A catalyst for preparing allyl alcohol by isomerization of propylene oxide and its preparation and use

Abstract

The application provides a catalyst for preparing allyl alcohol by isomerization of epoxide, a preparation method and application thereof. The catalyst is characterized by comprising an alkaline molecular sieve carrier and an alkali metal oxide active component; the alkaline molecular sieve is an alkali metal type molecular sieve with a FAU structure; the alkali metal oxide active component is at least one of oxides of lithium, sodium, potassium, rubidium and cesium; the catalyst preparation method is simple; the application further provides a reaction method for preparing allyl alcohol by isomerization of propylene oxide. The catalyst shows high epoxide conversion rate and allyl alcohol selectivity in a reaction system for preparing allyl alcohol by isomerization of propylene oxide.

Description

Technical Field

[0001] This invention relates to a catalyst for the isomerization of propylene oxide to prepare allyl alcohol and its preparation method, belonging to the field of chemical engineering. Background Technology

[0002] Allyl alcohols are an important class of chemical intermediates and fine chemical products. Because their molecular structure contains both carbon-carbon double bonds and hydroxyl groups, allyl alcohols can react with ethers, esters, aldehydes, and other compounds. Many widely used downstream products can be synthesized from allyl alcohols; therefore, they are indispensable intermediates in the fine chemical industry, especially in pharmaceuticals, fragrances, and surfactants. Hydroquinone (hydroquinone and catechol) is an important chemical raw material and intermediate with a very wide range of applications. Commonly used industrial synthesis methods for allyl alcohols include the allyl chloride hydrolysis method (saponification method), acrolein reduction method, propylene oxide isomerization method, and propylene acetate hydrolysis method. The allyl chloride hydrolysis method is the earliest industrial method for producing allyl alcohols. Allyl chloride is saponified to produce allyl alcohol with a yield of 85%-95%, while generating 5%-10% byproducts. This method uses propylene as a starting material, first chlorinating it at high temperature to obtain allyl chloride, producing a large amount of HCl as a byproduct; then, allyl chloride undergoes a saponification reaction to produce allyl alcohol, while producing a large amount of NaCl as a byproduct. The allyl aldehyde reduction method is an intermediate step in the synthesis of glycerol from allyl aldehyde. Under the action of a catalyst, propylene is first oxidized to allyl aldehyde, which is then hydrogen-exchanged with ethanol or isopropanol to obtain allyl alcohol. The advantages of this method are that it does not require chlorine and has lower production costs. However, the separation and purification of allyl aldehyde is complex, and the equipment investment cost is high, making it suitable only for large-scale production. The epoxide isomerization method, adopted in the 1990s, involves isomerizing epoxides into allyl alcohol via liquid or gas phase. Because the gas phase method is simple to operate, does not corrode equipment, and meets the requirements of green chemistry, it is currently more favored both domestically and internationally for the production of allyl alcohol. The gas phase production of allyl alcohol mainly involves the vaporization and preheating of propylene oxide under the action of a lithium phosphate catalyst, followed by isomerization into allyl alcohol under the catalyst's action. To date, the synthesis of allyl alcohol via epoxide isomerization generally suffers from low epoxide conversion and poor selectivity for allyl alcohol. Large quantities of propanal, acetone, and n-propanol are also produced as byproducts during the isomerization reaction, making subsequent separation and purification complex. Furthermore, the commonly used lithium phosphate catalyst suffers from severe coking and short lifespan. In short, the lack of mature technology in China currently hinders the development of this method domestically. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention aims to provide a strongly basic isomerization catalyst. This catalyst improves the acid-base active sites on the catalyst, increases the base strength of the basic sites, and makes the isomerization reaction more favorable for the formation of allyl alcohol. While improving the selectivity of allyl alcohol, it also reduces carbon deposition on the catalyst, effectively extending the catalyst's lifespan.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] The catalyst comprises an alkali metal molecular sieve support and an alkali metal oxide active component; wherein, it comprises an alkali metal molecular sieve support and an alkali metal oxide active component; the alkali metal molecular sieve support is an alkali metal molecular sieve with an FAU structure; the alkali metal oxide active component is at least one of the oxides of lithium, sodium, potassium, rubidium, and cesium.

[0006] The catalyst is prepared according to the following steps:

[0007] (1) After ion exchange of the molecular sieve with alkali metal precursor solution, the solid is washed, filtered, dried and calcined to obtain the alkali metal molecular sieve carrier.

[0008] (2) The alkali metal molecular sieve support obtained in step (1) is impregnated with an impregnation solution containing alkali metal ions in an equal volume. The impregnated solid is dried and then calcined to obtain the catalyst used for the catalytic isomerization of propylene oxide to prepare allyl alcohol.

[0009] The mass ratio of the alkali metal molecular sieve carrier to the alkali metal oxide active component is 20 to 1:1, preferably 15 to 3:1.

[0010] The alkali metal molecular sieve is at least one of the alkali metal ion exchange modified FAU structure molecular sieves;

[0011] Preferably, the FAU structure molecule is screened from at least one of X molecular sieve and Y molecular sieve;

[0012] The silica-alumina ratio of the molecular sieve is 1 to 5.

[0013] The alkali metal precursor is at least one of a soluble salt compound containing lithium ions, potassium ions, rubidium ions, and cesium ions; the ion exchange conditions are as follows: the concentration of the alkali metal precursor solution is 0.1-0.8 mol / L (preferably 0.1-0.5 mol / L), the exchange is performed 1-5 times (preferably 3-4 times) at 60-80℃, each time for 30-120 min (preferably 30-60 min), and the solid-liquid ratio of FAU structure molecular sieve powder to alkali metal precursor solution is 10-50 mL / g; after washing and filtering with water, the mixture is dried at 80-120℃, and calcined at 500-800℃ for 5-10 h to obtain an alkali metal molecular sieve support.

[0014] The alkali metal ion exchange modified FAU structure molecular sieve has an alkali metal ion exchange degree of 20-60% (preferably 30-40%).

[0015] The catalyst is dried at room temperature to 150°C (preferably 80 to 150°C) and calcined at 500 to 800°C for 1 to 8 hours.

[0016] The epoxide is one of propylene oxide or methyl propylene oxide;

[0017] The method for preparing allyl alcohol by isomerization of propylene oxide involves placing a catalyst in a fixed-bed reactor, controlling the reactor temperature at 300–500°C (preferably 400–500°C), and treating at this temperature for 1–5 hours (preferably 2–4 hours). Then, propylene oxide is preheated to 30–150°C (preferably 30–80°C) and pumped into the fixed-bed reactor, using nitrogen as a carrier gas. The reactor temperature is controlled at 200–500°C (preferably 200–400°C, more preferably 280–350°C), and the reaction is carried out at this temperature. The product is condensed in an ice-water bath and then analyzed by gas chromatography. The epoxide is one or both of propylene oxide or methylpropylene oxide.

[0018] The mass hourly space velocity of the propylene oxide is 5–20 h⁻¹. -1 (Preferred 10-20h) -1 More preferably 10-15h -1 The nitrogen flow rate was 5-50 mL / min. The product was condensed in an ice-water bath and then analyzed by gas chromatography.

[0019] The catalyst preparation method is simple; the present invention also provides a reaction method for the isomerization of propylene oxide to prepare allyl alcohol. The catalyst exhibits high propylene oxide conversion and allyl alcohol selectivity in the propylene oxide isomerization reaction system.

[0020] The beneficial effects of the present invention include, but are not limited to:

[0021] (1) The catalyst provided by this invention is used in the catalytic isomerization of epoxides to produce allyl alcohol, and has the characteristics of high epoxide conversion and high selectivity of allyl alcohol in the product. Alkali metal molecular sieves have strong basicity and weak acidity sites. After loading alkali metal oxides, the basicity of the basicity sites is further improved. Under the action of this catalyst, epoxides can be effectively activated at the weak acidity sites and then isomerized with high selectivity to allyl alcohol through the action of strong basicity sites;

[0022] (2) The catalyst provided by this invention has high stability and long service life. Because the catalyst contains abundant strong basic sites, it effectively inhibits carbon deposition on the catalyst surface and extends the service life of the catalyst.

[0023] (3) The method for preparing allyl alcohol by epoxide isomerization reaction provided by the present invention is simple to operate, meets the requirements of industrial production, and is convenient for large-scale industrial production. Detailed Implementation

[0024] The following embodiments are merely illustrative of the present invention, but the invention is not limited to these embodiments. Furthermore, the embodiments only provide some conditions for the preparation of allyl alcohol, and do not imply that these conditions must be met to achieve this objective. Any structures similar to those of the present invention and similar variations thereof are included within the scope of protection of the present invention.

[0025] The lithium phosphate catalyst in the comparative example was prepared according to the co-precipitation method described in publicly available literature.

[0026] Product analysis was performed on an Agilent 7890A chromatograph equipped with an HP-5 (30m × 0.320mm × 0.25μm) capillary column and an FID flame ionization detector. The conversion rate X of propylene oxide in the examples and comparative examples is shown. PO Selectivity of allyl alcohol AA Conversion rate X of 2-methylepoxypropane m-PO Selectivity of 2-methylallyl alcohol m-AA The definition is as follows:

[0027] X PO =(n / n PO )×100% (1)

[0028] S AA =(n AA / n PO )×100 (2)

[0029] Where: n—the total amount of propylene oxide reacted, in mol;

[0030] —Injection volume of propylene oxide, in mol;

[0031] n AA—Amount of allyl alcohol in the product, in mol.

[0032] X m-PO =(n / n m-PO )×100% (1)

[0033] S m-AA =(n m-AA / n m-PO )×100 (2)

[0034] Where: n——the total amount of 2-methylepoxypropane reacted, in mol;

[0035] —Injection volume of 2-methylepoxypropane, in mol;

[0036] nm- AA —Amount of 2-methylallyl alcohol in the product, in mol.

[0037] Comparative Example 1

[0038] This comparative example illustrates the effect of using lithium phosphate as a catalyst to catalyze the isomerization reaction of propylene oxide to prepare allyl alcohol.

[0039] 38g of sodium phosphate dodecahydrate was dissolved in 100mL of water to prepare an aqueous sodium phosphate solution. 4g of sodium hydroxide and 12g of lithium hydroxide monohydrate were dissolved in 100mL of water to obtain an alkaline lithium hydroxide solution. The aqueous sodium phosphate solution was added to a three-necked flask, and lithium hydroxide solution was added dropwise to the sodium phosphate solution at 60℃ over 1 hour. After the addition was completed, this temperature was maintained to allow the precipitate to mature for 2 hours. The mixture was then filtered and washed with deionized water until the pH reached 12. The resulting white solid powder was dried in a vacuum drying oven at 120℃ for 6 hours and then calcined in air at 320℃ for 8 hours to obtain an alkaline lithium phosphate catalyst.

[0040] The lithium phosphate catalyst was compressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the lithium phosphate catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The propylene oxide flow rate was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 300℃; and the resulting product was condensed in an ice-water bath. Samples were taken hourly for chromatographic analysis.

[0041] Comparative Example 2

[0042] 380g of sodium phosphate dodecahydrate was dissolved in 1000mL of water to prepare an aqueous sodium phosphate solution. 40g of sodium hydroxide and 120g of lithium hydroxide monohydrate were dissolved in 1000mL of water to obtain an alkaline lithium hydroxide solution. The aqueous sodium phosphate solution was added to a three-necked flask, and lithium hydroxide solution was added dropwise to the sodium phosphate solution at 60℃ over 2 hours. After the addition was completed, this temperature was maintained to allow the precipitate to mature for 2 hours. The mixture was then filtered and washed with deionized water until the pH reached 12. The resulting white solid powder was dried in a vacuum drying oven at 120℃ for 6 hours and then calcined in air at 320℃ for 8 hours to obtain a lithium phosphate catalyst.

[0043] The prepared lithium phosphate catalyst was mixed and ground with 100g of vinyl acetate emulsion in a ball mill for 4 hours to emulsify the mixture into a uniform suspension. The resulting suspension was added to the feed tank of a spraying device and stirred. 100g of silica gel balls with a diameter of 2mm were placed in a rotating drum. The carrier was heated and dried by hot air. When the carrier temperature reached 120℃, the feed nozzle was opened, and the catalytic active material suspension was sprayed onto the carrier surface. After rapid drying with hot air, the spraying time was controlled to ensure that the content of the catalyst active material reached 20% of the carrier mass. Spraying was then stopped, thus obtaining a coated lithium phosphate catalyst. The prepared catalyst was added to a fixed-bed single-tube reactor for activity evaluation. The single-tube reactor used had an inner diameter of 45mm and a tube length of 2000mm. A forced-circulation molten salt was used as the heat exchanger outside the reactor tube. The catalyst loading was 2.0L, nitrogen was used as the carrier gas, and the reactor was treated at 250℃ for 3 hours. The reactor temperature was controlled at 250℃, and the mass hourly space velocity of propylene oxide was 15h⁻¹. -1 The reaction products are collected in a product tank after passing through a condenser, and a sampling port is set at the lower end of the reaction tube.

[0044] Comparative Example 3

[0045] Commercially purchased X molecular sieve powder (Si / Al = 1.23) was used as the matrix. It was exchanged three times at 80℃ using a 0.5 mol / L CsNO3 solution (the matrix and solution were mixed and filtered to complete one exchange; the solid was then mixed with the solution again and filtered to complete the next exchange, for a total of three exchanges, each with a mixing time of 30 min). The solid-liquid ratio of X molecular sieve powder to CsNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange rate was 40%. After washing and filtering with deionized water, the sample was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsX. The CsX-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The flow rate of propylene oxide was controlled using a metering pump to achieve a WHSV of 15 h⁻¹. -1The propylene oxide preheating temperature was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken hourly for chromatographic analysis.

[0046] Comparative Example 4

[0047] Using commercially purchased X molecular sieve powder as the base (Si / Al = 1.23), a 1.0 mol / L CsNO3 solution was prepared and impregnated onto the X molecular sieve sample using an equal-volume impregnation method. The sample was dried overnight at room temperature and calcined at 550℃ in air for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / X-1. The Cs2O / X-1 catalyst was pressed into tablets and sieved to 20-40 mesh. 5.0 g of the catalyst was weighed and packed into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The flow rate of propylene oxide was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 300℃; and the resulting product was condensed in an ice-water bath. Samples were taken hourly for chromatographic analysis.

[0048] Example 1

[0049] Using commercially purchased X molecular sieve powder as the matrix (Si / Al = 1.23), it was exchanged three times at 80℃ with 0.5 mol / L CsNO3 solution (the matrix and solution were mixed and filtered to complete one exchange; the solid was mixed with the solution again and filtered to complete the next exchange, for a total of three exchanges, with each exchange mixing time being 30 min). The solid-liquid ratio of X molecular sieve powder to CsNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 40%. After washing and filtering with deionized water, it was dried overnight at 100℃ (12 hours, the same below), and calcined in air at 550℃ for 5 hours. The resulting alkali metal molecular sieve support sample was labeled CsX. A 1.0 mol / L CsNO3 solution was prepared and impregnated onto the CsX sample using an equal-volume impregnation method. The sample was dried overnight at room temperature and calcined at 550 °C in air for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsX-1, with a mass ratio of alkali metal molecular sieve support to alkali metal oxide of 7:3. The Cs2O / CsX-1 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and packed into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300 °C for 3 h. The flow rate of propylene oxide was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0050] Example 2

[0051] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged four times at 80℃ with 0.3 mol / L LiNO3 solution (each exchange mixing time 30 min). The solid-liquid ratio of X molecular sieve powder to LiNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 30%. After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled LiX, and the mass ratio of alkali metal molecular sieve support to alkali metal oxide was 8:2. A 0.6 mol / L LiNO3 solution was prepared and impregnated onto the LiX sample using an equal-volume impregnation method. After drying at room temperature overnight, it was calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Li2O / LiX-1. The Li₂O / LiX-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The propylene oxide flow rate was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0052] Example 3

[0053] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged four times at 80℃ with 0.3 mol / L KNO3 solution (each exchange mixing time 30 min). The solid-liquid ratio of X molecular sieve powder to KNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 20%. After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled KX. A 1.3 mol / L KNO3 solution was prepared and impregnated onto the KX sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled K2O / KX-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:4. The K2O / KX-1 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The propylene oxide flow rate was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0054] Example 4

[0055] Using commercially purchased Y molecular sieve powder as the parent material (Si / Al = 3), it was exchanged three times at 80℃ with 0.5 mol / L CsNO3 solution (each exchange mixing time 30 min). The solid-liquid ratio of Y molecular sieve powder to CsNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 30%. After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsY. A 1 mol / L CsNO3 solution was prepared and impregnated onto the CsY sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsY-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:3. The Cs₂O / CsY-1 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 320℃ for 3 h. The propylene oxide flow rate was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 50℃; the reaction temperature was set to 320℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0056] Example 5

[0057] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged five times at 80℃ with 0.5 mol / L CsNO3 solution (each exchange mixing time 30 min). The solid-liquid ratio of Y molecular sieve powder to CsNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 50%. After washing and filtering with deionized water, it was dried overnight at 120℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsX. A 1.5 mol / L CsNO3 solution was prepared and impregnated onto the CsX sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsX-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:4.5. The Cs₂O / CsX-2 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 500℃ for 3 h. The propylene oxide flow rate was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature of propylene oxide was set to 150℃; the reaction temperature was set to 500℃; and the resulting product was condensed in an ice-water bath. Samples were taken hourly for chromatographic analysis.

[0058] Comparative Example 5

[0059] This comparative example illustrates the effect of using lithium phosphate as a catalyst to catalyze the isomerization reaction of 2-methylpropane to prepare 2-methylallyl alcohol.

[0060] 38g of sodium phosphate dodecahydrate was dissolved in 100mL of water to prepare an aqueous sodium phosphate solution. 4g of sodium hydroxide and 12g of lithium hydroxide monohydrate were dissolved in 100mL of water to obtain an alkaline lithium hydroxide solution. The aqueous sodium phosphate solution was added to a three-necked flask, and lithium hydroxide solution was added dropwise to the sodium phosphate solution at 60℃ over 1 hour. After the addition was completed, this temperature was maintained to allow the precipitate to mature for 2 hours. The mixture was then filtered and washed with deionized water until the pH reached 12. The resulting white solid powder was dried in a vacuum drying oven at 120℃ for 6 hours and then calcined in air at 320℃ for 8 hours to obtain an alkaline lithium phosphate catalyst.

[0061] Lithium phosphate catalyst was pressed into tablets, sieved to 20-40 mesh, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. Nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 200℃ for 3 h. The flow rate of 2-methylepoxypropane was controlled using a metering pump to maintain a WHSV of 5 h⁻¹. -1 The preheating temperature was set to 50℃; the reaction temperature was set to 200℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0062] Comparative Example 6

[0063] Commercially purchased X molecular sieve powder (Si / Al = 1.23) was used as the matrix. It was exchanged three times at 80℃ using a 0.5 mol / L CsNO3 solution (the matrix and solution were mixed and filtered to complete one exchange; the solid was then mixed with the solution again and filtered to complete the next exchange, for a total of three exchanges, each with a mixing time of 30 min). The solid-liquid ratio of X molecular sieve powder to CsNO3 solution was 1:10 (g:mL). After washing and filtering with deionized water, the sample was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsX, with an alkali metal ion exchange rate of 30%. The CsX-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300℃ for 3 h. The flow rate of propylene oxide was controlled using a metering pump to achieve a WHSV of 15 h⁻¹. -1 The preheating temperature was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken hourly for chromatographic analysis.

[0064] Comparative Example 7

[0065] Using commercially purchased X molecular sieve powder as the base (Si / Al = 1.23), a 1.0 mol / L CsNO3 solution was prepared and impregnated onto the X molecular sieve sample using an equal-volume impregnation method. The sample was dried overnight at room temperature and calcined at 550℃ in air for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / X-1. The mass ratio of the alkali metal molecular sieve support to the alkali metal oxide was 6:4. The Cs2O / X-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and packed into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 400℃ for 3 h. The flow rate of propylene oxide was controlled using a metering pump to maintain a WHSV of 15 h⁻¹. -1 The preheating temperature was set to 50℃; the reaction temperature was set to 400℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0066] Example 6

[0067] Using commercially purchased X molecular sieve powder as the matrix (Si / Al = 1.23), it was exchanged four times at 80℃ with 0.6 mol / L CsNO3 solution (the matrix and solution were mixed and filtered to complete one exchange; the solid was mixed with the solution again and filtered to complete the next exchange, for a total of four exchanges, with each exchange mixing time being 15 min). The solid-liquid ratio of X molecular sieve powder to CsNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 40%. After washing and filtering with deionized water, it was dried overnight at 120℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsX. A 1.55 mol / L CsNO3 solution was prepared and impregnated onto the CsX sample using an equal-volume impregnation method. The sample was dried overnight at room temperature (12 hours). It was then calcined at 550 °C in air for 5 hours to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsX-1, with a mass ratio of alkali metal molecular sieve support to alkali metal oxide of 6:4. The Cs2O / CsX-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 300 °C for 3 hours. The flow rate of 2-methylepoxypropane was controlled using a metering pump to maintain a WHSV of 5 h⁻¹. -1 The preheating temperature of 2-methylpropoxide was set to 50℃; the reaction temperature was set to 300℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0068] Example 7

[0069] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged four times at 80℃ with 0.5 mol / L LiNO3 solution (each exchange mixing time 15 min). The solid-liquid ratio of X molecular sieve powder to LiNO3 solution was 1:10 (g:mL), and the alkali metal ion exchange degree was 30%. After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled LiX. A 1 mol / L LiNO3 solution was prepared and impregnated onto the LiX sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Li2O / LiX-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:3. The Li₂O / LiX-1 catalyst was pressed into tablets and sieved into 20-40 mesh particles. 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 400℃ for 3 h. The flow rate of 2-methylepoxypropane was controlled using a metering pump to maintain a WHSV of 5 h⁻¹. -1The preheating temperature of 2-methylpropoxide was set to 50℃; the reaction temperature was set to 400℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0070] Example 8

[0071] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged three times at 80℃ with 0.8 mol / L KNO3 solution (each exchange mixing time 30 min), with a solid-liquid ratio of X molecular sieve powder to KNO3 solution of 1:10 (g:mL). After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled KX, with an alkali metal ion exchange degree of 50%. A 1.55 mol / L LiNO3 solution was prepared and impregnated onto the KX sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled K2O / KX-1, with a mass ratio of alkali metal molecular sieve support to alkali metal oxide of 6:4. The K2O / KX-1 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 500℃ for 3 h. The flow rate of 2-methylepoxypropane was controlled using a metering pump to ensure a WHSV of 10 h⁻¹. -1 The preheating temperature of 2-methylpropoxide was set to 50℃; the reaction temperature was set to 500℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0072] Example 9

[0073] Using commercially purchased Y molecular sieve powder as the parent material (Si / Al = 3), it was exchanged three times at 80℃ with 0.5 mol / L CsNO3 solution (each exchange mixing time 5 min). The solid-liquid ratio of Y molecular sieve powder to CsNO3 solution was 1:10 (g:mL). After washing and filtering with deionized water, it was dried overnight at 100℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsY, with an alkali metal ion exchange degree of 35%. A 0.5 mol / L CsNO3 solution was prepared and impregnated onto the CsY sample using an equal-volume impregnation method. The sample was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsY-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:1.5. The Cs₂O / CsY-1 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 320℃ for 3 h. The flow rate of 2-methylepoxypropane was controlled using a metering pump to ensure a WHSV of 10 h⁻¹. -1 The preheating temperature of 2-methylepoxypropane was set to 50℃; the reaction temperature was set to 320℃; the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0074] Example 10

[0075] Using commercially purchased X molecular sieve powder as the parent material (Si / Al = 1.23), it was exchanged five times at 80℃ with 0.5 mol / L CsNO3 solution (each exchange mixing time 5 min). The solid-liquid ratio of Y molecular sieve powder to CsNO3 solution was 1:10 (g:mL). After washing and filtering with deionized water, it was dried overnight at 120℃ and calcined in air at 550℃ for 5 h. The resulting alkali metal molecular sieve support sample was labeled CsX, with an alkali metal ion exchange degree of 45%. A 1.5 mol / L CsNO3 solution was prepared and impregnated onto the CsX sample using an equal-volume impregnation method. It was dried overnight at room temperature and calcined in air at 550℃ for 5 h to obtain an alkali metal oxide-supported alkali metal molecular sieve, labeled Cs2O / CsX-1. The mass ratio of alkali metal molecular sieve support to alkali metal oxide was 7:4.5. The Cs₂O / CsX-2 catalyst was tableted and sieved into 20-40 mesh particles, and 5.0 g of the catalyst was weighed and loaded into a fixed-bed reactor. The nitrogen flow rate was adjusted to 10 mL / min using a mass flow meter, and the reactor was treated at 400℃ for 3 h. The flow rate of 2-methylepoxypropane was controlled using a metering pump to ensure a WHSV of 10 h⁻¹. -1The preheating temperature of 2-methylpropoxide was set to 150℃; the reaction temperature was set to 400℃; and the obtained product was condensed in an ice-water bath. Samples were taken every hour for chromatographic analysis.

[0076] The reaction results are shown in Tables 1 and 2.

[0077] Table 1 Reaction Results

[0078]

[0079] Table 2 Reaction Results

[0080]

[0081] This invention is not limited to the examples described herein, which are illustrative and not restrictive. The scope of this invention is defined by the claims. Any modifications, rearrangements, or other techniques related to this invention made by those skilled in the art based on this invention are within the protection scope of this invention.

Claims

1. A catalyst for the preparation of allyl alcohols by epoxide isomerization, characterized in that, It comprises an alkali metal molecular sieve support and an alkali metal oxide active component; wherein the alkali metal molecular sieve support is at least one or more of alkali metal molecular sieves having an FAU structure; The active component of the alkali metal oxide is at least one or more oxides of lithium, sodium, potassium, rubidium, and cesium.

2. The catalyst according to claim 1, characterized in that, The mass ratio of the alkali metal molecular sieve support to the alkali metal oxide is 20:1 to 1:1, preferably 15 to 3:

1.

3. The catalyst according to claim 1, characterized in that, The alkali metal molecular sieve is at least one or more of the alkali metal ion exchange modified FAU structure molecular sieves. Preferably, the FAU structure molecule is selected from at least one or two of X molecular sieves and Y molecular sieves; The silica-alumina ratio of the molecular sieve is 1 to 5.

4. A method for preparing a catalyst for the isomerization of propylene oxide to allyl alcohol as described in claim 1, 2, or 3, characterized in that, Follow these steps: (1) After ion exchange of FAU structure molecular sieve with alkali metal precursor solution, solid-liquid separation is performed, and the solid is washed, filtered, dried and calcined to obtain the alkali metal molecular sieve carrier. (2) The alkali metal molecular sieve support obtained in step (1) is impregnated with an impregnation solution containing alkali metal ions in an equal volume. The impregnated solid is dried and then calcined to obtain the catalyst used for the catalytic isomerization of propylene oxide to prepare allyl alcohol.

5. The method for preparing the catalyst according to claim 4, characterized in that, In step (1): The alkali metal precursor is at least one or more of the following: soluble salt compounds containing lithium ions, potassium ions, rubidium ions, and cesium ions. The ion exchange conditions are as follows: the concentration of the alkali metal precursor solution is 0.1-0.8 mol / L (preferably 0.1-0.5 mol / L), the exchange is performed 1-5 times (preferably 3-4 times) at 60-80℃, each time for 30-120 min (preferably 30-60 min), the solid-liquid ratio of FAU structure molecular sieve powder to alkali metal precursor solution is 10-50 g / mL; after washing and filtering with water, the mixture is dried at 80-120℃, and calcined at 500-800℃ for 5-10 h to obtain the alkali metal molecular sieve support.

6. The method for preparing the catalyst according to claim 4, characterized in that, The alkali metal ion exchange modified FAU structure molecular sieve has an alkali metal ion exchange degree of 20-60% (preferably 30-40%).

7. The method for preparing the catalyst according to claim 4, characterized in that, In step (2): The drying temperature is room temperature to 150℃ (preferably 80 to 150℃), and the calcination conditions are 500 to 800℃ for 1 to 8 hours.

8. A method for preparing allyl alcohol by epoxide isomerization, characterized in that: The catalyst described in claim 1, 2, or 3 is placed in a fixed-bed reactor, and the reactor temperature is controlled at 300–500°C (preferably 400–500°C) and treated with nitrogen at this temperature for 1–5 hours (preferably 2–4 hours). Then, the epoxide is preheated at 30–150°C (preferably 30–80°C) and pumped into the fixed-bed reactor, with nitrogen as the carrier gas. The reactor temperature is controlled at 200–500°C (preferably 200–400°C, more preferably 280–350°C) and reacted at this temperature.

9. The method for preparing allyl alcohol by isomerization of propylene oxide according to claim 8, characterized in that, The epoxide is one or both of propylene oxide or methyl propylene oxide.

10. The method for preparing allyl alcohol by isomerization of propylene oxide according to claim 8 or 9, characterized in that, The mass hourly space velocity (MSV) of epoxides is 5–20 h⁻¹. -1 (Preferred 10-20h) -1 More preferably 10-15h -1 The flow rate of nitrogen gas is 5-50 mL / min; The product was condensed in an ice-water bath and then analyzed by gas chromatography.

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