Preparation method of 1, 1, 1, 2, 3-pentachloropropane and catalyst

Abstract

The invention relates to a preparation method of 1, 1, 1, 2, 3-pentachloropropane and a catalyst, and the 1, 1, 1, 2, 3-pentachloropropane is obtained by carrying out chlorination reaction on 1, 1, 1, 3-tetrachloropropane and chlorine in the presence of a loaded zero-valent bimetallic nanoparticle catalyst and a cocatalyst. The zero-valent bimetallic nanoparticle loaded catalyst comprises a carrier and an active component loaded on the carrier, the active component comprises zero-valent Sb-Al nanoparticles or Sb-Fe nanoparticles, and the cocatalyst comprises alkyl phosphine, aryl phosphine or alkyl aryl phosphine. On one hand, the oxidation inactivation and agglomeration phenomena of the catalyst are avoided, the surface area of the active component of the catalyst is increased, and the reaction is facilitated; on the other hand, the catalytic activity of the bimetallic nanoparticle catalyst is improved by using the cocatalyst, the reaction activation energy is reduced, and the reaction rate and the reaction selectivity are improved.

Description

Technical Field

[0001] The present invention belongs to the technical fields of organic fine chemicals and catalysts, relates to fluoroolefin intermediates, and particularly relates to a preparation method of 1,1,1,2,3-pentachloropropane and a catalyst therefor. Background Art

[0002] 1,1,1,2,3-Pentachloropropane (CAS No. 21700-31-2, molecular formula C3H3Cl5, molecular weight 216.32, boiling point 196 °C) is an important intermediate for preparing HCC-1230xa. As one of the main intermediates for preparing the chemical herbicide triallate, HCC-1230xa is also the main intermediate for the new generation of environmentally friendly refrigerant HFO-1234yf. As a single-component refrigerant, HFO-1234yf has excellent environmental parameters (ODP = 0, GWP = 4), and its system performance is superior to that of 1,1,1,2-tetrafluoroethane (ODP = 0, GWP = 1430), and it is considered a potential alternative for the new generation of automotive refrigerants. Using HCC-1230xa as the raw material for producing HFO-1234yf has the characteristics of simple production process and being most easily industrialized. HCC-1230xa can be obtained by highly efficient catalytic dehydrochlorination of 1,1,1,2,3-pentachloropropane. Therefore, how to synthesize 1,1,1,2,3-pentachloropropane conveniently, efficiently and at low cost is the key to preparing 2,3,3,3-tetrafluoropropene (HFO-1234yf).

[0003] The preparation method of 1,1,1,2,3-pentachloropropane disclosed in Patent WO2010123148A1 uses 1,1,1,3-tetrachloropropane as the raw material to first dehydrochlorinate under alkaline conditions to obtain a trichloropropene product, and then add chlorine under UV light for an addition reaction to obtain 1,1,1,2,3-pentachloropropane. This process uses a large amount of alkaline solution for dehydrochlorination, generating a large amount of wastewater and having a greater environmental protection pressure; at the same time, the chloroaddition reaction must be carried out under UV light, which easily produces chlorine substitution reactions to generate polychloroalkanes, increasing the by-products and making the reaction selectivity worse.

[0004] The method for preparing the chlorinated hydrocarbon 1,1,1,2,3-pentachloropropane disclosed in Patent CN104130100A uses 1,1,1,3-tetrachloropropane as the raw material and directly carries out a chlorination reaction by heating with chlorine under the catalysis of ferric trichloride to obtain 1,1,1,2,3-pentachloropropane. This process realizes obtaining the product in one step, but the catalyst ferric trichloride is easily deactivated, there are more high-boiling by-products, the selectivity is low, and the subsequent waste treatment pressure is greater.

[0005] The method for preparing 1,1,1,2,3-pentachloropropane disclosed in Patent CN108069817A uses ferric chloride or a combination of iron and ferric chloride as a catalyst. First, 1,1,1,3-tetrachloropropane is dehydrochlorinated to obtain 1,1,3-trichloropropene. When the content of the intermediate trichloropropene in the system reaches a certain amount, chlorine is introduced for a catalytic addition reaction, and the content of trichloropropene in the system is controlled at 1% - 6%. When the content of 1,1,1,2,3-pentachloropropane generated in the system reaches more than 90%, the reaction is terminated. This process does not mention the stability of the catalyst, and there are side reactions such as isomerization and polymerization. At the same time, this process requires constant attention to the content changes of each component in the reaction system, increasing the complexity of the operation.

[0006] According to the above patents and literature reports, the most commonly used synthetic route for the preparation of 1,1,1,2,3-pentachloropropane currently is to use 1,1,1,3-tetrachloropropane as the raw material, and through one or two steps of reaction to obtain the product under the action of a catalyst. The raw material is relatively easy to obtain, and the synthesis process is simple. However, there have always been problems such as low reaction selectivity and unsatisfactory yield in the existing processes. On the one hand, the raw materials and intermediates used are extremely prone to polychlorination and polymerization during the chlorination reaction, generating high-boiling by-products such as hexachloropropane, pentachlorohexene, and hexachlorohexane. Moreover, these by-products will cause the inactivation of the catalyst and affect the catalytic effect. On the other hand, most of the catalysts used are Lewis acid catalysts such as ferric chloride or a combination of iron and ferric chloride. This kind of catalyst is easily affected by harmful impurities in the system and causes inactivation. Moreover, this homogeneous catalyst is not conducive to the subsequent recovery and reuse of the catalyst.

[0007] In summary, there is a need in the art to develop a catalyst for the reaction of 1,1,1,2,3-pentachloropropane with higher catalytic efficiency, stronger stability, larger active surface area, and higher selectivity. Summary of the Invention

[0008] In view of the above-mentioned state of the prior art, the inventors of the present invention have conducted in-depth and extensive research in the field of catalytic preparation of 1,1,1,2,3-pentachloropropane and found that: on the one hand, making the main catalytic active component into nano-aluminum or nano-iron and loading it on a modified bentonite carrier has good catalytic effects. It not only increases the surface area of the active components of the catalyst but also avoids the agglomeration phenomenon of the catalyst. At the same time, adding a second nano-metal component, antimony, during the preparation process can not only solve the problem that freshly prepared nano-aluminum or nano-iron catalysts are easily oxidized and their activity is reduced when exposed to air but also play a role in synergistic catalysis, which is beneficial to the progress of the reaction. On the other hand, the preparation method uses a cocatalyst such as alkylphosphine, arylphosphine, or alkylarylphosphine, which can form a complex with the active metal, enhance the catalytic activity of the bimetallic nano-catalyst, reduce the reaction activation energy, and improve the reaction rate and selectivity of the reaction. The present invention is completed based on the above findings.

[0009] Therefore, an object of the present invention is to provide a method for preparing 1,1,1,2,3-pentachloropropane. The core is to use a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst to catalyze the chlorination reaction of 1,1,1,3-tetrachloropropane to obtain 1,1,1,2,3-pentachloropropane.

[0010] The second object of the present invention is to provide the above-mentioned catalytic system for preparing 1,1,1,2,3-pentachloropropane and a preparation method of the catalyst.

[0011] The technical solutions for achieving the above-mentioned invention objects can be summarized as follows:

[0012] A catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine to prepare 1,1,1,2,3-pentachloropropane. The catalyst is a supported zero-valent bimetallic nanoparticle catalyst, including a carrier and active components loaded on the carrier. The active components are one of Sb-Al bimetallic nanoparticles and Sb-Fe bimetallic nanoparticles.

[0013] According to the present invention, preferably, in the Sb-Al bimetallic nanoparticles, the mass percentage of Sb in Al is 1% - 50%, and more preferably 5% - 10%; in the Sb-Fe bimetallic nanoparticles, the mass percentage of Sb in Fe is 1% - 50%, and more preferably 10% - 20%.

[0014] According to the present invention, preferably, the carrier is bentonite; more preferably, the bentonite is obtained by modification treatment with tetradecyltrimethylammonium bromide.

[0015] According to the present invention, preferably, the process for modifying bentonite is as follows: Mix an aqueous solution of bentonite with tetradecyltrimethylammonium bromide, adjust the pH value to acidic, stir at 30°C to 100°C for 2 - 4 h, wash, and dry, thus completing the modification of bentonite; preferably, the mass ratio of tetradecyltrimethylammonium bromide to bentonite is 0.25 - 0.8:1.

[0016] According to the present invention, preferably, the loading amount of the active component is 2.5 - 75 wt%, and more preferably 5 - 20 wt%.

[0017] According to the present invention, the preparation method of the catalyst for catalytic chlorination reaction of 1,1,1,3 - tetrachloropropane with chlorine to prepare 1,1,1,2,3 - pentachloropropane includes the following steps:

[0018] (a) Add the carrier to an ethanol - aqueous solution of the first metal salt, and dropwise add a reducing agent solution under stirring to carry out a reduction reaction;

[0019] (b) Add the second metal salt to the reaction solution in step (a), and continue to carry out the reduction reaction;

[0020] (c) Filter the reaction solution obtained in step (b) by suction, wash with deionized water, and dry in vacuum to obtain the catalyst.

[0021] According to the present invention, preferably, the entire reaction process is carried out under continuous introduction of nitrogen and in an air - isolated condition.

[0022] According to the present invention, preferably, the first metal salt in step (a) is an aluminum salt or an iron salt, and more preferably aluminum chloride, ferric chloride or ferrous chloride; preferably, the volume ratio of ethanol to water in the ethanol - aqueous solution is 0.1 - 100:1; preferably, the reducing agent is sodium borohydride or potassium borohydride, and the molar ratio of the first metal salt to the reducing agent is 1:1 - 2.5.

[0023] According to the present invention, preferably, the second metal salt in step (b) is an antimony salt, preferably antimony chloride; preferably, the molar ratio of the second metal salt to the reducing agent is 1:1.5 - 3.

[0024] According to the present invention, preferably, the vacuum drying temperature in step (c) is 80°C - 120°C, and the drying time is 2 - 6 h.

[0025] According to the present invention, a method for preparing 1,1,1,2,3 - pentachloropropane includes using the above - mentioned catalyst loaded with zero - valent bimetallic nanoparticles, and the steps are as follows:

[0026] In the presence of a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst, 1,1,1,3-tetrachloropropane reacts with chlorine in a chlorination reaction to obtain 1,1,1,2,3-pentachloropropane. The cocatalyst is one of an alkylphosphine, an arylphosphine, or an alkylarylphosphine.

[0027] According to the present invention, preferably, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine is 1:0.8 to 1.2; the reaction temperature during the chlorination reaction is 25 to 130 °C, the reaction pressure is 0.1 to 2.0 MPa, and the reaction time is 2 to 32 h.

[0028] More preferably, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine is 1:0.9 to 1.05; the reaction temperature during the chlorination reaction is 40 to 80 °C, the reaction pressure is 0.25 to 0.7 MPa, and the reaction time is 3 to 10 h.

[0029] According to the present invention, preferably, the addition amount of the supported zero-valent bimetallic nanoparticle catalyst is 0.2% to 20% of the mass of 1,1,1,3-tetrachloropropane, and more preferably 0.6% to 1%.

[0030] According to the present invention, preferably, the addition amount of the cocatalyst is 1% to 5% of the mass of 1,1,1,3-tetrachloropropane, and more preferably 1.5% to 2.5%.

[0031] According to the present invention, preferably, the cocatalyst is one of tributylphosphine, triphenylphosphine, and tert-butyldiphenylphosphine, and triphenylphosphine is preferred.

[0032] Compared with the prior art, the beneficial effects that the present invention can produce include:

[0033] 1. In the present invention, the zero-valent bimetal is supported on a carrier, which can avoid the problem that the catalyst is prone to agglomeration, has good catalytic performance, and the catalyst is easily separated from the reaction kettle after the reaction. At the same time, adding a second nano-metal component antimony during the preparation process can not only solve the problem that the freshly prepared nano-aluminum or nano-iron catalyst is easily oxidized and its activity is reduced when exposed to air, but also play a role in synergistic catalysis, which is beneficial to the progress of the reaction.

[0034] 2. The zero-valent bimetal used in the present invention is in the form of nanoparticles, which has a smaller particle size, a larger specific surface area, and better catalytic effects compared with commercially available metal powders or inorganic salts and other compound catalysts.

[0035] 3. In the catalyst of the present invention, the carrier is modified, which can better adhere to the active components, increase the contact area with the active components, and is beneficial to improving the catalytic efficiency.

[0036] 4. The preparation method of 1,1,1,2,3 - pentachloropropane in the present invention uses a cocatalyst which is one of alkyl phosphines, aryl phosphines or alkyl - aryl phosphines. It can form a complex with the active metal, enhance the catalytic activity of the bimetallic nanocatalyst, lower the reaction activation energy, and improve the reaction rate and selectivity of the reaction. Description of the Drawings

[0037] Figure 1 HNMR spectrum of 1,1,1,2,3 - pentachloropropane obtained in Example 1 1

[0038] Figure 2 CNMR spectrum of 1,1,1,2,3 - pentachloropropane obtained in Example 1 13 Detailed Embodiments

[0039] The present invention provides a preparation method of 1,1,1,2,3 - pentachloropropane and a catalyst. Its core technologies include a supported zero - valent bimetallic nanoparticle catalyst and a cocatalyst. On the one hand, the main catalytically active component is made into nano - aluminum or nano - iron and supported on a modified bentonite carrier, which has a good catalytic effect. It not only increases the surface area of the active component of the catalyst but also avoids the agglomeration of the catalyst. At the same time, adding a second nano - metal component antimony during the preparation process can not only solve the problem that the freshly prepared nano - aluminum or nano - iron catalyst is easily oxidized and its activity is reduced when exposed to air but also play a role in synergistic catalysis, which is beneficial to the progress of the reaction. On the other hand, the preparation method uses a cocatalyst of alkyl phosphine, aryl phosphine or alkyl - aryl phosphine, which can form a complex with the active metal, enhance the catalytic activity of the bimetallic nanocatalyst, lower the reaction activation energy, and improve the reaction rate and selectivity of the reaction.

[0040] The catalyst for the chlorination reaction of 1,1,1,3 - tetrachloropropane with chlorine to prepare 1,1,1,2,3 - pentachloropropane in the present invention is a supported zero - valent bimetallic nanoparticle catalyst, including a carrier and an active component supported on the carrier. The active component is one of Sb - Al bimetallic nanoparticles and Sb - Fe bimetallic nanoparticles.

[0041] According to the present invention, the main catalytically active component of the catalyst is nano - aluminum or nano - iron. Adding a second nano - metal component antimony can not only solve the problem that the freshly prepared nano - aluminum or nano - iron catalyst is easily oxidized and its activity is reduced when exposed to air but also play a role in synergistic catalysis, which is beneficial to the progress of the reaction.

[0042] ​​In one or more preferred embodiments, in the Sb-Al bimetallic nanoparticles, the mass percentage of Sb in Al is 1% - 50%, more preferably 5% - 10%; in the Sb-Fe bimetallic nanoparticles, the mass percentage of Sb in Fe is 1% - 50%, more preferably 10% - 20%.

[0043] According to the present invention, loading the active components of the catalyst on the carrier has a good catalytic effect, not only increasing the surface area of the active components of the catalyst, but also avoiding the agglomeration of the catalyst.

[0044] In one or more preferred embodiments, the carrier is bentonite; more preferably, the bentonite is obtained by modifying with tetradecyltrimethylammonium bromide.

[0045] According to the present invention, modifying the bentonite can better adhere the active components, increasing the contact area with the active components, which is beneficial to improving the catalytic efficiency.

[0046] In one or more preferred embodiments, the process of modifying the bentonite is as follows: mixing the bentonite aqueous solution with tetradecyltrimethylammonium bromide, adjusting the pH value to acidic, stirring at 30°C - 100°C for 2 - 4 h, washing, and drying, then the modification of the bentonite is completed; preferably, the mass ratio of tetradecyltrimethylammonium bromide to bentonite is 0.25 - 0.8:1.

[0047] In one or more preferred embodiments, the loading amount of the active component is 2.5 - 75 wt%, more preferably 5 - 20 wt%.

[0048] According to the present invention, the preparation method of the catalyst for catalytic chlorination reaction of 1,1,1,3 - tetrachloropropane with chlorine to prepare 1,1,1,2,3 - pentachloropropane includes the following steps:

[0049] (a) Adding the carrier to the ethanol - aqueous solution of the first metal salt, and dropwise adding the reducing agent solution under stirring for reduction reaction;

[0050] (b) Adding the second metal salt to the reaction solution in step (a), and continuing the reduction reaction;

[0051] (c) Filtering the reaction solution obtained in step (b) by suction filtration, washing with deionized water, and drying in vacuum to obtain the catalyst.

[0052] In one or more preferred embodiments, the whole reaction process is carried out under continuous nitrogen flow and air - isolation conditions to prevent the oxidation of the active components.

[0053] In one or more preferred embodiments, the first metal salt in step (a) is an aluminum salt or an iron salt, more preferably aluminum chloride, iron chloride or ferrous chloride; preferably, the volume ratio of ethanol to water in the ethanol-aqueous solution is 0.1 to 100:1; preferably, the reducing agent is sodium borohydride or potassium borohydride, and the molar ratio of the first metal salt to the reducing agent is 1:1 to 2.5.

[0054] In one or more preferred embodiments, the second metal salt in step (b) is an antimony salt, preferably antimony chloride; preferably, the molar ratio of the second metal salt to the reducing agent is 1:1.5 to 3.

[0055] In one or more preferred embodiments, the vacuum drying temperature in step (c) is 80°C to 120°C, and the drying time is 2 to 6 h.

[0056] According to the present invention, a method for preparing 1,1,1,2,3-pentachloropropane includes using the above-mentioned supported zero-valent bimetallic nanoparticle catalyst, and the steps are as follows:

[0057] In the presence of a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst, 1,1,1,3-tetrachloropropane reacts with chlorine gas to obtain 1,1,1,2,3-pentachloropropane, and the cocatalyst is one of alkyl phosphines, aryl phosphines or alkylaryl phosphines.

[0058] In one or more preferred embodiments, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas is 1:0.8 to 1.2; the reaction temperature during the chlorination reaction is 25 to 130°C, the reaction pressure is 0.1 to 2.0 MPa, and the reaction time is 2 to 32 h;

[0059] More preferably, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas is 1:0.9 to 1.05; the reaction temperature during the chlorination reaction is 40 to 80°C, the reaction pressure is 0.25 to 0.7 MPa, and the reaction time is 3 to 10 h.

[0060] In one or more preferred embodiments, the addition amount of the supported zero-valent bimetallic nanoparticle catalyst is 0.2% to 20% of the mass of 1,1,1,3-tetrachloropropane, more preferably 0.6% to 1%.

[0061] In one or more preferred embodiments, the addition amount of the cocatalyst is 1% to 5% of the mass of 1,1,1,3-tetrachloropropane, more preferably 1.5% to 2.5%.

[0062] According to the present invention, during the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine, a cocatalyst can form a complex with the active metal, enhancing the catalytic activity of the bimetallic nanocatalyst, reducing the reaction activation energy, and increasing the reaction rate and selectivity of the reaction.

[0063] In one or more preferred embodiments, the cocatalyst is one of tributylphosphine, triphenylphosphine, and tert-butyldiphenylphosphine, preferably triphenylphosphine.

[0064] The following specific examples illustrate the technical content of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific examples, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0065] Unless otherwise specified, the reagents used in the examples and comparative examples of the present invention are all conventional chemical reagents, which can be purchased from regular reagent production or sales companies. All reagents have CAS registration numbers, and their chemical and physical properties can be found on major chemical websites.

[0066] Example 1

[0067] 1) Modification treatment of the carrier bentonite:

[0068] Prepare bentonite into a 16% slurry with deionized water, add the surfactant cetyltrimethylammonium bromide (the mass ratio of the surfactant to bentonite is 0.4:1), and adjust the pH to 5 with 10% hydrochloric acid; then heat in an oil bath to 85°C, stir for 4 hours, filter, wash with deionized water until no bromide ions are detected; finally, vacuum dry the filter cake in an oven at 120°C for 4 hours.

[0069] 2) Preparation of the supported zero-valent bimetallic nanoparticle catalyst:

[0070] (a) Add the above-modified carrier bentonite to an ethanol-aqueous solution of ferrous chloride (bentonite: ferrous chloride = 1:0.38, ethanol: water = 10:1), adjust the pH < 5 with 1 mol / L HCl, and dropwise add the reducing agent sodium borohydride solution under stirring (the molar ratio of sodium borohydride to ferrous chloride is 1.8:1).

[0071] (b) Add antimony chloride to the reaction solution in step (a) (antimony chloride: ferrous chloride = 0.083:1), and continue the reduction reaction for 2 hours.

[0072] (c) Filter the reaction solution obtained in step (b), wash it with deionized water, and dry it in a vacuum drying oven at 115 °C for 3 h to obtain a catalyst loaded with zero-valent bimetallic Sb-Fe nanoparticles (Sb loading 1.5%, Fe loading 13%). Nitrogen is continuously introduced throughout the reaction and operation process to avoid contact with air.

[0073] 3) Preparation of 1,1,1,2,3-pentachloropropane:

[0074] Carry out a chlorination reaction on 1,1,1,3-tetrachloropropane and chlorine with a molar ratio of 1:1 under the action of the catalyst loaded with zero-valent bimetallic Sb-Fe nanoparticles and the cocatalyst triphenylphosphine prepared above. The reaction temperature is 65 °C, the reaction pressure is 0.45 MPa, and the reaction time is 6 h to obtain 1,1,1,2,3-pentachloropropane. The addition amount of the catalyst loaded with zero-valent bimetallic Sb-Fe nanoparticles is 0.6% of the mass of 1,1,1,3-tetrachloropropane, and the addition amount of the cocatalyst triphenylphosphine is 1.65% of the mass of 1,1,1,3-tetrachloropropane.

[0075] Example 2

[0076] 1) Modification treatment of the carrier bentonite:

[0077] Prepare bentonite into a 20% slurry with deionized water, add the surfactant cetyltrimethylammonium bromide (the mass ratio of the surfactant to bentonite is 0.5:1), and adjust the pH to 4 with 5% hydrochloric acid; then heat it in an oil bath to 90 °C, stir for 3 h, filter, wash with deionized water until no bromide ions are detected; finally, vacuum dry the filter cake in an oven at 120 °C for 4 h.

[0078] 2) Preparation of a catalyst loaded with zero-valent bimetallic nanoparticles:

[0079] (a) Add the above-modified carrier bentonite to an aqueous solution of ferric chloride (bentonite: ferric chloride = 1:0.24), adjust the pH < 4 with 1 mol / L HCl, and dropwise add a reducing agent potassium borohydride solution (the molar ratio of potassium borohydride to ferric chloride is 2:1) under stirring.

[0080] (b) Add antimony chloride to the reaction solution in step (a) (antimony chloride: ferric chloride = 0.065:1), and continue the reduction reaction for 2 h.

[0081] (c) Filter the reaction solution obtained in step (b), wash it with deionized water, and dry it in a vacuum drying oven at 120 °C for 3 h to obtain a catalyst loaded with zero-valent bimetallic Sb-Fe nanoparticles (Sb loading 0.7%, Fe loading 6%). Nitrogen is continuously introduced throughout the reaction and operation process to avoid contact with air.

[0082] 3) Preparation of 1,1,1,2,3-pentachloropropane:

[0083] Carry out a chlorination reaction on 1,1,1,3-tetrachloropropane and chlorine with a molar ratio of 1:1.05 under the action of the supported zero-valent bimetallic Sb-Fe nanoparticle catalyst prepared above and the cocatalyst triphenylphosphine. The reaction temperature is 50 °C, the reaction pressure is 0.12 MPa, and the reaction time is 8 h to obtain 1,1,1,2,3-pentachloropropane. The addition amount of the supported zero-valent bimetallic Sb-Fe nanoparticle catalyst is 0.8% of the mass of 1,1,1,3-tetrachloropropane, and the addition amount of the cocatalyst triphenylphosphine is 3.0% of the mass of 1,1,1,3-tetrachloropropane.

[0084] Example 3

[0085] 1) Modification treatment of the carrier bentonite:

[0086] Prepare bentonite into a 10% slurry with deionized water, add the surfactant cetyltrimethylammonium bromide (the mass ratio of the surfactant to bentonite is 0.5:1), and adjust the pH to 4 with 15% hydrochloric acid; then heat in an oil bath to 90 °C, stir for 3 h, filter by suction, and wash with deionized water until no bromide ions are detected; finally, vacuum-dry the filter cake in an oven at 110 °C for 3 h.

[0087] 2) Preparation of the supported zero-valent bimetallic nanoparticle catalyst:

[0088] (a) Add the above-modified carrier bentonite to an aqueous solution of aluminum chloride (bentonite:aluminum chloride = 1:0.20), adjust the pH < 4 with 1 mol / L HCl, and dropwise add the reducing agent potassium borohydride solution (the molar ratio of potassium borohydride to aluminum chloride is 2.5:1) under stirring.

[0089] (b) Add antimony chloride to the reaction solution in step (a) (antimony chloride:aluminum chloride = 0.034:1), and continue the reduction reaction for 2 h.

[0090] (c) Filter the reaction solution obtained in step (b) by suction, wash with deionized water, and dry in a vacuum drying oven at 120 °C for 3 h to obtain the supported zero-valent bimetallic Sb-Al nanoparticle catalyst (Sb loading 0.46%, Al loading 5.8%). Nitrogen is continuously introduced throughout the reaction and operation process to avoid contact with air.

[0091] 3) Preparation of 1,1,1,2,3-pentachloropropane:

[0092] 1,1,1,3 - tetrachloropropane and chlorine with a molar ratio of 1:1 are subjected to a chlorination reaction under the action of the supported zero-valent bimetallic Sb-Al nanoparticle catalyst prepared above and the cocatalyst tert-butyldiphenylphosphine. The reaction temperature is 70 °C, the reaction pressure is 0.35 MPa, and the reaction time is 5 h, thus obtaining 1,1,1,2,3 - pentachloropropane. The addition amount of the supported zero-valent bimetallic Sb-Al nanoparticle catalyst is 0.8% of the mass of 1,1,1,3 - tetrachloropropane, and the addition amount of the cocatalyst tert-butyldiphenylphosphine is 2.5% of the mass of 1,1,1,3 - tetrachloropropane.

[0093] Comparative Example 1

[0094] Compared with Example 1, the difference in Comparative Example 1 is that in the preparation method of the supported zero-valent bimetallic nanoparticle catalyst, the operation in step (b) is cancelled, and the second metal nanoparticle is not loaded, obtaining a supported zero-valent iron nanoparticle catalyst. Other operation parameters and preparation methods are the same as those in Example 1.

[0095] Comparative Example 2

[0096] Compared with Example 1, the difference in Comparative Example 2 is that in the preparation method of 1,1,1,2,3 - pentachloropropane, the cocatalyst triphenylphosphine is not added. Other operation parameters and preparation methods are the same as those in Example 1.

[0097] Test Example 1

[0098] The products obtained by the preparation methods of 1,1,1,2,3 - pentachloropropane in Examples 1 - 3 and Comparative Examples 1 - 2 of the present invention are subjected to gas chromatography analysis, and the conversion rate of 1,1,1,3 - tetrachloropropane and the selectivity of the products are shown in Table 1.

[0099] Table 1

[0100] Number Conversion rate / % Selectivity / % Example 1 95.8 97.2 Example 2 96.5 95.6 Example 3 98.0 96.3 Comparative Example 1 91.8 90.3 Comparative Example 2 92.7 92.5

[0101] As can be seen from Table 1, introducing the second metal in the catalyst of the present invention can play a role in synergistic catalysis with the first metal. The introduction of the cocatalyst can form a complex with the active metal, improve the catalytic activity of the bimetallic nanocatalyst, and reduce the reaction activation energy. Generally, it can be seen that both the conversion rate of the raw material 1,1,1,3 - tetrachloropropane and the selectivity of the target product are significantly improved.

[0102] Test Example 2

[0103] After the catalysts of Example 1 and Comparative Examples 1 - 2 of the present invention are recycled 10 times, the products obtained by the preparation method of 1,1,1,2,3 - pentachloropropane are subjected to gas chromatography analysis, and the conversion rate of 1,1,1,3 - tetrachloropropane and the selectivity of the products are shown in Table 2.

[0104] Table 2

[0105] Number Conversion rate / % Selectivity / % Example 1 93.5 95.4 Comparative Example 1 85.7 81.4 Comparative Example 2 90.4 89.2

[0106] As can be seen from Table 2, the supported bimetallic catalyst system of the present invention and the cocatalyst have more obvious advantages in recycling. After recycling 10 times, the conversion rate and selectivity of the reaction still remain at a relatively high level. At the same time, the introduction of the second metal protects the catalyst from being easily oxidized during the recycling process, so that the catalyst activity still maintains a good level during the recycling process.

[0107] The above are only several embodiments of the present invention, and do not impose any form of limitation on the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, makes several improvements or modifications using the technical content disclosed above, which are equivalent to equivalent embodiments and all fall within the scope of the technical solution.

Claims

1. A catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine to prepare 1,1,1,2,3-pentachloropropane, characterized in that: The catalyst is a loaded zero-valent bimetallic nanoparticle catalyst, comprising a carrier and an active component loaded on the carrier, wherein the active component is one of Sb-Al bimetallic nanoparticles and Sb-Fe bimetallic nanoparticles.

2. The catalyst for preparing 1,1,1,2,3-pentachloropropane by catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine according to claim 1, characterized in that: In the Sb-Al bimetallic nanoparticles, the mass percentage of Sb to Al is 1% to 50%, and in the Sb-Fe bimetallic nanoparticles, the mass percentage of Sb to Fe is 1% to 50%.

3. The catalyst for preparing 1,1,1,2,3-pentachloropropane by catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine according to claim 1, characterized in that: The carrier is bentonite; preferably, the bentonite is modified by tetradecyltrimethylammonium bromide.

4. The catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine to prepare 1,1,1,2,3-pentachloropropane according to claim 3, characterized in that: The bentonite modification process is as follows: mixing the bentonite aqueous solution with tetradecyltrimethylammonium bromide, adjusting the pH value to acidic, stirring for 2-4 hours at 30°C to 100°C, washing, and drying to complete the bentonite modification process; preferably, the mass ratio of tetradecyltrimethylammonium bromide to bentonite is 0.25-0.8:

1.

5. The catalyst for preparing 1,1,1,2,3-pentachloropropane by catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine according to claim 1, characterized in that: The loading amount of active components is 2.5~75wt%.

6. A method for preparing a catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine gas to prepare 1,1,1,2,3-pentachloropropane according to any one of claims 1 to 5, comprising the following steps: (a) adding the carrier to an ethanol-water solution of a first metal salt, and dropping a reducing agent solution under stirring to carry out a reduction reaction; (b) adding a second metal salt to the reaction solution in step (a) to continue the reduction reaction; (c) The reaction solution obtained in step (b) is filtered, washed with deionized water, and vacuum dried to obtain a catalyst.

7. The method for preparing a catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine gas to prepare 1,1,1,2,3-pentachloropropane according to claim 6, characterized in that: The first metal salt in step (a) is an aluminum salt or an iron salt, preferably aluminum chloride, ferric chloride or ferrous chloride; preferably, the reducing agent is sodium borohydride or potassium borohydride, and the molar ratio of the first metal salt to the reducing agent is 1:1-2.5; preferably, the second metal salt in step (b) is an antimony salt, and the molar ratio of the second metal salt to the reducing agent is 1:1.5-3.

8. A method for preparing 1,1,1,2,3-pentachloropropane, comprising using the catalyst for catalyzing the chlorination reaction of 1,1,1,3-tetrachloropropane with chlorine as claimed in any one of claims 1 to 5 to prepare 1,1,1,2,3-pentachloropropane, comprising the following steps: In the presence of a supported zero-valent bimetallic nanoparticle catalyst and a co-catalyst, 1,1,1,3-tetrachloropropane is reacted with chlorine to obtain 1,1,1,2,3-pentachloropropane, wherein the co-catalyst is one of an alkyl phosphine, an aryl phosphine or an alkyl aryl phosphine.

9. The method for preparing 1,1,1,2,3-pentachloropropane according to claim 8, characterized in that: The molar ratio of 1,1,1,3-tetrachloropropane to chlorine is 1:0.8-1.2; the reaction temperature during the chlorination reaction is 25-130° C., the reaction pressure is 0.1-2.0 MPa, and the reaction time is 2-32 h; Preferably, the added amount of the supported zero-valent bimetallic nanoparticle catalyst is 0.2% to 20% of the mass of 1,1,1,3-tetrachloropropane.

10. The method for preparing 1,1,1,2,3-pentachloropropane according to claim 8, characterized in that: The co-catalyst is one of tributylphosphine, triphenylphosphine and tert-butyldiphenylphosphine; preferably, the amount of the co-catalyst added is 1% to 5% of the mass of 1,1,1,3-tetrachloropropane.

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