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

Abstract

The invention relates to a preparation method of 1, 1, 1, 3, 3-pentachloropropane and a catalyst, in the presence of a loaded zero-valent bimetallic nanoparticle catalyst and a cocatalyst, carbon tetrachloride and vinyl chloride are subjected to an addition reaction to obtain 1, 1, 1, 3, 3-pentachloropropane, the zero-valent bimetallic nanoparticle loaded catalyst comprises a carrier and an active component loaded on the carrier; the active component is prepared from zero-valent Pd-Fe nano particles or Cu-Fe nano particles; the cocatalyst comprises boric acid ester or acetyl citrate. The preparation method of 1, 1, 1, 3, 3-pentachloropropane can effectively avoid easy agglomeration when only Fe powder is used as a catalyst, the specific surface area of the iron powder is increased, the reaction is promoted, meanwhile, the used cocatalyst is a nitrogen-free and phosphorus-free catalyst, emission of three wastes containing nitrogen and phosphorus is avoided, and the preparation method is environment-friendly.

Description

Technical Field

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

[0002] 1,1,1,3,3-Pentachloropropane (abbreviated as HCC-240fa, CAS No. 23153-23-3) is an important fine chemical product, an important raw material for producing fluorohydrocarbons to replace CFCs and HCFCs, and an important intermediate for synthesizing 1,1,1,3,3-pentafluoropropane (abbreviated as HFC-245fa). HFC-245fa has excellent physical and chemical properties and has a quite wide range of applications. It is used for foaming rigid polyurethane and polyisocyanurate foam insulating plastics. Its ozone depletion potential (ODP) is zero, its global warming potential (GWP) is low, it is non-flammable and has low toxicity. It can replace the uses of CFC-11, CFC-12, and HCFC-141b, and is used as a foaming agent, refrigerant, cleaning agent, heat transfer medium, aerosol propellant, etc. that do not damage the ozone layer. Through the dehydrofluorination reaction of HFC-245fa prepared from HCC-240fa, 1,3,3,3-tetrafluoropropene (HFO-1234ze) with a low GWP value can be further prepared. HFO-1234ze is considered to be a potential good substitute for HFC-134a and other substances used in industries such as foaming agents, refrigerants, and aerosol propellants.

[0003] The preparation method of 1,1,1,3,3-pentachloropropane disclosed in Patent WO97 / 37956A1 is to first telomerize carbon tetrachloride and 1,1-dichloroethylene to synthesize hexachloropropane, and then reduce it to 1,1,1,3,3-pentachloropropane. Since the telomerization reaction has many side reactions and a low yield, and this route has a long process, large investment, and high energy consumption, it is not suitable for industrial production.

[0004] The preparation method of 1,1,1,3,3-pentachloropropane disclosed in Patent US5705729A is to first carry out a telomerization reaction using carbon tetrachloride and ethylene as raw materials to obtain 1,1,1,3-tetrachloropropane, and then carry out photochlorination to synthesize 1,1,1,3,3-pentachloropropane. The conversion rate of the photochlorination reaction in this route is not high and the selectivity is poor, making industrial scale-up difficult.

[0005] The preparation method of 1,1,1,3,3-pentachloropropane disclosed in Patent CN1335291A is to react carbon tetrachloride and vinyl chloride at 85-130 °C for 2-10 hours under the action of a copper chloride / alkanolamine composite catalyst to obtain pentachloropropane. In this route, after the copper chloride is coordinated and complexed with the alkanolamine, it is easy to form a viscous semi-solid substance, which causes serious equipment corrosion. Moreover, only water can be used to destroy and separate it, and the catalyst is difficult to recycle, and the generated waste solid catalyst is difficult to handle.

[0006] The preparation method of 1,1,1,3,3-pentachloropropane disclosed in Patent CN103274893A is to prepare a catalyst by using iron, iron chloride, and phosphate ester, and catalyze the telomerization reaction of vinyl chloride and carbon tetrachloride to obtain pentachloropropane. The iron powder used in this route is easy to agglomerate on the surface of the reactor after the reaction, which is difficult to clean. Moreover, the fine iron powder is dispersed in the organic liquid, resulting in high consumption and difficult separation and reuse.

[0007] According to the above patents and literature reports, the most commonly used synthetic route for the preparation of 1,1,1,3,3-pentachloropropane at present is to use carbon tetrachloride and vinyl chloride as raw materials. The raw materials are relatively easy to obtain and the synthesis process is simple; the catalysts used mainly include copper-amine systems and iron-phosphate ester systems. However, the iron powder in the currently used iron or its compounds and organic phosphorus compound catalysts is commercially available iron powder; when commercially available iron powder is used as the main catalyst, it is easy to agglomerate at the bottom of the reaction kettle. Due to long-term contact with air, an oxide film is formed on the surface, which reduces the reaction activity. At the same time, the co-catalysts used are organic nitrogen and organic phosphorus compounds. These compounds are easy to form inorganic-organic hybrid high-boiling substances, which are not easy to handle, form nitrogen and phosphorus pollutants, and cause great environmental protection pressure.

[0008] In summary, there is still a lack in the art of a 1,1,1,3,3-pentachloropropane reaction catalyst that has better dispersibility than commercially available iron powder, a larger contact area with reactants, higher selectivity, and is more environmentally friendly. Summary of the Invention

[0009] In view of the above-mentioned status of the prior art, the inventors of the present invention have conducted in-depth and extensive research in the field of catalytic preparation of 1,1,1,3,3-pentachloropropane and found that: on the one hand, improving the loading of the powdery iron-based catalyst can not only significantly improve the problem of easy agglomeration of commercially available iron powder, but also increase the specific surface area of iron. At the same time, adding a second nano-metal component during the preparation process effectively solves the problem that the freshly prepared nano-iron catalyst is easily oxidized when exposed to air, which is beneficial to the progress of the reaction; on the other hand, the preparation method uses a co-catalyst of borate or acetyl citrate ester, which can significantly avoid the emission of nitrogen and phosphorus-containing three wastes and is environmentally friendly. The present invention is completed based on the above discoveries.

[0010] Therefore, an object of the present invention is to provide a method for preparing 1,1,1,3,3-pentachloropropane, the core of which is to use a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst to catalyze the addition reaction of carbon tetrachloride and vinyl chloride to obtain 1,1,1,3,3-pentachloropropane.

[0011] The second object of the present invention is to provide the above-mentioned catalytic system for preparing 1,1,1,3,3-pentachloropropane and a preparation method of the catalyst.

[0012] The technical solutions for achieving the above-mentioned invention objects can be summarized as follows:

[0013] A catalyst for catalyzing the addition reaction of carbon tetrachloride and vinyl chloride to prepare 1,1,1,3,3-pentachloropropane. The catalyst 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 Pd-Fe bimetallic nanoparticles and Cu-Fe bimetallic nanoparticles.

[0014] According to the present invention, preferably, in the Pd-Fe bimetallic nanoparticles, the mass percentage of Pd to Fe is 0.02% - 20%, and more preferably 1% - 10%; in the Cu-Fe bimetallic nanoparticles, the mass percentage of Cu to Fe is 0.02% - 20%, and more preferably 0.5% - 5%.

[0015] According to the present invention, preferably, the carrier is bentonite or activated carbon; more preferably, the bentonite is obtained by modification treatment with octadecyltrimethylammonium chloride, and the activated carbon is obtained by modification treatment with an acid solution. The acid solution is preferably hydrochloric acid, phosphoric acid or nitric acid.

[0016] According to the present invention, preferably, the bentonite modification treatment process is: mixing an aqueous solution of bentonite with octadecyltrimethylammonium chloride, adjusting the pH value to acidic, stirring at 40°C - 90°C for 2 - 4 hours, washing, and drying to complete the bentonite modification treatment; preferably, the mass ratio of octadecyltrimethylammonium chloride to bentonite is 0.25 - 0.8:1.

[0017] According to the present invention, preferably, the activated carbon modification treatment process is: mixing the activated carbon with an acid solution and refluxing at 70 - 110°C to complete the activated carbon modification; preferably, the mass concentration of the acid solution is 5 - 30%, and the mass ratio of the activated carbon to the volume of the acid solution is 0.05 - 0.2 g:1 mL.

[0018] According to the present invention, preferably, the loading amount of the active component is 2.5 - 75 wt%, and more preferably 5 - 20 wt%.

[0019] According to the present invention, the preparation method of the catalyst for catalytic addition reaction of carbon tetrachloride and vinyl chloride to prepare 1,1,1,3,3-pentachloropropane comprises the following steps:

[0020] (a) Adding a carrier into an ethanol-aqueous solution of a first metal salt, and dropwise adding a reducing agent solution under stirring to carry out a reduction reaction;

[0021] (b) Adding a second metal salt into the reaction solution in step (a), and continuing to carry out the reduction reaction;

[0022] (c) Filtering the reaction solution obtained in step (b) by suction, washing with deionized water, and drying in vacuum to obtain the catalyst.

[0023] According to the present invention, preferably, the whole reaction process is carried out under the condition of continuously introducing nitrogen and isolating air.

[0024] According to the present invention, preferably, the first metal salt in step (a) is ferrous sulfate heptahydrate or ferrous chloride; preferably, the volume ratio of ethanol to water in the ethanol-aqueous solution is 0.1-4:1; 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.

[0025] According to the present invention, preferably, the second metal salt in step (b) is platinum chloride, sodium chloroplatinate, potassium chloroplatinate or cuprous chloride; preferably, the molar ratio of the second metal salt to the reducing agent is 1:1.5-3.

[0026] According to the present invention, preferably, the vacuum drying temperature in step (c) is 90°C-120°C, and the drying time is 3-6 h.

[0027] According to the present invention, a preparation method of 1,1,1,3,3-pentachloropropane comprises using the above-mentioned supported zero-valent bimetallic nanoparticle catalyst, and the steps are as follows:

[0028] In the presence of the supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst, carbon tetrachloride and vinyl chloride are subjected to an addition reaction to obtain 1,1,1,3,3-pentachloropropane, and the cocatalyst is one of borate ester and acetyl citrate ester.

[0029] According to the present invention, preferably, the molar ratio of vinyl chloride to carbon tetrachloride is 0.1-1.1:1; the reaction temperature in the addition reaction process is 90-130°C, the reaction pressure is 0.15-0.8 MPa, and the reaction time is 2-10 h;

[0030] Further preferably, the molar ratio of vinyl chloride to carbon tetrachloride is 0.5 - 0.9:1; the reaction temperature during the addition reaction is 110 - 115 °C, the reaction pressure is 0.25 - 0.35 MPa, and the reaction time is 3 - 5 h.

[0031] According to the present invention, preferably, the addition amount of the supported zero-valent bimetallic nanoparticle catalyst is 2% - 20% of the mass of carbon tetrachloride, and further preferably 6% - 10%.

[0032] According to the present invention, preferably, the addition amount of the cocatalyst is 1% - 5% of the mass of carbon tetrachloride, and further preferably 1.5% - 2.5%.

[0033] According to the present invention, preferably, the borate ester is one of tripropyl borate, tributyl borate, triethyl borate, and trimethyl borate; the acetyl citrate ester is one of triethyl acetyl citrate and tributyl acetyl citrate.

[0034] Compared with the prior art, the beneficial effects that can be produced by the present invention include:

[0035] 1. In the present invention, the zero-valent bimetal is supported on a carrier, which can significantly improve the problem of easy agglomeration when using pure commercially available iron powder as a catalyst. The catalytic performance is good, and the catalyst is easy to separate from the reaction kettle after the reaction. At the same time, adding the second nano-metal component Pt or Cu can effectively solve the problem that the freshly prepared nano-iron catalyst is easily oxidized when exposed to air, which is beneficial to the progress of the reaction.

[0036] 2. The zero-valent bimetal used in the present invention is in the form of nanoparticles. Compared with commercially available iron powder, inorganic salts, and other compound catalysts, the particle size is smaller, the specific surface area is larger, and the catalytic effect is better.

[0037] 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 nano-zero-valent iron, and is beneficial to the progress of the reaction.

[0038] 4. In the preparation method of 1,1,1,3,3-pentachloropropane of the present invention, the cocatalyst used is a borate ester or an acetyl citrate ester. Compared with traditional organic nitrogen and organic phosphorus compounds, the present invention can significantly avoid the emission of nitrogen and phosphorus-containing three wastes and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 For the 1,1,1,3,3-pentachloropropane obtained in Example 1 1 HNMR spectrum. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The present invention provides a preparation method of 1,1,1,3,3-pentachloropropane and a catalyst. Its core technologies include a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst. On the one hand, a supported iron main catalyst is used, which can significantly improve the problem of easy agglomeration of commercially available iron powder, increase the specific surface area of iron, and at the same time add a second nano-metal component during the preparation process, effectively solving the problem that freshly prepared nano-iron catalyst is easily oxidized when exposed to air, which is beneficial to the reaction; on the other hand, a cocatalyst is borate or acetyl citrate ester, which can significantly avoid the emission of nitrogen and phosphorus-containing three wastes and is environmentally friendly.

[0041] The catalyst for the addition reaction of carbon tetrachloride and vinyl chloride to prepare 1,1,1,3,3-pentachloropropane according to 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 Pd-Fe bimetallic nanoparticles and Cu-Fe bimetallic nanoparticles.

[0042] According to the present invention, adding a second nano-metal component to the active component of the catalyst effectively solves the problem that freshly prepared nano-iron catalyst is easily oxidized when exposed to air, which is beneficial to the reaction.

[0043] In one or more preferred embodiments, in the Pd-Fe bimetallic nanoparticles, the mass percentage of Pd in Fe is 0.02% - 20%, further preferably 1% - 10%; in the Cu-Fe bimetallic nanoparticles, the mass percentage of Cu in Fe is 0.02% - 20%, further preferably 0.5% - 5%.

[0044] According to the present invention, loading the active component on the carrier can significantly improve the problem of easy agglomeration of commercially available iron powder and increase the specific surface area of iron.

[0045] In one or more preferred embodiments, the carrier is bentonite or activated carbon; further preferably, the bentonite is obtained by modification treatment with octadecyltrimethylammonium chloride, and the activated carbon is obtained by modification treatment with an acid solution, and the acid solution is preferably hydrochloric acid, phosphoric acid or nitric acid. After the carrier is modified, it can better adhere to the active component, increase the contact area with nano-zero-valent iron, and is beneficial to the reaction.

[0046] In one or more preferred embodiments, the process of bentonite modification treatment is: mixing an aqueous solution of bentonite with octadecyltrimethylammonium chloride, adjusting the pH value to acidic, stirring at 40°C - 90°C for 2 - 4 hours, washing, and drying, then the bentonite modification treatment is completed; preferably, the mass ratio of octadecyltrimethylammonium chloride to bentonite is 0.25 - 0.8:1.

[0047] In one or more preferred embodiments, the activated carbon modification process is as follows: Mix the activated carbon with an acid solution and reflux at 70-110 °C to complete the modification of the activated carbon. Preferably, the mass concentration of the acid solution is 5-30%, and the mass-to-volume ratio of the activated carbon to the acid solution is 0.05-0.2 g:1 mL.

[0048] In one or more preferred embodiments, the loading amount of the active component is 2.5-75 wt%, more preferably 5-20 wt%.

[0049] According to the present invention, the preparation method of the catalyst for catalytic addition reaction of carbon tetrachloride and vinyl chloride to prepare 1,1,1,3,3-pentachloropropane includes the following steps:

[0050] (a) Add the carrier to the ethanol-aqueous solution of the first metal salt, and dropwise add the reducing agent solution under stirring to carry out a reduction reaction;

[0051] (b) Add the second metal salt to the reaction solution in step (a) and continue the reduction reaction;

[0052] (c) Filter the reaction solution obtained in step (b), wash with deionized water, and dry in vacuum to obtain the catalyst.

[0053] According to the present invention, the whole reaction process is carried out under the condition of continuously introducing nitrogen and isolating air.

[0054] In one or more preferred embodiments, the first metal salt in step (a) is ferrous sulfate heptahydrate or ferrous chloride; preferably, the volume ratio of ethanol to water in the ethanol-aqueous solution is 0.1-4:1; 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.

[0055] In one or more preferred embodiments, the second metal salt in step (b) is platinum chloride, sodium chloroplatinate, potassium chloroplatinate or cuprous chloride; preferably, the molar ratio of the second metal salt to the reducing agent is 1:1.5-3.

[0056] In one or more preferred embodiments, the vacuum drying temperature in step (c) is 90 °C - 120 °C, and the drying time is 3-6 h.

[0057] According to the present invention, a method for preparing 1,1,1,3,3-pentachloropropane includes using the above-mentioned supported zero-valent bimetallic nanoparticle catalyst, and the steps are as follows:

[0058] In the presence of a supported zero-valent bimetallic nanoparticle catalyst and a cocatalyst, carbon tetrachloride and vinyl chloride are subjected to an addition reaction to obtain 1,1,1,3,3-pentachloropropane. The cocatalyst is one of a borate ester and an acetylcitrate ester.

[0059] According to the present invention, preferably, the molar ratio of vinyl chloride to carbon tetrachloride is 0.1 to 1.1:1; the reaction temperature during the addition reaction is 90 to 130 °C, the reaction pressure is 0.15 to 0.8 MPa, and the reaction time is 2 to 10 h.

[0060] More preferably, the molar ratio of vinyl chloride to carbon tetrachloride is 0.5 to 0.9:1; the reaction temperature during the addition reaction is 110 to 115 °C, the reaction pressure is 0.25 to 0.35 MPa, and the reaction time is 3 to 5 h.

[0061] According to the present invention, preferably, the addition amount of the supported zero-valent bimetallic nanoparticle catalyst is 2% to 20% of the mass of carbon tetrachloride, and more preferably 6% to 10%.

[0062] According to the present invention, preferably, the addition amount of the cocatalyst is 1% to 5% of the mass of carbon tetrachloride, and more preferably 1.5% to 2.5%.

[0063] According to the present invention, the active ingredient of the main catalyst will form a ferrous ion salt required for the telomerization reaction during the pyrolysis of the material. The introduction of the cocatalyst can form an organic coordination bond with it, improving the compatibility and homogeneity of the catalytic reaction system, increasing the catalytic activity of the reaction, improving the catalytic efficiency of the telomerization reaction, and at the same time avoiding the sedimentation of the ferrous ion salt to block the equipment pipeline, and improving the continuous operation of the process.

[0064] In one or more preferred embodiments, the borate ester is one of tripropyl borate, tributyl borate, triethyl borate, and trimethyl borate; the acetylcitrate ester is one of triethyl acetylcitrate and tributyl acetylcitrate. The cocatalyst used is a borate ester or an acetylcitrate ester. Compared with traditional organic nitrogen and organic phosphorus compounds, the present invention can significantly avoid the emission of nitrogen- and phosphorus-containing three wastes and is environmentally friendly.

[0065] 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.

[0066] 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 the reagents used have CAS registration numbers, and their chemical and physical properties can be found on major chemical websites.

[0067] Example 1

[0068] 1) Modification treatment of the carrier bentonite:

[0069] The bentonite was made into a 15% slurry with deionized water, and octadecyltrimethylammonium chloride surfactant (the mass ratio of the surfactant to bentonite is 0.4:1) was added. The pH was adjusted to 4 with 10% hydrochloric acid; then it was heated in an oil bath to 80 °C, stirred for 4 h, filtered by suction, and washed with deionized water until no chloride ions were detected; finally, the filter cake was vacuum dried in an oven at 120 °C for 4 h.

[0070] 2) Preparation of the supported zero-valent bimetallic nanoparticle catalyst:

[0071] (a) The above-modified carrier bentonite was added to an ethanol-aqueous solution of ferrous chloride (bentonite: ferrous chloride = 1:0.38, ethanol: water = 4:1), and the pH was adjusted to < 4 with 1 mol / L HCl. A reducing agent sodium borohydride solution (the molar ratio of sodium borohydride to ferrous chloride is 2:1) was added dropwise under stirring.

[0072] (b) Potassium chloroplatinate was added to the reaction solution in step (a) (potassium chloroplatinate: ferrous chloride = 0.037:1), and the reduction reaction was continued for 2 h.

[0073] (c) The reaction solution obtained in step (b) was filtered by suction, washed with deionized water, and dried in a vacuum drying oven at 120 °C for 3 h to obtain a supported zero-valent bimetallic Pt-Fe nanoparticle catalyst (Pt loading 0.04%, Fe loading 13%). Nitrogen was continuously introduced throughout the reaction process to isolate the air.

[0074] 3) Preparation of 1,1,1,3,3-pentachloropropane:

[0075] Vinyl chloride and carbon tetrachloride with a molar ratio of 0.75:1 were subjected to a telomerization reaction under the action of the supported zero-valent bimetallic Pt-Fe nanoparticle catalyst and the co-catalyst tributyl acetylcitrate. The reaction temperature was 115 °C, the reaction pressure was 0.25 MPa, and the reaction time was 4 h to obtain 1,1,1,3,3-pentachloropropane. The addition amount of the supported zero-valent bimetallic Pt-Fe nanoparticle catalyst was 6% of the mass of carbon tetrachloride, and the addition amount of the co-catalyst tributyl acetylcitrate was 1.5% of the mass of carbon tetrachloride.

[0076] Example 2

[0077] 1) Modification treatment of the carrier bentonite:

[0078] Prepare bentonite into a 15% slurry with deionized water, add the surfactant octadecyltrimethylammonium chloride (the mass ratio of the surfactant to bentonite is 0.5:1), and adjust the pH to 3 with 10% hydrochloric acid; then heat in an oil bath to 90 °C, stir for 3 h, filter by suction, wash with deionized water until no chloride ions are detected; finally, vacuum dry the filter cake in an oven at 120 °C for 4 h.

[0079] 2) Preparation of the supported zero-valent bimetallic nanoparticle catalyst:

[0080] (a) Add the above-modified carrier bentonite to an aqueous solution of ferrous chloride (bentonite: ferrous chloride = 1:0.19), 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 ferrous chloride is 2:1) under stirring.

[0081] (b) Add platinum chloride to the reaction solution in step (a) (platinum chloride: ferrous chloride = 0.037:1), and continue the reduction reaction for 2 h.

[0082] (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 Pt-Fe nanoparticle catalyst (Pt loading 0.04%, Fe loading 6%). Nitrogen is continuously introduced throughout the reaction process to isolate air.

[0083] 3) Preparation of 1,1,1,3,3-pentachloropropane:

[0084] Carry out a telomerization reaction on vinyl chloride and carbon tetrachloride with a molar ratio of 0.35:1 under the action of the supported zero-valent bimetallic Pt-Fe nanoparticle catalyst and the co-catalyst tributyl borate. The reaction temperature is 110 °C, the reaction pressure is 0.3 MPa, and the reaction time is 6 h to obtain 1,1,1,3,3-pentachloropropane. The addition amount of the supported zero-valent bimetallic Pt-Fe nanoparticle catalyst is 12% of the mass of carbon tetrachloride, and the addition amount of the co-catalyst tributyl borate is 3.0% of the mass of carbon tetrachloride.

[0085] Example 3

[0086] 1) Modification treatment of activated carbon:

[0087] Mix activated carbon with a 10% hydrochloric acid solution (the mass-volume ratio of activated carbon to hydrochloric acid is 0.2 g / ml), and reflux at 80 °C for 2 h.

[0088] 2) Preparation of the supported zero-valent bimetallic nanoparticle catalyst:

[0089] (a) Add the above modified activated carbon into an aqueous solution of ferrous chloride (activated carbon: ferrous chloride = 1:0.19), adjust the pH < 4 with 1 mol / L HCl, and dropwise add the reducing agent potassium borohydride solution under stirring (the molar ratio of potassium borohydride to ferrous chloride is 1.2:1).

[0090] (b) Add platinum(II) chloride into the reaction solution in step (a) (copper(II) chloride: ferrous chloride = 0.037:1), and continue the reduction reaction for 2 h.

[0091] (c) Filter the reaction solution obtained in step (b) by suction filtration, 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 Cu-Fe nanoparticles (Cu loading 0.04%, Fe loading 6%). Nitrogen is continuously introduced throughout the reaction process to isolate air.

[0092] 3) Preparation of 1,1,1,3,3-pentachloropropane:

[0093] Carry out a telomerization reaction on vinyl chloride and carbon tetrachloride with a molar ratio of 0.5:1 under the action of the catalyst loaded with zero-valent bimetallic Cu-Fe nanoparticles prepared above and the co-catalyst triethyl acetylcitrate. The reaction temperature is 120 °C, the reaction pressure is 0.25 MPa, and the reaction time is 4 h to obtain 1,1,1,3,3-pentachloropropane. The addition amount of the catalyst loaded with zero-valent bimetallic Cu-Fe nanoparticles is 6% of the mass of carbon tetrachloride, and the addition amount of the co-catalyst triethyl acetylcitrate is 2% of the mass of carbon tetrachloride.

[0094] Comparative Example 1

[0095] Compared with Example 1, the difference in Comparative Example 1 is that in the preparation method of the catalyst loaded with zero-valent bimetallic nanoparticles, the operation in step (b) is cancelled, the second metal particles are not loaded, and a catalyst loaded with zero-valent iron nanoparticles is obtained. Other operation parameters and preparation methods are the same as those in Example 1.

[0096] Comparative Example 2

[0097] Compared with Example 1, the difference in Comparative Example 2 is that in the preparation method of 1,1,1,3,3-pentachloropropane, commercially available iron powder is used as the main catalyst, and the co-catalyst is changed to tributyl phosphate. Other operation parameters and preparation methods are the same as those in Example 1.

[0098] Test Example 1

[0099] Carry out gas chromatography analysis on the products obtained by the preparation methods of 1,1,1,3,3-pentachloropropane in Examples 1-3 and Comparative Examples 1-2 of the present invention, and the conversion rate of vinyl chloride and the selectivity of the products are shown in Table 1.

[0100] Table 1

[0101] Number Conversion rate / % Selectivity / % Example 1 99.8 99.5 Example 2 98.5 99.2 Example 3 99.0 98.7 Comparative Example 1 99.1 97.3 Comparative Example 2 94.7 93.0

[0102] As can be seen from Table 1, compared with the traditional commercially available iron powder as the main catalyst, the conversion rate of vinyl chloride and the selectivity of the target product of the catalyst of the present invention have been greatly improved.

[0103] Test Example 2

[0104] After the catalysts of Example 1 and Comparative Examples 1-2 of the present invention were recycled 10 times, the products obtained by the preparation method of 1,1,1,3,3-pentachloropropane were subjected to gas chromatography analysis, and the conversion rate of vinyl chloride and the selectivity of the product are shown in Table 2.

[0105] Table 2

[0106] Number Conversion rate / % Selectivity / % Example 1 97.5 95.0 Comparative Example 1 95.0 85.4 Comparative Example 2 88.4 74.2

[0107] As can be seen from Table 2, compared with the traditional catalyst, the supported bimetallic catalyst system of the present invention has more obvious advantages in recycling. After 10 cycles, the conversion rate and selectivity of the reaction still remain at a high level. At the same time, the introduction of the second metal protects the catalyst from being easily oxidized, so that the catalyst activity still maintains a good level during the recycling process.

[0108] The above are only several implementation cases 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 all equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride, 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 Pd-Fe bimetallic nanoparticles and Cu-Fe bimetallic nanoparticles.

2. The catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride according to claim 1, characterized in that: In the Pd-Fe bimetallic nanoparticles, the mass percentage of Pd to Fe is 0.02% to 20%; in the Cu-Fe bimetallic nanoparticles, the mass percentage of Cu to Fe is 0.02% to 20%.

3. The catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride according to claim 1, characterized in that: The carrier is bentonite or activated carbon; Preferably, the bentonite is modified by octadecyltrimethylammonium chloride, and the activated carbon is modified by an acid solution, wherein the acid solution is preferably hydrochloric acid, phosphoric acid or nitric acid.

4. The catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride according to claim 3, characterized in that: The bentonite modification process is as follows: the bentonite aqueous solution is mixed with octadecyl trimethyl ammonium chloride, the pH value is adjusted to acidic, stirred at 40°C to 90°C for 2-4 hours, washed, and dried to complete the bentonite modification process; preferably, the mass ratio of octadecyl trimethyl ammonium chloride to bentonite is 0.25-0.8:1; Preferably, the activated carbon modification process is: mixing the activated carbon with an acid solution, and reflux treatment at 70-110°C to complete the activated carbon modification; preferably, the mass concentration of the acid solution is 5-30%, and the volume ratio of the mass of the activated carbon to the acid solution is 0.05-0.2g:1mL.

5. A method for preparing a catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride as claimed in any one of claims 1 to 4, 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.

6. The method for preparing a catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride according to claim 5, characterized in that: The first metal salt in step (a) is ferrous sulfate heptahydrate or ferrous chloride; preferably, the volume ratio of ethanol to water in the ethanol-water solution is 0.1-4:1; 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; Preferably, the second metal salt in step (b) is platinous chloride, sodium chloroplatinite, potassium chloroplatinite or cuprous chloride; preferably, the molar ratio of the second metal salt to the reducing agent is 1:1.5-3; Preferably, in step (c), the vacuum drying temperature is 90° C. to 120° C., and the drying time is 3 to 6 hours.

7. A method for preparing 1,1,1,3,3-pentachloropropane, comprising using the catalyst for preparing 1,1,1,3,3-pentachloropropane by catalyzing the addition reaction of carbon tetrachloride and vinyl chloride as claimed in any one of claims 1 to 4, comprising the following steps: In the presence of a supported zero-valent bimetallic nanoparticle catalyst and a co-catalyst, carbon tetrachloride and vinyl chloride are subjected to an addition reaction to obtain 1,1,1,3,3-pentachloropropane, wherein the co-catalyst is one of boric acid ester and acetylcitrate.

8. The method for preparing 1,1,1,3,3-pentachloropropane according to claim 7, characterized in that: The molar ratio of vinyl chloride to carbon tetrachloride is 0.1-1.1:1; the reaction temperature during the addition reaction is 90-130° C., the reaction pressure is 0.15-0.8 MPa, and the reaction time is 2-10 hours.

9. The method for preparing 1,1,1,3,3-pentachloropropane according to claim 7, characterized in that: The amount of the catalyst added to catalyze the addition reaction of carbon tetrachloride and vinyl chloride to prepare 1,1,1,3,3-pentachloropropane is 2% to 20% of the mass of carbon tetrachloride; preferably, the amount of the co-catalyst added is 1% to 5% of the mass of carbon tetrachloride.

10. The method for preparing 1,1,1,3,3-pentachloropropane according to claim 7, characterized in that: The borate ester is one of tripropyl borate, tributyl borate, triethyl borate and trimethyl borate; the acetyl citrate is one of triethyl acetyl citrate and tributyl acetyl citrate.

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