added to the ethanol before the stirring step.

3. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The reaction temperature is 110-130° C., the reaction pressure is 0.9-1.1 MPa, and the reaction time is 3-5 hours.

4. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The amount of the carbon-coated elemental iron catalyst added is 0.6-1.0 wt% of the total mass of carbon tetrachloride, and the amount of the co-catalyst added is 0.5-0.7 wt% of the total mass of carbon tetrachloride.

5. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The co-catalyst is tributyl phosphate or triethyl phosphite.

6. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: In the method for preparing the carbon-coated elemental iron catalyst, the ratio of ferric citrate to ethanol is 1:100-150, wherein the ferric citrate is measured in g and the ethanol is measured in mL.

7. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 2, characterized in that: The mass ratio of the ferric citrate to glucose is 1:0.4-0.

6.

8. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The high temperature pyrolysis temperature is 500-900°C and the time is 4-6 hours.

9. 1,1,1,3-tetrachloropropane, characterized in that The compound is prepared by the synthesis method according to any one of claims 1 to 8.

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