Catalytic system and method for preparing 1, 1, 1, 3-tetrachloropropane

Abstract

The present application discloses a catalytic system for the preparation of 1, 1, 1, 3-tetrachloropropane, comprising an iron-based catalyst, the iron-based catalyst comprising iron and a halide of iron; and a cocatalyst selected from the group consisting of tributyl phosphate, tri (C2-C4 alkyl) phosphite, or a combination thereof. The invention also discloses a method for preparing 1, 1, 1, 3-tetrachloropropane, which comprises the following steps: i) in the presence of the catalytic system provided by the invention, introducing ethylene into a carbon tetrachloride solution in a certain manner, and reacting in a reaction zone at a reaction pressure p1 and a reaction temperature T to obtain a reaction product liquid; and ii) carrying out post-treatment on the reaction production liquid in a post-treatment area to obtain a target product.

Description

Technical Field

[0001] The present application relates to the field of chemical synthesis. Specifically, the present application relates to a catalytic system and method for preparing 1,1,1,3-tetrachloropropane. Background Art

[0002] The information provided in this section is for the purpose of generally presenting the background of the present disclosure. To the extent described in this section, the work of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure.

[0003] As a substance with strong ozone depletion potential, the conversion of carbon tetrachloride into high value-added chemicals has become a highly concerned issue in the environmental protection and chemical industry. In the catalytic conversion of carbon tetrachloride, the 1,1,1,3-tetrachloropropane produced by its polymerization reaction with ethylene is an important chemical raw material, especially in the field of fluorine chemical industry, it can be used as an important intermediate for the synthesis of environmentally friendly fluorine-containing compounds, such as the new refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf).

[0004] In the prior art, the catalyst system for the polymerization reaction of carbon tetrachloride and ethylene mainly includes, for example, copper-based catalysts and nitrile co-catalysts; alkyl phosphites and ferric chloride catalysts and nitrile co-catalysts; iron powder catalysts and ester co-catalysts, etc. In these catalytic systems, iron powder is widely used as a traditional catalyst, but there are problems of low reaction efficiency, especially poor product selectivity, resulting in increased separation costs of product mixtures containing by-products such as trichloropropane, hexachloropropane, etc. Copper-based catalysts or nitrile co-catalysts have defects such as easy deactivation or poisoning of the catalyst, high toxicity of the co-catalyst, or difficulty in recovery. In addition, the one-time introduction of ethylene in the traditional process is prone to cause gas phase enrichment, further exacerbating the generation of side reactions, and reaction conditions such as gas pressure and reaction temperature may also affect the yield of the target product. Summary of the invention

[0005] The present application provides a catalytic system and method for preparing 1,1,1,3-tetrachloropropane to solve one or more of the above-mentioned problems and other problems, or to provide an alternative technical solution to the prior art.

[0006] According to one aspect of the present application, a catalytic system for preparing 1,1,1,3-tetrachloropropane is provided, comprising:

[0007] an iron-based catalyst comprising iron and an iron halide; and

[0008] A co-catalyst, wherein the co-catalyst is selected from tributyl phosphate, tri(C2-C4 alkyl) phosphite or a combination thereof.

[0009] In the catalytic system according to the present application, preferably, the molar ratio of iron in the iron-based catalyst to the promoter is in the range of 1:0.4 to 1:2.0, preferably in the range of 1:1.4 to 1:1.8.

[0010] In the catalytic system according to the present application, preferably, the iron-based catalyst comprises iron and ferric chloride, and the co-catalyst is tributyl phosphate.

[0011] In the catalytic system according to the present application, preferably, the molar ratio of iron to ferric chloride in the iron-based catalyst is 20:3.

[0012] According to another aspect of the present application, there is provided a method for preparing 1,1,1,3-tetrachloropropane, comprising the following steps:

[0013] i) in the presence of the catalyst system according to the present application, ethylene is introduced into a carbon tetrachloride solution in a certain manner so that it reacts in a reaction zone at a reaction pressure p1 and a reaction temperature T to obtain a reaction product liquid;

[0014] ii) obtaining the target product by post-treating the reaction product in a post-treatment zone.

[0015] In the catalytic system according to the present application, preferably, the ethylene is introduced in batches, which includes:

[0016] Initially, ethylene is introduced to an initial pressure of p0;

[0017] When the pressure in the reaction zone is substantially stable, ethylene is introduced a second time to a reaction pressure of p1, and ethylene is allowed to react continuously at p1 for several hours.

[0018] In the catalytic system according to the present application, preferably, the initial pressure p0 is in the range of 0.30 to 0.60 MPa, preferably in the range of 0.40 to 0.50 MPa.

[0019] In the catalytic system according to the present application, preferably, the reaction temperature T is in the range of 90 to 120°C, preferably in the range of 100 to 110°C.

[0020] In the catalytic system according to the present application, preferably, the secondary introduction method includes one-time introduction, intermittent introduction and continuous introduction, preferably continuous introduction.

[0021] According to another aspect of the present application, there is provided use of the catalytic system according to the present application in the preparation of 1,1,1,3-tetrachloropropane by the reaction of carbon tetrachloride and ethylene.

[0022] Compared with the prior art, the technical solution provided in one aspect of the present application achieves a significant improvement in the selectivity of the target product 1,1,1,3-tetrachloropropane in laboratory and industrial-scale reactions by adopting a catalytic system comprising tributyl phosphate or tri(C2-C4 alkyl) phosphite as a co-catalyst, combined with gas phase pressure regulation by ethylene batch feeding, thereby providing an efficient conversion path for the synthesis of 1,1,1,3-tetrachloropropane by gas-liquid-solid three-phase reaction. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the catalytic system and method for preparing 1,1,1,3-tetrachloropropane according to the present application are described in detail below. It should be understood that all descriptions are exemplary and should not be used to form any limitation on the present application. For any single technical feature described or implied in each embodiment mentioned in this article, the present application still allows any combination or deletion between these technical features (or their equivalents) without any technical obstacles, so it should be considered that these more embodiments according to the present application are also included in the scope of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by those skilled in the art in the art described in this application. In the event of any inconsistency, the definitions provided in this application shall prevail.

[0025] In this application, unless otherwise stated, the numerical ranges listed herein are intended to include the endpoints of the range, and all numerical values ​​and all sub-ranges within the range.

[0026] In this application, unless otherwise indicated, all numbers expressing quantities, percentages, and so forth, in the specification and claims of this application are to be understood as being modified in all instances by the term "about".

[0027] As used in this application, the terms "comprising" and "including" encompass the case where other elements not explicitly mentioned are also included or comprised as well as the case where the item consists of the mentioned elements.

[0028] As used herein, the term "tributyl phosphate" refers to a trialkyl phosphate having the general formula OP(OR)3, wherein R is a C4 straight or branched chain alkyl group.

[0029] In the present application, unless otherwise stated, all reactions are carried out at normal temperature and pressure.

[0030] Catalytic system for preparing 1,1,1,3-tetrachloropropane

[0031] According to the first aspect of the present application, the present application provides a catalytic system for preparing 1,1,1,3-tetrachloropropane. The catalytic system may include

[0032] an iron-based catalyst, which may include iron and iron halides; and

[0033] The co-catalyst may be selected from tributyl phosphate, tri(C2-C4 alkyl) phosphite or a combination thereof.

[0034] For the catalytic system according to the present application, the iron-based catalyst may include metallic iron and an iron halide providing metal ions. The metallic iron suitable for the iron-based catalyst according to the present application includes but is not limited to iron wire, iron filings and iron powder, preferably a metallic iron fine powder having a particle size of less than 300 meshes.

[0035] In the catalytic system according to the present application, the divalent ferrous ions and the trivalent ferrous ions derived from the above-mentioned iron-based catalyst may serve as components having catalytic activity.

[0036] Preferably, the iron-based catalyst can be a mixture of iron and ferric chloride. The molar ratio of iron powder to ferric chloride in the mixture can be determined based on the selectivity of the target product and the reaction activity. Preferably, the molar ratio of iron powder to ferric chloride in the iron-based catalyst according to the present application can be 20:3.

[0037] In some embodiments, for the catalytic system according to the present application, the co-catalyst for preparing 1,1,1,3-tetrachloropropane may include tributyl phosphate, such as tri-n-butyl phosphate, tri-isobutyl phosphate, tri-sec-butyl phosphate, tri-tert-butyl phosphate, or a combination thereof. Preferably, the co-catalyst may be tri-n-butyl phosphate.

[0038] In some embodiments, for the catalytic system according to the present application, the cocatalyst for preparing 1,1,1,3-tetrachloropropane may include tri(C2-C4 alkyl)phosphite. In such embodiments, the cocatalyst may also optionally include an additional inhibitor conventionally used to prevent the self-polymerization of the reactants. The component includes, but is not limited to, 2,4-di-tert-butylphenol, hydroquinone, quinone compounds, nitroso compounds, or a combination thereof. Preferably, the cocatalyst may be triethyl phosphite present as a separate component.

[0039] Preferably, the molar ratio of iron to promoter present in the catalytic system according to the present application may be in the range of 1:0.4 to 1:2.0, preferably in the range of 1:1.4 to 1:1.8.

[0040] It is known that the co-catalyst according to the present application can effectively increase the contact area between the reactants and the above-mentioned catalytically active components at the gas-liquid interface formed between the reactants, promote the reaction, and can serve as a ligand to form a complex with the catalyst used. Further, the inventors have found that the co-catalyst according to the present application, especially tributyl phosphate with a longer alkyl chain, helps to inhibit the occurrence of side reactions and improve the selectivity of the 1,1,1,3-tetrachloropropane product without the need to use an additional inhibitor.

[0041] The inventors of the present application have also found that when the molar ratio of iron to the promoter in the iron-based catalyst is within the range of the present application, especially when the molar ratio of iron powder to the promoter is within the high promoter content range of 1:1.4 to 1:1.8, the reactant conversion rate and the 1,1,1,3-tetrachloropropane product selectivity can change in a nonlinear manner in response to the content of the promoter and show a significant improvement.

[0042] Method for preparing 1,1,1,3-tetrachloropropane

[0043] According to the second aspect of the present application, the present application provides a method for preparing 1,1,1,3-tetrachloropropane, which may include the following steps:

[0044] i) in the presence of the catalyst system according to the present application, ethylene is introduced into a carbon tetrachloride solution in a certain manner so that it reacts in a reaction zone at a reaction pressure p1 and a reaction temperature T to obtain a reaction product liquid;

[0045] ii) obtaining the target product by post-treating the reaction product in a post-treatment zone.

[0046] For the method according to the application, the above steps can be carried out with or without another solvent. In some embodiments, the catalytic system according to the application is dispersed in the liquid carbon tetrachloride that can serve as a reaction mass and a solvent, and a mixture comprising a solid phase (such as iron powder) and a liquid phase (such as dissolved iron chloride, a co-catalyst and carbon tetrachloride) is formed in the reaction zone. Subsequently, reaction mass gas ethylene is passed, wherein part of the ethylene gas can be dissolved in the liquid phase carbon tetrachloride as the reaction proceeds, thereby a three-phase system consisting of undissolved gas phase ethylene, a liquid phase reaction mixture and a solid phase catalyst that are continuously passed through for maintaining the reaction pressure can be formed.

[0047] In some embodiments, for the method according to the present application, the ethylene can be introduced in batches, which can specifically include two-stage introduction, i.e., initial introduction and secondary introduction. In the initial introduction, ethylene gas is introduced to an initial pressure p0, and a secondary introduction to a reaction pressure p1 is performed until the pressure in the reaction zone is substantially stable, i.e., the pressure change is less than 0.01 MPa / 10 min or lower. In the secondary introduction, p1 is maintained so that ethylene continues to react for several hours.

[0048] Preferably, the above initial pressure p0 may be in the range of 0.30 to 0.60 MPa, preferably in the range of 0.40 to 0.50 MPa.

[0049] Preferably, the secondary introduction of ethylene can be carried out in the form of one-time introduction, intermittent introduction and continuous introduction. Generally, those skilled in the art can select a suitable reaction gas feeding method according to factors such as the required reaction start-up time, the gas-liquid equilibrium requirements adapted to the reaction system, the stability of the reaction pressure, and configure suitable gas input parameters, such as flow rate, and components for controlling such parameters during operation according to the reaction scale, required time, etc. For the method according to the present application, the secondary introduction of ethylene can preferably be carried out in the form of continuous introduction.

[0050] The inventors of the present application have found that by introducing ethylene in batches and selecting the value of the initial pressure p0, combined with the catalytic system according to the present application, it is possible to ensure the efficiency of 1,1,1,3-tetrachloropropane production while effectively preventing side reactions caused by uneven local concentration of ethylene in a safe, stable and simple process, thereby regulating the selectivity of the product.

[0051] Preferably, in the method according to the present application, the reaction temperature T can be in the range of 90 to 120° C., preferably in the range of 100 to 110° C. The reaction temperature T can be controlled by a heating system equipped in the reaction device in the reaction zone. The heating rate set by the heating system can be adjusted as needed according to the reaction progress and other relevant parameters in the process.

[0052] The reaction time can usually be determined by routine experiments based on the reaction temperature, pressure, and activity of the catalyst system. In some embodiments, for the method according to the present application, for example, in the temperature range of 90 to 120° C., the reaction time of the telomerization reaction of ethylene and carbon tetrachloride can be set to 3 to 8 hours, preferably 4 to 6 hours.

[0053] In some embodiments, for the method according to the present application, those skilled in the art can select a suitable reaction device in the reaction zone according to the reaction scale and process requirements. For example, a 50-500mL small reactor can be used for laboratory tests, and a 1-10L large reactor can be used for industrial amplification. The reaction device can be equipped with a stirring device adapted to its size and scale. The stirring form and gas distribution system can refer to the conventional design of multiphase catalytic reactions. Those skilled in the art can use the known structure of such a device to effectively maintain sufficient contact between the gas, liquid and solid phases and stable control of the reaction conditions.

[0054] For the method according to the present application, the reaction liquid produced after the reaction is completed can enter the post-treatment zone from the reaction zone for post-treatment to obtain a purified target product. For example, the post-treatment steps performed in the post-treatment zone may include separating the solids in the reaction liquid by conventional means, such as filtering or centrifuging; washing the organic phase in the obtained filtrate with a suitable solvent in an appropriate volume ratio to remove residual catalyst or catalytic promoter and by-products, such as washing with a saturated sodium chloride solution or water to neutrality; drying, such as dehydrating with a desiccant; purifying the target product by distillation or rectification, wherein the conditions used for distillation or rectification, such as the distillation temperature, can be adjusted based on the boiling point difference and purity requirements of the products with reference to conventional chemical separation technology.

[0055] Those skilled in the art can select any suitable post-treatment means according to the actual product composition and equipment configuration, and can use known processes in organic synthesis and industrial catalytic reactions for operation. In addition, the separated carbon tetrachloride, catalyst and co-catalyst can be recycled by conventional methods without substantially affecting the reaction efficiency.

[0056] use

[0057] According to the third aspect of the present application, the present application provides use of the catalytic system as described above in the preparation of 1,1,1,3-tetrachloropropane by the reaction of carbon tetrachloride and ethylene.

[0058] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, suitable embodiments are described below. The embodiments should be interpreted as solving the technical problems of the present application, so that they are not limited to the combination of features explicitly described, but the illustrated features can be combined again without restriction.

[0059] Example

[0060] The following will further illustrate the concept of the present application and the technical effects produced in conjunction with the embodiments, so that those skilled in the art can fully understand the purpose, features and effects of the present application. Those skilled in the art will understand that the embodiments herein are only for illustrative purposes and are not intended to limit the scope of the present application. If not clearly stated, the raw materials used in the embodiments are those commonly used in the art.

[0061] Example 1

[0062] According to the following method, 1,1,1,3-tetrachloropropane is prepared by telomerization of carbon tetrachloride and ethylene in the presence of the catalytic system according to the present application.

[0063] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 0.405g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0064] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 34.7%, and the selectivity of 1,1,1,3-tetrachloropropane is 80.5%.

[0065] Example 2

[0066] This example is carried out in the same manner as in Example 1, except that tributyl phosphate is replaced by triethyl phosphite.

[0067] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 0.405g of triethyl phosphite, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0068] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 73.0%, and the selectivity of 1,1,1,3-tetrachloropropane is 71.3%.

[0069] Example 3

[0070] This example is carried out in the same manner as in Example 1, except that the amount of tributyl phosphate used is 0.749 g.

[0071] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 0.749g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0072] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 46.8%, and the selectivity of 1,1,1,3-tetrachloropropane is 81.9%.

[0073] Example 4

[0074] This example is carried out in the same manner as in Example 1, except that the amount of tributyl phosphate used is 1.124 g.

[0075] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.124g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0076] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 60.5%, and the selectivity of 1,1,1,3-tetrachloropropane is 83.4%.

[0077] Example 5

[0078] This example is carried out in the same manner as in Example 1, except that the amount of tributyl phosphate used is 1.199 g.

[0079] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.199g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0080] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 49.8%, and the selectivity of 1,1,1,3-tetrachloropropane is 78.5%.

[0081] Example 6

[0082] This example is carried out in the same manner as Example 4, except that the initial pressure of the introduced ethylene gas is 0.5 MPa.

[0083] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.124g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.50MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0084] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 29.1%, and the selectivity of 1,1,1,3-tetrachloropropane is 67.4%.

[0085] Example 7

[0086] This example was carried out with the same steps as Example 4, except that the reaction temperature was 110°C.

[0087] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.124g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.5MPa, then heat the reactor to a reaction temperature of 110°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0088] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 47.9%, and the selectivity of 1,1,1,3-tetrachloropropane is 79.8%.

[0089] Example 8

[0090] This example is carried out with the same steps as Example 4, except that the reaction temperature is 100°C.

[0091] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.124g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.5MPa, then heat the reactor to a reaction temperature of 100°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0092] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 40.3%, and the selectivity of 1,1,1,3-tetrachloropropane is 88.1%.

[0093] Example 9

[0094] This example is based on the parameters of Example 4, and the process is scaled up in a 1L high-pressure reactor. Those skilled in the art can routinely adjust the process parameters involved in the following specific steps according to the scale and form of the reactor used.

[0095] Weigh 792.52g of carbon tetrachloride and add it to a reactor, then add 43.30g of tributyl phosphate, 2.29g of ferric chloride and 6.08g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0096] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 56.4%, and the selectivity of 1,1,1,3-tetrachloropropane is 85.7%.

[0097] Example 10

[0098] This example is carried out in the same manner as Example 9, except that the amount of tributyl phosphate used is 50.51 g.

[0099] Weigh 792.52g of carbon tetrachloride and add it to a reactor, then add 50.51g of tributyl phosphate, 2.29g of ferric chloride and 6.08g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0100] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 97.4%, and the selectivity of 1,1,1,3-tetrachloropropane is 88.8%.

[0101] Embodiment 11

[0102] This example is carried out in the same manner as in Example 9, except that the amount of tributyl phosphate used is 57.51 g.

[0103] Weigh 792.52g of carbon tetrachloride and add it to a reactor, then add 57.51g of tributyl phosphate, 2.29g of ferric chloride and 6.08g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0104] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 87.0%, and the selectivity of 1,1,1,3-tetrachloropropane is 66.3%.

[0105] Comparative Example 1

[0106] This comparative example was carried out in the same manner as in Example 1, except that tributyl phosphate was replaced by triethyl phosphate.

[0107] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 0.405g of triethyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0108] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 81.2%, and the selectivity of 1,1,1,3-tetrachloropropane is 41.6%.

[0109] Comparative Example 2

[0110] This comparative example was carried out in the same manner as Example 1, except that tributyl phosphate was replaced by dibutyl phosphate.

[0111] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 0.405g of dibutyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.40MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0112] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 89.3%, and the selectivity of 1,1,1,3-tetrachloropropane is 43.2%.

[0113] Comparative Example 3

[0114] This comparative example was carried out with reference to Example 4, except that the initial pressure of the introduced ethylene gas was 0.25 MPa.

[0115] Weigh 27.3g of carbon tetrachloride and add it to a 100mL reactor, then add 1.124g of tributyl phosphate, 0.103g of ferric chloride and 0.206g of iron powder in sequence, and mix thoroughly under stirring. After sealing the reactor, introduce ethylene gas at a rate of 0.1MPa / min to an initial pressure of 0.25MPa, then heat the reactor to a reaction temperature of 120°C, and monitor the pressure change in the reactor in real time. When the pressure fluctuation tends to be flat (less than 0.01MPa / 10min), introduce ethylene twice at a rate of 0.1MPa / min to a total pressure of 0.9MPa, maintain the temperature and pressure, and continue the reaction for 5 hours.

[0116] After the reaction is completed, the reactor is cooled and the residual pressure is slowly released. The reaction liquid is filtered through a filter, the iron powder is sieved out and mixed with a saturated sodium chloride solution in a volume ratio of 1:2. The mixture is mechanically stirred and allowed to stand for phase separation, and repeatedly washed with water until the water phase is neutral (pH = 7). The obtained organic phase is dried and then distilled to obtain the 1,1,1,3-tetrachloropropane product. According to gas chromatography analysis, the conversion rate of carbon tetrachloride is 23.7%, and the selectivity of 1,1,1,3-tetrachloropropane is 59.3%.

[0117] As can be seen from the above-mentioned embodiments of the present application, relative to the comparative example, the composite catalytic system using iron powder and ferric chloride as catalyst, tributyl phosphate or triethyl phosphite as a co-catalyst helps to significantly improve the selectivity of the target product 1,1,1,3-tetrachloropropane. According to the preparation method of the present application, the mode of passing ethylene in batches is also adopted, and in combination with the optimized temperature and pressure conditions, particularly by controlling the gas phase pressure, the selectivity of the target product is further improved, and the formation of ethylene autopolymers and other unwanted polychlorinated by-products is effectively suppressed. On this basis, the enlarged embodiment (embodiment 9-11) is verified by further optimizing the consumption of tributyl phosphate according to the catalytic system and preparation method of the present application in the relatively large-scale industrial telomerization reaction The feasibility of synthesizing fluoroalkanes and the excellent conversion rate of the reactant and the selectivity of the target product.

Claims

1. A catalytic system for preparing 1,1,1,3-tetrachloropropane, characterized in that: Include an iron-based catalyst comprising iron and an iron halide; and A co-catalyst, wherein the co-catalyst is selected from tributyl phosphate, tri(C2-C4 alkyl) phosphite or a combination thereof.

2. The catalytic system according to claim 1, characterized in that The molar ratio of iron in the iron-based catalyst to the promoter is in the range of 1:0.4 to 1:2.0, preferably in the range of 1:1.4 to 1:1.

8.

3. The catalytic system according to claim 1, characterized in that The iron-based catalyst comprises iron and ferric chloride, and the promoter is tributyl phosphate.

4. The catalytic system according to claim 3, characterized in that The molar ratio of iron to ferric chloride in the iron-based catalyst is 20:

3.

5. A method for preparing 1,1,1,3-tetrachloropropane, characterized in that: The following steps are involved: i) in the presence of the catalyst system according to any one of claims 1 to 4, ethylene is introduced into a carbon tetrachloride solution in a certain manner so that it reacts in a reaction zone at a reaction pressure p1 and a reaction temperature T to obtain a reaction product; ii) obtaining the target product by post-treating the reaction product in a post-treatment zone.

6. The preparation method according to claim 5, characterized in that: The ethylene introduction method is batch-wise introduction, which comprises: Initially, ethylene is introduced to an initial pressure of p0; When the pressure in the reaction zone is substantially stable, ethylene is introduced a second time to a reaction pressure of p1, and ethylene is allowed to react continuously at p1 for several hours.

7. The preparation method according to claim 5, characterized in that: The initial pressure p0 is in the range of 0.30 to 0.60 MPa, preferably in the range of 0.40 to 0.50 MPa.

8. The preparation method according to claim 5, characterized in that: The reaction temperature T is in the range of 90 to 120°C, preferably in the range of 100 to 110°C.

9. The preparation method according to claim 5, characterized in that: The secondary introduction method includes one-time introduction, intermittent introduction and continuous introduction, preferably continuous introduction.

10. Use of the catalytic system according to any one of claims 1 to 4 in the preparation of 1,1,1,3-tetrachloropropane by the reaction of carbon tetrachloride and ethylene.