Solid bifunctional catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of synthesis of propylene carbonate, and discloses a solid bifunctional catalyst as well as a preparation method and application thereof. The catalyst comprises a titanium silicalite molecular sieve and an acidic metal oxide loaded on the titanium silicalite molecular sieve. In the presence of the solid bifunctional catalyst provided by the invention, propylene carbonate can be directly and continuously synthesized from propylene, an oxidant and carbon dioxide through a one-step reaction; the traditional two-step process is obviously simplified, the separation, purification, storage and transportation links of the epoxypropane are canceled, the process energy consumption is obviously reduced, and the economical efficiency of the whole process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of propylene carbonate synthesis, and in particular to a solid bifunctional catalyst and a preparation method and application thereof. Background Art

[0002] The direct synthesis of propylene carbonate from propylene and carbon dioxide belongs to the new generation of propylene carbonate synthesis technology. This technical route significantly simplifies the process, eliminates the separation, purification, storage and transportation of propylene oxide, significantly reduces process energy consumption, and improves the economic efficiency of the whole process. In addition, the whole process generates nearly zero waste, which solves the problems of poor selectivity and high separation cost of propylene oxide synthesis, high energy consumption of urea alcoholysis, poor intrinsic safety of epoxidation and cycloaddition reactions, and complex processes.

[0003] The direct synthesis of propylene carbonate from propylene and carbon dioxide includes two series reaction steps: propylene epoxidation to generate propylene oxide and carbon dioxide and propylene oxide cycloaddition to generate propylene carbonate. Therefore, if the direct synthesis of propylene carbonate from propylene and carbon dioxide is to be realized, a corresponding bifunctional catalyst is required, which has both epoxidation function and cycloaddition function. At present, the synthesis of propylene carbonate from propylene epoxidation usually uses hydrogen peroxide or organic peroxide (tert-butyl hydroperoxide, cumene hydroperoxide, peroxy acid, etc.) as an oxidant, and mainly uses titanium silicon molecular sieve as a catalyst, while the synthesis of propylene carbonate from carbon dioxide and propylene oxide cycloaddition is mainly based on homogeneous catalysts such as metal complexes, metal halides, non-metallic organic matter and ionic liquids. The existing catalytic system for directly synthesizing propylene carbonate from propylene and carbon dioxide is usually a physical mixture of two types of catalysts. Since the catalyst for synthesizing propylene carbonate from the cycloaddition of carbon dioxide and propylene oxide is often a homogeneous catalyst, it is difficult to recover the composite catalyst, and the cost of the homogeneous catalyst used is often high, which seriously limits the development of a new generation of propylene carbonate synthesis technology for directly synthesizing propylene carbonate from propylene and carbon dioxide.

[0004] For example, patent application CN 105348248 B discloses a method for directly preparing propylene carbonate from carbon dioxide and propylene, and the catalyst used is a homogeneous catalytic system of metal porphyrin and composite surfactant. Among them, the metal porphyrin catalyst is an expensive homogeneous catalyst, which has high cost and difficulty in subsequent separation, limiting the promotion of this technology. Patent application CN106966862 B discloses a method for preparing propylene glycol and propylene carbonate simultaneously, which is divided into two steps, first oxidizing propylene to propylene oxide under epoxidation conditions, and then contacting the obtained propylene oxide, water, and carbon dioxide with another catalyst to synthesize propylene carbonate. This method is divided into a two-step reaction, requiring two catalytic systems, and the process conditions are also different. Patent application CN 105367539 B discloses a method for synthesizing propylene carbonate. In this method, propylene carbonate is synthesized by contacting an azeotrope of propylene oxide and a solvent, carbon dioxide and a catalyst under cycloaddition reaction conditions. In its claims, propylene oxide is prepared by the following method: in the presence of methanol, propylene is contacted with hydrogen peroxide and titanium silicon molecular sieve for reaction, and the reaction product is separated to obtain propylene oxide. This method still belongs to a two-step synthesis method, and the two-step reactions of epoxidation and cycloaddition are carried out separately, using different catalysts respectively, and the process is complicated.

[0005] Heterogeneous catalysts are easier to separate than homogeneous catalysts, and they can be regenerated when their activity decreases, so they have attracted the attention of the industry. In order to promote the development of a new generation of propylene carbonate synthesis technology, the key technical challenges currently faced are to develop a bifunctional catalyst for the direct synthesis of propylene carbonate from propylene and carbon dioxide, to achieve the immobilization of carbon dioxide and propylene oxide cycloaddition catalysts on propylene epoxidation catalysts, and to achieve efficient coupling of the two functions. Summary of the invention

[0006] The purpose of the present invention is to provide a solid bifunctional catalyst for preparing propylene carbonate and a preparation method and application thereof. The solid bifunctional catalyst can make propylene, an oxidant and CO 2 Propylene carbonate is directly and continuously synthesized through a one-step reaction. The process is significantly simplified, the separation, purification, storage and transportation of propylene oxide are eliminated, and continuous production improves production efficiency; it significantly reduces process energy consumption and improves the economy of the entire process.

[0007] In order to solve the above technical problems, the first aspect of the present invention provides a solid bifunctional catalyst, which includes a titanium silicalite molecular sieve and an acidic metal oxide supported on the titanium silicalite molecular sieve.

[0008] Preferably, the titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

[0009] Preferably, the acidic metal oxide is selected from ZnO, CrO 3 and Mn2 O 7 One or more of the following.

[0010] Preferably, the solid bifunctional catalyst further comprises a halogen supported on the titanium silicalite molecular sieve.

[0011] A second aspect of the present invention provides a method for preparing a solid bifunctional catalyst, the method comprising the following steps:

[0012] (1) tetrapropylammonium hydroxide, tetrabutyl titanate, a halogen-containing compound, silica sol and water are mixed, then crystallized and filtered, and optionally calcined to obtain a titanium silicon molecular sieve;

[0013] (2) mixing the titanium silicon molecular sieve with a tetrapropylammonium hydroxide solution, and then filtering and washing to obtain a catalyst intermediate;

[0014] (3) The catalyst intermediate is mixed with an acidic metal precursor solution, followed by filtering and washing, and then calcining.

[0015] Preferably, in step (1), the weight ratio of tetrabutyl titanate, silica sol, tetrapropylammonium hydroxide and halogen-containing compound is 1:1-10:0.5-1:0.05-1, wherein the silica sol is calculated as silicon dioxide and the halogen-containing compound is calculated as halogen.

[0016] Preferably, in step (1), the halogen-containing compound is butylammonium bromide and / or propylammonium bromide.

[0017] Preferably, in step (1), the crystallization conditions include: a temperature of 150-200° C. and a time of 1-5 days;

[0018] Preferably, in step (1), the calcination conditions include: a temperature of 400-800° C. and a time of 1-10 h.

[0019] Preferably, in step (2), the weight ratio of titanium silicon molecular sieve to tetrapropylammonium hydroxide is 1:1-2.

[0020] Preferably, in step (2), the mixing conditions include: temperature of 60-100° C. and time of 1-24 h.

[0021] Preferably, the weight ratio of the catalyst intermediate to the acidic metal precursor is 1:2-10.

[0022] Preferably, in step (3), the calcination conditions include: temperature of 100-500° C. and time of 1-10 h.

[0023] The third aspect of the present invention provides a solid bifunctional catalyst prepared according to the method described above.

[0024] The fourth aspect of the present invention provides the application of the aforementioned solid bifunctional catalyst in the preparation of propylene carbonate.

[0025] The fifth aspect of the present invention provides a method for preparing propylene carbonate, which includes reacting propylene, an oxidant, and carbon dioxide in the presence of a solid catalyst;

[0026] wherein, the solid catalyst is the aforementioned solid bifunctional catalyst.

[0027] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0028] 1. In the presence of the solid bifunctional catalyst of the present invention, propylene, an oxidant, and carbon dioxide can be directly and continuously synthesized into propylene carbonate through a one-step reaction.

[0029] 2. The solid bifunctional catalyst of the present invention can realize the two-step reactions of propylene epoxidation to synthesize propylene oxide and the cycloaddition of carbon dioxide and propylene oxide to synthesize propylene carbonate under the same reaction conditions, avoiding the problem in the prior art that the two-step reactions are carried out separately and the reaction conditions need to be switched between the two steps.

[0030] 3. By using the solid bifunctional catalyst of the present invention to prepare propylene carbonate, the traditional two-step process can be significantly simplified, the separation, purification, storage, and transportation links of propylene oxide are eliminated, the process energy consumption is significantly reduced, and the economy of the whole process is improved.

[0031] 4. The solid bifunctional catalyst of the present invention is cheap and easy to obtain and is easy to separate and recycle, with a relatively low overall cost. Detailed Embodiments

[0032] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention and are not used to limit the present invention.

[0033] The endpoints and any values disclosed in this article are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the values between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0034] The first aspect of the present invention provides a solid bifunctional catalyst, which includes titanium silicalite molecular sieve and an acidic metal oxide supported on the titanium silicalite molecular sieve.

[0035] The solid bifunctional catalyst of the present invention has the dual catalytic functions of catalyzing the epoxidation of propylene to synthesize propylene oxide and catalyzing the cycloaddition of carbon dioxide and propylene oxide to synthesize propylene carbonate, and can realize the two-step reaction of epoxidation of propylene to synthesize propylene oxide and the cycloaddition of carbon dioxide and propylene oxide to synthesize propylene carbonate under the same reaction conditions to directly synthesize propylene carbonate; it avoids the situation that the prior art performs the two-step reaction separately, and the two-step reaction uses different catalysts and different reaction conditions. Based on this, the process of propylene carbonate can be significantly simplified, the separation and purification of propylene oxide and the storage and transportation links are eliminated, and the process energy consumption is significantly reduced.

[0036] In a preferred embodiment, the titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

[0037] In order to further improve the catalytic performance of the solid bifunctional catalyst and increase the yield of propylene carbonate, in a preferred embodiment, the acidic metal oxide is selected from ZnO, CrO 3 and Mn 2 O 7 One or more of the following.

[0038] In a preferred embodiment, the solid bifunctional catalyst also includes a halogen supported on the titanium silicalite. Through the further coordination of the titanium silicalite, the acidic metal oxide and the halogen, the catalytic performance of the catalyst can be further improved, and the yield of propylene carbonate can be further improved. In the present invention, the titanium silicalite can have a multi-level pore structure (such as micropores, mesopores), and the halogen can be supported on the pores of the titanium silicalite.

[0039] A second aspect of the present invention provides a method for preparing a solid bifunctional catalyst, the method comprising the following steps:

[0040] (1) tetrapropylammonium hydroxide, tetrabutyl titanate, a halogen-containing compound, silica sol and water are mixed, then crystallized and filtered, and optionally calcined to obtain a titanium silicon molecular sieve;

[0041] (2) mixing the titanium silicon molecular sieve with a tetrapropylammonium hydroxide solution, and then filtering and washing to obtain a catalyst intermediate;

[0042] (3) The catalyst intermediate is mixed with an acidic metal precursor solution, followed by filtering and washing, and then calcining.

[0043] In a preferred embodiment, the specific process of step (1) includes: mixing tetrapropylammonium hydroxide with water, then adding tetrabutyl titanate under stirring conditions, then adding a halogen-containing compound, and then adding silica sol to mix, transferring the mixed mixture to a crystallization kettle for crystallization, and then filtering, and optionally calcining to obtain a titanium silicon molecular sieve.

[0044] In a preferred embodiment, in step (1), the weight ratio of tetrabutyl titanate, silica sol, tetrapropylammonium hydroxide and halogen-containing compound is 1:1-10:0.5-1:0.05-1, wherein the silica sol is calculated as silicon dioxide and the halogen-containing compound is calculated as halogen.

[0045] In a specific embodiment, the weight ratio of tetrabutyl titanate to silica sol can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10; the weight ratio of tetrabutyl titanate to tetrapropylammonium hydroxide can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1; the weight ratio of tetrabutyl titanate to the halogen-containing compound can be 1:0.05, 1:0.08, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.28, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1.

[0046] In a specific embodiment, the concentration of silicon dioxide in the silica sol may be 20-40 wt %.

[0047] According to some specific embodiments of the present invention, in step (1), the halogen-containing compound may be butylammonium bromide and / or propylammonium bromide.

[0048] Preferably, in step (1), the crystallization conditions include: a temperature of 150-200°C and a time of 1-5 days; specifically, the crystallization temperature can be 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C or 200°C, and the crystallization time can be 1 day, 2 days, 3 days, 4 days or 5 days.

[0049] Further preferably, when calcination is carried out in step (1), the calcination conditions include: a temperature of 400-800°C and a time of 1-10h; specifically, the calcination temperature can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, and the calcination time can be 1h, h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h.

[0050] In the present invention, the tetrapropylammonium hydroxide can be provided by a tetrapropylammonium hydroxide aqueous solution having a concentration of 30 wt%.

[0051] In a preferred embodiment, in step (2), the weight ratio of titanium silicon molecular sieve to tetrapropylammonium hydroxide is 1:1-2; specifically, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0052] In a preferred embodiment, in step (2), the mixing conditions include: a temperature of 60-100° C. and a time of 1-24 h; specifically, the mixing temperature may be 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., 90° C. or 95° C., and the mixing time may be 1 h, 5 h, 10 h, 12 h, 14 h, 15 h, 16 h, 18 h, 20 h, 22 h or 24 h. The mixing may be performed by stirring.

[0053] In the method of the present invention, in step (2), the filter residue obtained by filtration is washed, and water can be used as the washing liquid until the washing filtrate is neutral.

[0054] In the present invention, the acidic metal precursor may be selected from soluble acidic metal salts, and more preferably, the acidic metal precursor is selected from one or more of zinc salts, manganese salts and chromium salts. The zinc salt may be zinc nitrate and / or zinc bromide, the manganese salt may be manganese nitrate and / or manganese bromide, and the chromium salt may be chromium nitrate and / or chromium bromide.

[0055] In the present invention, in order to promote the coordination of titanium silicon molecular sieve and acidic metal oxide and further promote the catalytic effect of the solid bifunctional catalyst, the amount of the catalyst intermediate and the acidic metal precursor can be reasonably controlled. In a preferred case, the weight ratio of the catalyst intermediate to the acidic metal precursor is 1:2-10; specifically, it can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0056] In the method of the present invention, in step (3), the mixing can be carried out by conventional stirring mixing in the art. In a specific embodiment, the mixing conditions include: a temperature of 60-100° C. and a time of 0.5-2 h.

[0057] In a preferred embodiment, in step (3), the calcination conditions include: a temperature of 100-500°C and a time of 1-10h; specifically, the calcination temperature can be 100°C, 150°C, 180°C, 200°C, 220°C, 240°C, 250°C, 260°C, 280°C, 300°C, 350°C, 400°C, 450°C or 500°C; and the calcination time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h.

[0058] In the method of the present invention, in step (3), the filter residue obtained by filtration is washed, and water can be used as the washing liquid until the washing filtrate is neutral.

[0059] In the present invention, the TS-1 titanium silicalite can be partially desiliconized by step (2), and then acidic metals such as Zn, Cr, and Mn are introduced into the TS-1 titanium silicalite by step (3) to form Lewis acidic active centers, which can promote the polarization ring opening of propylene oxide.

[0060] The third aspect of the present invention provides a solid bifunctional catalyst prepared according to the method described above. Compared with existing catalysts, the solid bifunctional catalyst can couple two functions of propylene epoxidation to synthesize propylene oxide and carbon dioxide and propylene oxide cycloaddition to synthesize propylene carbonate to a catalyst surface, and the catalyst is a solid heterogeneous catalyst and is easy to separate and recycle, and is a cheap and efficient solid bifunctional catalyst.

[0061] The fourth aspect of the present invention provides the use of the aforementioned solid bifunctional catalyst in the preparation of propylene carbonate.

[0062] A fifth aspect of the present invention provides a method for preparing propylene carbonate, the method comprising: reacting propylene, an oxidant and carbon dioxide in the presence of a solid catalyst;

[0063] Wherein, the solid catalyst is the solid bifunctional catalyst described above.

[0064] In a preferred embodiment, the oxidant is selected from one or two of cumene hydroperoxide, hydrogen peroxide and tert-butyl hydroperoxide.

[0065] In a preferred embodiment, the reaction conditions include: temperature of 40-120° C., time of 1-24 h, and pressure of 1-6 MPa.

[0066] In a preferred embodiment, the weight ratio of the solid catalyst to the oxidant (ie, the agent-to-material ratio) is 0.1%-15%.

[0067] In a preferred embodiment, the molar ratio of propylene to oxidant is 1:0.1-1.

[0068] In a preferred embodiment, the molar ratio of propylene to carbon dioxide is 1:1-10.

[0069] In the present invention, the injection of carbon dioxide can be carried out in a conventional manner in the art, and can be reasonably adjusted according to the pressure bearing capacity of the reactor and the molar ratio of propylene to carbon dioxide, for example, a one-time feeding method or a semi-continuous feeding method can be used.

[0070] In a specific embodiment, the reactor is a 316L stainless steel high-pressure reactor, and the reactor volume is 0.025L-1L.

[0071] According to some specific embodiments of the present invention, the method for preparing propylene carbonate comprises the following steps: adding the solid bifunctional catalyst and oxidant described above into a reactor, then introducing propylene into the reactor, and then introducing carbon dioxide into the reactor for reaction.

[0072] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0073] Example 1

[0074] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration is 30wt%), and stirring is continued for 24h; then, the solution is transferred to a crystallization kettle, crystallized at 170°C for 3 days, filtered, and calcined at 550°C for 5h to remove the template agent to obtain TS-1 titanium silicalite;

[0075] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0076] (3) Weigh 13.76 g of zinc nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc nitrate solution, stir at 80° C. for 1 h, then filter and wash until the washing filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-a.

[0077] Example 2

[0078] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0079] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0080] (3) Weigh 13.76 g of zinc nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc nitrate solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-b.

[0081] Example 3

[0082] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0083] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicon molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the filtrate is neutral to obtain a catalyst intermediate;

[0084] (3) Weigh 18.51 g of chromium nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the chromium nitrate solution, stir at 80° C. for 1 h, filter, and wash until the washing filtrate is neutral to obtain a catalyst precursor Cr / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst CrO 3 / TS-1-a.

[0085] Example 4

[0086] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template to obtain TS-1 titanium silicalite;

[0087] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0088] (3) Weigh 18.51 g of chromium nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the chromium nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Cr / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst CrO 3 / TS-1-b.

[0089] Example 5

[0090] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0091] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0092] (3) Weigh 11.61 g of manganese nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-a.

[0093] Example 6

[0094] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0095] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0096] (3) Weigh 11.61 g of manganese nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-b.

[0097] Example 7

[0098] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol ((SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0099] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0100] (3) Weigh 10.42 g of zinc bromide and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc bromide solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-c.

[0101] Example 8

[0102] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0103] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0104] (3) Weigh 10.42 g of zinc bromide and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc bromide solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-d.

[0105] Example 9

[0106] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0107] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral, to obtain a catalyst intermediate;

[0108] (3) Weigh 9.93 g of manganese bromide and dissolve it in 40 g of water, stir until the solution is clear and set aside; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese bromide solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-c.

[0109] Example 10

[0110] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170 ° C for 3 days, filtered, and calcined at 550 ° C for 5 h to remove the template agent to obtain TS-1 titanium silicon molecular sieve;

[0111] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0112] (3) Weigh 9.93 g of manganese bromide and dissolve it in 40 g of water, stir until the solution is clear and set aside; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese bromide solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-d.

[0113] Embodiment 11

[0114] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0115] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0116] (3) Weigh 13.76 g of zinc nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc nitrate solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-e.

[0117] Example 12

[0118] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0119] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0120] (3) Weigh 13.76 g of zinc nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc nitrate solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-f.

[0121] Example 13

[0122] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0123] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing the TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0124] (3) Weigh 18.51 g of chromium nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the chromium nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Cr / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst CrO 3 / TS-1-c.

[0125] Embodiment 14

[0126] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0127] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0128] (3) Weigh 18.51 g of chromium nitrate and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the chromium nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Cr / TS-1; then calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst CrO 3 / TS-1-d.

[0129] Embodiment 15

[0130] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0131] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0132] (3) Weigh 11.61 g of manganese nitrate and dissolve it in 40 g of water, stir until the solution is clear and set aside; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-e.

[0133] Example 16

[0134] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0135] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0136] (3) Weigh 11.61 g of manganese nitrate and dissolve it in 40 g of water, stir until the solution is clear and set aside; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese nitrate solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-f.

[0137] Embodiment 17

[0138] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0139] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral, to obtain a catalyst intermediate;

[0140] (3) Weigh 10.42 g of zinc bromide and dissolve it in 40 g of water, stir until the solution is clear for use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc bromide solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-g.

[0141] Embodiment 18

[0142] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0143] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicon molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0144] (3) Weigh 10.42 g of zinc bromide and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the zinc bromide solution, stir at 80° C. for 1 h, then filter and wash until the filtrate is neutral to obtain a catalyst precursor Zn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst ZnO / TS-1-h.

[0145] Embodiment 19

[0146] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2 g of tetrapropylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0147] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0148] (3) Weigh 9.93 g of manganese bromide and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese bromide solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2O 7 / TS-1-g.

[0149] Embodiment 20

[0150] (1) 5.06 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) was dissolved in 15.42 g of water. Under stirring, 2.12 g of tetrabutyl titanate was slowly added to the solution. After the addition, the solution was stirred for 6 h (the solution became transparent). 2.42 g of tetrabutylammonium bromide was added to the solution. Then, 30 g of silica sol (SiO 2 The concentration was 30 wt %), and stirring was continued for 24 h; then, the solution was transferred to a crystallization kettle, crystallized at 170° C. for 3 days, and then filtered to obtain TS-1 titanium silicalite;

[0151] (2) dissolving 15 g of tetrapropylammonium hydroxide aqueous solution (concentration: 30 wt%) in 53 g of water, introducing 3 g of TS-1 titanium silicalite molecular sieve obtained in step (1) into the solution, stirring at 80° C. for 16 h, filtering, and then washing until the washing filtrate is neutral to obtain a catalyst intermediate;

[0152] (3) Weigh 9.93 g of manganese bromide and dissolve it in 40 g of water, stir until the solution is clear for later use; weigh 2 g of the catalyst intermediate obtained in step (2) and put it into the manganese bromide solution, stir at 80° C. for 1 h, filter, and wash until the filtrate is neutral to obtain a catalyst precursor Mn / TS-1; then, calcine at 200° C. for 5 h to obtain a solid bifunctional catalyst Mn 2 O 7 / TS-1-h.

[0153] Test Case

[0154] The performance of the catalysts prepared in the examples and comparative examples was tested, and the testing method included the following steps:

[0155] 1. Add the sample to be tested (drug-to-material ratio of 5.8%) and the oxidant (isopropylbenzene hydroperoxide) into a 316L stainless steel reactor in sequence and seal it;

[0156] 2. Propylene was introduced into the reactor, and the molar ratio of propylene to cumene hydroperoxide was controlled to be 8:1;

[0157] 3. Introduce carbon dioxide into the reactor, and the pressure of the reactor is 2.5MPa;

[0158] 4. Raise the temperature to 110°C and react at 1000 rpm for 16 hours. Stop the reaction and detect the product composition by gas chromatography-mass spectrometry. Calculate the yield of propylene carbonate with cumene hydroperoxide.

[0159] The test results are shown in Table 1.

[0160] Table 1

[0161]

[0162]

[0163] It can be seen from Table 1 that the solid bifunctional catalyst of the present invention can realize the direct synthesis of propylene carbonate from propylene and carbon dioxide.

[0164] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A solid bifunctional catalyst, It is characterized in that The catalyst comprises titanium silicate molecular sieve and acidic metal oxide supported on the titanium silicate molecular sieve.

2. The solid bifunctional catalyst according to claim 1, It is characterized in that The titanium silicate molecular sieve is TS-1 titanium silicate molecular sieve.

3. The solid bifunctional catalyst according to claim 1 or 2, It is characterized in that The acidic metal oxide is selected from ZnO, CrO 3 and Mn 2 O 7 One or more of the following.

4. A solid bifunctional catalyst according to any one of claims 1 to 3, It is characterized in that The solid bifunctional catalyst also includes halogen supported on the titanium silicalite molecular sieve.

5. A method for preparing a solid bifunctional catalyst, It is characterized in that The method comprises the following steps: (1) tetrapropylammonium hydroxide, tetrabutyl titanate, a halogen-containing compound, silica sol and water are mixed, then crystallized and filtered, and optionally calcined to obtain a titanium silicon molecular sieve; (2) mixing the titanium silicon molecular sieve with a tetrapropylammonium hydroxide solution, and then filtering and washing to obtain a catalyst intermediate; (3) The catalyst intermediate is mixed with an acidic metal precursor solution, followed by filtering and washing, and then calcining.

6. The method according to claim 5, It is characterized in that In step (1), the weight ratio of tetrabutyl titanate, silica sol, tetrapropylammonium hydroxide and halogen-containing compound is 1:1-10:0.5-1:0.05-1, wherein the silica sol is calculated as silicon dioxide and the halogen-containing compound is calculated as halogen.

7. The method according to claim 5 or 6, It is characterized in that In step (1), the halogen-containing compound is butylammonium bromide and / or propylammonium bromide.

8. The method according to any one of claims 5 to 7, It is characterized in that In step (1), the crystallization conditions include: a temperature of 150-200° C. and a time of 1-5 days; Preferably, in step (1), the calcination conditions include: a temperature of 400-800° C. and a time of 1-10 h.

9. The method according to claim 5, It is characterized in that In step (2), the weight ratio of titanium silicalite to tetrapropylammonium hydroxide is 1:1-2.

10. The method according to any one of claims 5 to 9, It is characterized in that In step (2), the mixing conditions include: temperature of 60-100° C. and time of 1-24 h.

11. The method according to any one of claims 5 to 10, It is characterized in that In step (3), the weight ratio of the catalyst intermediate to the acidic metal precursor is 1:2-10.

12. The method according to claim 5, It is characterized in that In step (3), the calcination conditions include: temperature of 100-500° C. and time of 1-10 h.

13. A solid bifunctional catalyst prepared by the method according to any one of claims 5 to 12.

14. Use of the solid bifunctional catalyst according to any one of claims 1 to 4 and 13 in the preparation of propylene carbonate.

15. A method for preparing propylene carbonate, It is characterized in that The method comprises: reacting propylene, an oxidant and carbon dioxide in the presence of a solid catalyst; Wherein, the solid catalyst is the solid bifunctional catalyst described in any one of claims 1-4 and 13.

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