Highly efficient catalysts for the production of haloalkanes and their preparation methods

Abstract

This invention provides a highly efficient catalyst for the production of haloalkanes and a method for preparing the same. The highly efficient catalyst for haloalkane production comprises the following components: a supported solid acid catalyst and a rare earth element-containing complex. When the highly efficient catalyst for haloalkane production prepared from the supported solid acid catalyst and the rare earth element-containing complex provided in this application is used to prepare haloalkanes, it exhibits high selectivity and a high yield of the produced haloalkanes. Furthermore, even after long-term storage at low temperatures, the highly efficient catalyst still maintains relatively high selectivity and a high yield of the produced haloalkanes, with no significant decrease in selectivity or yield.

Description

Technical Field

[0001] This invention belongs to the technical field of haloalkanes production, specifically relating to highly efficient catalysts for haloalkanes production and their preparation methods. Background Technology

[0002] Halogenated alkanes are an important class of chemical substances widely used in industry and scientific research. Their basic chemical structure consists of hydrogen atoms in the alkane molecule being replaced to varying degrees by halogen atoms such as chlorine atoms. Depending on the degree of substitution, halogenated alkanes can be classified into several main forms, such as chloromethane, dichloromethane, trichloromethane, tetrachloromethane, and perchloroethane. These compounds play a crucial role in the chemical industry, serving not only as solvents and refrigerants but also in organic synthesis.

[0003] With the acceleration of global industrialization, the demand for haloalkanes is increasing, which also places higher demands on their production processes. Against this backdrop, the development of highly efficient catalysts is particularly important. Currently, mainstream technologies rely on traditional catalyst systems for the halogenation reactions of alkanes such as methane or ethane. These catalysts typically include metal-based catalysts such as anhydrous aluminum chloride and Lewis acid catalysts such as calcium trifluoromethanesulfonate. While metal-based catalysts such as anhydrous aluminum chloride exhibit certain activity in industrial applications, they still suffer from several problems, including decreased activity at low temperatures (below 5°C), and unsatisfactory selectivity and yield. Furthermore, to avoid activity reduction due to low temperatures, the catalysts must be stored above 5°C, increasing storage costs. In addition, Lewis acid catalysts such as calcium trifluoromethanesulfonate also face the challenge of simultaneously achieving ideal selectivity and yield. Therefore, addressing the problems of existing catalysts, and ensuring that selectivity and yield are maintained even at low temperatures while reducing storage costs, is a problem that this invention urgently aims to solve. Summary of the Invention

[0004] The purpose of this invention is to provide a highly efficient catalyst for the production of haloalkanes and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, the present invention provides a high-efficiency catalyst for the production of haloalkanes, comprising the following components: a supported solid acid catalyst and a rare earth element complex.

[0006] In some embodiments of the present invention, the mass ratio of the supported solid acid catalyst to the rare earth element complex is 0.4-0.6:1.

[0007] In some embodiments of the present invention, the mass ratio of the supported solid acid catalyst to the rare earth element-containing complex can be 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1 or any two of these values. Optionally, the mass ratio of the supported solid acid catalyst to the rare earth element-containing complex is 1:0.4-0.5.

[0008] In some embodiments of the present invention, the raw materials for preparing the supported acid catalyst include attapulgite clay, acidic reagents, and salt compounds.

[0009] In some embodiments of the present invention, the acidic reagents include, but are not limited to, hydrochloric acid, acetic acid, etc.

[0010] In some embodiments of the present invention, the method for preparing the supported acid catalyst includes the following steps:

[0011] The attapulgite clay was impregnated in an acidic reagent and stirred thoroughly. After filtration and washing with water until neutral, it was dried, ground, activated, and cooled to obtain the agent to be treated.

[0012] The salt compound was dissolved in an organic solvent, and after thorough treatment, the agent to be treated was added. The mixture was heated under reflux, filtered, washed with alcohol until no anions were detected, dried, ground, cured, and cooled to obtain a supported acid catalyst.

[0013] In some embodiments of the present invention, the salt compound is a metal chloride.

[0014] In some embodiments of the present invention, the metal chlorides include, but are not limited to, metal salts such as aluminum chloride and zinc chloride.

[0015] In some embodiments of the present invention, the mass ratio of attapulgite clay to salt compound is 1:0.2-0.5.

[0016] In some embodiments of the present invention, the mass ratio of attapulgite clay to salt compound is 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5 or any two of these values. Optionally, the mass ratio of attapulgite clay to salt compound is 1:0.3-0.5.

[0017] In some embodiments of the present invention, the raw materials for preparing rare earth element complexes include lanthanum nitrate hexahydrate and zinc nitrate hexahydrate.

[0018] In some embodiments of the present invention, the molar ratio of lanthanum nitrate hexahydrate and zinc nitrate hexahydrate is 1:0.8-1.2.

[0019] In some embodiments of the present invention, the molar ratio of lanthanum nitrate hexahydrate and zinc nitrate hexahydrate is 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2, or any range thereof. Optionally, the molar ratio of lanthanum nitrate hexahydrate and zinc nitrate hexahydrate is 1:0.9-1.1. In some embodiments of the present invention, the preparation method of the rare earth element-containing complex includes the following steps:

[0020] Lanthanum nitrate hexahydrate and zinc nitrate hexahydrate were fully dissolved in distilled water, and then the pH was adjusted to alkaline to prepare a pretreatment agent.

[0021] The pretreatment agent was subjected to a hydrothermal reaction, and after cooling, centrifugation, washing, and drying, it was calcined. After complete calcination, a rare earth element-containing composite was obtained.

[0022] On the other hand, the present invention also provides a method for preparing a high-efficiency catalyst for the production of haloalkanes, comprising the following steps: thoroughly mixing a supported solid acid catalyst and a rare earth element-containing complex to obtain a high-efficiency catalyst for the production of haloalkanes.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: When the high-efficiency catalyst for the production of haloalkanes prepared by the supported solid acid catalyst and rare earth element complex provided in this application is used to prepare haloalkanes, the high-efficiency catalyst for the production of haloalkanes has high selectivity and the prepared haloalkanes have high yield. Even after long-term storage at low temperature, the high-efficiency catalyst for the production of haloalkanes still has relatively high selectivity and the prepared haloalkanes still have high yield. The decrease in selectivity and yield is not significant. Detailed Implementation

[0024] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0025] In the following examples, except for the supported solid acid catalyst A and the rare earth element complex A, all other compound monomers and related reagents used can be purchased from the market. Among them, the attapulgite clay was purchased from Lingshou Ruifeng Mineral Products Co., Ltd., with a particle size of 0.25 mm.

[0026] The preparation method of supported acid catalyst A includes the following steps:

[0027] (1) 0.5 kg of attapulgite clay was impregnated in hydrochloric acid with a concentration of 10 mol / L. After magnetic stirring for 16 h at room temperature, it was filtered, washed with water until neutral, dried (drying temperature was 110℃), ground through a 120 mesh sieve, activated in a muffle furnace at 300℃ for 2 h, and then cooled at room temperature to obtain the agent to be treated, A.

[0028] 0.2 kg of aluminum chloride was dissolved in anhydrous ethanol and saturated at 80 °C. The agent A to be treated obtained in step (1) was added, heated under reflux, filtered, washed with alcohol until no chloride ions were detected, dried (drying temperature was 110 °C), ground through a 120-mesh sieve, cured in a muffle furnace at 300 °C for 3 h, and cooled to room temperature to obtain supported acid catalyst A.

[0029] The preparation method of rare earth element-containing complex A includes the following steps:

[0030] 10 mol of lanthanum nitrate hexahydrate and 10 mol of zinc nitrate hexahydrate were fully dissolved in 120 mL of distilled water, and then a 6 mol / L potassium hydroxide solution was added dropwise to adjust the pH to 9.5 to obtain the pretreatment agent.

[0031] The pretreatment agent was subjected to a hydrothermal reaction at 180℃ for 12 hours, cooled to room temperature, centrifuged, washed three times with distilled water, dried at 70℃ for 15 hours, and then calcined at 650℃ for 12 hours to obtain rare earth element-containing complex A.

[0032] A method for preparing a highly efficient catalyst AI for the production of haloalkanes includes the following steps:

[0033] A highly efficient catalyst for the production of haloalkanes was prepared by thoroughly mixing a supported solid acid catalyst and a rare earth element-containing complex. The stirring speed during mixing was 60 r / min and the mixing time was 2 min.

[0034] Example 1:

[0035] A high-efficiency catalyst for the production of haloalkanes comprises the following components: a supported solid acid catalyst A and a rare earth element-containing complex A, wherein the mass ratio of the supported solid acid catalyst A to the rare earth element-containing complex A is 0.4:1.

[0036] Example 2:

[0037] A high-efficiency catalyst for the production of haloalkanes comprises the following components: a supported solid acid catalyst A and a rare earth element-containing complex A, wherein the mass ratio of the supported solid acid catalyst A to the rare earth element-containing complex A is 0.5:1.

[0038] Example 3:

[0039] A high-efficiency catalyst for the production of haloalkanes comprises the following components: a supported solid acid catalyst A and a rare earth element-containing complex A, wherein the mass ratio of the supported solid acid catalyst A to the rare earth element-containing complex A is 0.45:1.

[0040] Example 4:

[0041] A high-efficiency catalyst for the production of haloalkanes comprises the following components: a supported solid acid catalyst A and a rare earth element-containing complex A, wherein the mass ratio of the supported solid acid catalyst A to the rare earth element-containing complex A is 0.3:1.

[0042] Example 5:

[0043] A high-efficiency catalyst for the production of haloalkanes comprises the following components: a supported solid acid catalyst A and a rare earth element-containing complex A, wherein the mass ratio of the supported solid acid catalyst A to the rare earth element-containing complex A is 1:1.

[0044] Comparative Example 1:

[0045] A high-efficiency catalyst for the production of haloalkanes comprises the following components: supported solid acid catalyst A and anhydrous aluminum chloride, wherein the mass ratio of supported solid acid catalyst A to anhydrous aluminum chloride is 0.4:1.

[0046] Comparative Example 2:

[0047] A high-efficiency catalyst for the production of haloalkanes comprises the following components: calcium trifluoromethanesulfonate and rare earth element-containing complex A, wherein the mass ratio of calcium trifluoromethanesulfonate to rare earth element-containing complex A is 0.4:1.

[0048] The method for preparing perchloroethane includes the following steps:

[0049] 3 mol of hexachloro-1,3-butadiene and 0.02 mol of catalyst were added to a reactor. The mixture was stirred and heated to 50°C. Chlorine gas was then introduced and the reactor pressure was controlled at 0.5 MPa. The reaction was stopped when the reactor pressure rose and did not decrease even after the chlorine gas was stopped. The reacted material was placed in cold water to precipitate and filter out the filter cake. The filter cake was washed with water, washed with alkali, dried, and sublimated to obtain perchloroethane.

[0050] The catalysts used in the preparation of AI from perchloroethane are shown in Table 1 below:

[0051] Table 1

[0052] perchloroethane catalyst Perchloroethane A Catalyst prepared in Example 1 Perchloroethane B Catalyst prepared in Example 2 perchloroethane C Catalyst prepared in Example 3 perchloroethane D Catalyst prepared in Example 4 perchloroethane E Catalyst prepared in Example 5 perchloroethane F Catalyst prepared in Comparative Example 1 perchloroethane G Catalyst prepared in Comparative Example 2 perchloroethane H Catalyst prepared in Example 1 perchloroethane I Catalyst prepared in Example 2

[0053] The catalysts used in the preparation of perchloroethane A to perchloroethane G were those stored at 0°C for 60 days. The catalysts used in the preparation of perchloroethane H to perchloroethane I were those stored at 25°C for 60 days. Simultaneously, the conversion rate, selectivity, and yield of the obtained perchloroethanes A to I were calculated using the following methods:

[0054] Conversion rate = (amount of hexachloro-1,3-butadiene added - amount of hexachloro-1,3-butadiene remaining) / amount of hexachloro-1,3-butadiene added × 100%;

[0055] Selectivity = (Total chloroethane yield / Conversion) × 100%;

[0056] Total chloroethane yield = Actual total chloroethane production / Theoretical production.

[0057] The results of the selectivity and yield calculations are shown in Table 2, as follows:

[0058] Table 2

[0059] Test Project Selective Yield Perchloroethane A 98.3％ 95.8％ Perchloroethane B 98.1％ 95.3％ perchloroethane C 98.0％ 93.7％ perchloroethane D 95.9％ 89.8％ perchloroethane E 96.8％ 91.8％ perchloroethane F 91.6％ 78.4％ perchloroethane G 93.2％ 84.7％ perchloroethane H 98.9％ 97.2％ perchloroethane I 98.6％ 96.8％

[0060] A comparison of perchloroethane A, perchloroethane F, and perchloroethane G shows that the high-efficiency catalyst for the production of haloalkanes prepared by the supported solid acid catalyst and rare earth element complex provided in this application exhibits high selectivity when used to prepare haloalkanes such as perchloroethane after long-term storage at low temperature, and the produced haloalkanes have a high yield.

[0061] A comparison of perchloroethane A, perchloroethane D, and perchloroethane E shows that when the mass ratio of the supported solid acid catalyst and the rare earth element complex provided in this application is within a suitable range, the high-efficiency catalyst for the production of haloalkanes obtained has higher selectivity and higher yield when used to prepare haloalkanes such as perchloroethane, even after long-term storage at low temperature.

[0062] A comparison of perchloroethane A and perchloroethane H, as well as perchloroethane B and perchloroethane I, shows that the high-efficiency catalyst for the production of haloalkanes prepared by the supported solid acid catalyst and rare earth element complex provided in this application has high selectivity when stored at room temperature, and the produced haloalkanes have a higher yield. Even when stored at low temperature for a long time, the selectivity of the high-efficiency catalyst for the production of haloalkanes and the yield of the produced haloalkanes do not decrease significantly.

[0063] A comparison of perchloroethane A to perchloroethane C shows that the high-efficiency catalyst for the production of haloalkanes prepared by the supported solid acid catalyst and rare earth element complex provided in this application exhibits high selectivity and high yield when used to prepare haloalkanes. Even after long-term storage at low temperatures, the high-efficiency catalyst for the production of haloalkanes still maintains relatively high selectivity and high yield when used to prepare haloalkanes, with no significant decrease in selectivity and yield.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-efficiency catalyst for the production of haloalkanes, characterized in that: It contains the following components: a supported solid acid catalyst and a rare earth element-containing complex; The raw materials for preparing the rare earth element-containing complex include lanthanum nitrate hexahydrate and zinc nitrate hexahydrate; The raw materials for preparing the supported solid acid catalyst include attapulgite clay, acidic reagents, and salt compounds. The mass ratio of the supported solid acid catalyst to the rare earth element-containing composite is 0.4-0.6:1; The salt compound is aluminum chloride; The preparation method of the rare earth element-containing complex includes the following steps: Lanthanum nitrate hexahydrate and zinc nitrate hexahydrate were fully dissolved in distilled water, and then the pH was adjusted to alkaline to prepare a pretreatment agent. The pretreatment agent was subjected to a hydrothermal reaction, and after cooling, centrifugation, washing, and drying, it was calcined. After complete calcination, a rare earth element-containing composite was obtained.

2. The high-efficiency catalyst for the production of haloalkanes according to claim 1, characterized in that: The preparation method of the supported solid acid catalyst includes the following steps: The attapulgite clay was impregnated in an acidic reagent and stirred thoroughly. After filtration and washing with water until neutral, it was dried, ground, activated, and cooled to obtain the agent to be treated. The salt compound was dissolved in an organic solvent, and after thorough treatment, the agent to be treated was added. The mixture was heated under reflux, filtered, washed with alcohol until no anions were detected, dried, ground, cured, and cooled to obtain a supported solid acid catalyst.

3. The high-efficiency catalyst for the production of haloalkanes according to claim 1, characterized in that: The mass ratio of the attapulgite clay to the salt compound is 1:0.2-0.

5.

4. The high-efficiency catalyst for the production of haloalkanes according to claim 1, characterized in that: The molar ratio of lanthanum nitrate hexahydrate and zinc nitrate hexahydrate is 1:0.8-1.

2.

5. The method for preparing the high-efficiency catalyst for the production of haloalkanes according to any one of claims 1-4, characterized in that: Includes the following steps: A highly efficient catalyst for the production of haloalkanes was prepared by thoroughly mixing a supported solid acid catalyst and a rare earth element complex.