Propylene dimerization catalyst carrier, and propylene dimerization catalyst comprising same

Abstract

Provided in the present invention are a propylene dimerization catalyst carrier and a propylene dimerization catalyst comprising same. The catalyst carrier is obtained by mixing an alkali metal salt, a cyclodextrin compound, a reinforcing agent and water, and then forming and roasting the mixture. When the catalyst is subsequently used for propylene dimerization, the selectivity of the target product is high, the conversion rate of propylene raw material is high, and the catalyst has relatively good strength performance.

Description

Propylene dimerization catalyst support and propylene dimerization catalyst containing the same

[0001] Cross-reference information

[0002] This application claims priority to Chinese Patent Application No. 202411514225.9, filed on October 28, 2024, entitled "Catalyst Support and Catalyst Containing the Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of propylene dimerization catalysts, and more specifically to a propylene dimerization catalyst support and a propylene dimerization catalyst containing the same. Background Technology

[0004] Supported alkali metals are a crucial class of solid base catalysts, exhibiting unique catalytic activity in reactions such as olefin double bond isomerization, Markovnikov addition, side-chain alkylation of aromatics, and heterocyclic carbon chain substitution. They can selectively produce products that are difficult to generate under acid catalysis. For example, in the catalytic dimerization of propylene, the thermodynamically unstable target product 4-methyl-1-pentene (4MP1) is obtained, whereas 4MP1 is largely lost using an acid catalyst. Furthermore, supported alkali metal solid catalysts do not deactivate due to rapid coking like acid catalysts. Moreover, acid catalysts typically require very high temperature and pressure environments, while supported alkali metal solid catalysts do not, significantly reducing the severity of process conditions. Therefore, the research of these supported alkali metal solid catalysts, especially supported super-strong alkali metal solid catalysts, holds great promise for applications.

[0005] Currently, catalysts with high 4MP1 selectivity are mainly alkali metals, prepared by dispersing alkali metals on alkali metal carbonates and / or bicarbonates. Alkali metal carbonates such as potassium carbonate are excellent supports for propylene dimerization to 4MP1 catalysts, possessing low specific surface area and simple pore structure, resulting in low isomerization activity and good 4MP1 selectivity. However, they also suffer from low activity leading to low propylene conversion, and insufficient particle strength causing catalyst fragility. Therefore, it is crucial to resolve the contradiction between improving catalyst activity and ensuring selectivity, while also increasing catalyst strength, and to develop a catalyst with high selectivity, high propylene conversion, and high strength. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems, the present invention aims to provide a propylene dimerization catalyst support and a propylene dimerization catalyst containing the same. When the catalyst is used for propylene dimerization, it can improve the selectivity of the target product and the conversion rate of the raw material propylene, and the catalyst has good strength performance.

[0007] To achieve the above objectives, the present invention provides a propylene dimerization catalyst support, which is obtained by mixing an alkali metal salt, a cyclodextrin compound, a reinforcing agent, and water, followed by molding and calcination. The cyclodextrin compound is selected from cyclodextrins and / or cyclodextrin derivatives; the reinforcing agent is selected from borates and / or silicates.

[0008] The catalytic activity of solid base catalysts is related to the number and intensity of surface base sites. Furthermore, the microenvironment of these sites, including specific surface area, pore structure and size, and surface affinity to the substrate, also plays a role. In solid base catalysts, the dispersion of alkali metals on the support surface is primarily at unsaturated coordination centers and lattice defects, rather than a dense, uniform monolayer. Therefore, a unique vacancy structure and uniform dispersion of base sites on the support surface are favorable conditions for the formation of uniformly distributed catalytic active centers.

[0009] Cyclodextrins are oligosaccharides with a hollow cylindrical structure that is hydrophilic on the outside and hydrophobic on the inside. Their hydrophobic interior and hydrophilic exterior allow them to form inclusion complexes and molecular assemblies with many organic and inorganic molecules through van der Waals forces, hydrophobic interactions, and host-guest molecular pairing. Cyclodextrins can be modified with groups while maintaining their macrocyclic backbone, resulting in products with different properties or functions, i.e., cyclodextrin derivatives, such as cyclodextrin ester derivatives, bridged cyclodextrins, cyclodextrin cross-linked polymers, cyclodextrins linked to polymers, and cyclodextrins modified with embedded functional groups.

[0010] This invention introduces a cyclodextrin compound with an internal cavity structure that undergoes complexation with an alkali metal salt, followed by removal through pretreatment methods such as calcination. This process forms a catalyst support with a unique vacancy structure and uniform dispersion. Such a catalyst support has lattice defects on its surface. During subsequent alkali metal loading to form the catalyst, the alkali metal fully integrates with the lattice defects on the support surface, achieving equilibrium size and uniform dispersion, thus yielding a catalyst with high propylene conversion.

[0011] Furthermore, the mixing of cyclodextrin compounds and alkali metal salts can form a host-guest inclusion state. After calcination to remove the organic compounds, a gray or black alkali metal salt support is obtained. The support obtained by introducing cyclodextrin compounds does not disrupt the aggregation state of the crystalline particles or exhibit molten crosslinking, thus maintaining the original three-dimensional particle state. This is beneficial for the subsequent dispersion and loading of alkali metals.

[0012] Furthermore, this invention unexpectedly discovered that the introduction of cyclodextrin compounds also reduced the content of the byproduct 1-hexene (1-Hexene or 1-Hex) in the propylene dimerization product, resulting in higher selectivity for the target product 4MP1. The addition of cyclodextrin compounds reduced the peroxide content in the catalyst, effectively suppressing the anti-Markovnikov addition reaction during propylene dimerization, thereby reducing the 1-hexene selectivity and increasing the 4MP1 selectivity. The reduced peroxide content in the catalyst effectively suppressed the anti-Markovnikov addition reaction during propylene dimerization, thereby reducing the content of the byproduct 1-hexene and improving the 4MP1 selectivity.

[0013] In addition, the present invention introduces reinforcing agents borates and / or silicates, which do not affect the selectivity of the aforementioned target product and the conversion rate of raw materials, and can make the support easier to form and significantly improve the strength of the support, thereby reducing catalyst breakage and improving catalyst life.

[0014] The alkali metal salt support prepared by the above method exhibits spherical particle aggregation (as shown under an electron microscope), with a primary particle size ≤1 μm (primary particles refer to the crystalline grains during support preparation). The average pore size of the alkali metal salt support is 100 nm to 10000 nm ("average pore size" refers to the assumption that all pores are identical cylindrical pores during calculation based on mercury porosimetry), and the total pore volume is greater than 0.2 mL / g. Preferably, the average pore size is 100 nm to 5000 nm, and the total pore volume is greater than 0.25 mL / g (mercury porosimetry).

[0015] Furthermore, the amount of cyclodextrin compounds used is 0.1 to 20 wt% of the weight of the alkali metal salt, more preferably 0.5 to 15 wt%, even more preferably 1 to 10 wt%, and even more preferably 1.5 to 10 wt%.

[0016] Further, the amount of reinforcing agent is 0.1 to 10 wt% of the weight of the alkali metal salt, more preferably 0.5 to 6 wt%, even more preferably 1 to 5 wt%, and even more preferably 2 to 5 wt%.

[0017] Excessive introduction of cyclodextrin compounds slightly reduces the strength of the support, while insufficient introduction reduces the improvement in propylene conversion and 4MP1 selectivity. Excessive introduction of reinforcing agents such as silicates and / or borates affects 4MP1 selectivity, while insufficient introduction reduces the improvement in catalyst strength. Therefore, to balance these properties of the catalyst, selecting appropriate amounts of reinforcing agents and cyclodextrin compounds can further enhance the catalyst's strength, propylene conversion, and 4MP1 selectivity simultaneously.

[0018] In a preferred embodiment, the cyclodextrin is selected from one or more combinations of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and δ-cyclodextrin. The cyclodextrin derivative is selected from one or more combinations of hydroxypropyl-α-cyclodextrin, glucosyl-α-cyclodextrin, methyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin, dihydroxypropyl-β-cyclodextrin, ethyl-β-cyclodextrin, acetyl-β-cyclodextrin, carboxymethyl-β-cyclodextrin, glucosyl-β-cyclodextrin, and 6-O-α-maltosyl-β-cyclodextrin.

[0019] In a preferred embodiment, the borate is selected from one or more combinations of lithium borate, potassium borate, sodium borate, rubidium borate, magnesium borate, calcium borate, strontium borate, and barium borate. More preferably, the borate is sodium borate and / or magnesium borate. Even more preferably, the borate is sodium borate, which is easy to use, widely available, and has better compatibility with alkali metal carbonates.

[0020] In a preferred embodiment, the silicate is selected from one or more combinations of lithium silicate, potassium silicate, sodium silicate, cesium silicate, rubidium silicate, magnesium silicate, calcium silicate, and barium silicate. Preferably, the silicate is selected from sodium silicate and / or potassium silicate. More preferably, the silicate is selected from sodium silicate, which is easy to use, widely available, and has better compatibility with alkali metal carbonates.

[0021] In a preferred embodiment, the mixed raw materials for preparing the catalyst support also include graphite. The introduction of graphite in this invention serves as a lubricant, facilitating support formation and further improving catalyst activity and propylene conversion. Furthermore, the amount of graphite used is 0.2–1.5 wt% of the weight of the alkali metal salt, preferably 1–1.5 wt%.

[0022] In some optional embodiments, the alkali metal salt raw materials can be ground and sieved before mixing. Preferably, alkali metal salt powder of 100-350 mesh can be selected for use in a relatively narrow fraction, such as 200-300 mesh or 250-350 mesh; it can also be used in a wider fraction for mixing or directly sieved into a wider fraction, such as 100-200 mesh and 200-300 mesh mixed in a ratio of 40wt% and 60wt%, or other fractions and ratios, or directly sieved into a wider fraction, such as 100-350 mesh.

[0023] In a preferred embodiment, the alkali metal salt is an alkali metal carbonate and / or an alkali metal bicarbonate, preferably one or a combination of two or more of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate, more preferably potassium carbonate and / or sodium carbonate.

[0024] In some alternative embodiments, the forming process can be performed by extrusion molding, tableting, spheroidizing, or rotational molding. The formed shape can be cylindrical, clover-shaped, four-leaf-shaped, spherical, tablet-shaped, or other granular shapes. Preferably, extrusion molding is used, and an extruder is employed for extrusion. The extrudate can have any diameter, but to obtain better catalytic activity and ease of handling and processing, the diameter of the extrudate can be 1–5 mm, such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm; the extruded shape can be cylindrical, ring-shaped, clover-shaped, four-leaf-shaped, or other shapes. After the extrudate passes through the extruder, it can be cut into uniform lengths if necessary. However, a uniform length is not required, so the extrudate can be allowed to break into any length on its own, typically about 1–8 times its diameter width.

[0025] In some alternative embodiments, when using dry alkali metal salts, the weight ratio (g / g) of water to alkali metal salts during the extrusion process is in the range of about 0.23 to 0.33, preferably in the range of about 0.24 to 0.29, and more preferably in the range of 0.25 to 0.28.

[0026] In some preferred embodiments, the molded carrier is first dried and then calcined. Drying can be done naturally in an environment or at a low temperature (e.g., 25–40°C) in convective gas, depending on the humidity level. If the environment is dry, natural drying is sufficient; if the humidity is high, it can be dried in a convective gas environment, such as a forced-air drying oven at 25–40°C. After the carrier appears dry, it is placed in a heating device such as a forced-air drying oven or vacuum drying oven at 60–150°C for further drying. After drying, it is placed in a muffle furnace or ashing furnace for subsequent calcination.

[0027] In a preferred embodiment, the calcination temperature is 200–600°C, more preferably 250–500°C, and even more preferably 260–400°C. The calcination time is 1–10 h, more preferably 3–6 h, and even more preferably 3–7 h. The calcination temperature and calcination time are interrelated; higher calcination temperatures require shorter calcination times, while lower calcination temperatures allow for longer calcination times. Calcination can be carried out at high temperature with an oxygen-rich environment followed by an inert environment, or it can be carried out entirely in air to remove organic compounds and obtain an alkali metal salt carrier with a gray or black surface.

[0028] The present invention also provides a propylene dimerization catalyst, which includes the aforementioned propylene dimerization catalyst support and an alkali metal supported thereon.

[0029] Furthermore, the catalyst of the present invention can be in the shape of cylindrical, clover-shaped, four-leaf clover-shaped, spherical, tablet-shaped, irregularly shaped, or other particulate forms.

[0030] Furthermore, the alkali metal can be sodium and / or potassium.

[0031] Further, the weight of the alkali metal is 0.5 to 20 wt% of the catalyst support, preferably 0.5 to 10 wt%, more preferably 1 to 15 wt%, even more preferably 2 to 10 wt%, and even more preferably 3.5 to 10 wt%.

[0032] Due to the reactive chemical properties of alkali metals sodium and / or potassium, traditional impregnation, sol-gel, and precipitation methods are not suitable for loading alkali metals onto the catalyst supports mentioned above. Alternative loading methods include alkali metal melt loading, alkali metal loading through azide compound decomposition, and impregnation with liquid ammonia solution containing alkali metals.

[0033] In a preferred embodiment, the loading of the present invention can be a molten loading method of alkali metal and support; or it can be to dissolve alkali metal in liquid ammonia, completely impregnate the support, and then evaporate the ammonia from the solution-impregnated support to obtain the catalyst.

[0034] For example, the loading is carried out by molten loading of an alkali metal and a carrier. Preferably, the molten loading is carried out in a protective gas atmosphere. Preferably, the protective gas is selected from nitrogen, helium, and argon. Preferably, the temperature of the molten loading is 10–240°C higher than the melting point of the alkali metal; more preferably, it is 20–200°C higher than the melting point of the alkali metal; and even more preferably, it is 30–100°C higher than the melting point of the alkali metal. In some optional embodiments, the processing temperature of the molten loading is 150–170°C, and the processing time is 3–7 hours.

[0035] Specifically, the implementation scheme for molten loading can be as follows: Weigh the carrier and alkali metal into a pressure bath in an anhydrous and oxygen-free chamber, then place the pressure bath in a homogeneous reactor and heat and rotate it. Alternatively, a three-necked flask or reactor under nitrogen protection can be used for stirring loading. Or, a customized loading device can be used for loading. Those skilled in the art can select the above loading schemes according to the material dosage, and will not be elaborated further here.

[0036] In summary, this invention improves the surface microenvironment of the catalyst support, creating a unique and uniformly dispersed vacancy structure on the support surface, which facilitates the uniform dispersion of the active metal. The resulting catalyst exhibits excellent performance, and unexpectedly, it was found that the content of the byproduct 1-hexene was significantly reduced in the catalytic propylene dimerization product. Therefore, the catalyst combines high propylene conversion and high selectivity at 4MP1. Furthermore, this invention improves the catalyst strength, making it particularly suitable for fixed-bed high-pressure reaction operations. Attached Figure Description

[0037] Figure 1 is a scanning electron microscope image of the catalyst support in Example 1.

[0038] Figure 2 is a scanning electron microscope image of the catalyst support in Comparative Example 1. Detailed Implementation

[0039] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0040] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".

[0041] (a) The process of determining the strength of the catalyst support includes:

[0042] The strength test is the crushing strength of a single particle. A catalyst carrier particle of recorded length is placed on a test platform, and a uniform load is applied until the particle crushes. The applied load at the point of crushing is recorded. Typically, 10-20 catalyst carrier particles are selected for the strength test, and the average strength is recorded as the catalyst carrier particle strength. The calculation method for catalyst carrier particle strength is: Strength (N / cm) = Applied load at catalyst carrier particle crushing (N) / Catalyst carrier particle length (cm).

[0043] (ii) The process of evaluating catalysts includes:

[0044] (A) Batch reactor reaction: Under a nitrogen atmosphere, a certain amount of the prepared catalyst was added to a 300 mL autoclave. The mass of the autoclave was measured as m1. Then, propylene was injected into the autoclave, and the mass of the autoclave was measured as m2. The amount of propylene added was calculated as m. 丙 m 丙 =m2-m1. Then, the reactor is heated to the reaction temperature and reacted for a certain time. The reaction system is cooled to below 20℃, and the remaining gaseous components in the reactor are sampled and vented. The mass of the reactor after venting is measured as m3. The mass of the liquid recovered is calculated as m. 液 m 液 =m3-m1. Perform product component content analysis on gaseous and liquid samples. Calculate propylene conversion, 4MP1 selectivity, and 1-Hex selectivity.

[0045] (1) Propylene conversion rate C: C=(m 液 (1-X 液丙 )+(m 丙 -m 液 (1-X) 气丙 )) / m 丙 ×100%

[0046] (2) 4MP1 selectivity S: S = X 4MP1 / (100-X 液丙 )×100%

[0047] (3) 1-Hex selective S H S H =X Hex / (1-X 液丙 )×100%

[0048] in:

[0049] m 丙 —The mass of propylene added before the reaction;

[0050] m 液 —Mass of the liquid collected after the reaction;

[0051] X 液丙 —The mass percentage of propylene in the gas chromatography of a liquid;

[0052] X 气丙 —The mass percentage of propylene in the gas chromatogram of the gas;

[0053] X 4MP1 —The mass percentage of 4 MPa in the gas chromatograph of a liquid;

[0054] X Hex —The mass percentage of 1-Hexene in the gas chromatogram of the liquid.

[0055] (B) Fixed-bed gas-phase reaction: Under nitrogen protection, approximately 200 mL of catalyst is loaded into the isothermal zone of the fixed-bed reactor, with the top and bottom supported by quartz or magnetic balls. Polymer-grade propylene is pumped into the reaction apparatus via a horizontal flow pump, entering the reactor through a vaporizer. The reaction temperature in the vaporizer and reactor is 140-160℃, and the pressure is controlled at 8-12 MPa, with a controlled space velocity. The reaction product passes through a pressure controller and a six-way valve into a product condenser. Propylene is slowly discharged from the top of the product condenser, leaving a propylene dimer intermediate at the bottom. The sample passing through the six-way valve can be analyzed by online chromatography. The propylene conversion, 4MPa selectivity, and 1-Hex selectivity are calculated.

[0056] (1) Propylene conversion rate C: C=(1-X 丙 )×100%

[0057] (2) 4MP1 selectivity S: S = X 4MP1 / (1-X 丙 )×100%

[0058] (3) 1-Hex selective S H S H =X Hex / (1-X 丙 )×100%

[0059] in:

[0060] X 丙 —The mass percentage of propylene in the gas chromatography of the product;

[0061] X 4MP1 —The mass percentage of 4 MPa in the gas chromatogram of the product;

[0062] X Hex —The mass percentage of 1-Hexexe in the gas chromatogram of the product.

[0063] Anhydrous potassium carbonate powder examples

[0064] Anhydrous potassium carbonate was ground using a grinder and sieved using 100-mesh, 150-mesh, 200-mesh, 250-mesh, 300-mesh, and 350-mesh sieves to obtain anhydrous potassium carbonate powders of <100 mesh, 100-150 mesh, 150-200 mesh, 200-250 mesh, 250-300 mesh, and 300-350 mesh grades, respectively.

[0065] Example 1

[0066] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0067] (1) Carrier preparation

[0068] The carrier preparation in this embodiment includes the following process:

[0069] Weigh 100g of anhydrous potassium carbonate powder (150-300 mesh). Add 5g of hydroxypropyl-β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 2.0g of sodium silicate in 24g of deionized water, add it to the anhydrous potassium carbonate powder, and grind and mix to form a uniform wet block mixture.

[0070] The above wet block mixture was extruded using an extruder, producing cylindrical extrudates with a diameter of 2.5 mm. The extrudates were left to air dry overnight, then dried in a forced-air drying oven at 100°C for 6 hours, followed by calcination in a muffle furnace at 300°C for 5 hours to form a carrier, which was then sealed and stored. The carrier strength was measured to be 147 N / cm.

[0071] The obtained support was analyzed by scanning electron microscopy, as shown in Figure 1. As can be seen from Figure 1, the potassium carbonate support is granular, with particles clustered (or granular) together, and the primary particle size is ≤1 μm; at the same time, the total pore volume was measured to be 0.3343 mL / g and the average pore size was 1312 nm by mercury porosimetry.

[0072] (2) Metal load

[0073] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 5.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 2 hours. The resulting catalyst was black. 100mL of purified and dehydrated cyclohexane was added and sealed for later use.

[0074] (3) Catalyst Evaluation

[0075] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis, and then calculate. The analytical results of the propylene dimer liquid phase product are shown in Table 1 below; the propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0076] Example 2

[0077] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0078] (1) Carrier preparation

[0079] Weigh 100g of 100-300 mesh sodium bicarbonate powder. Add 3g of β-cyclodextrin and 1.2g of graphite to the sodium bicarbonate powder and mix thoroughly. Dissolve 3g of lithium tetraborate in 28g of deionized water, add it to the above sodium bicarbonate mixture, and grind and mix to form a uniform wet block mixture.

[0080] The above wet block mixture was extruded using an extruder, producing cylindrical extrudates with a diameter of 2.0 mm. The extrudates were left to air dry overnight, then dried in a vacuum drying oven at 100°C for 6 hours, followed by calcination in a muffle furnace at 320°C for 5 hours to form a carrier, which was then sealed and stored. The carrier strength was measured to be 161 N / cm.

[0081] (2) Metal load

[0082] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 3.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was black. 100mL of purified and dehydrated cyclohexane was added and sealed for later use.

[0083] (3) Catalyst Evaluation

[0084] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0085] Example 3

[0086] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0087] (1) Carrier preparation

[0088] Weigh 100g of anhydrous potassium carbonate powder (100-300 mesh). Add 6g of glucosyl-α-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3.0g of sodium silicate in 30g of deionized water and add it to the above anhydrous potassium carbonate mixture. Grind and mix to form a uniform wet block mixture.

[0089] The mixture was extruded using an extruder, producing cylindrical extrudates with a diameter of 2.5 mm. The extrudates were dried overnight at 40°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 260°C for 7 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 146 N / cm.

[0090] (2) Metal load

[0091] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 1.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0092] (3) Catalyst Evaluation

[0093] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase, and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The analytical results of the propylene dimer liquid intermediate are shown in Table 1. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0094] Example 4

[0095] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0096] (1) Carrier preparation

[0097] Weigh 100g of anhydrous potassium carbonate powder (150-250 mesh). Add 8g of β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3g of sodium silicate in 33g of deionized water, add it to the mixture, and grind and mix to form a uniform wet block mixture.

[0098] The mixture was extruded using an extruder to produce four-leaf clover-shaped extruders with a diameter of 3.0 mm. The extrudates were dried overnight at 30°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 400°C for 3 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 151 N / cm.

[0099] (2) Metal load

[0100] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 3.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0101] (3) Catalyst Evaluation

[0102] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 160℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0103] Example 5

[0104] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0105] (1) Carrier preparation

[0106] Weigh out 30g of anhydrous potassium carbonate powder (150-200 mesh), 40g of powder (200-250 mesh), and 30g of powder (250-350 mesh), totaling 100g. Add 1.5g of γ-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3g of sodium silicate in 28g of deionized water, add it to the mixture, and grind until a uniform wet block mixture is formed.

[0107] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.0 mm. The extrudates were dried overnight at 30°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 380°C for 5 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 159 N / cm.

[0108] (2) Metal load

[0109] In an anhydrous and oxygen-free chamber, 80g of the above-prepared support was added to a 200mL pressure bath, and 4.8g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 170℃, and rotated for 5 hours. The resulting catalyst was black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0110] (3) Catalyst Evaluation

[0111] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 160℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0112] Example 6

[0113] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0114] (1) Carrier preparation

[0115] Weigh 100g of anhydrous potassium carbonate powder (150-350 mesh). Add 10.0g of methyl-β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 2g of lithium tetraborate in 30g of deionized water and add it to the above anhydrous potassium carbonate mixture, then grind and mix to form a uniform wet block mixture.

[0116] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.5 mm. The extrudates were dried overnight at 40°C in a forced-air drying oven, then dried at 100°C for 6 hours, and finally calcined in a muffle furnace at 380°C for 4 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 153 N / cm.

[0117] (2) Metal load

[0118] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 6g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0119] (3) Catalyst Evaluation

[0120] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0121] Example 7

[0122] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0123] (1) Carrier preparation

[0124] Weigh 100g of anhydrous potassium carbonate powder (150-350 mesh). Add 0.5g of α-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 5g of lithium tetraborate in 27g of deionized water, add it to the above anhydrous potassium carbonate mixture, and grind and mix to form a uniform wet block mixture.

[0125] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.5 mm. The extrudates were dried overnight at 40°C in a forced-air drying oven, then dried at 100°C for 6 hours, and finally calcined in a muffle furnace at 380°C for 4 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 185 N / cm.

[0126] (2) Metal load

[0127] In an anhydrous and oxygen-free chamber, 80g of the above-prepared support was added to a 200mL pressure bath, and 4.0g of sodium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0128] (3) Catalyst Evaluation

[0129] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0130] Example 8

[0131] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0132] (1) Carrier preparation

[0133] Weigh 100g of anhydrous potassium carbonate powder (100-300 mesh). Add 14g of hydroxypropyl-β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 4g of lithium tetraborate in 32g of deionized water and add it to the above anhydrous potassium carbonate mixture, then grind and mix to form a uniform wet block mixture.

[0134] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.5 mm. The extrudates were dried overnight at 40°C in a forced-air drying oven, then dried at 100°C for 6 hours, and finally calcined in a muffle furnace at 380°C for 5 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 125 N / cm.

[0135] (2) Metal load

[0136] In an anhydrous and oxygen-free chamber, 80g of the above-prepared support was added to a 200mL pressure bath, and 0.5g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 3 hours. The resulting catalyst was black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0137] (3) Catalyst Evaluation

[0138] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 160℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0139] Example 9

[0140] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0141] (1) Carrier preparation

[0142] Weigh 100g of anhydrous potassium carbonate powder (150-350 mesh). Add 20g of β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3g of sodium silicate in 33g of deionized water, add it to the mixture, and grind and mix to form a uniform wet block mixture.

[0143] The mixture was extruded using an extruder to produce four-leaf clover-shaped extruders with a diameter of 3.0 mm. The extrudates were dried overnight at 30°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 400°C for 5 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 90 N / cm.

[0144] (2) Metal load

[0145] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 8.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 7 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0146] (3) Catalyst Evaluation

[0147] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0148] Example 10

[0149] This embodiment provides a method for preparing a supported alkali metal catalyst, comprising the following steps:

[0150] (1) Carrier preparation

[0151] Weigh out 25g each of anhydrous sodium carbonate powder of 100-150 mesh, 150-200 mesh, 200-250 mesh, and 250-300 mesh, for a total of 100g. Add 10g of β-cyclodextrin and 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Add 28g of deionized water to the mixture and grind and mix to form a uniform wet block mixture.

[0152] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.5 mm. The extrudates were dried overnight at 30°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 320°C for 5 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 84 N / cm.

[0153] (2) Metal load

[0154] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 12g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 7 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0155] (3) Catalyst Evaluation

[0156] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0157] Example 11

[0158] This embodiment uses a fixed-bed continuous reaction to evaluate the catalyst prepared in Example 1:

[0159] Measure 50 mL of the catalyst from Example 1 and pack it into the fixed-bed reactor. Pump propylene using a horizontal flow pump, raise the reactor bed hot spot temperature to 150°C, set the pressure to 10 MPa, and adjust the space velocity to 1.1 h⁻¹. -1 The reaction proceeded continuously. After 24 hours, the propylene conversion was 45.3%, the 4MP1 selectivity was 88.9%, and the 1-Hexene selectivity was 3.9%. After 48 hours, the propylene conversion was 43.6%, the 4MP1 selectivity was 89.1%, and the 1-Hexene selectivity was 4.1%.

[0160] Comparative Example 1

[0161] This comparative example prepares a supported alkali metal catalyst, including the following process:

[0162] (1) Carrier preparation

[0163] Weigh 100g of anhydrous potassium carbonate powder (150-300 mesh). Add 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 2.0g of sodium silicate in 24g of deionized water, add it to the anhydrous potassium carbonate powder, and grind and mix to form a uniform wet block mixture.

[0164] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.5 mm. The extrudates were left to air dry overnight, then dried in a forced-air drying oven at 100°C for 6 hours, followed by calcination in a muffle furnace at 300°C for 5 hours to form a carrier, which was then sealed and stored. The carrier strength was measured to be 154 N / cm.

[0165] The obtained support was analyzed by scanning electron microscopy, as shown in Figure 2. Figure 2 shows that the potassium carbonate support without cyclodextrin treatment exhibits a lamellar, cross-linked aggregate structure, with primary particle size > 1 μm. The total pore volume was determined to be 0.0721 mL / g using mercury porosimetry, with an average pore size of 78 nm.

[0166] (2) Metal load

[0167] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 5.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 2 hours. The resulting catalyst was black. 100mL of purified and dehydrated cyclohexane was added and sealed for later use.

[0168] (3) Catalyst Evaluation

[0169] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction, cool the system to below 20℃, vent the air phase, and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The analysis results of the liquid phase after flash evaporation of the propylene dimerization intermediate are shown in Table 1. The propylene conversion rate, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0170] Comparative Example 2

[0171] This comparative example prepares a supported alkali metal catalyst, including the following process:

[0172] (1) Carrier preparation

[0173] Weigh 100g of anhydrous potassium carbonate powder (100-300 mesh). Add 1.2g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3g of lithium tetraborate in 28g of deionized water, add it to the above anhydrous potassium carbonate mixture, and grind and mix to form a uniform wet block mixture.

[0174] The mixture was extruded using an extruder to produce cylindrical extrudates with a diameter of 2.0 mm. The extrudates were left to air dry overnight, then dried in a vacuum drying oven at 100°C for 6 hours, followed by calcination in a muffle furnace at 320°C for 5 hours to form a carrier, which was then sealed and stored. The carrier strength was measured to be 150 N / cm.

[0175] (2) Metal load

[0176] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 3.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was black. 100mL of purified and dehydrated cyclohexane was added and sealed for later use.

[0177] (3) Catalyst Evaluation

[0178] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0179] Comparative Example 3

[0180] This comparative example prepares a supported alkali metal catalyst, including the following process:

[0181] (1) Carrier preparation

[0182] Weigh 100g of anhydrous potassium carbonate powder (100-300 mesh). Add 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Dissolve 3.0g of sodium silicate in 30g of deionized water and add it to the above anhydrous potassium carbonate mixture. Grind and mix to form a uniform wet block mixture.

[0183] The mixture was extruded using an extruder to produce cylindrical extruders with a diameter of 2.5 mm. The extrudates were dried overnight at 40°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 260°C for 7 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 131 N / cm.

[0184] (2) Metal load

[0185] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 1.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0186] (3) Catalyst Evaluation

[0187] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 150℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0188] Comparative Example 4

[0189] This comparative example prepares a supported alkali metal catalyst, including the following process:

[0190] (1) Carrier preparation

[0191] Weigh 100g of anhydrous potassium carbonate powder (150-250 mesh). Add 1.0g of graphite to the anhydrous potassium carbonate powder and mix thoroughly. Add 33g of deionized water and grind and mix to form a uniform wet block mixture.

[0192] The mixture was extruded using an extruder to produce four-leaf clover-shaped extruders with a diameter of 3.0 mm. The extrudates were dried overnight at 30°C in a forced-air drying oven, then dried at 100°C for 7 hours, and finally calcined in a muffle furnace at 400°C for 3 hours to form a carrier, which was then sealed and stored. The strength of the carrier was measured to be 84 N / cm.

[0193] (2) Metal load

[0194] In an anhydrous and oxygen-free chamber, 80g of the above-prepared carrier was added to a 200mL pressure bath, and 3.0g of potassium was weighed and added to the pressure bath. The mixture was then sealed. The pressure bath was placed in a homogeneous reactor, heated to 150℃, and rotated for 5 hours. The resulting catalyst was purplish-black. 100mL of anhydrous cyclohexane was added, and the mixture was sealed and stored for later use.

[0195] (3) Catalyst Evaluation

[0196] Weigh 12g of the catalyst prepared above and add it to a 300mL high-pressure reactor. Then, inject 90g of propylene into the reactor. Heat the material in the reactor to 160℃ and react for 10h. After the reaction is complete, cool the system to below 20℃, vent the air phase and take a sample for gas chromatography analysis. Collect the liquid phase and perform gas chromatography analysis. The propylene conversion, 4MP1 selectivity, and 1-Hexene selectivity are shown in Table 2.

[0197] Table 1 shows the analytical results of the propylene dimer liquid phase intermediates in Examples 1, 3 and Comparative Example 1.

[0198] Table 1

[0199] Table 2 shows the gas chromatographic analysis data and carrier strength analysis data of the propylene dimer intermediates in Examples 1-10 and Comparative Examples 1-4.

[0200] Table 2

[0201] As shown in Tables 1 and 2, compared to Comparative Example 1 without cyclodextrin, Example 1 of the present invention, by adding cyclodextrin during carrier treatment, significantly improved the selectivity of the target product 4MP1 and the propylene conversion rate. Compared to Comparative Example 2 without cyclodextrin, Example 2 of the present invention, by adding cyclodextrin during carrier treatment, significantly improved the selectivity of the target product 4MP1 and the propylene conversion rate. Compared to Comparative Example 3 without cyclodextrin, Example 3 of the present invention, by adding cyclodextrin during carrier treatment, significantly improved the selectivity of the target product 4MP1 and the propylene conversion rate. Compared to Comparative Example 4 without cyclodextrin and reinforcing agent, Example 4 of the present invention, by adding cyclodextrin and reinforcing agent during carrier treatment, not only significantly improved the selectivity of the target product 4MP1 and the propylene conversion rate, but also further endowed the carrier with good strength properties.

Claims

1. A propylene dimerization catalyst support, wherein, The propylene dimerization catalyst support is obtained by mixing an alkali metal salt, a cyclodextrin compound, a reinforcing agent, and water, followed by molding and calcination; the cyclodextrin compound is selected from cyclodextrins and / or cyclodextrin derivatives; the reinforcing agent is selected from borates and / or silicates.

2. The propylene dimerization catalyst support according to claim 1, wherein, The amount of the cyclodextrin compound used is 0.1 to 20 wt% of the weight of the alkali metal salt.

3. The propylene dimerization catalyst support according to claim 1, wherein, The amount of the reinforcing agent is 0.1 to 10 wt% of the weight of the alkali metal salt.

4. The propylene dimerization catalyst support according to claim 1, wherein, The cyclodextrin is selected from one or more of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and δ-cyclodextrin; The cyclodextrin derivative is selected from one or more combinations of hydroxypropyl-α-cyclodextrin, glucosyl-α-cyclodextrin, methyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin, dihydroxypropyl-β-cyclodextrin, ethyl-β-cyclodextrin, acetyl-β-cyclodextrin, carboxymethyl-β-cyclodextrin, glucosyl-β-cyclodextrin, and 6-O-α-maltosyl-β-cyclodextrin.

5. The propylene dimerization catalyst support according to claim 1, wherein, The borates are selected from one or more combinations of lithium borate, potassium borate, sodium borate, rubidium borate, magnesium borate, calcium borate, strontium borate, and barium borate.

6. The propylene dimerization catalyst support according to claim 1, wherein, The silicate is selected from one or more combinations of lithium silicate, potassium silicate, sodium silicate, cesium silicate, rubidium silicate, magnesium silicate, calcium silicate, and barium silicate.

7. The propylene dimerization catalyst support according to claim 1, wherein, The catalyst support also includes graphite in its mixed raw materials; the amount of graphite used is 0.2 to 1.5 wt% of the weight of the alkali metal salt.

8. The propylene dimerization catalyst support according to claim 1, wherein, The alkali metal salt is an alkali metal carbonate and / or an alkali metal bicarbonate.

9. The propylene dimerization catalyst support according to claim 1, wherein, The roasting process is carried out at a temperature of 200–600°C for 1–10 hours.

10. The propylene dimerization catalyst support according to claim 1, wherein, The amount of the cyclodextrin compound used is 1.5 to 10 wt% of the weight of the alkali metal salt.

11. The propylene dimerization catalyst support according to claim 1, wherein, The amount of the reinforcing agent is 2 to 5 wt% of the weight of the alkali metal salt.

12. The propylene dimerization catalyst support according to claim 1, wherein, The primary particle size of the catalyst support is ≤1μm; the average pore size of the catalyst support is 100~10000nm, and the total pore volume is greater than 0.2mL / g.

13. The propylene dimerization catalyst support according to claim 1, wherein, The roasting process is carried out at a temperature of 260–400°C for 3–7 hours.

14. A propylene dimerization catalyst, wherein, The propylene dimerization catalyst comprises the propylene dimerization catalyst support according to any one of claims 1 to 13 and an alkali metal supported thereon.

15. The propylene dimerization catalyst according to claim 14, wherein, The weight of the alkali metal is 0.5 to 20 wt% of the weight of the propylene dimerization catalyst support.

16. The propylene dimerization catalyst according to claim 14, wherein, The alkali metal is sodium and / or potassium.

17. The propylene dimerization catalyst according to claim 14, wherein, The alkali metal is loaded onto the propylene dimerization catalyst support by means of molten loading; the processing temperature of the molten loading is 10 to 240°C higher than the melting point of the alkali metal.

18. The propylene dimerization catalyst according to claim 14, wherein, The processing temperature of the molten load is 150–170°C, and the processing time is 3–7 hours.

19. The propylene dimerization catalyst according to claim 14, wherein, The weight of the alkali metal is 3.5 to 10 wt% of the weight of the propylene dimerization catalyst support.

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