Pentachloropropane dehydrochlorination catalyst and preparation process of tetrachloropropene

Abstract

The present application belongs to the technical field of catalyst preparation, and particularly relates to a pentachloropropane dehydrochlorination catalyst and a preparation process of tetrachloropropene. The catalyst preparation process comprises the following steps: (1) modifying gamma-alumina powder by using an epoxy-containing silane coupling agent to obtain activated gamma-alumina powder; (2) dispersing the activated gamma-alumina powder and polyamino POSS in a solvent, and stirring to obtain modified gamma-alumina powder; (3) preparing modified gamma-alumina powder loaded with trivalent metal salt, and drying to obtain the pentachloropropane dehydrochlorination catalyst. The epoxy-containing silane coupling agent not only improves the dispersing performance of the alumina, but also plays a medium role, so that the POSS is attached to the surface of the alumina powder, and the stability of the catalyst is improved. The amino groups on the POSS are used to complex trivalent metal ions, and the small molecule itself can also be used as a transmission track of the substrate, so that the catalytic activity is improved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a pentachloropropane dehydrochlorination catalyst and a preparation process for tetrachloropropylene. Background Technology

[0002] Currently, the widely used refrigerant 1,1,1,2-tetrafluoroethane is being phased out due to its high global warming potential. 2,3,3,3-tetrafluoropropylene, on the other hand, has no flash point, an auto-ignition point of 405℃, and good stability. The hazard of HF (high-toxicity fluoride), a harmful substance produced by the combustion and thermal decomposition of 2,3,3,3-tetrafluoropropylene in automotive air conditioning systems, is comparable to that of 1,1,1,2-tetrafluoroethane, falling into the same order of magnitude, making it a safe and reliable refrigerant. Furthermore, 2,3,3,3-tetrafluoropropylene is less toxic than 1,1,1,2-tetrafluoroethane, classifying it as a low-toxicity substance. More importantly, 2,3,3,3-tetrafluoropropylene exhibits good compatibility with most organic polymers, comparable to that of 1,1,1,2-tetrafluoroethane. 2,3,3,3-Tetrafluoropropylene is non-reactive and non-corrosive to metals such as carbon steel, stainless steel, copper, and brass. At the same time, 2,3,3,3-tetrafluoropropylene has good miscibility with common lubricating oils and is applicable to a wide range of fields.

[0003] 1,1,2,3-Tetrachloropropene is an important precursor of 2,3,3,3-tetrafluoropropene, and is prepared by the dehydrochlorination of 1,1,1,2,3-pentachloropropane. Currently, the dehydrochlorination of 1,1,1,2,3-pentachloropropane typically employs a homogeneous liquid-phase reaction process. CN109134190A discloses a gas-phase preparation method for 1,1,2,3-tetrachloropropene. Under the action of a catalyst, 1,1,1,2,3-pentachloropropane undergoes a gas-phase catalytic dehydrochlorination reaction at a temperature of 150-250℃ and a contact time of 1-15 seconds. The reaction product is collected and subjected to vacuum distillation to obtain the 1,1,2,3-tetrachloropropene product. Although this method is simple, it has high energy consumption, requires sophisticated equipment, exhibits low product selectivity and reaction efficiency, and generates a large amount of waste salt, making it difficult to promote its widespread use. CN115160104A discloses a method for producing pesticide-grade 1,1,2,3-tetrachloropropene. Using 1,2,3-trichloropropane as the starting material, the method involves a two-step reaction of chlorination and liquid-phase dehydrochlorination to produce 1,1,2,3-tetrachloropropene. The deactivated catalyst is regenerated by immersion in an alcohol solvent. Compared to the traditional four-step synthesis of 1,1,2,3-tetrachloropropene from 1,2,3-trichloropropane, this method has a shorter process flow, produces less wastewater containing organic matter, and is more environmentally friendly. The Fe-ZSM-5 / Al-MCM-41 catalytic mixed pentachloropropane liquid-phase heterogeneous dehydrochlorination process has lower energy consumption compared to high-temperature gas-phase dehydrochlorination. After the dehydrochlorination reaction, the liquid-phase reaction products and the solid catalyst can be separated by filtration, solving the problem of difficult separation from homogeneous catalysts such as aluminum chloride and ferric chloride. However, the preparation of this dehydrochlorination catalyst requires alkali treatment, crystallization, and repeated calcination, making the preparation process complex and limiting the improvement in catalytic efficiency. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an efficient method for preparing 1,1,2,3-tetrachloropropene. Using 1,1,1,2,3-pentachloropropane as a raw material, 1,1,2,3-tetrachloropropene is prepared by a dehydrochlorination reaction in a reactor under the action of a catalyst. This method features high selectivity, simple process, low equipment requirements, and ease of industrialization.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0006] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0007] (1) Place γ-alumina powder in a solvent, then add an epoxy-containing silane coupling agent, heat to react, and then treat to obtain activated γ-alumina powder;

[0008] (2) Activated γ-alumina powder and polyamino POSS are dispersed in a solvent, stirred and reacted for a certain time, and then modified γ-alumina powder is obtained after post-treatment; the molar ratio of polyamino POSS to epoxy silane coupling agent is (0.2-0.5):1;

[0009] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying.

[0010] γ-alumina powder possesses a high specific surface area and abundant pore structure, making it easier for supported metal ions to disperse on its surface. Its tunable pore structure reduces diffusion resistance of supported metal ions and minimizes unnecessary pore blockage. Simultaneously, the adjustable surface acidity of γ-alumina powder plays a stabilizing role in the catalyst used in the dehydrochlorination process and significantly influences coking behavior during the catalytic reaction. Using γ-alumina powder as a support can greatly improve the adhesion efficiency of trivalent metal salts.

[0011] However, relying solely on the physical properties of γ-alumina powder limits its adhesion. In previous work (CN120058466A, CN120054641A), the inventors directly modified alumina with an aminosilane coupling agent, utilizing the complexation effect of amino groups to allow the active component to adhere to the alumina matrix. This catalyst can improve the dehydrochlorination ability of 1,1,1,3-tetrachloropropane. However, due to the strong hydrolysis and complexation effects of the aminosilane coupling agent, the adhesion efficiency of the alumina support micropores and other structures is reduced, affecting the loading of trivalent metals and the weakly acidic structure of the alumina surface, making it unsuitable as a dehydrochlorination catalyst for 1,1,1,2,3-pentachloropropane. POSS, on the other hand, is a molecule with a three-dimensional structure. The POSS structure has a polyhedral cage-like structure formed by inorganic Si-O-Si segments as its core, and the periphery of the POSS inorganic core has organic substituent groups directly connected to the vertex Si. Therefore, it combines the performance advantages of both organic substituents and inorganic silica. Alumina modified with amino-containing POSS is employed. The amino groups on the POSS complex with trivalent metal ions, and the small POSS molecule itself also serves as a transport orbital for the substrate. This allows the substrate to not only directly contact the catalyst but also permeate into the POSS molecule from various directions, enhancing catalytic activity, reducing costs, and minimizing environmental pollution from metal ions and organic solvents. Compared to divalent iron ions and divalent metal ions such as copper, zinc, magnesium, and palladium, trivalent metal ions are more stable; more importantly, they more readily undergo complexation reactions with amino groups, further improving catalyst stability.

[0012] However, amino-containing POSS cannot directly modify alumina powder, while epoxy-containing silane coupling agents not only improve the dispersion performance of alumina but also act as a mediator. Modification with epoxy-containing silane coupling agents has two main advantages: firstly, the silicon-oxygen bonds in the coupling agent can hydrolyze with the hydroxyl groups on the surface of γ-alumina powder, overcoming physical forces such as van der Waals forces and electrostatic attraction between γ-alumina particles and improving powder dispersion. Secondly, the epoxy groups in the epoxy-containing silane coupling agent can react with some of the amino groups on the polyamino POSS or form strong hydrogen bonds, allowing POSS to adhere to the alumina powder surface and improving catalyst stability. Since POSS has a hexahedral structure, some of its amino groups can react with the epoxy groups on the coupling agent, while others can act as complexes for metal ions. Furthermore, due to the excellent thermal stability of POSS, its reaction with epoxy-containing silane coupling agents improves the thermal stability of the catalyst, allowing for recycling.

[0013] Furthermore, in step (1), the specific surface area of ​​the γ-alumina powder is 200-300 m². 2 / g, with an average pore size of 5-12nm and a pore volume of 0.3-1cm³. 3 / g. An appropriate specific surface area can not only load more active components, but also uniformly load silane coupling agents, thereby improving the catalyst's dehydrochlorination performance.

[0014] Furthermore, in step (1), the solvent is a mixed solution of ethanol and deionized water.

[0015] Furthermore, in step (1), the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:(0.1-0.4). Specifically, the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.1, 1:0.2, 1:0.3, or 1:0.4. More specifically, the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:(0.2-0.3), and even more specifically, 1:0.25. An appropriate amount of epoxy-containing silane coupling agent can both fully modify the alumina powder and avoid excessive coupling agent causing pore blockage, which is detrimental to POSS modification.

[0016] Furthermore, the epoxy silane coupling agent in step (1) is one or more of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane (i.e., KH560), 3-glycidyl etheroxypropyltriethoxysilane, 3-glycidyl etheroxypropylmethyldimethoxysilane, and 3-glycidyl etheroxypropylmethyldiethoxysilane.

[0017] Furthermore, in step (1), the heating temperature is 50-70℃, and the reaction time is 1-2 hours; the post-treatment involves filtration, washing, and drying. Appropriate heating can increase the rate of hydrolysis reaction, allowing the epoxy-containing silane coupling agent to be better grafted onto the surface of alumina powder.

[0018] Furthermore, in step (2), the polyamino POSS is one or more of hexaaminopropyl POSS, hexaaminophenyl POSS, octaaminophenyl POSS, and octaaminopropyl POSS; further, it is octaaminophenyl POSS (also known as octaaminophenyl cage-type silsesquioxane), which is a POSS with eight active amino groups, and can fully complex trivalent metal ions.

[0019] Furthermore, the solvent in step (2) is one or more of tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide.

[0020] Furthermore, in step (2), the stirring reaction temperature is 45-65℃, and the reaction time is 5-8h; the post-treatment is filtration, washing, and drying. Specifically, the stirring reaction temperature is 50-60℃, and more specifically 52-58℃. If the reaction temperature is too low, the reaction will be incomplete; if the reaction temperature is too high, large volumes of POSS will easily clog the pore structure of the carrier.

[0021] Furthermore, in step (3), the trivalent metal salt is one or more of iron, aluminum, and chromium salts; the trivalent metal salt loading is 10-40 wt%. In particular, the trivalent metal salt is impregnated in the form of an aqueous solution.

[0022] Furthermore, the pentachloropropane dehydrochlorination catalyst also includes a catalyst promoter; the catalyst promoter is selected from iron powder, ferrous chloride, pyridine compounds, phenanthroline compounds, and hindered amine compounds. In particular, phenanthroline compounds or pyridine compounds may be selected. The amount of catalyst promoter is not particularly limited, and its mass can be 0.1-10 wt% of the mass of the trivalent metal salt.

[0023] The complexation mechanism of polyamino POSS is mainly based on the coordination interaction between trivalent metal ions and polyamino POSS molecules. Polyamino POSS contains multiple electron-donating groups—amino groups—which possess lone pairs of electrons capable of forming coordinate bonds with trivalent metal ions. The aqueous solution of trivalent metal ions is acidic. During the complexation process, the metal ion acts as the central ion, and the polyamino POSS acts as a ligand, surrounding the metal ion within the molecular structure of the complexing agent through the formation of coordinate bonds. Polyamino POSS has strong complexing ability and can form stable complexes with metal ions. Through complexation, metal ions are stably loaded onto the alumina support, improving catalyst stability.

[0024] On the other hand, the present invention also provides a process for preparing tetrachloropropene, comprising the following steps: adding the catalyst prepared by the above process and 1,1,1,2,3-pentachloropropane into a reaction vessel, heating to react, and absorbing the tail gas to obtain 1,1,2,3-tetrachloropropene.

[0025] Furthermore, the mass ratio of the catalyst to 1,1,1,2,3-pentachloropropane is (0.3-7):100. In particular, the catalyst is activated by heating under nitrogen conditions.

[0026] Furthermore, the preparation process further includes the dehydrochlorination of 1,1,1,3-tetrachloropropane to prepare 1,1,3-trichloropropene, and the chlorination of 1,1,3-trichloropropene with chlorine gas to prepare 1,1,1,2,3-pentachloropropane. Both the dehydrochlorination and chlorination processes described above can employ commonly used processes in the prior art. In particular, the dehydrochlorination process can be carried out in the presence of a catalyst, which includes any one or more of ferric chloride, aluminum chloride, zinc chloride, ferric chloride, rhodium chloride, and chromium trichloride.

[0027] Furthermore, the reaction is stirred to promote mixing. Specifically, the reaction temperature is 80℃-200℃, and the reaction time is 1-10 hours.

[0028] The amino-containing POSS-modified catalyst allows the active component to adhere to the solid alumina matrix, enabling the dehydrochlorination reaction to occur on the surface of the solid matrix. Based on high conversion and selectivity, it further improves the stability of the catalyst, avoids the occurrence of side reactions, and facilitates the separation and recycling of the catalyst.

[0029] Beneficial effects: Modifying alumina with amino-containing POSS utilizes the amino groups on POSS to complex trivalent metal ions. Furthermore, the small POSS molecule itself acts as a transport orbital for the substrate, allowing the substrate to not only directly contact the catalyst but also permeate through the cavities within the POSS molecule from various directions, thus improving catalytic activity, reducing costs, and minimizing environmental pollution from metal ions and organic solvents. The epoxy-containing silane coupling agent not only improves the dispersion performance of alumina but also acts as a mediator. In addition, due to the excellent thermal stability of POSS, its reaction with the epoxy-containing silane coupling agent enhances the thermal stability of the catalyst, enabling its recycling. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention are described in detail below with reference to examples. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Unless otherwise specified, the types of raw materials and processes used in the following embodiments are the same.

[0031] Example 1

[0032] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0033] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 50°C for 2 hours. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.15; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0034] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 52°C for 8 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.2:1.

[0035] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0036] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 84.6%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.1%.

[0037] Example 2

[0038] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0039] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 70°C for 1 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.35; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltriethoxysilane;

[0040] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 60°C for 5 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.5:1.

[0041] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0042] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 88.7%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.5%.

[0043] Example 3

[0044] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0045] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.1; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0046] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 56°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.35:1.

[0047] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0048] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 83.8%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.3%.

[0049] Example 4

[0050] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0051] (1) Place γ-alumina powder in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, then add an epoxy-containing silane coupling agent, react at 50°C for 1 h, filter, wash, and dry to obtain activated γ-alumina powder; the specific surface area of ​​the γ-alumina powder is 271 m². 2 / g, average pore size is 8.3nm, pore volume is 0.69cm³. 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.16; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0052] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 60°C for 8 hours. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.5:1.

[0053] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0054] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 85.5%, and the selectivity of 1,1,2,3-tetrachloropropene was 98.1%.

[0055] Example 5

[0056] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0057] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.4; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0058] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 56°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.35:1.

[0059] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0060] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 86.4%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.8%.

[0061] Example 6

[0062] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0063] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 55°C for 1.2 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.21; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0064] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 54°C for 7.5 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.25:1.

[0065] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was aluminum chloride, and the aluminum chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0066] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 130°C for 3 hours, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 84.1%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.7%.

[0067] Example 7

[0068] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0069] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.25; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0070] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 45°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.35:1.

[0071] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0072] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 85.1%, and the selectivity of 1,1,2,3-tetrachloropropene was 97.2%.

[0073] Example 8

[0074] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0075] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 65°C for 1.8 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 271 m². 2 / g, average pore size is 8.3nm, pore volume is 0.69cm³. 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.35; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltriethoxysilane;

[0076] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 58°C for 5.5 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.45:1.

[0077] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0078] The catalyst, catalytic converter bipyridine, and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 126°C for 3.6 h. The tail gas was then absorbed to obtain 1,1,2,3-tetrachloropropene. The mass of bipyridine was 8% of the mass of the trivalent metal salt, and the mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 88.3%, and the selectivity for 1,1,2,3-tetrachloropropene was 98.2%.

[0079] Example 9

[0080] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0081] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.25; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0082] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 62°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.35:1.

[0083] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0084] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 86.2%, and the selectivity of 1,1,2,3-tetrachloropropene was 96.8%.

[0085] Example 10

[0086] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0087] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 62°C for 1.7 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 271 m². 2 / g, average pore size is 8.3nm, pore volume is 0.69cm³. 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.27; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltriethoxysilane;

[0088] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 57°C for 6.2 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.42:1.

[0089] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0090] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 133°C for 3.5 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 87.5%, and the selectivity of 1,1,2,3-tetrachloropropene was 98.5%.

[0091] Example 11

[0092] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0093] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.25; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0094] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 56°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy silane coupling agent was 0.35:1.

[0095] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0096] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 88.2%, and the selectivity of 1,1,2,3-tetrachloropropene was 99.1%.

[0097] Comparative Example 1

[0098] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0099] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.25; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0100] (3) The activated γ-alumina powder loaded with trivalent metal salt was prepared by the equal volume impregnation method and dried to obtain the pentachloropropane dehydrochlorination catalyst; the trivalent metal salt was ferric chloride, which was impregnated by the ferric chloride aqueous solution impregnation method to make the trivalent metal salt loading 25wt%.

[0101] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 71.5%, and the selectivity of 1,1,2,3-tetrachloropropene was 89.6%.

[0102] Comparative Example 2

[0103] A pentachloropropane dehydrochlorination catalyst, the preparation method of which includes the following steps:

[0104] (1) γ-alumina powder was placed in a mixed solvent of ethanol and deionized water in a volume ratio of 1:1, and then an epoxy-containing silane coupling agent was added. The mixture was reacted at 60°C for 1.5 h. After filtration, washing, and drying, activated γ-alumina powder was obtained. The specific surface area of ​​the γ-alumina powder was 284 m². 2 / g, average pore size 7.1nm, pore volume 0.65cm³ 3 / g; the mass ratio of γ-alumina powder to epoxy-containing silane coupling agent is 1:0.25; the epoxy-containing silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane;

[0105] (2) Activated γ-alumina powder and polyamino POSS were dispersed in tetrahydrofuran solvent and stirred at 56°C for 7 h. After filtration, washing and drying, modified γ-alumina powder was obtained. The polyamino POSS was octaaminophenyl POSS. The molar ratio of polyamino POSS to epoxy-containing silane coupling agent was 1:1.

[0106] (3) Modified γ-alumina powder loaded with trivalent metal salt was prepared by equal volume impregnation method, and the pentachloropropane dehydrochlorination catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and the ferric chloride aqueous solution impregnation method was used to impregnate the powder so that the loading of trivalent metal salt was 25wt%.

[0107] The catalyst and 1,1,1,2,3-pentachloropropane were added to a reactor and reacted at 135°C for 3.2 h, followed by tail gas absorption to obtain 1,1,2,3-tetrachloropropene. The mass ratio of catalyst to 1,1,1,2,3-pentachloropropane was 6:100. Chromatographic analysis showed that the conversion rate of 1,1,1,2,3-pentachloropropane was 76.6%, and the selectivity of 1,1,2,3-tetrachloropropene was 92.2%.

[0108] As can be seen from the above examples and comparative examples, modifying alumina with amino-containing POSS utilizes the amino groups on the POSS to complex trivalent metal ions. Furthermore, the small POSS molecule itself can act as a transport orbital for the substrate, allowing the substrate to not only directly contact the catalyst but also permeate through the cavities within the POSS molecule from various directions, thus enhancing catalytic activity. The epoxy-containing silane coupling agent not only improves the dispersion performance of alumina but also acts as a mediator. In addition, due to the excellent thermal stability of POSS, its reaction with the epoxy-containing silane coupling agent improves the stability of the catalyst. Specifically, compared to Example 11, Comparative Example 1 did not use amino-containing POSS for modification; the support could not perform the complexation function, and the alumina could only rely on its porous structure to support the trivalent metal salt, resulting in lower catalytic activity. In Comparative Example 2, the amount of polyamino POSS was too large. Since the POSS structure itself has strong hydrophobicity, the excessive amount of POSS is not conducive to the uniform dispersion of active components and the improvement of catalytic activity, resulting in a decrease in the conversion rate of 1,1,1,2,3-pentachloropropane and the selectivity of 1,1,2,3-tetrachloropropene.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A pentachloropropane dehydrochlorination catalyst characterized by, The preparation method comprises the following steps: (1) placing γ-alumina powder in a solvent, then adding an epoxy-containing silane coupling agent, heating and reacting, and after post-treatment, obtaining activated γ-alumina powder; the mass ratio of the γ-alumina powder and the epoxy-containing silane coupling agent is 1:(0.1-0.4); the epoxy-containing silane coupling agent is one or more of 3-(2,3-epoxypropoxy)propyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-glycidyl ether propyl trimethoxysilane, 3-glycidyl ether propyl triethoxysilane, 3-glycidyl ether propyl methyl dimethoxysilane, and 3-glycidyl ether propyl methyl diethoxysilane; (2) dispersing the activated γ-alumina powder and polyamino POSS in a solvent, stirring and reacting for a certain time, and after post-treatment, obtaining modified γ-alumina powder; the molar ratio of the polyamino POSS and the epoxy-containing silane coupling agent is (0.2-0.5):1; the polyamino POSS is one or more of hexaaminopropyl POSS, hexaaminophenyl POSS, octaaminophenyl POSS, and octaaminopropyl POSS; the stirring and reaction temperature is 45-65 DEG C, and the reaction time is 5-8 h; the post-treatment is a filtration, washing, and drying process; (3) using an equal-volume impregnation method to prepare modified γ-alumina powder loaded with trivalent metal salt, and after drying, obtaining a pentachloropropane dehydrochlorination catalyst; the trivalent metal salt is one or more of iron salt, aluminum salt, and chromium salt; the trivalent metal salt loading amount is 10-40 wt%.

2. A pentachloropropane dehydrochlorination catalyst as claimed in claim 1, characterized in that, In step (1), the heating and reaction temperature is 50-70 DEG C, and the reaction time is 1-2 h; the post-treatment is a filtration, washing, and drying process.

3. A pentachloropropane dehydrochlorination catalyst as set forth in claim 1, characterized by, In step (2), the solvent is one or more of tetrahydrofuran, dimethyl sulfoxide, N-methyl pyrrolidone, N,N dimethylacetamide, and N,N dimethylformamide.

4. A pentachloropropane dehydrochlorination catalyst as set forth in claim 1, characterized by, The pentachloropropane dehydrochlorination catalyst further comprises a catalytic aid; the catalytic aid is selected from one of iron powder, ferrous chloride, ferric chloride, pyridine compounds, phenanthroline compounds, and hindered amine compounds.

5. A process for the preparation of tetrachloropropene, characterized in that, The preparation process further comprises dehydrochlorination of 1,1,1,3-tetrachloropropane to prepare 1,1,3-trichloropropene, and chlorination of 1,1,3-trichloropropene with chlorine gas to prepare 1,1,1,2,3-pentachloropropane.

6. A process for the preparation of tetrachloropropene as claimed in claim 5, wherein, ​