Platinum-based eggshell type catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of glycerol hydrogenolysis reaction, in particular to a platinum-based eggshell type catalyst as well as a preparation method and application thereof. The invention provides a platinum-based eggshell type catalyst. The platinum-based eggshell type catalyst comprises the following components in percentage by weight: 1-5wt% of platinum oxide; 0.1 wt% to 6 wt% of a transition metal oxide; 5 wt% to 20 wt% of WOx; 70 wt%-94 wt% of a spherical alumina carrier; the sum of the use amounts of the components is 100%. The platinum-based eggshell type catalyst provided by the invention can reduce the use amount of noble metals, and when the platinum-based eggshell type catalyst is used for preparing 1, 3-propylene glycol through glycerol hydrogenation, the conversion rate of glycerol and the selectivity and yield of 1, 3-propylene glycol can be improved.

Description

Technical Field

[0001] This invention relates to the field of glycerol hydrogenolysis reaction technology, and in particular to a platinum-based eggshell catalyst, its preparation method and application. Background Technology

[0002] With the continuous improvement of biomass-to-diesel technology, the production of glycerol using biomass diesel as a raw material is increasing. The glycerol molecule contains three hydroxyl groups, which allows for the conversion of glycerol into higher value-added chemical products through different reaction pathways. Depending on the reaction type, glycerol can be selectively catalytically converted into dihydroxyacetone, glyceric acid, 1,2-propanediol, 1,3-propanediol, syngas, acrolein, etc. Among these, 1,3-propanediol, due to its high added value and large market demand, has become a hot topic in biomass glycerol hydrogenolysis conversion research.

[0003] 1,3-Propanediol is an important organic chemical raw material with high added value. It is widely used in the chemical industry, including inks, coatings, cosmetics, pharmaceuticals, and antifreeze. In particular, as a polymer monomer, it can be used to synthesize high-performance polymer materials such as poly(1,3-propanediol) terephthalate (PTT). PTT combines the softness and better color fastness of nylon, the bulkiness of acrylic fiber, and the stain resistance of polyester, while also exhibiting high resilience, making it a promising material with a broad market prospect.

[0004] Currently, the main methods for synthesizing 1,3-propanediol include the ethylene oxide method (see patent application CN1201407A from Shell Research Ltd.), the bio-fermentation method (see patent application CN101144086A from DuPont and Genenor), and the acrolein hydration method (see patent application CN93114516.3 from Degussa Group). Among these, the ethylene oxide and acrolein hydration methods have demanding operating conditions, high production costs, and poor product quality. The bio-fermentation method suffers from low 1,3-propanediol product concentration, high separation energy consumption and costs, short enzyme lifespan, and strict requirements for raw materials. In contrast, glycerol, as a renewable resource, provides abundant and low-cost raw materials for the hydrogenation of glycerol to produce 1,3-propanediol, making the catalytic conversion of glycerol to produce 1,3-propanediol economically feasible and an effective route for the chemical utilization of glycerol.

[0005] Currently, Ir-Re-based and Pt-W-based catalysts are two highly efficient selective catalysts for the preparation of 1,3-propanediol (1,3-PDO) from glycerol. Among them, the Pt-W-based catalyst can exist stably in aqueous glycerol solution, and W is inexpensive, showing broad application prospects.

[0006] Patent application CN111389397A discloses a catalyst for the hydrogenation of glycerol to 1,3-propanediol and its preparation method. The catalyst comprises Pt, W, ZrO2, an additive, and a support. The loading of Pt is 1% to 5% of the support mass, the loading of W is 6% to 12% of the support mass, the loading of ZrO2 is 5% to 10% of the support mass, and the loading of the additive is 0.1% to 0.5% of the support mass. A fixed-bed reactor is used, with a 10% (w / w) aqueous solution of glycerol, a reaction temperature of 150°C, a reaction pressure of 5 MPa, a glycerol conversion rate of 43.5%, and a 1,3-propanediol selectivity of 38.8%.

[0007] Patent application CN107096564A discloses a SAPO-34 catalyst supported on Pt and WOx and its preparation method. The SAPO-34 molecular sieve with good hydrothermal stability is synthesized by hydrothermal synthesis. WOx is then supported on SAPO-34. When Pt is loaded again, the Pt can be dispersed on the surface of WOx. The interaction between the Pt and WOx interface has a significant impact on the selectivity of the catalyst for the hydrogenolysis of glycerol to 1,3-propanediol.

[0008] Patent application CN114762825A discloses the application of a Pt-based catalyst supported on a composite support in the hydrogenolysis of glycerol to 1,3-propanediol. The catalyst preparation method includes: 1) synthesizing a novel WO3-Al2O3 composite support via a sol-gel method-dynamic crystallization method; 2) obtaining a Pt / WO3-Al2O3 catalyst by wet impregnation of an active component precursor solution onto the WO3-Al2O3 support. The reaction is carried out in a high-pressure batch reactor with a 10% (w / w) aqueous glycerol solution, a reaction temperature of 180℃, a reaction pressure of 6 MPa, a reaction time of 12 h, a glycerol conversion rate of 65%, and a 1,3-propanediol selectivity of 57.6%.

[0009] In fixed-bed applications, precious metal catalysts are only processed by laboratory tableting and sieving to obtain particles of a certain size, which are then loaded into the fixed-bed reactor. Without industrial forming, they have poor mechanical strength and are easily pulverized after collision. Furthermore, in long-term continuous hydrogenation processes, there is a risk of catalyst powder loss after wetting, which limits their practical industrial application.

[0010] Spherical catalysts have good flowability and packing performance; however, there is a long diffusion path inside the spherical catalyst, which hinders the entry of large molecular reactants into the catalyst, resulting in low utilization of active components. Summary of the Invention

[0011] In view of this, the technical problem to be solved by the present invention is to provide a platinum-based eggshell catalyst, its preparation method and application. The platinum-based eggshell catalyst provided by the present invention can reduce the amount of precious metals used. When the platinum-based eggshell catalyst is used to prepare 1,3-propanediol by hydrogenation of glycerol, it can improve the conversion rate of glycerol and the selectivity and yield of 1,3-propanediol.

[0012] This invention provides a platinum-based eggshell-type catalyst, comprising:

[0013] Platinum oxide 1 wt%~5 wt%;

[0014] Transition metal oxides 0.1 wt%~6 wt%;

[0015] WO x 5 wt%~20 wt%;

[0016] Spherical alumina carrier 70 wt%~94 wt%;

[0017] The sum of the amounts of the above components is 100%.

[0018] Preferably, the transition metal oxide is selected from at least one of the oxides of Mo, Nd, Au, Co, Ce, and Ga.

[0019] This invention also provides a method for preparing the platinum-based eggshell catalyst described above, comprising the following steps:

[0020] S1, WO x The precursor is dissolved in the first solvent to obtain a tungsten-containing impregnation solution a'; the tungsten-containing impregnation solution a' is loaded onto a spherical alumina support by an equal volume impregnation method, dried, and then calcined at 400~800℃ to obtain material a;

[0021] The platinum precursor and the transition metal precursor are dissolved in a second solvent to obtain solution b;

[0022] S2. Load solution b onto material a, dry it, and then calcine it at 300~500℃ to obtain a platinum-based eggshell catalyst.

[0023] Preferably, the WO x The precursor is a soluble tungstate;

[0024] The first solvent is deionized water.

[0025] Preferably, the WO x The precursor is at least one of ammonium tungstate, ammonium metatungstate, and ammonium paratungstate;

[0026] The platinum precursor is one of chloroplatinic acid, platinum nitrate, or platinum powder dissolved in aqua regia.

[0027] Preferably, the transition metal precursor is at least one selected from the group consisting of a soluble chloride salt of a transition metal, a nitrate of a transition metal, an acetate of a transition metal, and an oxalate of a transition metal; the transition metal is selected from at least one selected from Mo, Nd, Au, Co, Ce, and Ga.

[0028] The second solvent is at least one of deionized water, ethanol, and acetone.

[0029] The present invention also provides an application of the platinum-based eggshell catalyst described above, or the platinum-based eggshell catalyst prepared by the method described above, as a catalyst for the hydrogenation of glycerol to 1,3-propanediol.

[0030] The present invention also provides a method for preparing 1,3-propanediol, comprising the following steps:

[0031] A. The catalyst is reduced and activated using a hydrogen-containing gas.

[0032] The catalyst is the platinum-based eggshell catalyst described above, or the platinum-based eggshell catalyst prepared by the preparation method described above;

[0033] B. The catalyst treated in step A, the aqueous glycerol solution, and hydrogen are mixed and subjected to a hydrogenation reaction to obtain 1,3-propanediol.

[0034] Preferably, the hydrogen-containing gas is hydrogen or a mixture of gases containing hydrogen; the hydrogen-containing mixture is a mixture of at least one of nitrogen, argon, and helium with hydrogen; and the volume content of hydrogen in the hydrogen-containing gas is 5% to 30%.

[0035] The reduction and activation treatment is performed at a temperature of 50~350℃ for 2~20 h.

[0036] Preferably, the mass concentration of the glycerol aqueous solution is 30% to 90%;

[0037] The hydrogenation reaction is carried out at a temperature of 100~200℃ and a pressure of 4.0~10.0 MPa.

[0038] The volume ratio of the glycerol aqueous solution to hydrogen gas is 1:500~2000, and the mass hourly space velocity (HSV) of the glycerol solution is 0.5~2.0 h⁻¹. -1 .

[0039] The eggshell-shaped catalyst provided by this invention can effectively shorten the diffusion path of reactants and improve the utilization rate of active components because the active components are mainly distributed near the catalyst surface.

[0040] This invention uses spherical alumina as a carrier and prepares eggshell-shaped catalysts by adjusting the type of impregnation solution, pH value of the impregnation solution, adding filling solvent, and adjusting the loading method. At the same time, different auxiliary metals are added so that the precious metal active components are highly dispersed on the surface of the carrier and do not diffuse into the interior of the catalyst carrier, thereby improving the utilization rate of the active components and the catalytic efficiency of the catalyst, while reducing the amount of precious metals used and lowering the cost of the catalyst.

[0041] The platinum-based eggshell catalyst provided by this invention can reduce the amount of precious metals used. When the platinum-based eggshell catalyst is used to prepare 1,3-propanediol by hydrogenation of glycerol, it can improve the conversion rate of glycerol and the selectivity and yield of 1,3-propanediol. Attached Figure Description

[0042] Figure 1 This is a cross-sectional view of the platinum-based eggshell catalyst of Example 1;

[0043] Figure 2 This is a cross-sectional view of the platinum-based catalyst in Comparative Example 1. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] This invention provides a platinum-based eggshell-type catalyst, comprising:

[0046] Platinum oxide 1 wt%~5 wt%;

[0047] Transition metal oxides 0.1 wt%~6 wt%;

[0048] WO x 5 wt%~20 wt%;

[0049] Spherical alumina carrier 70 wt%~94 wt%;

[0050] The sum of the amounts of the above components is 100%.

[0051] In some embodiments of the present invention, the transition metal oxide is selected from at least one of the oxides of Mo, Nd, Au, Co, Ce, and Ga; for example, MoO3, RuO2, CeO2, and Au2O3.

[0052] In some embodiments of the present invention, the content of platinum oxide is 2.3 wt%, 1.8 wt%, 2.4 wt%, 2.9 wt%, or 3.5 wt%.

[0053] In some embodiments of the present invention, the content of the transition metal oxide is 2.3 wt%, 1.3 wt%, 1.9 wt%, 2.2 wt%, 3.4 wt%, 2.8 wt%, 4.7 wt%, and 5.4 wt%.

[0054] In some embodiments of the present invention, the WO x The contents were 12.6 wt%, 8.8 wt%, 15.1 wt%, and 10 wt%.

[0055] In some embodiments of the present invention, the content of the spherical alumina carrier is 82.8 wt%, 88.1 wt%, 80.7 wt%, 83.4 wt%, 84.2 wt%, 81.7 wt%, 77.9 wt%, and 78.5 wt%.

[0056] In this invention, most of the catalyst active components are distributed at the outer edge of the spherical alumina support, forming an eggshell-shaped distribution.

[0057] This invention also provides a method for preparing the platinum-based eggshell catalyst described above, comprising the following steps:

[0058] S1, WO x The precursor is dissolved in the first solvent to obtain a tungsten-containing impregnation solution a'; the tungsten-containing impregnation solution a' is loaded onto a spherical alumina support by an equal volume impregnation method, dried, and then calcined at 400~800℃ to obtain material a;

[0059] The Pt precursor and the transition metal precursor are dissolved in a second solvent to obtain solution b;

[0060] S2. Load solution b onto material a, dry it, and then calcine it at 300~500℃ to obtain a platinum-based eggshell catalyst.

[0061] Regarding step S1:

[0062] Will WO x The precursor is dissolved in the first solvent to obtain a tungsten-containing impregnation solution a'; the tungsten-containing impregnation solution a' is loaded onto a spherical alumina support by an equal volume impregnation method, dried, and then calcined at 400~800℃ to obtain material a.

[0063] In some embodiments of the present invention, the WO xThe precursor is a soluble tungstate, such as at least one of ammonium tungstate, ammonium metatungstate, and ammonium paratungstate. The first solvent is deionized water. The amount of the first solvent is calculated based on a water absorption rate of 70% to 75% for the spherical alumina carrier, for example, 73.15%.

[0064] In some embodiments of the present invention, the drying includes low-temperature drying and high-temperature drying; the temperature of the low-temperature drying is 30~50℃, for example 40℃; the time of the low-temperature drying is 8~14 h, for example 12 h; the temperature of the high-temperature drying is 100~120℃, for example 110℃; the time of the high-temperature drying is 4~12 h, for example 4 h.

[0065] In some embodiments of the present invention, the calcination temperature is 650°C; the time is 2 to 8 hours, for example, 3 hours.

[0066] In some embodiments of the present invention, the Pt precursor is one of chloroplatinic acid, platinum nitrate, or platinum powder dissolved in aqua regia; the transition metal precursor is at least one of a soluble chloride salt of a transition metal, a nitrate of a transition metal, an acetate of a transition metal, or an oxalate of a transition metal. The transition metal is selected from at least one of Mo, Nd, Au, Co, Ce, and Ga. Specifically, the transition metal precursor is ammonium molybdate tetrahydrate, ruthenium trichloride, cerium nitrate hexahydrate, chloroauric acid, cobalt nitrate hexahydrate, neodymium chloride, or gallium nitrate.

[0067] In some embodiments of the present invention, the second solvent is at least one of deionized water, ethanol, and acetone.

[0068] Regarding step S2:

[0069] Solution b was loaded onto material a, dried, and then calcined at 300-500℃ to obtain a platinum-based eggshell catalyst.

[0070] In some embodiments of the present invention, the method of loading solution b onto material a can be impregnation or spraying. Specifically, solution b can be loaded onto material a by adjusting the type of impregnation solution, adjusting the pH value of the impregnation solution, adding a filler solvent, adjusting the loading method, etc.

[0071] In some embodiments of the present invention, the drying includes low-temperature drying and high-temperature drying; the temperature of the low-temperature drying is 30~50℃, for example 40℃; the time of the low-temperature drying is 8~14 h, for example 12 h; the temperature of the high-temperature drying is 100~120℃, for example 110℃; the time of the high-temperature drying is 4~12 h, for example 4 h.

[0072] In some embodiments of the present invention, the drying temperature is 90~110°C, for example 100°C; and the time is 1~3h, for example 2h.

[0073] In some embodiments of the present invention, the calcination temperature is 350~500℃, for example 500℃; the time is 3~10 h, for example 4~10 h, specifically 4 h.

[0074] The present invention also provides an application of the platinum-based eggshell catalyst described above, or the platinum-based eggshell catalyst prepared by the method described above, as a catalyst for the hydrogenation of glycerol to 1,3-propanediol.

[0075] The present invention also provides a method for preparing 1,3-propanediol, comprising the following steps:

[0076] A. The catalyst is reduced and activated using a hydrogen-containing gas.

[0077] The catalyst is the platinum-based eggshell catalyst described above, or the platinum-based eggshell catalyst prepared by the preparation method described above;

[0078] B. The catalyst treated in step A, the aqueous glycerol solution, and hydrogen are mixed and subjected to a hydrogenation reaction to obtain 1,3-propanediol.

[0079] Regarding step A:

[0080] The catalyst is activated by reduction with a hydrogen-containing gas.

[0081] The catalyst is the platinum-based eggshell catalyst described above, or the platinum-based eggshell catalyst prepared by the preparation method described above.

[0082] In some embodiments of the present invention, the hydrogen-containing gas is hydrogen or a mixture of gases containing hydrogen; the hydrogen-containing mixture can be a mixture of at least one of nitrogen, argon, and helium with hydrogen. The hydrogen volume content in the hydrogen-containing gas is 5% to 30%, preferably 10% to 25%, for example, 10%.

[0083] In some embodiments of the present invention, the temperature of the reduction and activation treatment is 50~350℃, preferably 150~300℃; and the time is 2~20 h.

[0084] Regarding step B:

[0085] The catalyst treated in step A, an aqueous solution of glycerol, and hydrogen were mixed and subjected to a hydrogenation reaction to obtain 1,3-propanediol.

[0086] In some embodiments of the present invention, the mass concentration of the glycerol aqueous solution is 30% to 90%.

[0087] In some embodiments of the present invention, the temperature of the hydrogenation reaction is 100~200°C, for example 140~190°C, specifically 160°C; and the pressure is 4.0~10.0 MPa, for example 5.0~8.0 MPa, specifically 5 MPa. The hydrogenation reaction is carried out in a fixed-bed reactor.

[0088] In some embodiments of the present invention, the volume ratio of the glycerol aqueous solution to hydrogen gas is 1:500~2000, for example 1:500~1000; the mass hourly space velocity (HSV) of the glycerol solution is 0.5~2.0 h⁻¹. -1 For example, 0.5~1.5 h -1 .

[0089] The present invention does not impose any special restrictions on the source of the raw materials used above, and they can be commercially available.

[0090] To further illustrate the present invention, the following detailed description of a platinum-based eggshell catalyst, its preparation method, and its application, in conjunction with embodiments, is provided by the present invention, but should not be construed as limiting the scope of protection of the present invention.

[0091] Example 1

[0092] 1) Dissolve 1.40 g of ammonium metatungstate in 6.1 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0093] Material a was prepared by loading tungsten-containing impregnation solution a' onto 8.28g of alumina microspheres using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0094] Weigh 1.79g of chloroplatinic acid and 1.93g of ammonium molybdate tetrahydrate and dilute to 6.5mL with ethanol to prepare impregnation solution b.

[0095] 2) The impregnation solution b was loaded onto material a by impregnation method, dried at a low temperature of 40℃ for 12 h, dried at a high temperature of 110℃ for 4 h, and then calcined at 500℃ for 4 h to obtain a platinum-based eggshell catalyst. Figure 1 This is a cross-sectional view of the platinum-based eggshell catalyst from Example 1. From... Figure 1 As can be seen from the cross-sectional diagram of the catalyst, the active components of the catalyst are mainly distributed at the outer edge of the support. The middle of the catalyst cross-section is white, and the outer ring is black, forming an eggshell-shaped distribution.

[0096] The platinum-based eggshell catalyst comprises:

[0097] Platinum oxide 2.3 wt%

[0098] Transition metal oxide MoO3 2.3 wt%

[0099] WO x 12.6 wt%

[0100] Spherical alumina carrier: 82.8 wt%.

[0101] 3) Preparation of 1,3-propanediol:

[0102] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0103] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0104] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0105] The products were analyzed using gas chromatography.

[0106] Example 2

[0107] 1) Dissolve 0.98g of ammonium metatungstate in 6.8mL of deionized water to obtain tungsten-containing impregnation solution a';

[0108] Material a was prepared by loading tungsten-containing impregnation solution a' onto a 9.32g alumina microsphere carrier using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0109] Weigh 1.34 g of chloroplatinic acid and 0.20 g of ruthenium trichloride, and dilute to 7.1 mL with acetone to prepare impregnation solution b.

[0110] 2) The impregnation solution b was loaded onto material a by impregnation method, dried at a low temperature of 40℃ for 12 h, dried at a high temperature of 110℃ for 4 h, and then calcined at 500℃ for 4 h to obtain a platinum-based eggshell catalyst.

[0111] The platinum-based eggshell catalyst comprises:

[0112] Platinum oxide 1.8 wt%

[0113] Transition metal oxide RuO2 1.3 wt%

[0114] WO x 8.8 wt%

[0115] Spherical alumina carrier: 88.1 wt%.

[0116] 3) Preparation of 1,3-propanediol:

[0117] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0118] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0119] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0120] The products were analyzed using gas chromatography.

[0121] Example 3

[0122] 1) Dissolve 1.68 g of ammonium metatungstate in 5.9 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0123] Material a was prepared by loading tungsten-containing impregnation solution a' onto 8.07g of alumina microspheres using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0124] Weigh 1.79g of chloroplatinic acid and 0.46g of cerium nitrate hexahydrate, dilute to 6.2mL with deionized water, and add nitric acid to adjust the pH to 1-2 to prepare impregnation solution b.

[0125] 2) The impregnation solution b was loaded onto material a by impregnation method, dried at a low temperature of 40℃ for 12 h, dried at a high temperature of 110℃ for 4 h, and then calcined at 500℃ for 4 h to obtain a platinum-based eggshell catalyst.

[0126] The platinum-based eggshell catalyst comprises:

[0127] Platinum oxide 2.3 wt%

[0128] Transition metal oxide CeO2 1.9 wt%

[0129] WO x 15.1 wt%

[0130] Spherical alumina carrier: 80.7 wt%.

[0131] 3) Preparation of 1,3-propanediol:

[0132] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0133] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0134] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0135] The products were analyzed using gas chromatography.

[0136] Example 4

[0137] 1) Dissolve 1.40 g of ammonium metatungstate in 6.1 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0138] Material a was prepared by loading tungsten-containing impregnation solution a' onto 8.34g of alumina microspheres using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0139] 2) Weigh the first intermediate material a to 8.66 g (denoted as m1); add the first intermediate to n-butanol (as a filling solvent to fully occupy the internal pores of the support and prevent the Pt impregnation solution from entering the support), impregnate evenly, filter, and weigh, denoted as mass m2. The mass increment (m2-m1) is the mass of n-butanol in the impregnated intermediate, 6.62 g; place in an oven to evaporate 30 wt% of n-butanol (evaporation mass 1.98 g), to obtain the second intermediate; mix the second intermediate with 3 mL of impregnation solution b (weigh 1.3 g of chloroplatinic acid and 0.21 g of chloroauric acid and make up to 3.03 mL to prepare impregnation solution b), impregnate at room temperature for 3 h, then dry at 100 °C for 2 h, and calcine at 500 °C for 4 h to obtain the platinum-based eggshell catalyst.

[0140] The platinum-based eggshell catalyst comprises:

[0141] Platinum oxide 1.8 wt%

[0142] Transition metal oxide Au₂O₃ 2.2 wt%

[0143] WO x 12.6 wt%

[0144] Spherical alumina carrier: 83.4 wt%.

[0145] 3) Preparation of 1,3-propanediol:

[0146] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0147] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0148] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0149] The products were analyzed using gas chromatography.

[0150] Example 5

[0151] 1) Dissolve 1.12 g of ammonium metatungstate in 6.2 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0152] Material a was prepared by loading tungsten-containing impregnation solution a' onto 8.42g of alumina microspheres using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0153] 2) Weigh the first intermediate material a to 8.75 g (denoted as m1); add the first intermediate to n-butanol (as a filling solvent to fully occupy the internal pores of the support and prevent the Pt impregnation solution from entering the support), impregnate evenly, filter and weigh, denoted as mass m2, then the mass increment (m2-m1) is the mass of n-butanol in the impregnated intermediate, 6.74 g; place in an oven to volatilize 30 wt% n-butanol (2.1 g volatilized), to obtain the second intermediate; mix the second intermediate with 3 mL of impregnation solution b (weigh 1.79 g chloroplatinic acid and 0.31 g chloroauric acid and make up to 3.03 mL to prepare impregnation solution b), impregnate at room temperature for 3 h, then dry at 100 °C for 2 h, and calcine at 500 °C for 4 h to obtain the platinum-based eggshell catalyst.

[0154] The platinum-based eggshell catalyst comprises:

[0155] Platinum oxide 2.4 wt%

[0156] Transition metal oxide Au₂O₃ 3.4 wt%

[0157] WO x 10 wt%

[0158] Spherical alumina carrier: 84.2 wt%.

[0159] 3) Preparation of 1,3-propanediol:

[0160] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0161] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0162] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0163] The products were analyzed using gas chromatography.

[0164] Example 6

[0165] 1) Dissolve 1.40 g of ammonium metatungstate in 5.9 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0166] Material a was prepared by loading tungsten-containing impregnation solution a' onto 8.42g of alumina microspheres using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0167] Weigh 2.24g of chloroplatinic acid and 0.49g of cobalt nitrate hexahydrate and dissolve them in 50g of deionized water to prepare solution b.

[0168] 2) Place material a in a sugar coating machine and spray the solution b. While material a is rolling, blow hot air onto it. After drying, spray a second time. The number of sprays is 3 times to make the solution b evenly coat the surface of material a. Then dry at 100℃ for 2 hours and calcine at 500℃ for 4 hours to obtain a platinum-based eggshell catalyst.

[0169] The platinum-based eggshell catalyst comprises:

[0170] Platinum oxide 2.9 wt%

[0171] Transition metal oxide Co2O3 2.8 wt%

[0172] WO x12.6 wt%

[0173] Spherical alumina carrier: 81.7 wt%.

[0174] 3) Preparation of 1,3-propanediol:

[0175] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0176] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0177] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0178] The products were analyzed using gas chromatography.

[0179] Example 7

[0180] 1) Dissolve 1.68 g of ammonium metatungstate in 5.7 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0181] Material a was prepared by loading tungsten-containing impregnation solution a' onto a 7.79g alumina microsphere carrier using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0182] Weigh 1.79 g of chloroplatinic acid and 0.049 g of neodymium chloride and dilute to 5.7 mL with a mixture of water and ethanol to prepare impregnation solution b.

[0183] 2) The impregnation solution b was loaded onto material a by impregnation method, dried at 110℃ for 4h, and then calcined at 500℃ for 4h to obtain a platinum-based eggshell catalyst.

[0184] The platinum-based eggshell catalyst comprises:

[0185] Platinum oxide 2.3 wt%

[0186] Transition metal oxide Nd₂O₃ 4.7 wt%

[0187] WO x 15.1 wt%

[0188] Spherical alumina carrier: 77.9 wt%.

[0189] 3) Preparation of 1,3-propanediol:

[0190] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0191] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0192] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0193] The products were analyzed using gas chromatography.

[0194] Example 8

[0195] 1) Dissolve 1.40 g of ammonium metatungstate in 5.7 mL of deionized water to obtain tungsten-containing impregnation solution a';

[0196] Material a was prepared by loading tungsten-containing impregnation solution a' onto a 7.82g alumina microsphere carrier using an equal-volume impregnation method, drying at a low temperature of 40℃ for 12 h, drying at a high temperature of 110℃ for 4 h, and then calcining at 650℃ for 3 h.

[0197] Weigh 2.68g of chloroplatinic acid and 0.73g of gallium nitrate hydrate and dissolve them in 50g of deionized water to prepare solution b.

[0198] 2) Place material a in a sugar coating machine and spray the solution b. While material a is rolling, blow hot air onto it. After drying, spray a second time. The number of sprays is 3 times to make the solution b evenly coat the surface of material a. Then dry at 100℃ for 2 hours and calcine at 500℃ for 4 hours to obtain a platinum-based eggshell catalyst.

[0199] The platinum-based eggshell catalyst comprises:

[0200] Platinum oxide 3.5 wt%

[0201] Transition metal oxide Ga2O3 5.4 wt%

[0202] WO x 12.6 wt%

[0203] Spherical alumina carrier: 78.5 wt%.

[0204] 3) Preparation of 1,3-propanediol:

[0205] The platinum-based eggshell catalyst was reduced and activated at 200°C for 8 hours in a mixed gas atmosphere containing hydrogen.

[0206] The hydrogen-containing gas mixture includes hydrogen and argon; the volume content of hydrogen in the hydrogen-containing gas mixture is 10%.

[0207] A fixed-bed reactor was selected, with a catalyst loading of 5 mL, a glycerol aqueous solution concentration of 60%, a hydrogen pressure of 5 MPa, a reaction temperature of 160 °C, a glycerol solution to hydrogen volume ratio of 1:600, and a glycerol solution mass hourly space velocity (WHSV) of 1.0 h⁻¹. -1 The reaction time was 10 h to obtain 1,3-propanediol.

[0208] The products were analyzed using gas chromatography.

[0209] Comparative Example 1

[0210] The difference from Example 1 is as follows:

[0211] Replace impregnation solution b with deionized water, and follow the same steps as in Example 1 to obtain the following result. Figure 2 The platinum-based catalyst shown has a uniform distribution of active components. 1,3-Propanediol was then prepared. Figure 2 This is a cross-sectional view of the platinum-based catalyst in Comparative Example 1. From... Figure 2 It can be seen that the catalyst cross-section is uniformly blackish-gray, and the obtained catalyst is not an eggshell-shaped catalyst.

[0212] The platinum-based catalyst comprises:

[0213] Platinum oxide 2.3 wt%

[0214] Transition metal oxide MoO3 2.3 wt%

[0215] WO x 12.6 wt%

[0216] Spherical alumina carrier: 82.8 wt%.

[0217] The products were analyzed using gas chromatography.

[0218] Comparative Example 2

[0219] The difference from Example 3 is that the impregnation solution b does not contain cerium nitrate hexahydrate;

[0220] That is: the preparation method of impregnation solution b is as follows:

[0221] Weigh 1.79g of chloroplatinic acid and dilute to 6.2mL with deionized water. Add nitric acid to adjust the pH to 1-2 to prepare impregnation solution b.

[0222] The remaining steps were the same as in Example 3, yielding a platinum-based eggshell catalyst. This catalyst was then used to prepare 1,3-propanediol.

[0223] The platinum-based catalyst comprises:

[0224] Platinum oxide 2.3 wt%

[0225] WO x 15.1 wt%

[0226] Spherical alumina carrier: 82.6 wt%.

[0227] The products were analyzed using gas chromatography.

[0228] Comparative Example 3

[0229] The difference from Example 5 is as follows:

[0230] In step 3), the mass concentration of the glycerol aqueous solution is replaced with 70%.

[0231] The remaining steps were the same as in Example 5, and 1,3-propanediol was prepared.

[0232] The products were analyzed using gas chromatography.

[0233] The catalytic performance of the catalysts in Examples 1-8 and Comparative Examples 1-3 was studied, and the results are shown in Table 1.

[0234] Table 1 Catalytic performance of the catalysts in Examples 1-8 and Comparative Examples 1-3

[0235]

[0236] Table 1 shows the data for glycerol conversion and 1,3-propanediol selectivity (calculated by gas chromatography). The comparison shows that using the eggshell-type catalyst of this invention can reduce the amount of precious metals used, and doping with transition metals can improve the conversion of glycerol and the selectivity and yield of 1,3-propanediol.

[0237] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A platinum-based eggshell-type catalyst, comprising: Platinum oxide 1 wt%~5 wt%; Transition metal oxides 0.1 wt%~6 wt%; WO x 5 wt%~20 wt%; Spherical alumina carrier 70 wt%~94 wt%; The sum of the amounts of the above components is 100%.

2. The platinum-based eggshell catalyst according to claim 1, characterized in that, The transition metal oxide is selected from at least one of the oxides of Mo, Nd, Au, Co, Ce, and Ga.

3. A method for preparing the platinum-based eggshell catalyst according to any one of claims 1 to 2, comprising the following steps: S1, WO x The precursor is dissolved in the first solvent to obtain a tungsten-containing impregnation solution a'; the tungsten-containing impregnation solution a' is loaded onto a spherical alumina support by an equal volume impregnation method, dried, and then calcined at 400~800℃ to obtain material a; The platinum precursor and the transition metal precursor are dissolved in a second solvent to obtain solution b; S2. Load solution b onto material a, dry it, and then calcine it at 300~500℃ to obtain a platinum-based eggshell catalyst.

4. The preparation method according to claim 3, characterized in that, The WO x The precursor is a soluble tungstate; The first solvent is deionized water.

5. The preparation method according to claim 3, characterized in that, The WO x The precursor is at least one of ammonium tungstate, ammonium metatungstate, and ammonium paratungstate; The platinum precursor is one of chloroplatinic acid, platinum nitrate, or platinum powder dissolved in aqua regia.

6. The preparation method according to claim 3, characterized in that, The transition metal precursor is at least one of a soluble chloride salt of a transition metal, a nitrate salt of a transition metal, an acetate salt of a transition metal, and an oxalate salt of a transition metal; the transition metal is selected from at least one of Mo, Nd, Au, Co, Ce, and Ga. The second solvent is at least one of deionized water, ethanol, and acetone.

7. The application of a platinum-based eggshell catalyst according to any one of claims 1 to 2, or a platinum-based eggshell catalyst prepared by any one of claims 3 to 6, as a catalyst for the hydrogenation of glycerol to 1,3-propanediol.

8. A method for preparing 1,3-propanediol, comprising the following steps: A. The catalyst is reduced and activated using a hydrogen-containing gas. The catalyst is the platinum-based eggshell catalyst according to any one of claims 1 to 2, or the platinum-based eggshell catalyst prepared by the preparation method according to any one of claims 3 to 6; B. The catalyst treated in step A, the aqueous glycerol solution, and hydrogen are mixed and subjected to a hydrogenation reaction to obtain 1,3-propanediol.

9. The preparation method according to claim 8, characterized in that, The hydrogen-containing gas is hydrogen or a mixture of gases containing hydrogen; the hydrogen-containing mixture is a mixture of at least one of nitrogen, argon, and helium with hydrogen; the volume content of hydrogen in the hydrogen-containing gas is 5% to 30%. The reduction and activation treatment is performed at a temperature of 50~350℃ for 2~20 h.

10. The preparation method according to claim 8, characterized in that, The mass concentration of the glycerol aqueous solution is 30%~90%; The hydrogenation reaction is carried out at a temperature of 100~200℃ and a pressure of 4.0~10.0 MPa. The volume ratio of the glycerol aqueous solution to hydrogen gas is 1:500~2000, and the mass hourly space velocity (WHSV) of the glycerol solution is 0.5~2.0 h⁻¹. -1 .

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