Catalyst for synthesizing propylene oxide by HPPO method, preparation method and application thereof
阅读说明：本技术 一种hppo法合成环氧丙烷催化剂及其制备方法和应用 (Catalyst for synthesizing propylene oxide by HPPO method, preparation method and application thereof ) 是由 赵正恒 周余坤 吕焕芝 江洁静 陈国兴 邹建平 余成 蓝永韵 李城男 杨晓婕 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种HPPO法合成环氧丙烷催化剂及其制备方法和应用。该制备方法包括步骤：制备MWW分子筛前驱体、制备MWW分子筛、制备钛硅分子筛Ti-MWW即为HPPO法合成环氧丙烷的催化剂。本发明方法制备的催化剂用于HPPO法合成环氧丙烷中,可以提高丙烯的转化率以及环氧丙烷的选择性。(The invention discloses a propylene oxide catalyst synthesized by an HPPO method, a preparation method and application thereof. The preparation method comprises the following steps: preparing MWW molecular sieve precursors, preparing MWW molecular sieves, and preparing titanium silicalite molecular sieves Ti-MWW, namely the catalyst for synthesizing propylene oxide by the HPPO method. The catalyst prepared by the method is used for synthesizing propylene oxide by an HPPO method, and can improve the conversion rate of propylene and the selectivity of propylene oxide.)
1. A preparation method of a propylene oxide catalyst synthesized by an HPPO method comprises the following steps:
(1) preparing an MWW molecular sieve precursor: mixing a silicon source, a first template agent, a second template agent, water and an alkali source to form glue, and carrying out first hydrothermal crystallization to obtain an MWW molecular sieve precursor;
(2) preparing MWW molecular sieve: treating the MWW molecular sieve precursor obtained in the step (1) under carrier gas loaded with an alcohol solvent, and performing first roasting to obtain the MWW molecular sieve;
(3) preparing a titanium silicalite Ti-MWW: mixing the first titanium source solution and the MWW molecular sieve obtained in the step (2), performing second hydrothermal crystallization, and performing second roasting; and mixing the roasted product with a second titanium source solution, performing third hydrothermal crystallization, and performing third roasting to obtain the Ti-Si molecular sieve Ti-MWW.
2. The preparation method according to claim 1, wherein the alcohol solvent in step (2) is one or more of low-boiling alcohols, the boiling point is less than or equal to 79 ℃; preferably one or more of ethanol and methanol, more preferably ethanol;
and/or, in the step (2), the treatment temperature is 20-78 ℃, and the treatment time is 2-5 hours; the volume space velocity of the carrier gas is 500-1000 h-1；
And/or the carrier gas is any one or more of carbon monoxide, nitrogen, inert gas or carbon dioxide;
and/or in the step (2), the volume ratio of the alcohol solvent to the carrier gas is 0.05-2: 1, preferably 0.5 to 1: 1;
and/or the first roasting in the step (2) is carried out at the temperature of 400-600 ℃ for 1-10 h, preferably 2-4 h.
3. The preparation method according to claim 1, wherein the first template in step (1) is any one or more of piperidine, N-trimethyl-1-adamantyl ammonium hydroxide;
and/or, the second template agent in the step (1) is hexamethyleneimine;
and/or the molar ratio of the first template to the second template in the step (1) is (0.2-1.2): 1;
and/or, in the step (1), the alkali source is calculated by metal ions, and the silicon source is calculated by SiO2The total amount of the first template agent and the second template agent, and the amount of water H2The molar ratio of O is (0.01-1.0): 1: (0.2-1.2): (15-50), preferably (0.05-0.07): 1: (0.5-1.0): (20-40).
4. The preparation method according to claim 1, wherein the alkali source in the step (1) is any one or more of potassium carbonate, sodium carbonate and lithium carbonate;
and/or the silicon source in the step (1) is any one or more of silica sol, silicic acid and silica gel;
and/or the water in the step (1) is deionized water.
5. The method according to claim 1, wherein the first hydrothermal crystallization in the step (1) is performed under a crystallization reaction condition of 150 to 220 ℃ for 2 to 8 days.
6. The method according to claim 1, wherein the first titanium source solution is prepared by mixing a first titanium source with ethanol to prepare a first titanium source solution in step (3);
and/or the molar ratio of the first titanium source to the ethanol in terms of Ti is 0.5-5: 1;
and/or the first titanium source is TiCl4、TiBr4、TiI4、Ti(SO4)2Preferably TiCl, preferably TiCl4、Ti(SO4)2One or more of (a).
7. The preparation method according to claim 1, wherein the second titanium source solution in the step (3) is prepared by mixing a second titanium source, ammonium acetate and HF, and the pH of the mixed solution is 6 to 7;
and/or the molar ratio of the second titanium source to the ammonium acetate is 0.5-5: 1 in terms of Ti;
and/or the second titanium source is hexafluorotitanic acid H2TiF6。
8. The preparation method according to claim 1, wherein the solid-liquid mass ratio in the crystallized liquid of the second hydrothermal crystallization in the step (3) is 1: 10-40; the reaction temperature of the second hydrothermal crystallization is 30-150 ℃, and the reaction time is 2-10 h;
and/or the solid-liquid mass ratio of the crystallized liquid of the third hydrothermal crystallization in the step (3) is 1: 10-40; the reaction temperature of the third hydrothermal crystallization is 30-150 ℃, and the reaction time is 2-10 h.
9. A catalyst prepared by the preparation method of any one of claims 1 to 8, wherein the catalyst has a Ti: the Si molar ratio is (0.005-0.1): 1, preferably (0.04 to 0.1): 1; the specific surface area of the catalyst is 500-700 m2/g。
10. A catalyst prepared by the preparation method of any one of claims 1 to 8 or the application of the catalyst of claim 9 in propylene epoxidation reaction.
Technical Field
The invention relates to a preparation method of a propylene oxide catalyst synthesized by an HPPO method, a catalyst and application, belonging to the field of novel green environment-friendly materials.
Background
Propylene Oxide (PO), also known as propylene oxide, is an important propylene derivative, which is mainly used for producing Polyether Polyol (PPG), Propylene Glycol (PG), propylene glycol ether, isopropanolamine, propylene carbonate, etc., and the derivative is one of the main raw materials for producing Polyurethane (PU), nonionic surfactant, emulsifier, oil field demulsifier, flame retardant, plasticizer, lubricating oil, etc.
Currently, there are chlorohydrin processes (CP processes), co-oxidation processes, and direct oxidation processes for producing propylene oxide. The direct oxidation method is classified into a hydrogen peroxide direct oxidation method (HPPO method), an oxygen direct oxidation method, a photocatalytic oxidation method, and the like. Among the industrial production methods, the HPPO method has the characteristics of mild conditions, simple process, good selectivity of target products, friendly process environment, high atom utilization rate and the like, and becomes the most promising production technology for the fastest development at present. The HPPO process was first developed by Enichem, Italy in the early 80 th century by using a titanium silicalite TS-1 as catalyst for the reaction of propylene with H2O2In methanol solvent to form PO and water. The method has mild reaction conditions, high product selectivity and simple process flow, and belongs to environment-friendly green raw materialsThe production process. In the technology for producing propylene oxide, the key to research is how to simultaneously improve the conversion rate of reactant propylene and the utilization rate of hydrogen peroxide under the condition of improving the selectivity of propylene oxide. The presence of titanium silicalite catalysts allows for low concentrations of H2O2The selective oxidation of the organic compound under the oxidation condition is possible, the reaction process is greatly simplified, the reaction product is simpler, the environmental pollution is less, and the complicated oxidation process and the environmental pollution problem are avoided. However, in the research process, the performance of the catalyst has room for improvement, whether the stability of the catalyst can be further examined in industrialization and mass production needs to be met, the production cost needs to be optimized, and the service life and the regeneration performance of the catalyst need to be deeply researched.
The Ti-MWW molecular sieve has a special pore channel structure, shows excellent catalytic activity on large and small molecules, and also shows a solvent effect different from titanium-silicon molecular sieves such as TS-1, Ti-Beta and the like. The preparation method of the Ti-MWW molecular sieve generally adopts boric acid as a structural assistant to synthesize the Ti-MWW molecular sieve by a hydrothermal method, for example, CN110054198A discloses a method which takes a silicon source, boric acid, organic amine, a template agent, seed crystals and water as a mixture A, takes a titanium source and organic alcohol as a mixture B, mixes, evaporates and grinds the two mixtures to prepare dry powder, suspends the dry powder in the air and puts the dry powder into the template agent containing water and organic amine for static crystallization at constant temperature, and synthesizes the Ti-MWW molecular sieve by washing, drying, acid washing, roasting and the like on the solid. The molecular sieve is only used for preparing epoxy hexane by epoxidation of n-hexene, wherein the conversion rate of the n-hexene is low.
Therefore, the development of the titanium silicalite molecular sieve for HPPO production has very important significance in improving the selectivity of propylene oxide, the conversion rate of reactant propylene and the utilization rate of hydrogen peroxide.
Disclosure of Invention
The invention aims to provide a catalyst for synthesizing propylene oxide by using an HPPO method, a preparation method and application thereof, aiming at the problems of low conversion rate of propylene and low selectivity of propylene oxide in the production of HPPO in the prior art. The catalyst can improve the conversion rate of propylene and the selectivity of propylene oxide in the epoxidation reaction of propylene.
The first aspect of the invention provides a preparation method for synthesizing a propylene oxide catalyst by an HPPO method, which comprises the following steps:
(1) preparing an MWW molecular sieve precursor: mixing a silicon source, a first template agent, a second template agent, water and an alkali source to form glue, and carrying out first hydrothermal crystallization to obtain an MWW molecular sieve precursor;
(2) preparing MWW molecular sieve: treating the MWW molecular sieve precursor obtained in the step (1) under carrier gas loaded with an alcohol solvent, and performing first roasting to obtain the MWW molecular sieve;
(3) preparing a titanium silicalite Ti-MWW: mixing the first titanium source solution and the MWW molecular sieve obtained in the step (2), performing second hydrothermal crystallization, and performing second roasting; and mixing the roasted product with a second titanium source solution, performing third hydrothermal crystallization, and performing third roasting to obtain the Ti-Si molecular sieve Ti-MWW.
According to the invention, the titanium silicalite Ti-MWW is a catalyst for preparing propylene oxide by an HPPO method.
According to the invention, in the step (1), the alkali source is calculated by metal ions, and the silicon source is calculated by SiO2The total amount of the first template agent and the second template agent, and the amount of water H2The molar ratio of O is (0.01-1.0): 1: (0.2-1.2): (15-50), preferably (0.05-0.07): 1: (0.5-1.0): (20-40).
According to the invention, the first template agent in the step (1) is any one or more of piperidine, N, N, N-trimethyl-1-adamantyl ammonium hydroxide, abbreviated as TMAAdOH. The second template agent is hexamethyleneimine, abbreviated as HMI. The molar ratio of the first template to the second template is (0.2-1.2): 1.
according to the invention, the alkali source in the step (1) is any one or more of potassium carbonate, sodium carbonate and lithium carbonate.
According to the invention, the silicon source in the step (1) is any one or more of silica sol, silicic acid and silica gel.
According to the present invention, the water in step (1) is preferably deionized water.
According to the invention, the first hydrothermal crystallization in step (1) is carried out in a reaction vessel. The reaction condition of the first hydrothermal crystallization is crystallization for 2-8 days at 150-220 ℃.
According to the invention, after the first hydrothermal crystallization in the step (1), the product is subjected to first filtration and first drying. The temperature of the first drying is 100-180 ℃, and the time is 1-10 hours; preferably, the temperature is 140-160 ℃ and the time is 3-5 h.
According to the invention, the first roasting condition in the step (2) is roasting at the temperature of 400-600 ℃ for 1-10 h, preferably 2-4 h.
According to the invention, the carrier gas in the step (2) is any one or more of carbon monoxide, nitrogen, inert gas or carbon dioxide.
According to the invention, the alcohol solvent in the step (2) is one or more of low-boiling point alcohols; the boiling point is less than or equal to 79 ℃; preferably one or more of ethanol and methanol, more preferably ethanol.
According to the invention, the temperature of the treatment in the step (2) is 20-78 ℃, and the time is 2-5 h. The volume space velocity of the carrier gas is 500-1000 h-1。
According to the invention, the volume ratio of the alcohol solvent to the carrier gas in the step (2) is 0.05-2: 1, preferably 0.5 to 1: 1.
according to the invention, gas-solid-liquid separation is carried out after the treatment in the step (2); and distilling the liquid collected after separation to obtain the recovered template agent. The distillation is carried out at a temperature not exceeding 70 ℃, preferably 50-70 ℃.
According to the invention, the preparation process of the first titanium source solution in the step (3) is as follows: the first titanium source is mixed with ethanol to prepare a first titanium source solution. Wherein the molar ratio of the first titanium source to the ethanol in terms of Ti is 0.5-5: 1; the first titanium source is TiCl4、TiBr4、TiI4、Ti(SO4)2Preferably TiCl, preferably TiCl4、Ti(SO4)2One or more of (a).
According to the invention, the preparation process of the second titanium source solution in the step (3) is as follows: mixing the second titanium source and ammonium acetate, and adding HF until the pH value of the solution is 6-7. The second titanium source is calculated by Ti and the mol of ammonium acetateThe ratio is 0.5-5: 1. the second titanium source is hexafluorotitanic acid H2TiF6(ii) a An appropriate amount of water may be added to dissolve the ammonium acetate before mixing.
According to the present invention, the production of the first titanium source solution or the second titanium source solution in step (3) is preferably carried out in a polytetrafluoroethylene container. The first titanium source solution or the second titanium source solution is preferably prepared at 70 to 90 ℃.
According to the invention, the solid-liquid mass ratio in the crystallized liquid of the second hydrothermal crystallization in the step (3) is 1: 10 to 40. The reaction temperature of the second hydrothermal crystallization is 30-150 ℃, and the reaction time is 2-10 h.
According to the present invention, the second hydrothermal crystallization in step (3) is followed by a second filtration separation and a second drying. The second drying temperature is 110-200 ℃, and the time is 2-10 h.
According to the invention, the temperature of the second roasting in the step (3) is 400-600 ℃, and the time is 2-10 h.
According to the invention, the solid-liquid mass ratio of the crystallized liquid of the third hydrothermal crystallization in the step (3) is 1: 10 to 40. The reaction temperature of the third hydrothermal crystallization is 30-150 ℃, and the reaction time is 2-10 h.
According to the present invention, the third hydrothermal crystallization in step (3) is followed by a third filtration separation and a third drying. The third drying temperature is 110-200 ℃, and the time is 2-10 h.
According to the invention, the temperature of the third roasting in the step (3) is 400-600 ℃, and the time is 2-10 h.
A second aspect of the present invention provides a catalyst prepared by the above process. The Ti: the Si molar ratio is (0.005-0.1): 1, preferably (0.04 to 0.1): 1. the specific surface area of the catalyst is 500-700 m2/g。
The third aspect of the present invention provides the use of the catalyst prepared by the above-mentioned preparation method in the epoxidation reaction of propylene.
According to the invention, the method of application is: propylene, a Ti-MWW molecular sieve catalyst and acetonitrile are mixed according to the mass ratio of 1: (0.05-0.5): (10-15) adding the mixture into a reactor, then adding hydrogen peroxide according to the molar ratio of propylene to hydrogen peroxide of 1 (1-3), uniformly stirring, reacting for 1-6 h at the reaction pressure of 0-3 MPa and the temperature of 30-80 ℃, and separating according to a conventional method to obtain the propylene/hydrogen peroxide composite material.
Compared with the prior art, the invention has the following technical effects:
1. the preparation method for synthesizing the propylene oxide catalyst by the HPPO method comprises the steps of firstly synthesizing an MWW molecular sieve precursor, then removing a template agent by adopting a mode of pretreatment of an alcohol solvent and roasting, and finally introducing various titanium sources in multiple steps. Compared with the conventional method for treating the molecular sieve, the method can not only keep the framework structure of the molecular sieve undamaged, but also completely separate the template from the framework, and most of the removed template can be recycled. The alcohol solvent is added before roasting to remove the template agent, and a plurality of titanium sources are introduced in a multi-step manner, so that the prepared molecular sieve has high framework titanium content, high titanium dispersion and large specific surface area, and can greatly improve the conversion rate of propylene and the selectivity of propylene oxide when being used in the reaction of synthesizing propylene oxide by an HPPO method.
2. The catalyst prepared by the method has high framework titanium content, high titanium dispersion and large specific surface area, and further improves the conversion rate of propylene and the selectivity of propylene oxide in the synthesis of propylene oxide by the HPPO method.
3. The preparation method of the catalyst effectively overcomes the defects of low hydrogen peroxide conversion rate and low propylene oxide selectivity in HPPO production in the prior art, and can improve the propylene conversion rate to be more than 92.0 percent and the propylene oxide selectivity to be 98 percent in the propylene oxide synthesis by the HPPO method by adopting the catalyst, thereby achieving better technical effect.
Drawings
FIG. 1 is an XRD pattern of Ti-MWW molecular sieve catalyst product C obtained in example 3.
Detailed Description
The technical solutions of the present invention are further illustrated by the following examples and comparative examples, but the scope of the present invention is not limited by the examples.
In the present invention, the specific surface area of the catalyst is measured on a physical adsorption apparatus model ASAP 2020 manufactured by Micromerics, USA, and the sample is first vacuum pretreated at 623K for 10h, then cooled to 77K with liquid nitrogen, and then subjected to low temperature N2Adsorption/desorption, and the specific surface area was calculated by the BET method.
In the invention, XRD analysis is carried out on a D & A DVANCEX ray powder diffractometer manufactured by Bruke company, Cu-Ka is a radiation source, the wavelength lambda is 0.154nm, the working voltage U is 40kV, the working current I is 40mA, an emergent slit is 0.1mm, incident slits are 1mm, 2mm and 0.2mm respectively, the scanning range 2 theta is 2-35 degrees, and the scanning speed is 2 degrees/min.
In the invention, EDX is adopted to test the contents of Si and Ti in the catalyst, and the molar ratio of Ti to Si is calculated.
Example 1
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2The molar ratio of O is 0.05: 1: 0.14: 0.26: 30. then the MWW molecular sieve precursor is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so that the MWW molecular sieve precursor is obtained.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 40 ℃, and N is used2Introducing ethanol into the carrier gas, wherein the ethanol/N2The volume ratio is 0.5: 1, fully contacting ethanol with a molecular sieve precursor for 3 hours, wherein the volume space velocity of carrier gas is 600h-1(ii) a Then gas-solid-liquid separation is carried out to obtain the molecular sieve with most of the template agent removedAnd (4) driving the body. The collected liquid is distilled, the temperature is controlled to be 70 ℃, and the collected fraction can be recycled as the recovered template agent. And roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and stirring at 70 deg.C to obtain first titanium source solution containing titanium ions and C2H5The molar ratio of OH is 0.8: 1; ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring at 80 deg.C to completely mix, wherein H2TiF6And the mol ratio of ammonium acetate is 2: and 1, adding HF to the solution until the pH value of the solution is 6 to prepare a second titanium source solution. Putting the prepared first titanium source solution into a reactor, and mixing the first titanium source solution and the prepared first titanium source solution according to a solid-liquid mass ratio of 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and roasting for 2 hours at the temperature of 500 ℃ to obtain the Ti-MWW molecular sieve precursor. And putting the prepared second titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the Ti-MWW molecular sieve precursor while stirring, reacting at 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with 80 ℃ deionized water to be neutral, drying at 120 ℃ for 3 hours, and roasting at 500 ℃ for 2 hours to obtain the Ti-MWW molecular sieve catalyst product A. The XRD pattern is similar to that of example 3.
Catalyst product a, Ti: si molar ratio of 0.065: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 610m2/g。
Evaluation conditions were as follows: adding propylene, a titanium silicalite molecular sieve catalyst A, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite molecular sieve catalyst A to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2h under the conditions of 0.5MPa and 60 ℃, separating out the catalyst by a conventional filtration method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Example 2
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) as a first template agent and Hexamethyleneimine (HMI) as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2The molar ratio of O is 0.06: 1: 0.23: 0.47: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 40 ℃, and N is used2Introducing ethanol into the carrier gas, wherein the ethanol/N2Volume 0.5: 1, fully contacting ethanol with a molecular sieve precursor for 3 hours, wherein the volume space velocity of carrier gas is 700h-1(ii) a And then gas-solid-liquid separation is carried out to obtain the molecular sieve precursor with most of the template agent removed. The collected liquid is distilled, the temperature is controlled to be 63 ℃, and the collected fraction can be recycled as the recovered template agent. And roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and continuously stirring at 70 deg.C to completely mix to obtain a first titanium source solution; wherein titanium ion and C2H5The molar ratio of OH is 1: 1; ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6Of ammonium acetateThe molar ratio is 2: and 1, adding HF to the solution until the pH value of the solution is 6 to prepare a second titanium source solution. Putting the prepared first titanium source solution into a reactor, and mixing the first titanium source solution and the prepared first titanium source solution according to a solid-liquid mass ratio of 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and then roasting for 2 hours at 500 ℃ to obtain the Ti-MWW molecular sieve precursor. And putting the prepared second titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the Ti-MWW molecular sieve precursor while stirring, reacting at 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with 80 ℃ deionized water to be neutral, drying at 120 ℃ for 3 hours, and roasting at 500 ℃ for 2 hours to obtain a Ti-MWW molecular sieve catalyst product B. The XRD pattern is similar to that of example 3.
Catalyst product B, Ti: si molar ratio 0.08: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 614m2/g。
Evaluation conditions were as follows: adding propylene, a titanium silicalite molecular sieve catalyst B, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite molecular sieve catalyst B to the acetonitrile is 1:0.05:10, the molar ratio of propylene to hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2h at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Example 3
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxideThe second template agent is hexamethylene imine, and the water is H2Molar ratio of O0.07: 1: 0.41: 0.59: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 40 ℃, and N is used2Introducing ethanol into the carrier gas, wherein the ethanol/N2Volume 0.6: 1, fully contacting ethanol with a molecular sieve precursor for 4 hours, wherein the volume space velocity of carrier gas is 700h-1And then gas-solid-liquid separation is carried out to obtain the molecular sieve precursor with most of the template agent removed. The collected liquid is distilled, the temperature is controlled to be 65 ℃, and the collected fraction can be recycled as the recovered template agent. And roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and continuously stirring at 70 deg.C to completely mix to obtain a first titanium source solution; wherein titanium ion and C2H5The molar ratio of OH is 2: 1; ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6The molar ratio of ammonium acetate is 0.5: and 1, adding HF to the solution until the pH value of the solution is 6, and preparing a second titanium source solution. Putting the prepared first titanium source solution into a reactor, and mixing the first titanium source solution and the prepared first titanium source solution according to a solid-liquid mass ratio of 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and then roasting for 2 hours at 500 ℃ to obtain the Ti-MWW molecular sieve precursor. And putting the prepared second titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the Ti-MWW molecular sieve precursor while stirring, reacting at 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, and filling the solid with 80 ℃ deionized waterAnd washing to neutrality, drying at 120 deg.c for 3 hr, and roasting at 500 deg.c for 2 hr to obtain Ti-MWW molecular sieve catalyst product C. The XRD pattern is shown in figure 1.
Catalyst product C, Ti: si molar ratio 0.06: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 620m2/g。
Evaluation conditions were as follows: adding propylene, titanium silicalite molecular sieve catalyst C, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite molecular sieve catalyst C to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Example 4
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2The molar ratio of O is 0.07: 1: 0.17: 0.83: 40. then the solution is put into a reaction kettle to be crystallized for 5 days at 190 ℃, and is dried for 4 hours at 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 60 ℃, introducing methanol by taking carbon dioxide as a carrier gas, wherein the methanol/N2Volume 0.8: 1, fully contacting methanol with a molecular sieve precursor for 3 hours, wherein the volume space velocity of carrier gas is 800h-1And then gas-solid-liquid separation is carried out to obtain the molecular sieve precursor with most of the template agent removed. Harvesting machineThe collected liquid is distilled, the temperature is controlled at 60 ℃, and the fraction is collected to obtain the recycled template agent which can be reused. And roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and stirring at 70 deg.C to obtain first titanium source solution containing titanium ions and C2H5The molar ratio of OH is 2.4: 1; ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6The molar ratio of ammonium acetate is 0.8: and 1, adding HF to the solution until the pH value of the solution is 6, and preparing a second titanium source solution. Putting the prepared first titanium source solution into a reactor, and mixing the first titanium source solution and the prepared first titanium source solution according to a solid-liquid mass ratio of 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and then roasting for 2 hours at 500 ℃ to obtain the Ti-MWW molecular sieve precursor. And putting the prepared second titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the Ti-MWW molecular sieve precursor while stirring, reacting at 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with 80 ℃ deionized water to be neutral, drying at 120 ℃ for 3 hours, and roasting at 500 ℃ for 2 hours to obtain the Ti-MWW molecular sieve catalyst product D. The XRD pattern is similar to that of example 3.
Catalyst product D, Ti: si molar ratio 0.08: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 616m2/g。
Evaluation conditions were as follows: adding propylene, a titanium silicalite molecular sieve catalyst D, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite molecular sieve catalyst D to the acetonitrile is 1:0.05:10, and the mass ratio of the propylene to the acetonitrile is 1:0.05: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2h under the conditions of 0.5MPa and 60 ℃, separating out the catalyst by a conventional filtration method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Example 5
A catalyst was prepared as in example 2, except that the templating agent was the templating agent recovery solution of example 2. The amount of the template recovery solution is the same as the total amount of the first template and the second template in example 2. Obtaining Ti-MWW molecular sieve catalyst product E. The XRD pattern is similar to that of example 3.
Catalyst product E, Ti: the Si molar ratio is 0.079: 1. the specific surface area 611m of the Ti-MWW molecular sieve catalyst is measured2/g。
Evaluation conditions were as follows: adding propylene, a titanium silicalite molecular sieve catalyst E, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite molecular sieve catalyst E to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2h at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Comparative example 1
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2Molar ratio of O0.07: 1: 0.41: 0.59: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
And (2) roasting the molecular sieve precursor in the step (1) at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and continuously stirring at 70 deg.C to completely mix to obtain a first titanium source solution; wherein titanium ion and C2H5The molar ratio of OH is 2: 1; ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6The molar ratio of ammonium acetate is 0.5: and 1, adding HF to the solution until the pH value of the solution is 6 to prepare a second titanium source solution. Putting the prepared first titanium source solution into a reactor, and mixing the first titanium source solution and the prepared first titanium source solution according to a solid-liquid mass ratio of 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and then roasting for 2 hours at 500 ℃ to obtain the Ti-MWW molecular sieve precursor. And putting the prepared second titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the Ti-MWW molecular sieve precursor while stirring, reacting at 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with 80 ℃ deionized water to be neutral, drying at 120 ℃ for 3 hours, and roasting at 500 ℃ for 2 hours to obtain the Ti-MWW molecular sieve catalyst product A1.
Catalyst product a1, Ti: the Si molar ratio is 0.057: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 5972(ii) in terms of/g. The EDX analysis shows that Si/Ti is larger than the charge ratio.
Evaluation conditions were as follows: adding propylene, titanium silicalite molecular sieve catalyst A1, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite catalyst A1 to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Comparative example 2
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2Molar ratio of O0.07: 1: 0.41: 0.59: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 40 ℃, and N is used2Introducing ethanol into the carrier gas, wherein the ethanol/N2Volume 0.6: 1, fully contacting ethanol with a molecular sieve precursor for 4 hours, wherein the volume space velocity of carrier gas is 700h-1And then gas-solid-liquid separation is carried out to obtain the molecular sieve precursor with most of the template agent removed. And roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6The mol ratio of ammonium acetate is 2.5: 1, adding HF until the pH value of the solution is 6 to prepare a titanium source solution. Placing the prepared titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting at the temperature of 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying at the temperature of 120 ℃ for 4 hours, and then roasting at 500 ℃ for 2 hours to obtain a Ti-MWW molecular sieve catalyst product B1.
Catalyst product B1In (1), Ti: si molar ratio of 0.054: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 590m2/g。
Evaluation conditions were as follows: adding propylene, titanium silicalite molecular sieve catalyst B1, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite catalyst B1 to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Comparative example 3
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2Molar ratio of O0.07: 1: 0.41: 0.59: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
And (2) roasting the molecular sieve precursor in the step (1) at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve completely removed with the template agent.
(3) Preparation of titanium silicalite Ti-MWW
Ammonium acetate is added with a proper amount of deionized water to be completely dissolved, and then added into H2TiF6Stirring the solution at 80 deg.C to mix completely, wherein H2TiF6The mol ratio of ammonium acetate is 2.5: 1, adding HF to the solution until the pH value of the solution is 6 to prepare a titanium source solution. Placing the prepared titanium source solution into a reactor according to the solid-liquid mass ratioIs 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting at the temperature of 60 ℃ for 2 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying at the temperature of 120 ℃ for 4 hours, and then roasting at 500 ℃ for 2 hours to obtain the Ti-MWW molecular sieve catalyst product C1.
Catalyst product C1, Ti: the Si molar ratio is 0.051: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is determined to be 572m2/g。
Evaluation conditions were as follows: adding propylene, titanium silicalite molecular sieve catalyst C1, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite catalyst C1 to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Comparative example 4
(1) Preparing an MWW molecular sieve precursor:
preparing a mixed solution A from N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMAADOH) serving as a first template agent and Hexamethyleneimine (HMI) serving as a second template agent according to a metering ratio; preparing a mixed solution B from silica sol and potassium carbonate according to a metering ratio; and slowly dripping the solution B into the solution A under the condition of continuous stirring to mix the glue. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The first template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, the second template agent is calculated by hexamethyleneimine, and water is calculated by H2Molar ratio of O0.07: 1: 0.41: 0.59: 40. then the mixture is put into a reaction kettle to be crystallized for 5 days at the temperature of 180 ℃, and is dried for 4 hours at the temperature of 150 ℃ after being filtered, so as to obtain the MWW molecular sieve precursor.
(2) Preparation of MWW molecular sieve
Loading the molecular sieve precursor obtained in the step (1) into a reactor, wherein the reaction temperature is 40 ℃, and N is used2Introducing ethanol into the carrier gas, wherein the ethanol/N2Volume 0.6: 1, fully connecting ethanol with a molecular sieve precursorThe contact time is 4 hours, and the volume space velocity of the carrier gas is 700 hours-1And then carrying out gas-solid-liquid separation to obtain a molecular sieve precursor with most of the template agent removed, and roasting the solid product at the temperature of 500 ℃ for 2h to obtain the MWW molecular sieve with the template agent completely removed.
(3) Preparation of titanium silicalite Ti-MWW
Mixing TiCl4Slowly adding into ethanol, and continuously stirring at 70 deg.C to completely mix to obtain titanium source solution; wherein titanium ion and C2H5The molar ratio of OH is 2.5: 1; placing the prepared titanium source solution into a reactor, wherein the solid-liquid mass ratio is 1: 20, slowly adding the powdery MWW molecular sieve while stirring, reacting for 3 hours at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, drying for 4 hours at the temperature of 120 ℃, and then roasting for 2 hours at 500 ℃ to obtain the Ti-MWW molecular sieve precursor. Obtaining the Ti-MWW molecular sieve catalyst product D1.
Catalyst product D1, Ti: the Si molar ratio is 0.056: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 581m2/g。
Evaluation conditions were as follows: adding propylene, titanium silicalite molecular sieve catalyst D1, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite catalyst D1 to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
Comparative example 5
Silica sol is used as a silicon source, N, N, N-trimethyl adamantyl ammonium hydroxide is used as a template agent, potassium carbonate is used as an alkali source, and the materials are mixed and stirred according to a metering ratio to form the gel. Wherein the potassium carbonate is represented by K+The silicon source is calculated by SiO2The template agent is calculated by N, N, N-trimethyl-1-adamantyl ammonium hydroxide, and the water is calculated by H2The molar ratio of O is 0.07: 1: 1: and 40, crystallizing at 180 ℃ for 5 days, filtering, and drying at 150 ℃ for 4 hours to obtain the MWW molecular sieve precursor.
Mixing the prepared molecular sieve precursor with tetrabutyl titanate solution with the concentration of 0.1mol/L according to the solid-liquid mass ratio of 1: 20, reacting at 80 ℃ for 3 hours, cooling to room temperature after the reaction is finished, filtering the sample, fully washing the solid with deionized water, and drying at 120 ℃ for 4 hours to obtain the titanium-silicon molecular sieve precursor.
Mixing the prepared titanium silicalite molecular sieve precursor and nitric acid with the concentration of 2mol/L according to the proportion of 1: mixing at a mass ratio of 50, carrying out acid treatment at the temperature of 80 ℃ for 2 hours, filtering after the acid treatment is finished, filtering out solids, washing, drying at the temperature of 120 ℃ for 3 hours, and roasting at the temperature of 500 ℃ for 6 hours to obtain the titanium silicalite molecular sieve catalyst E1.
In molecular sieve catalyst E1, Ti: si molar ratio 0.05: 1. the specific surface area of the Ti-MWW molecular sieve catalyst is measured to be 530m2/g。
Evaluation conditions were as follows: adding propylene, a titanium silicalite molecular sieve catalyst E1, acetonitrile and 30.3 mass percent hydrogen peroxide into a reactor, wherein: the mass ratio of the propylene to the titanium silicalite catalyst E1 to the acetonitrile is 1:0.05:10, propylene: the molar ratio of hydrogen peroxide is 1: 1, stirring uniformly, reacting for 2 hours at the temperature of 60 ℃ under the pressure of 0.5MPa, separating out the catalyst by a conventional filtering method, and then separating to obtain a product by conventional operation. The evaluation results are shown in Table 1.
TABLE 1 evaluation results of catalysts
Selectivity to propylene oxide, mol%
Conversion of propylene, mol%
Example 1
98.7
93.3
Example 2
99.2
92.9
Example 3
98.6
93.2
Example 4
99.1
93.3
Example 5
98.9
92.8
Comparative example 1
96.4
89.3
Comparative example 2
95.1
88.2
Comparative example 3
93.6
86.8
Comparative example 4
95.9
88.9
Comparative example 5
91.5
85.2
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种加氢裂化催化剂及其制备方法和应用