High-efficiency catalyst for halogenated alkane production and preparation method thereof

Abstract

The invention provides a high-efficiency catalyst for haloalkane production and a preparation method thereof. The high-efficiency catalyst for halogenated alkane production comprises the following components: a supported solid acid catalyst and a rare earth element-containing compound. When the supported solid acid catalyst and the high-efficiency catalyst for halogenated alkane production prepared from the rare earth element-containing compound provided by the invention are used for preparing halogenated alkane, the high-efficiency catalyst for halogenated alkane production has high selectivity, and the prepared halogenated alkane has high yield; and even if the efficient catalyst for haloalkane production is used for preparing haloalkane after being stored at a low temperature for a long time, the efficient catalyst still has relatively high selectivity, the prepared haloalkane still has high yield, and the selectivity and the yield are not obviously reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of halogenated alkane production, and specifically relates to a high-efficiency catalyst for halogenated alkane production and a preparation method thereof. Background Art

[0002] Halogenated alkanes are a class of important chemical substances and are widely used in industrial and scientific research fields. Their basic chemical structure is formed by the hydrogen atoms in alkane molecules being replaced by halogen atoms such as chlorine atoms to varying degrees. According to the degree of substitution, halogenated alkanes can be divided into several main forms, such as methyl chloride, dichloromethane, trichloromethane, tetrachloromethane, perchloroethane, etc. These compounds play a key role in the chemical industry, serving not only as solvents, refrigerants, but also as organic synthesis reagents.

[0003] With the acceleration of the global industrialization process, the demand for halogenated alkanes is increasing day by day, which also puts higher requirements on their production processes. In this context, the research and development of high-efficiency catalysts is particularly important. In the current production process, the mainstream technology relies on traditional catalyst systems for halogen substitution reactions of alkanes such as methane or ethane. These catalysts usually include metal-based catalysts such as anhydrous aluminum chloride and Lewis acid catalysts such as calcium trifluoromethanesulfonate. Among them, metal-based catalysts such as anhydrous aluminum chloride show certain activity in industrial applications, but they still have many problems such as a decrease in storage activity at low temperatures (below 5°C), and the selectivity and yield still do not meet the requirements. Moreover, when storing the catalyst, in order to avoid a decrease in activity caused by low temperature, it is necessary to store it above 5°C, resulting in an increase in storage costs. In addition, Lewis acid catalysts such as calcium trifluoromethanesulfonate also have problems in that it is difficult to simultaneously achieve ideal selectivity and yield. Therefore, aiming at the problems of existing catalysts, how to ensure that the selectivity and yield of the catalyst can still be maintained even during storage at low temperatures and reduce storage costs is an urgent problem to be solved by the present invention. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-efficiency catalyst for halogenated alkane production and a preparation method thereof to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: On the one hand, the present invention provides a high-efficiency catalyst for halogenated alkane production, which comprises the following components: a supported solid acid catalyst and a rare earth element-containing complex.

[0006] In some embodiments of the present invention, the mass ratio of the supported solid acid catalyst to the rare earth element-containing 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 a numerical range between any two of them. 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 preparation raw materials of the supported acid catalyst include attapulgite clay, acidic reagent, and salt compound.

[0009] In some embodiments of the present invention, the acidic reagent includes, but is not limited to, hydrochloric acid, acetic acid, etc.

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

[0011] Immerse the attapulgite clay in the acidic reagent, stir well, then filter, wash with water until neutral, and then continue with drying, grinding, activation, and cooling to obtain the agent to be treated;

[0012] Dissolve the salt compound in an organic solvent, fully treat it, add the agent to be treated, heat under reflux, filter, wash with alcohol until no anions are detected, dry, grind, solidify, and cool to obtain the 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 the salt compound is 1:0.2 - 0.5.

[0016] In some embodiments of the present invention, the mass ratio of attapulgite clay to the 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 a numerical range between any two of them. Optionally, the mass ratio of attapulgite clay to the salt compound is 1:0.3 - 0.5.

[0017] In some embodiments of the present invention, the preparation raw materials of the rare earth element-containing complex include lanthanum nitrate hexahydrate and zinc nitrate hexahydrate.

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

[0019] In some embodiments of the present invention, the molar ratio of lanthanum nitrate hexahydrate to 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 the numerical range between any two of them. Optionally, the molar ratio of lanthanum nitrate hexahydrate to zinc nitrate hexahydrate is 1:0.9 - 1.1. In some embodiments of the present invention, the method for preparing the rare earth element-containing complex includes the following steps:

[0020] Fully dissolve lanthanum nitrate hexahydrate and zinc nitrate hexahydrate in distilled water, and then adjust the pH to be alkaline to obtain a pretreatment agent;

[0021] Perform a hydrothermal reaction on the pretreatment agent, cool, centrifuge, wash, and dry it, and then perform calcination. After sufficient calcination, a rare earth element-containing complex is obtained.

[0022] On the other hand, the present invention also provides a method for preparing a highly efficient catalyst for the production of halogenated alkanes, including the following steps: After fully mixing a supported solid acid catalyst and a rare earth element-containing complex, a highly efficient catalyst for the production of halogenated alkanes is obtained.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: When the highly efficient catalyst for the production of halogenated alkanes prepared from the supported solid acid catalyst and the rare earth element-containing complex provided in this application is used to prepare halogenated alkanes, the highly efficient catalyst for the production of halogenated alkanes has high selectivity, and the prepared halogenated alkanes have high yields. Moreover, even after long-term storage at low temperatures, when the highly efficient catalyst for the production of halogenated alkanes is used to prepare halogenated alkanes, it still has relatively high selectivity, and the prepared halogenated alkanes still have high yields, and the decline in selectivity and yield is not obvious. Detailed implementation manners

[0024] The following will illustrate the present invention in combination with specific implementation manners. It should be noted that the following examples are examples of the present invention, only for illustrating the present invention, and not for limiting the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the inventive concept of the present invention can be made.

[0025] In the following examples, except for the supported solid acid catalyst A and the rare earth element-containing complex A, the compound monomers and related reagents used can all be purchased from the market. Among them, attapulgite clay is purchased from Ruifeng Mineral Products Co., Ltd. in Lingshou County, and the particle size is 0.25 MM.

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

[0027] (1) 0.5 kg of attapulgite clay was immersed in 10 mol / L hydrochloric acid, magnetically stirred at room temperature for 16 h, filtered, washed with water until neutral, dried (drying temperature was 110 ° C), ground through a 120 mesh sieve, activated in a muffle furnace at 300 ° C for 2 h, and cooled at room temperature to prepare a treatment agent A;

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

[0029] The preparation method of rare earth element-containing composite A comprises 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 6 mol / L potassium hydroxide solution was added dropwise to adjust the pH to 9.5 to prepare a pretreatment agent;

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

[0032] The preparation method of high-efficiency catalyst AI for halogenated alkane production comprises the following steps:

[0033] The supported solid acid catalyst and the rare earth element-containing composite are fully mixed to obtain a high-efficiency catalyst for producing halogenated alkanes, wherein the stirring speed during mixing is 60 r / min and the mixing time is 2 min.

[0034] Example 1:

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

[0036] Example 2:

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

[0038] Embodiment 3:

[0039] A highly efficient catalyst for the production of halogenated alkanes, comprising the following components: supported solid acid catalyst A and rare earth element-containing complex A, and the mass ratio of supported solid acid catalyst A to rare earth element-containing complex A is 0.45:1.

[0040] Example 4:

[0041] A highly efficient catalyst for the production of halogenated alkanes, comprising the following components: supported solid acid catalyst A and rare earth element-containing complex A, and the mass ratio of supported solid acid catalyst A to rare earth element-containing complex A is 0.3:1.

[0042] Example 5:

[0043] A highly efficient catalyst for the production of halogenated alkanes, comprising the following components: supported solid acid catalyst A and rare earth element-containing complex A, and the mass ratio of supported solid acid catalyst A to rare earth element-containing complex A is 1:1.

[0044] Comparative Example 1:

[0045] A highly efficient catalyst for the production of halogenated alkanes, comprising the following components: supported solid acid catalyst A and anhydrous aluminum chloride, and the mass ratio of supported solid acid catalyst A to anhydrous aluminum chloride is 0.4:1.

[0046] Comparative Example 2:

[0047] A highly efficient catalyst for the production of halogenated alkanes, comprising the following components: calcium trifluoromethanesulfonate and rare earth element-containing complex A, and the mass ratio of calcium trifluoromethanesulfonate to rare earth element-containing complex A is 0.4:1.

[0048] A method for preparing perchloroethane, comprising the following steps:

[0049] Add 3 mol of hexachloro-1,3-butadiene and 0.02 mol of catalyst into the reaction kettle respectively. While stirring, heat up to 50 °C, then introduce chlorine gas and control the pressure in the reaction kettle at 0.5 Mpa. React until the pressure in the reaction kettle rises and even if the introduction of chlorine gas stops, the pressure in the reaction kettle still does not drop, then the reaction ends. Place the reacted substance into cold water, precipitate, filter out the filter cake, wash the filter cake with water, wash it with alkali, dry it, and sublime it to obtain perchloroethane.

[0050] The catalysts used for the preparation of perchloroethane A-I are specifically 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] When preparing perchloroethanes A to G, the catalyst used was the catalyst stored at 0 °C for 60 days. When preparing perchloroethanes H to I, the catalyst used was the catalyst stored at 25 °C for 60 days. Meanwhile, the conversion rate, selectivity, and yield of the prepared perchloroethanes A to I were calculated, and the calculation methods are as follows:

[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 = (yield of perchloroethane / conversion rate) × 100%;

[0056] Yield of perchloroethane = actual output of perchloroethane / theoretical output.

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

[0058] Table 2

[0059] Test item Selectivity 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] From the comparison of perchloroethanes A, F, and G, it can be seen that the high-efficiency catalyst for halogenated alkane production prepared from the supported solid acid catalyst and rare earth element-containing complex provided by this application has high selectivity when used to prepare halogenated alkanes such as perchloroethane after long-term storage at low temperature, and the prepared halogenated alkanes have high yield;

[0061] From the comparison of perchloroethanes A, D, and E, it can be seen that when the mass ratio of the supported solid acid catalyst and rare earth element-containing complex provided by this application is within a suitable range, the high-efficiency catalyst for halogenated alkane production prepared has higher selectivity when used to prepare halogenated alkanes such as perchloroethane even after long-term storage at low temperature, and the prepared halogenated alkanes have higher yield;

[0062] From the comparison of perchloroethanes A and H, and perchloroethanes B and I respectively, it can be seen that the high-efficiency catalyst for halogenated alkane production prepared from the supported solid acid catalyst and rare earth element-containing complex provided by this application has high selectivity when stored at room temperature, and the prepared halogenated alkanes have higher yield. Even after long-term storage at low temperature, the selectivity of the high-efficiency catalyst for halogenated alkane production and the yield of the prepared halogenated alkanes do not decrease significantly;

[0063] Comparing perchloroethane A to perchloroethane C respectively, when the high-efficiency catalyst for halogenated alkane production prepared from the supported solid acid catalyst and the rare earth element-containing complex provided by this application is used to prepare halogenated alkanes, the high-efficiency catalyst for halogenated alkane production has high selectivity, the prepared halogenated alkanes have high yields, and even when the high-efficiency catalyst for halogenated alkane production is used to prepare halogenated alkanes after long-term storage at low temperature, it still has relatively high selectivity, the prepared halogenated alkanes still have high yields, and the decline in selectivity and yield is not obvious.

[0064] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An efficient catalyst for the production of halogenated alkanes, characterized in that: It comprises the following components: a supported solid acid catalyst and a rare earth element-containing complex.

2. The high-efficiency catalyst for the production of halogenated alkanes according to claim 1, characterized in that: The mass ratio of the supported solid acid catalyst to the rare earth element-containing complex is 0.4 - 0.6:

1.

3. The high-efficiency catalyst for halogenated alkane production according to claim 1, wherein: The preparation raw materials of the supported acid catalyst include attapulgite clay, an acidic reagent, and a salt compound.

4. The high-efficiency catalyst for halogenated alkane production according to claim 3, characterized in that: The preparation method of the supported acid catalyst comprises the following steps: Immerse the attapulgite clay in the acidic reagent, stir thoroughly, then carry out suction filtration, wash with water until neutral, and then continue with drying, grinding, activation, and cooling to obtain a treatment agent to be processed; Dissolve the salt compound in an organic solvent, fully process it, add the treatment agent to be processed, heat under reflux, carry out suction filtration, wash with alcohol until no anions are detected, dry, grind, solidify, and cool to obtain the supported acid catalyst.

5. The high-efficiency catalyst for the production of halogenated alkanes according to claim 3 or 4, characterized in that: The salt compound is a metal chloride.

6. The high-efficiency catalyst for halogenated alkane production according to claim 3, wherein: The mass ratio of the attapulgite clay to the salt compound is 1:0.2 - 0.

5.

7. The high-efficiency catalyst for halogenated alkane production according to claim 1, characterized in that: The preparation raw materials of the rare earth element-containing complex include lanthanum nitrate hexahydrate and zinc nitrate hexahydrate.

8. The high-efficiency catalyst for halogenated alkane production according to claim 7, wherein: The molar ratio of the lanthanum nitrate hexahydrate to the zinc nitrate hexahydrate is 1:0.8 - 1.

2.

9. The high-efficiency catalyst for halogenated alkane production according to claim 1 or 7, characterized in that: The preparation method of the rare earth element-containing complex comprises the following steps: Fully dissolve the lanthanum nitrate hexahydrate and the zinc nitrate hexahydrate in distilled water, and then adjust the pH to be alkaline to obtain a pretreatment agent; Carry out a hydrothermal reaction on the pretreatment agent, cool, centrifuge, wash, and dry, and then carry out calcination. After sufficient calcination, obtain the rare earth element-containing complex.

10. The preparation method of the high-efficiency catalyst for halogenated alkane production according to any one of claims 1-9, characterized in that: It includes the following steps: Fully mix the supported solid acid catalyst and the rare earth element-containing complex to obtain a high-efficiency catalyst for the production of halogenated alkanes.