Rhenium-based catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of rhenium-based catalysts, in particular to a rhenium-based catalyst and a preparation method and application thereof.The catalyst comprises an active component and an auxiliary component which are loaded on a carrier; the active component comprises a rhenium-containing compound, and the auxiliary component comprises a zirconium-containing compound and / or a boron-containing compound; the carrier is aluminum oxide, and the auxiliary agent component is combined with an alkaline hydroxyl group on the surface of the carrier to reduce the content of the alkaline hydroxyl group, so that the active component is accurately loaded on an acidic hydroxyl group on the surface of the carrier to form an active site; lewis acid sites are additionally introduced into the auxiliary component, and the auxiliary component is also used for loading the active component and increasing the active sites; the additive component and the active component have a synergistic effect and are used for catalyzing a double decomposition reaction of unsaturated fatty acid ester and olefin, so that the technical effects that the conversion rate of the unsaturated fatty acid ester is 43-65%, and the selectivity of the product is 56-68% are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rhenium-based catalysts, in particular to a rhenium-based catalyst, a preparation method and application thereof. BACKGROUND

[0002] Olefin metathesis reaction, also known as olefin exchange reaction, refers to the process of cutting and recombining two carbon-carbon double bonds under the action of a metal catalyst. That is, the process of olefin [2+2] cycloaddition-reverse cycloaddition reaction under the action of a catalyst to generate a new olefin molecule. Olefin metathesis reaction can realize the growth of carbon chain of organic molecules and the construction of special cyclic molecules, and has important significance in polymer material chemistry and organic synthesis chemistry. The reaction can be used to adjust the molecular chain length of olefins, and to prepare terminal olefins from internal olefins, so as to obtain high-value products. For example, the metathesis reaction of methyl oleate and ethylene can produce 1-decene and 9-decene methyl ester, 1-decene is a key raw material for poly-alpha-olefin-based base oil, and 9-decene methyl ester is used in the fields of fragrances, polyesters, dyes, etc., all of which have the prospect of high-value industrial application.

[0003] The catalyst used for olefin metathesis reaction is usually a homogeneous ruthenium-based carbene catalyst. CN114634436A discloses a ruthenium-containing catalyst, a preparation method and use thereof, which improves the activity of the metathesis reaction of dimethyl maleate and methyl oleate through ligand modification effect, and the prepared ruthenium-containing catalyst has catalytic effect on the ethenolysis reaction of dimethyl maleate and methyl oleate, the ring-opening metathesis polymerization reaction of cyclooctene and the ring-closing reaction of diethyl 2,3-diallylmalonate. Although the homogeneous catalyst in the technical solution has high activity, the catalyst has high cost and is difficult to recover, which limits its large-scale application.

[0004] Therefore, there are also heterogeneous catalysts in the prior art, such as Re2O7 / Al2O3, MoO x / Al2O3, WO3 / Al2O3, among which Re2O7 / Al2O3 has attracted the attention of many researchers due to its relatively mild reaction conditions. Sibeijn et al. synthesized a phosphoric acid-modified Re2O7 / P-Al2O3, which improved the activity of the catalyst (IR studies of Re2O7metathesis catalysts supported on alumina and phosphated alumina J. Catal. Lett. 1991, 8, 201-208). Pillai et al. reported a ZnCl2-modified ReO xFunctionalized value-added products via metathesis of methyloleate over methyltrioxorhenium supported on ZnCl2-promoted mesoporous alumina Fuel. 2013, 110, 32-39). However, the loading of rhenium in the above catalysts is as high as 16wt%, and the price of rhenium is expensive, resulting in high preparation cost. Or as disclosed in CN1886192A, a method for preparing a heterogeneous catalyst containing active component rhenium and inert carrier medium, before the active component is loaded on the carrier, the inert carrier is first treated with a chlorinated silane compound, and the activation of the heterogeneous catalyst is carried out by heat treatment and then rapid final cooling. The technical solution reduces the loading of rhenium, but the pretreatment of the carrier is complex, such as precalcination of the carrier, then pretreatment of silane with a chlorinated compound, calcination in air, cooling in nitrogen, and finally impregnated twice with rhenium to obtain the corresponding catalyst.

[0005] Based on the above situation, there are technical problems to be solved in the prior art, such as high cost of homogeneous catalyst, difficulty in recovery, and complex preparation process of heterogeneous catalyst. SUMMARY

[0006] To solve the above technical problems, the present application provides a rhenium-based catalyst, which comprises an active component and an auxiliary component loaded on a carrier; the active component comprises a rhenium-containing compound, and the auxiliary component comprises a zirconium-containing compound and / or a boron-containing compound; The carrier is alumina, the auxiliary component is combined with the basic hydroxyl on the surface of the carrier to reduce the content of the basic hydroxyl, so that the active component is accurately loaded on the acidic hydroxyl on the surface of the carrier to form active sites; and the auxiliary component additionally introduces Lewis acid sites, which are also used to load the active component and increase the active sites; The content of the rhenium-containing compound in the active component accounts for 1-16% of the total catalyst mass content, and the content of the zirconium-containing compound and / or the boron-containing compound in the auxiliary component accounts for 0.05-7% of the total catalyst mass content.

[0007] Further, the carrier accounts for 77-98.95% of the total catalyst mass content.

[0008] Further, the specific surface area of the alumina is 100-300 m 2 / g, with an average pore size of 10-40nm.

[0009] Furthermore, the alumina is one or more of α-Al2O3, β-Al2O3, η-Al2O3, and γ-Al2O3.

[0010] Furthermore, the rhenium-containing compounds in the active component account for 1.5-5% of the total mass content of the catalyst.

[0011] Furthermore, the zirconium-containing compound in the additive component accounts for 0.05-1% of the total mass content of the catalyst.

[0012] Furthermore, the zirconium-containing compound in the additive component accounts for 0.1-1% of the total mass content of the catalyst.

[0013] Furthermore, the boron-containing compounds in the auxiliary component account for 0.05-6% of the total mass content of the catalyst.

[0014] Furthermore, the boron-containing compounds in the auxiliary component account for 1-4% of the total mass content of the catalyst.

[0015] Furthermore, the rhenium-containing compound is rhenium heptoxide (Re2O7).

[0016] Furthermore, the zirconium-containing compound is zirconium dioxide (ZrO2).

[0017] Furthermore, the boron-containing compound is boron trioxide (B2O3).

[0018] This invention provides a method for preparing the above-mentioned rhenium-based catalyst, wherein the preparation method involves sequentially loading zirconium, boron and rhenium onto a support to obtain the rhenium-based catalyst, wherein zirconium and boron are auxiliary agents.

[0019] Furthermore, the preparation method of the rhenium-based catalyst specifically includes the following steps: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use; Step 2: Immerse the carrier in the zirconium source solution, and after impregnation, perform post-processing to obtain a zirconium-loaded carrier; Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution. After immersion, perform post-processing to obtain the zirconium- and boron-loaded support. Step 4: Impregnate the zirconium and boron-supported powder from Step 3 into the rhenium source solution. After impregnation, post-processing is performed to obtain the rhenium-based catalyst.

[0020] Furthermore, the solvent used in the metal source solution in step 1 is water.

[0021] Furthermore, the water is deionized water or ultrapure water.

[0022] Furthermore, in step 1, the metal source solution is prepared by mixing and stirring the metal salt with the solvent.

[0023] Furthermore, the stirring temperature is 20-60℃, and the stirring time is 5-60 minutes.

[0024] Furthermore, the concentration of the metal compound in the metal source solution in step 1 is 0.0003-0.02 g / mL.

[0025] Furthermore, the concentration of zirconium-containing solute in the zirconium source solution in step 1 is 0.0003-0.003 g / mL.

[0026] Furthermore, the zirconium-containing solute in the zirconium source solution in step 1 is one or more of zirconium oxychloride, zirconium chloride, zirconium nitrate, and zirconium oxysulfate.

[0027] Furthermore, the concentration of boron-containing solute in the boron source solution in step 1 is 0.001-0.0075 g / mL.

[0028] Furthermore, the boron-containing solute in the boron source solution in step 1 is one or more of boric acid, ammonium borate, and boron trioxide.

[0029] Furthermore, the concentration of rhenium solute in the rhenium source solution in step 1 is 0.001-0.006 g / mL.

[0030] Furthermore, the rhenium-containing solute in the rhenium source solution in step 1 is one or more of ammonium perrhenate, rhenium heptoxide, sodium perrhenate, and potassium perrhenate.

[0031] Furthermore, the impregnation method in step 2, or step 3, or step 4 is independently one of the over-impregnation method and the equal-volume impregnation method.

[0032] Furthermore, the immersion temperature in step 2, or step 3, or step 4 is independently 20-50°C.

[0033] Furthermore, during the soaking process in step 2, or step 3, or step 4, stirring is required, and the stirring time is independently 1-12 hours.

[0034] Furthermore, the mass of the zirconium source solution in step 2 is 3-20 times the mass of the carrier.

[0035] Furthermore, the post-processing methods in step 2, or step 3, or step 4 include one or a combination of evaporation, drying, grinding, and calcination.

[0036] Furthermore, the evaporation is rotary evaporation, with a pressure of 3-4 kPa, a rotation speed of 10-80 rpm, a temperature of 20-80℃, and a time of 60-180 min; The purpose of the evaporation is to remove the solvent from the metal source solution, so that the auxiliary components and / or active components are evenly distributed on the surface of the carrier.

[0037] Furthermore, the drying temperature is 60-130℃, and the time is 6-15h.

[0038] Furthermore, the calcination is carried out in an air atmosphere, with a calcination temperature of 350-800℃ and a calcination time of 1-8 hours.

[0039] Furthermore, the calcination temperature is preferably 400-600℃, and the calcination time is preferably 3-6h.

[0040] The present invention also provides a product of a metathesis reaction, obtained by catalyzing an unsaturated fatty acid using the above-mentioned rhenium-based catalyst; In the metathesis reaction, the conversion rate of the unsaturated fatty acid ester is 43-65%, and the product selectivity is 56-68%. The products include olefin products and / or olefin esters.

[0041] Furthermore, the unsaturated fatty acid ester includes one or more of the following: methyl or ethyl esters of oleic acid, palmitoleic acid, linoleic acid, and linolenic acid.

[0042] Furthermore, the unsaturated fatty acid ester is methyl oleate.

[0043] Furthermore, in the metathesis reaction, the pressure of the olefin used as a raw material is 0.1-3 MPa.

[0044] Furthermore, the olefin is a monoolefin containing 2-20 carbon atoms.

[0045] Furthermore, the monoolefin is one or more of ethylene, propylene, butene, pentene, and hexene.

[0046] Furthermore, the monoolefin is preferably ethylene.

[0047] Furthermore, the metathesis reaction is carried out in an organic solution containing tin.

[0048] Furthermore, the solvent in the organic solution is one or more of cyclohexane, dichloromethane, diethyl ether, tetrahydrofuran, and benzene.

[0049] Furthermore, the concentration of the unsaturated fatty acid ester in the organic solution is 0.1-2 mol / L, and the mass ratio of the rhenium-based catalyst to the unsaturated fatty acid ester is 1:(20-60).

[0050] Furthermore, the metathesis reaction is carried out in an inert gas atmosphere.

[0051] Furthermore, the inert gas is one or more of nitrogen, argon, and helium.

[0052] Furthermore, the tin element is derived from tetramethyltin.

[0053] Furthermore, the concentration of the tetramethyltin in the organic solution is 0.2-0.7 μmol / mL.

[0054] Furthermore, the time for the metathesis reaction is 3-5 hours.

[0055] Furthermore, the olefin product is 1-decene.

[0056] Furthermore, the olefinic ester is methyl 9-decenoate.

[0057] The present invention also provides a polyα-olefin, which is prepared using the product of the above-described metathesis reaction.

[0058] The present invention also provides a fragrance, which is prepared using the product of the above-mentioned metathesis reaction.

[0059] The present invention also provides a polyester prepared using the product of the above-described metathesis reaction.

[0060] The present invention also provides a dye prepared using the product of the above-described metathesis reaction.

[0061] The beneficial effects of this invention are as follows: 1. This invention provides a rhenium-based catalyst, which comprises an active component and an auxiliary component supported on a support; the active component includes a rhenium-containing compound, and the auxiliary component includes a zirconium-containing compound and / or a boron-containing compound; the catalyst and its preparation method provided by this invention are the first to use Zr and B as auxiliary agents, which can synergistically act with the active component Re to catalyze the metathesis reaction of unsaturated fatty acid esters and olefins, achieving a conversion rate of 43-65% for the unsaturated fatty acid esters and a product selectivity of 56-68%; 2. This invention employs a stepwise impregnation followed by calcination method to sequentially load the auxiliary component and the active component onto a support, which is alumina. The auxiliary component binds to the basic hydroxyl groups on the surface of the support to reduce the content of the basic hydroxyl groups, thereby ensuring that the active component is accurately loaded onto the acidic hydroxyl groups on the surface of the support, forming active sites. Furthermore, the auxiliary component additionally introduces Lewis acid sites, which are also used to load the active component, increasing the number of active sites. In other words, the rhenium-based catalyst prepared by this invention effectively improves the activity of the active component Re and significantly reduces the loading of Re, thus giving the prepared rhenium-based catalyst the characteristics of low cost and high activity. 3. The rhenium-based catalyst provided by this invention also has the characteristics of being easy to recover, having an easy-to-control preparation method, and being able to achieve industrial production. Attached Figure Description

[0062] Figure 1 This is a high-angle dark-field scanning transmission electron microscope (HAADF-STEM) image of the rhenium-based catalyst in Example 1 of the present invention. Figure 2 The XRD pattern of the rhenium-based catalyst in Example 2 of this invention is shown. Figure 3 This is a comparison chart of the carbon dioxide temperature-programmed desorption (CO2-TPD) between the support in Test Example 1 of the present invention and the catalysts in Example 2 and Comparative Example 5. Detailed Implementation

[0063] Examples 1-4 illustrate the rhenium-based catalyst and its preparation method of the present invention. Examples 5-9 illustrate the preparation methods of unsaturated fatty acids catalyzed by the rhenium-based catalyst prepared in Examples 1-4. The products of the metathesis reaction were qualitatively and quantitatively analyzed using an Agilent 8860 gas chromatograph with a flame ionization (FID) detector. The analytical method employed was area normalization. The chromatographic column was an HP-5 (25 m × 0.32 mm). The specific method (mm×0.3μm) is as follows: the injection volume is 1μL, the split ratio is 10:1, the carrier gas (N2) flow rate is 1mL / min, the air flow rate is 400mL / min, the H2 flow rate is 40mL / min, the injection port temperature is 280℃, the detector temperature is 300℃, the temperature is programmed to rise to 50℃, then rise to 140℃ at a rate of 5℃ / min and hold at 140℃ for 2min, then rise to 200℃ at a rate of 15℃ / min and hold at 200℃ for 5min, and finally rise to 240℃ at a rate of 5℃ / min and hold at 240℃ for 10min. The total injection time is 48min.

[0064] Example 1 This embodiment provides a rhenium-based catalyst, and the preparation method of the rhenium-based catalyst specifically includes the following steps: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use. Specifically: Add 0.0030 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0178 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Add 0.0564 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.939 g of γ-Al₂O₃ support into the zirconium source solution, wherein the specific surface area of ​​the γ-Al₂O₃ support is 200 m². 2 / g, with an average pore size of 26nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 60 minutes at a pressure of 3.3 kPa and a speed of 80 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain the zirconium-loaded support. Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution and stir at 25°C for 3 h. After impregnation, rotary evaporate at 60°C for 60 min at a pressure of 3.3 kPa and a rotation speed of 80 rpm. After removal, continue drying in an oven at 100°C for 12 h and grind to obtain the zirconium and boron-loaded support. Step 4: Impregnate the zirconium and boron-loaded support powder from Step 3 into the rhenium source solution, stir at 25°C for 2 hours. After impregnation, rotary evaporate at 60°C for 60 minutes at a pressure of 3.3 kPa and a rotation speed of 80 rpm. After removal, continue drying in an oven at 110°C for 12 hours, grind, and finally calcine in air at 450°C for 3 hours to obtain the rhenium-based catalyst prepared in this embodiment. The catalyst contains an active component and an auxiliary component supported on an Al2O3 support; the active component is Re2O7, and the auxiliary components include ZrO2 and B2O3. The active component contains 5% Re2O7 by mass, the auxiliary component contains 0.1% ZrO2 by mass, the auxiliary component contains 1% B2O3 by mass, and the remainder is an Al2O3 support, expressed as 5 wt% Re2O7 - 0.1 wt% ZrO2 - 1 wt% B2O3 / Al2O3.

[0065] The rhenium-based catalyst prepared in this embodiment was subjected to high-angle dark-field scanning transmission electron microscopy (HAADF-STEM image), and its image is shown below. Figure 1As shown, after stepwise impregnation with zirconium and boron, the hydroxyl groups on the surface of the Al2O3 support are consumed by the additives, resulting in the uniform distribution of the post-loaded Re particles on the surface of the Al2O3 support, which greatly improves the dispersion of Re and thus effectively enhances the activity of Re.

[0066] Example 2 This embodiment provides a rhenium-based catalyst, and the preparation method of the rhenium-based catalyst specifically includes the following steps: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use. Specifically: Add 0.006 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0712 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Add 0.0564 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.8664 g of γ-Al₂O₃ support into the zirconium source solution, wherein the specific surface area of ​​the γ-Al₂O₃ support is 200 m². 2 / g, with an average pore size of 26 nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 120 minutes at a pressure of 3.3 kPa and a speed of 60 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain the zirconium-loaded support. Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution and stir at 25°C for 3 h. After impregnation, rotary evaporate at 60°C for 120 min at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, continue drying in an oven at 100°C for 12 h and grind to obtain the zirconium and boron-loaded support. Step 4: Impregnate the zirconium and boron-loaded support powder from Step 3 into the rhenium source solution, stir at 25°C for 2 hours. After impregnation, rotary evaporate at 60°C for 120 minutes at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, continue drying in an oven at 110°C for 12 hours, grind, and finally calcine in air at 450°C for 3 hours to obtain the rhenium-based catalyst prepared in this embodiment. The catalyst contains an active component and an auxiliary component supported on an Al2O3 support; the active component is Re2O7, and the auxiliary components include ZrO2 and B2O3. The active component contains 5% Re2O7 by mass, the auxiliary component contains 0.2% ZrO2 by mass, the auxiliary component contains 4% B2O3 by mass, and the remainder is an Al2O3 support, expressed as 5 wt% Re2O7 - 0.2 wt% ZrO2 - 4 wt% B2O3 / Al2O3.

[0067] The rhenium-based catalyst prepared in this embodiment was subjected to XRD testing, and the test results are as follows: Figure 2 As shown, apart from the diffraction peaks related to alumina, no peaks related to additives or Re were observed, indicating that the additives and active species have good dispersibility.

[0068] Example 3 This embodiment provides a rhenium-based catalyst, and the preparation method of the rhenium-based catalyst specifically includes the following steps: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use. Specifically: Add 0.012 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0534 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Add 0.0226 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.912g of β-Al₂O₃ support into the zirconium source solution, wherein the specific surface area of ​​the β-Al₂O₃ support is 130m². 2 / g, with an average pore size of 19nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 180 minutes at a pressure of 3.3 kPa and a speed of 50 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain the zirconium-loaded support. Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution and stir at 25°C for 3 h. After impregnation, rotary evaporate at 60°C for 180 min at a pressure of 3.3 kPa and a rotation speed of 50 rpm. After removal, continue drying in an oven at 100°C for 12 h and grind to obtain the zirconium and boron-loaded support. Step 4: Impregnate the zirconium and boron-loaded support powder from Step 3 into the rhenium source solution, stir at 25°C for 2 hours. After impregnation, rotary evaporate at 60°C for 180 minutes at a pressure of 3.3 kPa and a rotation speed of 50 rpm. After removal, continue drying in an oven at 110°C for 12 hours, grind, and finally calcine in air at 450°C for 3 hours to obtain the rhenium-based catalyst prepared in this embodiment. The catalyst contains an active component and an auxiliary component supported on an Al2O3 support; the active component is Re2O7, and the auxiliary components include ZrO2 and B2O3. The active component contains 2% Re2O7 by mass of the overall catalyst, the auxiliary component contains 0.4% ZrO2 by mass of the overall catalyst, the auxiliary component contains 3% B2O3 by mass of the overall catalyst, and the remainder is an Al2O3 support, expressed as 2 wt% Re2O7 - 0.4 wt% ZrO2 - 3 wt% B2O3 / Al2O3.

[0069] Example 4 This embodiment provides a rhenium-based catalyst, and the preparation method of the rhenium-based catalyst specifically includes the following steps: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use. Specifically: Add 0.03 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0356 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Add 0.0170 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.912g of η-Al2O3 support into the zirconium source solution, wherein the specific surface area of ​​the η-Al2O3 support is 230m². 2 / g, with an average pore size of 32nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 120 minutes at a pressure of 3.3 kPa and a speed of 60 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain a zirconium-loaded support. Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution and stir at 25°C for 3 h. After impregnation, rotary evaporate at 60°C for 120 min at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, continue drying in an oven at 100°C for 12 h and grind to obtain the zirconium and boron-loaded support. Step 4: Impregnate the zirconium and boron-loaded support powder from Step 3 into the rhenium source solution, stir at 25°C for 2 hours. After impregnation, rotary evaporate at 60°C for 120 minutes at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, continue drying in an oven at 110°C for 12 hours, grind, and finally calcine in air at 450°C for 3 hours to obtain the rhenium-based catalyst prepared in this embodiment. The catalyst contains an active component and an auxiliary component supported on an Al2O3 support; the active component is Re2O7, and the auxiliary components include ZrO2 and B2O3. The active component contains 1.5% Re2O7 by mass, the auxiliary component contains 1% ZrO2 by mass, the auxiliary component contains 2% B2O3 by mass, and the remainder is an Al2O3 support, expressed as 1.5 wt% Re2O7 - 1 wt% ZrO2 - 2 wt% B2O3 / Al2O3.

[0070] Example 5 In this embodiment, the rhenium-based catalyst (5 wt% Re2O7 - 0.1 wt% ZrO2 - 1 wt% B2O3 / Al2O3) prepared in Example 1 was used to carry out the metathesis reaction of methyl oleate and ethylene in a batch reactor under N2 atmosphere. The specific conditions were: 0.4 mol / L methyl oleate n-hexane solution (tetramethyltin concentration in the methyl oleate n-hexane solution was 0.4 μmol / mL), the mass ratio of the rhenium-based catalyst to methyl oleate was 1:30, the ethylene pressure was 3 MPa, and the reaction time was 4 h. The products were detected by gas chromatography, and the results are shown in Table 1.

[0071] Example 6 In this embodiment, the rhenium-based catalyst (5 wt% Re2O7-0.2 wt% ZrO2-4 wt% B2O3 / Al2O3) prepared in Example 2 was used to carry out the metathesis reaction of methyl oleate and ethylene in a batch reactor under N2 atmosphere. The specific conditions were: 0.2 mol / L methyl oleate toluene solution (tetramethyltin concentration in the methyl oleate toluene solution was 0.6 μmol / mL), the mass ratio of the rhenium-based catalyst to methyl oleate was 1:30, the ethylene pressure was 3 MPa, the reaction time was 4 h, and the product was detected by gas chromatography. The results are shown in Table 1.

[0072] Example 7 In this embodiment, the rhenium-based catalyst (2 wt% Re2O7 - 0.4 wt% ZrO2 - 3 wt% B2O3 / Al2O3) prepared in Example 3 was used to carry out the metathesis reaction of methyl oleate and ethylene in a batch reactor under N2 atmosphere. The specific conditions were: 0.2 mol / L methyl oleate tetrahydrofuran solution (tetramethyltin concentration in the methyl oleate tetrahydrofuran solution was 0.3 μmol / mL), the mass ratio of the rhenium-based catalyst to methyl oleate was 1:30, the ethylene pressure was 3 MPa, and the reaction time was 4 h. The products were detected by gas chromatography, and the results are shown in Table 1.

[0073] Example 8 In this embodiment, the rhenium-based catalyst (1.5 wt% Re2O7-1 wt% ZrO2-2 wt% B2O3 / Al2O3) prepared in Example 4 was used to carry out the metathesis reaction of methyl oleate and ethylene in a batch reactor under N2 atmosphere. The specific conditions were: 0.2 mol / L methyl oleate n-hexane solution (tetramethyltin concentration in the methyl oleate n-hexane solution was 0.4 μmol / mL), the mass ratio of the rhenium-based catalyst to methyl oleate was 1:30, the ethylene pressure was 3 MPa, and the reaction time was 4 h. The products were detected by gas chromatography, and the results are shown in Table 1.

[0074] Example 9 In this embodiment, the rhenium-based catalyst (1.5 wt% Re2O7-1 wt% ZrO2-2 wt% B2O3 / Al2O3) prepared in Example 4 was used to carry out the metathesis reaction of methyl oleate and ethylene in a batch reactor under N2 atmosphere. The specific conditions were: 0.2 mol / L methyl oleate toluene solution (tetramethyltin concentration in the methyl oleate toluene solution was 0.5 μmol / mL), the mass ratio of the rhenium-based catalyst to methyl oleate was 1:30, the ethylene pressure was 3 MPa, the reaction time was 4 h, and the product was detected by gas chromatography. The results are shown in Table 1.

[0075] Comparative Example 1 This comparative example provides a catalyst containing only rhenium, and the preparation method of the catalyst specifically includes the following steps: Step 1: Prepare the rhenium source solution for later use, specifically as follows: Add 0.0564 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.9346 g of γ-Al₂O₃ support into the rhenium source solution, wherein the specific surface area of ​​the γ-Al₂O₃ support is 200 m² / g. 2 / g, with an average pore size of 26nm; stirred at 25℃ for 2 h, after impregnation, rotary evaporated at 60℃ for 60 min, with a pressure of 3.3 kPa and a rotation speed of 80 rpm, then dried in an oven at 110℃ for 12 h, ground, and finally calcined in air at 450℃ for 3 h to obtain the rhenium-only catalyst prepared in this comparative example, which contains the active component Re2O7 supported on an Al2O3 support; The active component contains 5% Re2O7 by mass of the overall catalyst, with the remainder being an Al2O3 support, expressed as 5wt%Re2O7 / Al2O3.

[0076] Comparative Example 2 This comparative example provides a catalyst containing only rhenium, and the preparation method of the catalyst specifically includes the following steps: Step 1: Prepare the rhenium source solution for later use, specifically as follows: Add 0.1805 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.8195g of γ-Al2O3 support into the rhenium source solution, wherein the specific surface area of ​​the γ-Al2O3 support is 200m². 2 / g, with an average pore size of 26nm; stirred at 25℃ for 2h, after impregnation, rotary evaporated at 60℃ for 120min, with a pressure of 3.3kpa and a rotation speed of 60rpm, and then dried in an oven at 110℃ for 12h, ground, and finally calcined in air at 450℃ for 3h to obtain the rhenium-only catalyst prepared in this comparative example, which contains the active component Re2O7 supported on an Al2O3 support; The active component contains 16% Re2O7 by mass of the overall catalyst, with the remainder being an Al2O3 support, expressed as 16wt%Re2O7 / Al2O3.

[0077] Comparative Example 3 This comparative example provides a catalyst comprising only rhenium and zirconium. The preparation method of the catalyst specifically includes the following steps: Step 1: Prepare zirconium source solution and rhenium source solution for later use, specifically as follows: Add 0.006 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0564 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.9376 g of γ-Al₂O₃ support into the zirconium source solution, wherein the specific surface area of ​​the γ-Al₂O₃ support is 200 m².2 / g, with an average pore size of 26nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 60 minutes at a pressure of 3.3 kPa and a speed of 80 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain the zirconium-loaded support. Step 3: The zirconium-loaded support is immersed in the rhenium source solution and stirred at 25°C for 2 hours. After immersion, it is rotary evaporated at 60°C for 60 minutes at a pressure of 3.3 kPa and a rotation speed of 80 rpm. After removal, it is dried in an oven at 110°C for 12 hours, ground, and finally calcined in air at 450°C for 3 hours to obtain the catalyst prepared in this comparative example, which contains only rhenium and zirconium elements. The catalyst contains the active component Re2O7 and the auxiliary component ZrO2 supported on the Al2O3 support. The active component contains 5% Re2O7 by mass of the overall catalyst, the auxiliary component contains 0.2% ZrO2 by mass of the overall catalyst, and the remainder is an Al2O3 support, expressed as 5 wt% Re2O7 - 0.2 wt% ZrO2 / Al2O3.

[0078] Comparative Example 4 This comparative example provides a catalyst comprising only rhenium and boron elements. The preparation method of the catalyst specifically includes the following steps: Step 1: Prepare boron source solution and rhenium source solution for later use, specifically as follows: Add 0.0712 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Add 0.0564 g of ammonium perrhenate to 10 ml of deionized water and stir at room temperature for 1 h to obtain a rhenium source solution; Step 2: Impregnate 0.8664g of γ-Al2O3 support into the boron source solution, wherein the specific surface area of ​​the γ-Al2O3 support is 200m². 2 / g, with an average pore size of 26nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 120 minutes at a pressure of 3.3 kPa and a speed of 60 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain a boron-loaded carrier. Step 3: The zirconium-loaded support is immersed in the rhenium source solution and stirred at 25°C for 2 h. After immersion, it is rotary evaporated at 60°C for 120 min at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, it is dried in an oven at 110°C for 12 h, ground, and finally calcined in air at 450°C for 3 h to obtain the catalyst prepared in this comparative example containing only rhenium and boron elements. The catalyst contains the active component Re2O7 and the auxiliary component B2O3 supported on the Al2O3 support. The active component contains 5% Re2O7 by mass of the overall catalyst, the auxiliary component contains 4% B2O3 by mass of the overall catalyst, and the remainder is an Al2O3 support, expressed as 5 wt% Re2O7 - 4 wt% B2O3 / Al2O3.

[0079] Comparative Example 5 This embodiment provides a method for preparing a catalyst containing only zirconium and boron elements, specifically including the following steps: Step 1: Prepare zirconium source solution and boron source solution for later use, specifically as follows: Add 0.006 g of zirconium oxychloride to 10 ml of deionized water and stir at room temperature for 1 h to obtain a zirconium source solution; Add 0.0712 g of boric acid to 10 ml of deionized water and stir at room temperature for 1 h to obtain a boron source solution; Step 2: Impregnate 0.8664g of γ-Al₂O₃ support into the zirconium source solution, wherein the specific surface area of ​​the γ-Al₂O₃ support is 200m². 2 / g, with an average pore size of 26nm; Stirred at 25℃ for 2 hours. After impregnation, rotary evaporated at 50℃ for 120 minutes at a pressure of 3.3 kPa and a speed of 60 rpm. After removal, dried in an oven at 110℃ for 8 hours and ground to obtain the zirconium-loaded support. Step 3: Impregnate the zirconium-loaded support from Step 2 into the boron source solution and stir at 25°C for 3 h. After impregnation, rotary evaporate at 60°C for 120 min at a pressure of 3.3 kPa and a rotation speed of 60 rpm. After removal, continue drying in an oven at 100°C for 12 h, grind, and finally calcine in air at 450°C for 3 h to obtain the rhenium-based catalyst prepared in this embodiment. The catalyst contains only the auxiliary component supported on the Al2O3 support; the auxiliary component includes ZrO2 and B2O3. In the catalyst component, ZrO2 accounts for 0.2% of the total catalyst mass, B2O3 accounts for 4% of the total catalyst mass, and the remainder is Al2O3 support, expressed as 0.2wt%ZrO2-4wt%B2O3 / Al2O3.

[0080] Comparative Example 6 This comparative example uses the catalyst (5 wt% Re2O7 / Al2O3) prepared in Comparative Example 1. The metathesis reaction of methyl oleate and ethylene is carried out in a batch reactor under N2 atmosphere. The specific conditions are: 0.2 mol / L methyl oleate n-hexane solution (tetramethyltin concentration in the methyl oleate n-hexane solution is 0.6 μmol / mL), the mass ratio of catalyst to methyl oleate is 1:30, the ethylene pressure is 3 MPa, the reaction time is 4 h, and the product is detected by gas chromatography. The results are shown in Table 1.

[0081] Comparative Example 7 This comparative example uses the catalyst (16wt% Re2O7 / Al2O3) prepared in Comparative Example 2. The metathesis reaction of methyl oleate and ethylene is carried out in a batch reactor under N2 atmosphere. The specific conditions are: 0.2 mol / L methyl oleate n-hexane solution (tetramethyltin concentration in the methyl oleate n-hexane solution is 0.6 μmol / mL), the mass ratio of catalyst to methyl oleate is 1:30, the ethylene pressure is 3 MPa, the reaction time is 4 h, and the product is detected by gas chromatography. The results are shown in Table 1.

[0082] Comparative Example 8 This comparative example uses the catalyst (5 wt% Re2O7-0.2 wt% ZrO2 / Al2O3) prepared in Comparative Example 3. The metathesis reaction of methyl oleate and ethylene is carried out in a batch reactor under N2 atmosphere. The specific conditions are: 0.2 mol / L methyl oleate toluene solution (tetramethyltin concentration in the methyl oleate toluene solution is 0.6 μmol / mL), the mass ratio of catalyst to methyl oleate is 1:30, the ethylene pressure is 3 MPa, the reaction time is 4 h, and the product is detected by gas chromatography. The results are shown in Table 1.

[0083] Comparative Example 9 This comparative example uses the catalyst (5 wt% Re2O7-4 wt% B2O3 / Al2O3) prepared in Comparative Example 4. The metathesis reaction of methyl oleate and ethylene is carried out in a batch reactor under N2 atmosphere. The specific conditions are: 0.2 mol / L methyl oleate toluene solution (tetramethyltin concentration in the methyl oleate toluene solution is 0.6 μmol / mL), the mass ratio of catalyst to methyl oleate is 1:30, the ethylene pressure is 3 MPa, the reaction time is 4 h, and the product is detected by gas chromatography. The results are shown in Table 1.

[0084] Comparative Example 10 This comparative example uses the catalyst (0.2 wt% ZrO2-4 wt% B2O3 / Al2O3) prepared in Comparative Example 5. The metathesis reaction of methyl oleate and ethylene is carried out in a batch reactor under N2 atmosphere. The specific conditions are: 0.2 mol / L methyl oleate toluene solution (tetramethyltin concentration in the methyl oleate toluene solution is 0.6 μmol / mL), the mass ratio of catalyst to methyl oleate is 1:30, the ethylene pressure is 3 MPa, and the reaction time is 4 h. The products are detected by gas chromatography, and the results are shown in Table 1.

[0085] Table 1. Comparison of metathesis reaction results between Examples 5-9 and Comparative Examples 6-10

[0086] As can be seen from the comparison results in Table 1, the addition of zirconium-containing compounds and boron-containing compounds as auxiliary components promotes the activity of rhenium-containing compounds, enabling them to reach or even exceed the activity of catalysts with rhenium-containing compounds as high as 16 wt% when the rhenium-containing compound loading is as low as 1.5-5 wt%.

[0087] Individual zirconium-containing compound additives or boron-containing compound additives alone have limited effect on improving the activity of rhenium-containing compounds. Only through synergy can the activity of rhenium-containing compounds be significantly improved.

[0088] Therefore, the rhenium-based catalyst provided by this invention is suitable for the metathesis reaction of unsaturated fatty acid esters and ethylene, and can achieve high activity at low Re loading, which greatly reduces the catalyst preparation cost.

[0089] Test Example 1 This test example compares the carbon dioxide temperature-programmed desorption of the catalysts prepared in Example 2 and Comparative Example 5, as well as the supports used. Figure 3 It can be seen that after loading the additives zirconium and boron, the basic hydroxyl groups on the surface of alumina are consumed, which helps Re to anchor on the acidic hydroxyl groups to form active centers.

[0090] Therefore, the rhenium-based catalyst prepared by this invention effectively improves the activity of the active component Re and significantly reduces the loading of Re, thereby making the prepared rhenium-based catalyst have the characteristics of low cost and high activity.

[0091] It should be understood that the present invention is not limited to what has been described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A rhenium-based catalyst, characterized in that, The catalyst comprises an active component and an auxiliary component supported on a support; the active component includes a rhenium-containing compound, and the auxiliary component includes a zirconium-containing compound and / or a boron-containing compound; The rhenium-containing compound in the active component accounts for 1-16% of the total mass of the catalyst, and the zirconium-containing compound and / or boron-containing compound in the auxiliary component accounts for 0.05-7% of the total mass of the catalyst.

2. The rhenium-based catalyst according to claim 1, characterized in that, The rhenium-containing compound is rhenium heptaoxide; the zirconium-containing compound is zirconium dioxide; and the boron-containing compound is boron trioxide.

3. A method for preparing the rhenium-based catalyst according to any one of claims 1-2, characterized in that, The preparation method involves sequentially loading zirconium, boron, and rhenium onto a support to obtain the rhenium-based catalyst.

4. The method for preparing the rhenium-based catalyst according to claim 3, characterized in that, Specifically, the steps include the following: Step 1: Prepare three metal source solutions, including zirconium source solution, boron source solution, and rhenium source solution, for later use; Step 2: Immerse the carrier in the zirconium source solution, and after impregnation, perform post-processing to obtain a zirconium-loaded carrier; Step 3: Immerse the zirconium-loaded support from Step 2 into the boron source solution. After immersion, perform post-processing to obtain the zirconium- and boron-loaded support. Step 4: Impregnate the zirconium and boron-supported powder from Step 3 into the rhenium source solution. After impregnation, post-processing is performed to obtain the rhenium-based catalyst.

5. The method for preparing the rhenium-based catalyst according to claim 4, characterized in that, The zirconium-containing solute in the zirconium source solution mentioned in step 1 is one or more of zirconium oxychloride, zirconium chloride, zirconium nitrate, and zirconium oxysulfate; The boron-containing solute in the boron source solution mentioned in step 1 is one or more of boric acid, ammonium borate, and boron trioxide; The rhenium-containing solute in the rhenium source solution mentioned in step 1 is one or more of ammonium perrhenate, rhenium heptoxide, sodium perrhenate, and potassium perrhenate.

6. A product of a metathesis reaction, characterized in that, Unsaturated fatty acids are obtained by catalyzing the rhenium-based catalyst according to any one of claims 1-2; In the metathesis reaction, the conversion rate of the unsaturated fatty acid ester is 43-65%, and the product selectivity is 56-68%. The products include olefin products and / or olefin esters.

7. A polyα-olefin, characterized in that, The poly-α-olefin is prepared using the product of the metathesis reaction described in claim 6.

8. A fragrance and flavoring, characterized in that, The flavoring and fragrance are prepared using the product of the metathesis reaction described in claim 6.

9. A polyester, characterized in that, The polyester is prepared using the product of the metathesis reaction described in claim 6.

10. A dye, characterized in that, The dye is prepared using the product of the metathesis reaction described in claim 6.

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