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

Abstract

The invention belongs to the field of organic synthesis technology, and in particular to a kind of 1,1,1,3 tetrachloropropane and its synthesis method.The synthetic method comprises the following steps:Carbon coated elemental iron catalyst, co-catalyst and carbon tetrachloride are added into reactor, ethylene is passed through to reaction pressure after being warming up to reaction temperature, after heat preservation and pressure holding are reacted, tetrachloropropane crude product is obtained, tetrachloropropane crude product is filtered, and 1,1,1,3 tetrachloropropane is obtained after distillation;The preparation method of coated elemental iron catalyst is:Ferric citrate is dissolved in ethanol, stirring is uniform, precursor solution is obtained, precursor powder is dried at 50 DEG C in a vacuum drying oven, and precursor powder is carried out high temperature pyrolysis under an inert atmosphere to obtain carbon coated elemental iron catalyst.1,1,1,3 tetrachloropropane synthetic reaction of the present invention has the advantages that carbon tetrachloride conversion is high, tetrachloropropane selectivity is high, reaction time is short and by-product generation amount is few.

Description

Technical Field

[0001] The 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] Under the Montreal Protocol, carbon tetrachloride is one of the ozone-depleting substances whose production and use are restricted. However, it can continue to be used as a chemical raw material. The conversion of carbon tetrachloride into other products is of great significance to the protection of the ozone layer and has good development and utilization prospects. 1,1,1,3-Tetrachloropropane is a key raw material for the production of hydrofluoroolefins (HFOs), a new generation of refrigerants. HFOs have low global warming potential (GWP) and zero ozone depletion potential (ODP), making them an ideal alternative to traditional CFC refrigerants, being more environmentally friendly and meeting environmental protection requirements.

[0003] There are many research methods for the synthesis of tetrachloropropane at home and abroad. According to different reaction conditions, they can be divided into peroxide activation method, electromagnetic wave radiation method, metal and co-catalyst catalysis method. After years of technical accumulation, carbon tetrachloride and ethylene as raw materials, iron as the main catalyst, and organic phosphorus compounds as co-catalysts have been widely used in industrial production.

[0004] CN106146247A discloses a 1,1,1,3-tetrachloropropane synthesis process using ferrous chloride / ferric chloride as a main catalyst and a phosphate series as a co-catalyst. 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 1,1,1,3-tetrachloropropane synthesis process using reduced iron powder as the main catalyst and tributyl phosphate as the co-catalyst. The catalyst in this process is cheap and readily available, so this method is widely used in industrial production. However, this method has the following main problems in the tetrachloropropane synthesis process: (1) High polymer (tar): A large amount of polymer is easily generated during the reaction, making product separation difficult, reducing product yield, and increasing the burden of equipment cleaning. (2) Low conversion rate and selectivity: The catalytic activity of existing catalysts is limited, resulting in low ethylene conversion rate and tetrachloropropane selectivity (less than 85%) and low raw material utilization. (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, which reduces production efficiency.

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

[0007] In order to solve the drawbacks of the above-mentioned prior art, the present invention discloses a method for synthesizing 1,1,1,3-tetrachloropropane, which adopts the following technical means:

[0008] A carbon-coated elemental iron catalyst, a co-catalyst, and carbon tetrachloride are added to a reactor, the temperature is raised to the reaction temperature, ethylene is introduced to the reaction pressure, and the temperature and pressure are maintained to react to obtain a crude tetrachloropropane product, and the crude tetrachloropropane product is filtered and distilled to obtain 1,1,1,3-tetrachloropropane;

[0009] The preparation method of the carbon-coated elemental iron catalyst comprises: 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 pyrolyzing the precursor powder at high temperature under an inert atmosphere to obtain a carbon-coated elemental iron catalyst.

[0010] Furthermore, in the preparation method of the carbon-coated elemental iron catalyst, glucose is also added to the ethanol before the stirring step. The ferric citrate selected by 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 the ferric citrate is easily detached from the carbon skeleton after being reduced at high temperature, thereby affecting the activity of the catalyst. The present invention adds glucose to the precursor solution, and during the pyrolysis process, a carbon layer can be coated again on the outermost layer to prevent the detachment of the elemental iron after reduction, thereby ensuring the activity of the catalyst.

[0011] Furthermore, the reaction temperature is 110-130° C., preferably 120° C.; the reaction pressure is 0.9-1.1 MPa, preferably 1.0 MPa; and the reaction time is 3-5 h, preferably 4 h.

[0012] Furthermore, the amount of the carbon-coated elemental iron catalyst added is 0.6~1.0wt% of the total mass of carbon tetrachloride, preferably, the amount of the carbon-coated elemental iron catalyst added is 0.8wt% of the total mass of carbon tetrachloride; the amount of the co-catalyst added is 0.5~0.7wt% of the total mass of carbon tetrachloride, preferably, the amount of the co-catalyst added is 0.6wt% of the total mass of carbon tetrachloride.

[0013] Furthermore, the co-catalyst is tributyl phosphate or triethyl phosphite.

[0014] Furthermore, 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, wherein ferric citrate is measured in g and ethanol is measured in mL.

[0015] Furthermore, the mass ratio of ferric citrate to glucose is 1:0.4-0.6, preferably 1:0.5.

[0016] Furthermore, the high-temperature pyrolysis temperature is 500-900° C., preferably 700° C.; and the time is 4-6 hours, preferably 5 hours.

[0017] The present invention also discloses 1,1,1,3-tetrachloropropane, which is prepared by any of the above-mentioned synthesis methods.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses a carbon-coated elemental iron catalyst as a main catalyst when synthesizing 1,1,1,3-tetrachloropropane. The main catalyst uses ferric citrate as an iron source during preparation. The prepared main catalyst has a high specific surface area and abundant active sites, effectively improving catalytic activity and shortening reaction time. The carbon coating layer can effectively inhibit the occurrence of reaction side reactions, improve the selectivity of tetrachloropropane, and reduce the generation of polymers (tar). The carbon coating layer can also prevent the agglomeration and oxidation of iron nanoparticles, thereby 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, high tetrachloropropane selectivity, short reaction time, and low by-product generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a SEM image of the carbon-coated elemental iron catalyst prepared in Example 1;

[0021] Figure 2 This is the XRD diffraction pattern of the carbon-coated elemental iron catalyst prepared in Example 1;

[0022] Figure 3 This is the verification chromatogram of 1,1,1,3-tetrachloropropane prepared in Example 1. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to the accompanying drawings and examples. Unless otherwise specified, the reagents, equipment and materials described in the following examples and comparative examples are all from the prior art and can be obtained from commercial channels.

[0024] Example 1

[0025] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 5.0 g of glucose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0026] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 599.8 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0027] Example 2

[0028] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 5.0 g of glucose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept at this temperature for 4 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0029] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 599.8 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0030] Example 3

[0031] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 900°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0032] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 587.8 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0033] Example 4

[0034] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0035] Synthesis of 1,1,1,3-tetrachloropropane: 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 were added to a reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 585.3 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0036] Example 5

[0037] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 6 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0038] Synthesis of 1,1,1,3-tetrachloropropane: 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 were added to a reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 603.6 g of crude tetrachloropropane was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0039] Example 6

[0040] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0041] Synthesis of 1,1,1,3-tetrachloropropane: 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 were added to a reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 590.2 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0042] Example 7

[0043] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0044] Synthesis of 1,1,1,3-tetrachloropropane: 4.0 g of the carbon-coated elemental iron catalyst obtained above, 3.5 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 604.6 g of crude tetrachloropropane product was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0045] Example 8

[0046] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 6.0 g of glucose was added, and the mixture was stirred evenly to obtain a precursor solution. The precursor powder was dried in a vacuum drying oven at 50°C to obtain a precursor powder. The precursor powder was heated to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0047] 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 reactor. The temperature was raised to 110°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 594.1 g of crude tetrachloropropane was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0048] Example 9

[0049] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder 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, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0050] 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 reactor. The temperature was raised to 130°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 611.3 g of crude tetrachloropropane was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0051] Example 10

[0052] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder 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, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0053] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 0.9 MPa. After maintaining the temperature and pressure for 4 hours, 607.8 g of crude tetrachloropropane product was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0054] Example 11

[0055] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder 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, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0056] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.1 MPa. After maintaining the temperature and pressure for 4 hours, 614.2 g of crude tetrachloropropane product was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0057] Example 12

[0058] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder 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, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0059] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 3 hours, 580.5 g of crude tetrachloropropane was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0060] Example 13

[0061] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric 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 powder 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, kept warm for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst.

[0062] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 5 hours, 603.3 g of crude tetrachloropropane was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0063] Example 14

[0064] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol and stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0065] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 589.7 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0066] Comparative Example 1

[0067] Synthesis of 1,1,1,3-tetrachloropropane: 4.0 g of 300-mesh reduced iron powder, 3.0 g of tributyl phosphate, and 500.0 g of carbon tetrachloride were added to a reactor. The temperature was raised to 120°C, and ethylene was introduced to a pressure of 1.0 MPa. After maintaining the temperature and pressure for 6 hours, 576.7 g of crude tetrachloropropane was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0068] Comparative Example 2

[0069] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferrocene was dissolved in 1000.0 mL of ethanol, 5.0 g of thiophene was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0070] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 590.8 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0071] Comparative Example 3

[0072] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric nitrate was dissolved in 1000.0 mL of ethanol, 5.0 g of sucrose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0073] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 587.2 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0074] Comparative Example 4

[0075] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 5.0 g of glucose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0076] Synthesis of 1,1,1,3-tetrachloropropane: 2.0 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 582.5 g of crude tetrachloropropane product was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0077] Comparative Example 5

[0078] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 3.0 g of glucose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0079] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 595.0 g of crude tetrachloropropane product was obtained, which was filtered and distilled to obtain 1,1,1,3-tetrachloropropane.

[0080] Comparative Example 6

[0081] Preparation of carbon-coated elemental iron catalyst: 10.0 g of ferric citrate was dissolved in 1000.0 mL of ethanol, 7.0 g of glucose was added, and the mixture was stirred to obtain a precursor solution. The precursor powder 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, kept at this temperature for 5 hours, and naturally cooled to room temperature to obtain a carbon-coated elemental iron catalyst;

[0082] 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 reactor. The temperature was raised to 120°C, and ethylene was introduced to 1.0 MPa. After maintaining the temperature and pressure for 4 hours, 592.8 g of crude tetrachloropropane was obtained. 1,1,1,3-tetrachloropropane was obtained by filtration and distillation.

[0083] The carbon tetrachloride conversion, tetrachloropropane selectivity, reaction time and tar production obtained by the methods described in the examples and comparative examples are shown in Table 1.

[0084] Table 1

[0085]

[0086] From the experimental results of Examples 1 to 14 and Comparative Examples 1 to 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 production.

[0087] Figure 1 This is the SEM image of the carbon-coated elemental iron catalyst prepared in Example 1. Figure 1 From (A) and (B), we can see that the material is a composite material of macropores and micropores, with the pore size of the macropores ranging from 10 to 20 μm. Figure 1 In the middle (C), it can be seen that the surface of the material is rough and is composed of tightly packed particles. The synergistic effect of the multi-sized pore structure helps to increase the reaction specific surface area and provide more active centers. Figure 2 The XRD diffraction pattern of the carbon-coated elemental iron catalyst prepared in Example 1 is as follows: Figure 2It can be seen that at 700℃ (pyrolysis temperature), the main components are Fe and Fe3C. At 500℃, Fe reduction is incomplete and there is no obvious Fe diffraction peak. At 900℃, the main component is Fe. Figure 3 is the chromatogram of the final product of the embodiment, Figure 3 The peak table of Figure 3 As can be seen from Table 2, the final product of Example 1 is 1,1,1,3-tetrachloropropane.

[0088] Table 2

[0089]

Claims

1. A method for synthesizing 1,1,1,3-tetrachloropropane, characterized in that: The steps include: A carbon-coated elemental iron catalyst, a co-catalyst, and carbon tetrachloride are added to a reactor, the temperature is raised to the reaction temperature, ethylene is introduced to the reaction pressure, and the temperature and pressure are maintained to react to obtain a crude tetrachloropropane product, and the crude tetrachloropropane product is filtered and distilled to obtain 1,1,1,3-tetrachloropropane; The carbon-coated elemental iron catalyst is prepared by dissolving ferric citrate in ethanol and stirring the mixture to obtain a precursor solution, drying the solution in a vacuum drying oven at 50°C to obtain a precursor powder, and pyrolyzing the precursor powder in an inert atmosphere at a high temperature to obtain a carbon-coated elemental iron catalyst, wherein the pyrolysis temperature is 500-900°C. In the preparation method of the carbon-coated elemental iron catalyst, glucose is added to the ethanol before the stirring step; The co-catalyst is tributyl phosphate or triethyl phosphite; The mass ratio of the ferric citrate to glucose is 1:0.4-0.

6.

2. 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.

3. 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.

4. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: In the preparation method of 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.

5. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The high temperature pyrolysis time is 4 to 6 hours.

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