Catalyst, preparation method thereof and method for preparing 1, 3-propylene glycol

Abstract

The invention relates to a catalyst, a preparation method thereof and a method for preparing 1, 3-propylene glycol, the catalyst comprises a carrier, a first active component and a second active component, the first active component and the second active component are loaded on the carrier; the carrier is a micro-mesoporous hierarchical pore molecular sieve, the first active component is tungsten oxide, and the second active component is nano-alloy; and the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy. The invention also relates to a preparation method of the catalyst, and the preparation method comprises the following steps: S1, impregnating a tungsten oxide-loaded micro-medium hierarchical pore molecular sieve by using a solution containing a nano-alloy, and then carrying out first solid-liquid separation to obtain a first solid material; and S2, carrying out first drying and first calcination on the first solid material. The invention also relates to a method for preparing 1, 3-propylene glycol, and the method comprises the step of contacting glycerol with the catalyst under hydrogenation conditions. The catalyst prepared by the invention has the characteristics of high selectivity of 1, 3-propylene glycol and high conversion activity of glycerol.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a catalyst and a preparation method thereof, and a method for preparing 1,3-propylene glycol. Background Art

[0002] Glycerol is the main by-product of bio-jet fuel production, accounting for about 10%. The further high-value-added utilization of glycerol is an issue worth considering. Among them, the selective synthesis of high-value-added 1,3-propylene glycol from glycerol is one of its optimized routes. 1,3-propylene glycol is an important monomer for the production of poly(1,3-trimethylene terephthalate) (PTT). PTT has the advantages of both polyethylene terephthalate and poly(butylene terephthalate) and can produce high-end plastic products. Therefore, the path to synthesize high-value-added 1,3-propylene glycol using glycerol obtained as a by-product of bio-jet fuel is proposed.

[0003] At present, the industrial production methods of 1,3-propylene glycol include Shell's ethylene oxide carbonylation hydrogenation method and Degussa and Dupont's acrolein hydration hydrogenation method. However, the above production process is complicated, the reaction conditions are harsh, and the environmental pollution is serious. The literature (Appl. Microbiol. Biotechnol. 1992, 36, 592-597) reported a method of using glycerol as a raw material and converting it into 1,3-propylene glycol through a biological fermentation method. However, this method is affected by the metabolic activity of the organism, the conversion efficiency is low, and the product contains other impurities such as vitamins and salts, which makes the separation energy consumption very high. Based on this, the high-value-added conversion upgrade of glycerol direct hydrogenolysis to produce 1,3-propylene glycol has received unprecedented attention. At present, the path of glycerol production of 1,3-propylene glycol has received a certain amount of attention, but there are still many problems, which has prevented this path from being industrialized. CN201010262066.X discloses a Pt / WO3 / TiO2-SiO2 catalyst for hydrogenating glycerol to produce 1,3-propylene glycol; CN201110026988.5 discloses a catalyst for directly hydrogenating glycerol to produce 1,3-propylene glycol, the composition of which contains at least Pt, W, Ti, SiO2, and at least one auxiliary component among La, Ce, Sn, Re, Zr, Zn, Cu, Rh and Ru. CN201310637597.6 discloses a catalyst for preparing 1,3-propylene glycol by hydrogenation of glycerol, which uses SiO2 or HZSM-5 molecular sieve as a carrier and Re and Ir as main active components. The glycerol conversion rate is lower than 59%, and the selectivity for 1,3-propylene glycol is up to 53%; CN201510933866.2 discloses a catalyst for preparing 1,3-propylene glycol by hydrogenolysis of glycerol, which includes a tungsten oxide-alumina (WO3-Al2O3) composite carrier and a noble metal active component and a transition metal; CN201611127797.7 discloses a catalyst composed of a tungsten oxide carrier doped with transition metals such as Nb and Ta and loaded with active components Pt, Pd or auxiliary metals. Catalyst; CN201710242714.7 discloses a catalyst for synthesizing 1,3-propylene glycol, wherein the catalyst loads Pt nanoparticles on a composite carrier WO3-Al2O3-SiO2, with a glycerol conversion rate of less than 50% and a 1,3-propylene glycol selectivity of up to 56%; CN201710411402.4 discloses a SAPO-34 loaded with Pt and WOx catalyst, with a glycerol conversion rate of less than 50% and a 1,3-propylene glycol selectivity of less than 20%; CN201710499695.6 discloses a loaded mesoporous molecular sieve catalyst Pt / W-Al-SBA-15; Similar catalysts have also been reported in the literature to varying degrees.The literature (ACS Catal. 2020, 10, 15217-15226) reported a Pt / W / β (Beta) catalyst with an optimal glycerol conversion of 84% and an optimal 1,3-propylene glycol selectivity of 46%.

[0004] However, current catalysts still suffer from low conversion and low selectivity. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of low conversion rate and low selectivity of existing catalysts, and to provide a catalyst and a preparation method thereof and a method for preparing 1,3-propylene glycol.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a catalyst, which includes a carrier, a first active component loaded on the carrier, and a second active component; the carrier is a micro-mesoporous molecular sieve, the first active component is tungsten oxide, and the second active component is a nano-alloy; the nano-alloy is PtSn nano-alloy and / or PtLa nano-alloy; the mass ratio of the nano-alloy, tungsten oxide and micro-mesoporous molecular sieve is 1:(1-14):(25-200).

[0007] Optionally, the mass ratio of the nano alloy, tungsten oxide and micro-meso-multi-level pore molecular sieve is preferably 1: (5-10): (50-100); in the PtSn nano alloy, the molar ratio of Pt to Sn is 1: (0.1-2); in the PtLa nano alloy, the molar ratio of Pt to La is 1: (0.1-2); the size of the nano alloy is 0.5-8nm, preferably 2-6nm; the specific surface area of ​​the micro-meso-multi-level pore molecular sieve is 150-500m 2 / g, a silicon-aluminum ratio of 5-100, and a pore size of 0.5-20nm; the micro-meso-multilevel pore molecular sieve includes at least one of a micro-meso-multilevel pore Beta molecular sieve, a micro-meso-multilevel pore ZSM-5 molecular sieve, a micro-meso-multilevel pore Y molecular sieve and a micro-meso-multilevel pore mordenite.

[0008] A second aspect of the present invention provides a method for preparing a catalyst, the method comprising:

[0009] S1. Using a solution containing a nano alloy to impregnate a micro-meso-multilevel pore molecular sieve loaded with tungsten oxide, and then performing a first solid-liquid separation to obtain a first solid material; the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy; the mass ratio of the nano alloy, tungsten oxide and the micro-meso-multilevel pore molecular sieve is 1:(1-14):(25-200);

[0010] S2. performing a first drying and a first calcination on the first solid material.

[0011] Optionally, in step S1, the mass ratio of the nano alloy, tungsten oxide and micro-mesoporous molecular sieve is preferably 1: (5-10): (50-100); in the PtSn nano alloy, the molar ratio of Pt to Sn is 1: (0.1-2); in the PtLa nano alloy, the molar ratio of Pt to La is 1: (0.1-2); the size of the nano alloy is 0.5-8nm, preferably 2-6nm; the solvent of the solution containing the nano alloy is ethanol aqueous solution; in the ethanol aqueous solution, the volume fraction of ethanol is 80-99%; the pH value of the solution containing the nano alloy is 8-11; in the solution containing the nano alloy, the content of the nano alloy is 0.1-2% by mass; in step S2, the first calcination temperature is 300-550°C, and the time is 2-8h.

[0012] Optionally, the method also includes: mixing a Pt source, an auxiliary metal source, a surfactant, an organic solvent, a base and water and heating and refluxing to prepare the nanoalloy; the auxiliary metal source includes a Sn source and / or a La source; relative to 100mL of water, the amount of the Pt source is 0.1-1g, the amount of the auxiliary metal source is 0.1-1g, the amount of the surfactant is 0.2-2g, the amount of the organic solvent is 20-500mL, and the amount of the base is 0.1-2g; the heating temperature is 100-200°C, and the reflux time is 1-5h.

[0013] Preferably, the Pt source is one of chloroplatinic acid solution, tetraammineplatinum nitrate, platinum chloride and platinum nitrate; the Sn source is at least one of stannous chloride dihydrate, tin tetrachloride, bis(acetylacetonate)tin dichloride and butyltin trichloride; the La source is at least one of lanthanum chloride, lanthanum nitrate hexahydrate, lanthanum carbonate and lanthanum sulfate; the surfactant is at least one of PVP, CTAB, oleylamine and sodium acetate; the organic solvent is at least one of ethanol, methanol, propanol and ethylene glycol; the alkali is at least one of sodium hydroxide, ammonia water, potassium hydroxide and sodium carbonate.

[0014] Optionally, the method further includes: using an aqueous solution of a tungsten-containing precursor to impregnate a micro-meso-multilevel pore molecular sieve and then performing a second solid-liquid separation to obtain a second solid material, performing a second drying and a second calcination on the second solid material to prepare the micro-meso-multilevel pore molecular sieve loaded with tungsten oxide; the tungsten-containing precursor is selected from at least one of sodium tungstate, ammonium paratungstate and ammonium metatungstate; the second calcination temperature is 400-700°C, and the time is 1-6h; the concentration of the tungsten-containing precursor in the aqueous solution of the tungsten-containing precursor is 1-20% by mass.

[0015] Optionally, the method further comprises: homogeneously reacting the microporous molecular sieve with an alkaline solution, and then performing a third solid-liquid separation to obtain a third solid material, and performing a third drying and a third calcination on the third solid material to prepare the micro-meso-hierarchical pore molecular sieve;

[0016] The specific surface area of ​​the microporous molecular sieve is 200-650m 2 / g, a silicon-aluminum ratio of 5-100, a pore size of 0.3-1nm; the specific surface area of ​​the micro-meso-multi-level pore molecular sieve is 150-500m 2 / g, a silicon-aluminum ratio of 5-100, and a pore size of 0.5-20nm; the microporous molecular sieve includes at least one of microporous Beta molecular sieve, microporous ZSM-5 molecular sieve, microporous Y molecular sieve and microporous mordenite; the micro-meso-multi-level pore molecular sieve includes at least one of micro-meso-multi-level pore Beta molecular sieve, micro-meso-multi-level pore ZSM-5 molecular sieve, micro-meso-multi-level pore Y molecular sieve and micro-meso-multi-level pore mordenite;

[0017] The mass ratio of the microporous molecular sieve to the alkaline solution is 1:(10-50); the homogeneous reaction temperature is 50-150°C, and the time is 6-36h; the third calcination temperature is 300-600°C, and the time is 1-6h; the alkali in the alkaline solution is at least one of sodium hydroxide, potassium hydroxide, tetrapropylammonium hydroxide and tetraethylammonium hydroxide; in the alkaline solution, the concentration of the alkali is 0.5-5% by mass.

[0018] The third aspect of the present invention provides a catalyst prepared by the method provided by the second aspect of the present invention.

[0019] The fourth aspect of the present invention provides a method for preparing 1,3-propylene glycol, the method comprising: contacting glycerol with the catalyst described in the third aspect of the present invention under hydrogenation conditions.

[0020] Optionally, the mass ratio of glycerol to the catalyst is 1:(0.01-0.3), preferably 1:(0.02-0.1); the hydrogenation conditions include: hydrogen pressure of 1-8Mpa, preferably 2-5Mpa, reaction temperature of 140-200°C, preferably 150-180°C, reaction time of 6-24h; glycerol is used in the form of a glycerol aqueous solution with a mass fraction of 5-90%, preferably in the form of a glycerol aqueous solution with a mass fraction of 10-50%.

[0021] Through the above technical scheme, the catalyst of the present invention uses a molecular sieve with a stable structure, water resistance and high temperature resistance as a carrier, and performs a mesoporous treatment on it, which not only enhances the stability during the reaction process, but also enhances its activity; different from the existing method of using Pt salt as a precursor for loading, the preparation of the catalyst of the present invention uses a series of pretreatment methods to synthesize PtSn and / or PtLa nano alloys with narrow distribution, and then loads it, which greatly enhances its hydrogen overflow ability, improves activity and target product selectivity. In addition, the alkaline ethanol aqueous solution is used as a solvent during the nano alloy loading process of the present invention, which enhances the combination of the two active components, improves stability, and enhances activity.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 This is a TEM image of the catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0026] The first aspect of the present invention provides a catalyst, which includes a carrier, a first active component loaded on the carrier, and a second active component; the carrier is a micro-mesoporous molecular sieve, the first active component is tungsten oxide, and the second active component is a nano alloy; the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy; the mass ratio of the nano alloy, tungsten oxide and the micro-mesoporous molecular sieve is 1:(1-14):(25-200).

[0027] According to the present invention, optionally, the size of the nano alloy is 0.5-8 nm, preferably 2-6 nm. The catalytic activity of the nano alloy of suitable size in the present invention is significantly higher than that of other sizes.

[0028] According to the present invention, optionally, the specific surface area of ​​the micro-meso-multi-level pore molecular sieve can be 150-500m 2 / g, the silicon-aluminum ratio can be 5-100, and the pore size can be 0.5-20nm; the micro-meso-multilevel pore molecular sieve includes at least one of micro-meso-multilevel pore Beta molecular sieve, micro-meso-multilevel pore ZSM-5 molecular sieve, micro-meso-multilevel pore Y molecular sieve and micro-meso-multilevel pore mordenite.

[0029] The inventors of the present invention have found that by using a microporous molecular sieve with a stable structure, water resistance and high temperature resistance as a carrier and subjecting it to mesoporation treatment, the treated molecular sieve has micro-meso-multi-level pores, which can not only stabilize Pt nanoparticles, but also enhance the contact probability of the two components, create more Pt-W interfaces, and enhance the stability during the reaction process, as well as enhance its activity, so that the catalyst prepared as a carrier is particularly suitable for catalyzing glycerol hydrogenation reaction, which can effectively improve the selectivity of the target product. The first active component, tungsten oxide, has strong aerobicity, and highly dispersed tungsten oxide can efficiently and selectively activate the secondary CO bond in glycerol; the second active component, PtSn nano alloy and / or PtLa nano alloy, has a uniform nano size, and the alloy component can improve the stability of the metal in a high-temperature hydrothermal reaction environment, and has a higher ability to activate hydrogen.

[0030] According to the present invention, optionally, the ratio of the carrier, the first active component and the second active component has a certain influence on the catalytic activity of the catalyst. In the present invention, the mass ratio of the nano alloy, tungsten oxide and micro-mesoporous molecular sieve is preferably 1: (5-10): (50-100). The above embodiment enables the catalyst to have good catalytic activity.

[0031] According to the present invention, optionally, in the PtSn nanoalloy, the molar ratio of Pt to Sn can be 1:(0.1-2); in the PtLa nanoalloy, the molar ratio of Pt to La can be 1:(0.1-2). The above embodiment can obtain PtSn and / or PtLa nanoalloys with narrow particle size distribution, enhance their hydrogen overflow capacity, and improve activity and target product selectivity.

[0032] A second aspect of the present invention provides a method for preparing a catalyst, the method comprising:

[0033] S1. Using a solution containing a nano alloy to impregnate a micro-meso-multilevel pore molecular sieve loaded with tungsten oxide, and then performing a first solid-liquid separation to obtain a first solid material; the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy; the mass ratio of the nano alloy, tungsten oxide and the micro-meso-multilevel pore molecular sieve is 1:(1-14):(25-200);

[0034] S2. performing a first drying and a first calcination on the first solid material.

[0035] According to the present invention, optionally, in step S1, the mass ratio of the nano alloy, tungsten oxide and micro-meso-multilevel pore molecular sieve can vary within a certain range, for example, the mass ratio of the nano alloy, tungsten oxide and micro-meso-multilevel pore molecular sieve is preferably 1:(5-10):(50-100); in the PtSn nano alloy, the molar ratio of Pt to Sn can be 1:(0.1-2); in the PtLa nano alloy, the molar ratio of Pt to La can be 1:(0.1-2); the size of the nano alloy is 0.5-8nm, preferably 2-6nm.

[0036] According to the present invention, optionally, in step S1, the specific surface area of ​​the micro-mesoporous molecular sieve can be 150-500m 2 / g, the silicon-aluminum ratio can be 5-100, and the pore size can be 0.5-20nm; the micro-meso-multilevel pore molecular sieve includes at least one of micro-meso-multilevel pore Beta molecular sieve, micro-meso-multilevel pore ZSM-5 molecular sieve, micro-meso-multilevel pore Y molecular sieve and micro-meso-multilevel pore mordenite.

[0037] According to the present invention, optionally, the solvent of the solution containing nano alloy is ethanol aqueous solution; in the ethanol aqueous solution, the volume fraction of ethanol can be 80-99%; the pH value of the solution containing nano alloy can be 8-11. Using ethanol aqueous solution as a solvent under alkaline conditions enhances the combination of the two active components, which can improve stability and enhance activity. In the solution containing nano alloy, the content of the nano alloy can be 0.1-2% by mass; within the above range, nano particles with uniform size and monodisperse can be synthesized.

[0038] According to the present invention, optionally, the first drying and the first calcination are conventional steps for preparing the catalyst, and the present invention has no particular limitation. For example, in step S2, the conditions for the first drying may be: a temperature of 80-120° C. and a time of 1-8 h. The conditions for the first calcination may be: a temperature of 300-550° C. and a time of 1-8 h. By calcining, the surfactant of the outer layer of the PtSn nanoalloy and / or the PtLa nanoalloy may be removed.

[0039] According to the present invention, optionally, the method further comprises: mixing a Pt source, an auxiliary metal source, a surfactant, an organic solvent, an alkali and water and heating and refluxing the mixture to prepare the nano alloy; the auxiliary metal source comprises a Sn source and / or a La source.

[0040] According to the present invention, optionally, relative to 100mL of water, the amount of the Pt source can be 0.1-1g, the amount of the auxiliary metal source can be 0.1-1g, the amount of the surfactant can be 0.2-2g, the amount of the organic solvent can be 20-500mL, and the amount of the base can be 0.1-2g; the heating temperature can be 100-200°C, and the reflux time can be 1-5h; within the above conditions, nano-alloy particles of uniform size can be obtained.

[0041] According to the present invention, optionally, the Pt source can be one of chloroplatinic acid solution, tetraammine platinum nitrate, platinum chloride and platinum nitrate. In a preferred embodiment, the Pt source is chloroplatinic acid solution; the Sn source can be at least one of stannous chloride dihydrate, tin tetrachloride, bis(acetylacetone)tin dichloride and butyltin trichloride. In a preferred embodiment, the Sn source is stannous chloride dihydrate; the La source can be at least one of lanthanum chloride, lanthanum nitrate hexahydrate, lanthanum carbonate and lanthanum sulfate. In a preferred embodiment, the La source is lanthanum chloride. The surfactant is known in the art, for example, the surfactant can be at least one of PVP, CTAB, oleylamine and sodium acetate. In a preferred embodiment, the surfactant can be PVP; the organic solvent can be one known to those skilled in the art, for example, it can be at least one of ethanol, methanol, propanol and ethylene glycol. The present invention is preferably ethanol; the alkali is at least one of sodium hydroxide, ammonia, potassium hydroxide and sodium carbonate. In a preferred embodiment, the alkali is sodium hydroxide. In the above-mentioned implementation mode, chloroplatinic acid solution is used as a Pt source, tin chloride dihydrate is used as a Sn source, and lanthanum chloride is used as a La source. The metal can be used as an oxidant, and an organic solvent can be used as a reducing agent to synthesize PtSn and / or PtLa nano-alloys. The use of a surfactant can make the size of the synthesized nano-alloy particles uniform, which is beneficial to enhancing the activity.

[0042] According to the present invention, optionally, the method further comprises: impregnating the micro-meso-multilevel pore molecular sieve with a tungsten-containing precursor aqueous solution and then performing a second solid-liquid separation to obtain a second solid material, and performing a second drying and a second calcination on the second solid material to prepare the micro-meso-multilevel pore molecular sieve loaded with tungsten oxide.

[0043] According to the present invention, optionally, the concentration of the tungsten-containing precursor in the tungsten-containing precursor aqueous solution can be 1-20% by mass. The concentration is within the above range, which can make the loaded tungsten species more dispersed. The tungsten-containing precursor is selected from at least one of sodium tungstate, ammonium paratungstate and ammonium metatungstate. In a preferred embodiment, the tungsten-containing precursor can be selected from sodium tungstate. The second calcination temperature can be 400-700°C, and the time is 1-6h.

[0044] According to the present invention, optionally, the method further comprises: homogeneously reacting the microporous molecular sieve with an alkaline solution, then performing a third solid-liquid separation to obtain a third solid material, and performing a third drying and a third calcination on the third solid material to prepare the micro-mesoporous multi-level pore molecular sieve.

[0045] According to the present invention, optionally, the specific surface area of ​​the microporous molecular sieve can be 200-650m 2 / g, the silicon-aluminum ratio can be 5-100, the pore size can be 0.3-1nm; the specific surface area of ​​the micro-meso-multi-level pore molecular sieve can be 150-500m 2 / g, the silicon-aluminum ratio can be 5-100, and the pore size can be 0.5-20nm; the microporous molecular sieve includes at least one of microporous Beta molecular sieve, microporous ZSM-5 molecular sieve, microporous Y molecular sieve and microporous mordenite; the micro-meso-multilevel pore molecular sieve includes at least one of micro-meso-multilevel pore Beta molecular sieve, micro-meso-multilevel pore ZSM-5 molecular sieve, micro-meso-multilevel pore Y molecular sieve and micro-meso-multilevel pore mordenite.

[0046] According to the present invention, optionally, the mass ratio of the microporous molecular sieve to the alkaline solution can vary within a certain range. In order to give full play to the optimal performance of the microporous molecular sieve, a suitable ratio of mesoporation conditions is provided. For example, the mass ratio of the microporous molecular sieve to the alkaline solution can be 1: (10-50). The alkali in the alkaline solution is at least one of sodium hydroxide, potassium hydroxide, tetrapropylammonium hydroxide and tetraethylammonium hydroxide; in the alkaline solution, the concentration of the alkali is 0.5-5% by mass. By treating the microporous molecular sieve with alkali, micro-meso-multiple pores can be introduced into the microporous molecular sieve channel system, which not only enhances the stability during the reaction, but also enhances its activity. The homogeneous reaction temperature is 50-150°C and the time is 6-36h; the third drying and the third calcination are conventional steps for preparing molecular sieves, and the present invention has no special restrictions. For example, the third drying temperature can be 80-150°C and the time is 4-18h; the third calcination temperature can be 300-600°C and the time is 1-6h.

[0047] The third aspect of the present invention provides a catalyst prepared by the method provided by the second aspect of the present invention.

[0048] The fourth aspect of the present invention provides a method for preparing 1,3-propylene glycol, the method comprising: contacting glycerol with the catalyst described in the third aspect of the present invention under hydrogenation conditions.

[0049] According to the present invention, optionally, the contact can be carried out in any reactor sufficient to allow the raw material containing glycerol to contact the catalyst under hydrogenation conditions for reaction, such as a fixed bed reactor or an autoclave reactor. The glycerol is used in the form of a glycerol aqueous solution with a mass fraction of 5 to 90%, preferably in the form of a glycerol aqueous solution with a mass fraction of 10 to 50%. The mass ratio of glycerol to the catalyst is 1: (0.01-0.3), preferably 1: (0.02-0.1); the hydrogenation conditions can refer to the prior art, and taking the evaluation of the autoclave reactor as an example, the hydrogenation conditions may include: a hydrogen pressure of 1 to 8 MPa, preferably 2 to 5 MPa, a reaction temperature of 140 to 200°C, preferably 150 to 180°C, and a reaction time of 6 to 24 hours.

[0050] The catalyst of the invention has high catalytic activity and 1,3-propylene glycol selectivity when used for preparing 1,3-propylene glycol, the glycerol conversion rate is 40-95%, and the 1,3-propylene glycol selectivity is 50-70%.

[0051] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0052] Example 1

[0053] Weigh 6 g of microporous Beta molecular sieve (specific surface area 536 m 2 / g, Si / Al ratio of 40, pore size of 0.7nm) was placed in a 100mL hydrothermal kettle, and 60mL of 0.15mol·L -1 NaOH solution was placed in a homogeneous reactor at 60°C for 6 hours, centrifuged, dried at 110°C for 8 hours, and then calcined at 550°C for 2 hours to obtain a micro-mesoporous Beta molecular sieve (specific surface area of ​​468 m 2 / g, silicon aluminum ratio is 50, pore size is 3.8nm), for standby use. Measure 100mL water, 400mL ethanol, place in a 1L round-bottom flask, weigh 0.16g 8% chloroplatinic acid solution, 0.12g stannous chloride dihydrate, 1.12g PVP, 0.5g NaOH, stir for 5 minutes, then heat to 100°C, reflux for 3 hours under argon atmosphere to obtain PtSn nano alloy solution, then add 100mL 1M hydrochloric acid solution, centrifuge and wash 3 times with acetone and n-hexane, separate and standby use. 1.07g sodium tungstate is dissolved in 5mL water to form a sodium tungstate aqueous solution, then add 6g micro-meso-multi-level pore Beta molecular sieve, stir for 6h, dry at 80°C for 12h, calcine at 600°C for 3h, and obtain a micro-meso-multi-level pore Beta molecular sieve loaded with 14% by weight of tungsten oxide. 0.09 g of PtSn nano-alloy was ultrasonically dispersed in an ethanol-water solution (volume ratio of 9:1), 6 g of micro-mesoporous Beta molecular sieve loaded with 14 wt% tungsten oxide was added, the pH value of the solution was adjusted to 9 with ammonia water, stirred for 3 hours, centrifuged and then dried at 80°C for 8 hours and calcined at 500°C for 3 hours to obtain the final PtSn-WOx-Beta catalyst. The composition of the catalyst was 1.5 wt% PtSn / 14 wt% W-Beta, calculated on the basis of metal elements and based on the dry weight of the catalyst, wherein the Pt:Sn atomic ratio in the PtSn alloy was 4:1 and the size of the PtSn alloy was 3 nm.

[0054] Example 2

[0055] The catalyst was prepared in the same manner as in Example 1, except that the amount of sodium tungstate used was 0.54 g, and a micro-meso-multi-level pore Beta molecular sieve loaded with 7 wt% tungsten oxide was obtained. The composition of the catalyst was 1.5 wt% PtSn / 7 wt% W-Beta, calculated on the basis of the metal elements and the dry weight of the catalyst.

[0056] Example 3

[0057] The catalyst was prepared in the same manner as in Example 1, except that the amount of PtSn nanoalloy used was 0.18 g, and the composition of the catalyst was 3 wt % PtSn / 14 wt % W-Beta, calculated as metal elements and based on the dry weight of the catalyst.

[0058] Example 4

[0059] The catalyst was prepared in the same manner as in Example 1, except that the amount of sodium tungstate used was 0.8 g, and a micro-meso-multilevel pore Beta molecular sieve loaded with 10 wt% tungsten oxide was obtained. The amount of PtSn nano alloy used was 0.12 g, and the composition of the catalyst was 2 wt% PtSn / 10 wt% W-Beta, calculated as metal elements and based on the dry weight of the catalyst.

[0060] Example 5

[0061] The catalyst was prepared by the same method as in Example 1, except that the auxiliary metal source used was La source, the amount of chloroplatinic acid solution used was 0.18 g, the amount of lanthanum chloride used was 0.13 g, the Pt:La atomic ratio in the PtLa alloy was 9:1, and the size of the PtLa alloy was 3 nm.

[0062] Example 6

[0063] The catalyst was prepared by the same method as in Example 1, except that the micro-mesoporous molecular sieve used was ZSM-5 (with a specific surface area of ​​450 m 2 / g, silicon-aluminum ratio of 25, pore size of 4.2nm), calculated in terms of metal elements and based on the dry weight of the catalyst, the composition of the catalyst is 1.5wt% PtSn / 14wt% W-ZSM-5.

[0064] Example 7

[0065] The catalyst was prepared by the same method as in Example 1, except that when the PtSn alloy was loaded, the solvent used was a neutral anhydrous ethanol solution, and the size of the PtSn alloy was 5 nm.

[0066] Comparative Example 1

[0067] The catalyst was prepared by the same method as in Example 1, except that the Pt loading method was a conventional equal volume impregnation method.

[0068] Comparative Example 2

[0069] The catalyst was prepared by the same method as in Example 1, except that the microporous Beta molecular sieve carrier was not subjected to mesoporation treatment.

[0070] Comparative Example 3

[0071] The catalyst was prepared in the same manner as in Example 1, except that the amount of sodium tungstate used was 5.35 g, and a micro-meso-multilevel pore Beta molecular sieve loaded with 70 wt% tungsten oxide was obtained. The amount of PtSn nano alloy used was 0.3 g, and the composition of the catalyst was 5 wt% PtSn / 70 wt% W-Beta, calculated as metal elements and based on the dry weight of the catalyst.

[0072] Test Case

[0073] The catalysts prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were tested for their catalytic activity in preparing 1,3-propylene glycol.

[0074] The catalysts obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were weighed respectively, placed in a 50 mL autoclave reactor, 20 g of 10 wt% glycerol was added, and the reaction temperature was 160° C. After 12 h of reaction, the mixture was centrifuged and the supernatant was taken for gas chromatography analysis. The test results are shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] The above embodiments and comparative examples show that the catalyst for preparing 1,3-propylene glycol by hydrogenolysis of glycerol synthesized by the present invention has the characteristics of high unit Pt space-time yield and high selectivity for 1,3-propylene glycol compared with the catalyst synthesized by the existing method, and has good industrial application value in the industrial synthesis of 1,3-propylene glycol from glycerol.

[0079] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0080] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0081] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalyst, characterized in that The catalyst comprises a carrier, a first active component loaded on the carrier, and a second active component; the carrier is a micro-meso-multilevel pore molecular sieve, the first active component is tungsten oxide, and the second active component is a nano alloy; the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy; the mass ratio of the nano alloy, tungsten oxide and the micro-meso-multilevel pore molecular sieve is 1:(1-14):(25-200).

2. The catalyst according to claim 1, wherein The mass ratio of the nano alloy, tungsten oxide and micro-mesoporous molecular sieve is preferably 1: (5-10): (50-100); In the PtSn nano alloy, the molar ratio of Pt to Sn is 1:(0.1-2); in the PtLa nano alloy, the molar ratio of Pt to La is 1:(0.1-2); The size of the nano alloy is 0.5-8nm, preferably 2-6nm; The specific surface area of ​​the micro-meso-multi-level pore molecular sieve is 150-500m 2 / g, silicon-aluminum ratio of 5-100, pore size of 0.5-20nm; The micro-meso-hierarchical pore molecular sieve includes at least one of micro-meso-hierarchical pore Beta molecular sieve, micro-meso-hierarchical pore ZSM-5 molecular sieve, micro-meso-hierarchical pore Y molecular sieve and micro-meso-hierarchical pore mordenite.

3. A method for preparing a catalyst, characterized in that: The method includes: S1. Using a solution containing a nano alloy to impregnate a micro-meso-multilevel pore molecular sieve loaded with tungsten oxide, and then performing a first solid-liquid separation to obtain a first solid material; the nano alloy is a PtSn nano alloy and / or a PtLa nano alloy; the mass ratio of the nano alloy, tungsten oxide and the micro-meso-multilevel pore molecular sieve is 1:(1-14):(25-200); S2. performing a first drying and a first calcination on the first solid material.

4. The method according to claim 3, wherein: In step S1, the mass ratio of the nano alloy, tungsten oxide and micro-mesoporous molecular sieve is preferably 1: (5-10): (50-100); In the PtSn nano alloy, the molar ratio of Pt to Sn is 1:(0.1-2); in the PtLa nano alloy, the molar ratio of Pt to La is 1:(0.1-2); The size of the nano alloy is 0.5-8nm, preferably 2-6nm; The solvent of the solution containing nano alloy is ethanol aqueous solution; the volume fraction of ethanol in the ethanol aqueous solution is 80-99%; the pH value of the solution containing nano alloy is 8-11; the content of the nano alloy in the solution containing nano alloy is 0.1-2% by mass; In step S2, the first calcination temperature is 300-550°C and the time is 2-8h.

5. The method according to claim 3 or 4, wherein: The method further comprises: mixing a Pt source, an auxiliary metal source, a surfactant, an organic solvent, an alkali and water and heating and refluxing the mixture to prepare the nano alloy; the auxiliary metal source comprises a Sn source and / or a La source; Relative to 100mL of water, the amount of the Pt source is 0.1-1g, the amount of the auxiliary metal source is 0.1-1g, the amount of the surfactant is 0.2-2g, the amount of the organic solvent is 20-500mL, and the amount of the base is 0.1-2g; The heating temperature is 100-200°C, and the reflux time is 1-5h; Preferably, the Pt source is one of chloroplatinic acid solution, tetraammineplatinum nitrate, platinum chloride and platinum nitrate; the Sn source is at least one of stannous chloride dihydrate, tin tetrachloride, bis(acetylacetonate)tin dichloride and butyltin trichloride; the La source is at least one of lanthanum chloride, lanthanum nitrate hexahydrate, lanthanum carbonate and lanthanum sulfate; the surfactant is at least one of PVP, CTAB, oleylamine and sodium acetate; the organic solvent is at least one of ethanol, methanol, propanol and ethylene glycol; the alkali is at least one of sodium hydroxide, ammonia water, potassium hydroxide and sodium carbonate.

6. The method according to claim 3, wherein: The method further comprises: impregnating the micro-meso-multilevel pore molecular sieve with a tungsten-containing precursor aqueous solution and then performing a second solid-liquid separation to obtain a second solid material, and performing a second drying and a second calcination on the second solid material to prepare the micro-meso-multilevel pore molecular sieve loaded with tungsten oxide; The tungsten-containing precursor is selected from at least one of sodium tungstate, ammonium paratungstate and ammonium metatungstate; the second calcination temperature is 400-700°C, and the time is 1-6h; the concentration of the tungsten-containing precursor in the tungsten-containing precursor aqueous solution is 1-20% by mass.

7. The method according to claim 3 or 6, wherein: The method further comprises: homogeneously reacting the microporous molecular sieve with an alkaline solution, then performing a third solid-liquid separation to obtain a third solid material, and performing a third drying and a third calcination on the third solid material to prepare the micro-meso-hierarchical pore molecular sieve; The specific surface area of ​​the microporous molecular sieve is 200-650m 2 / g, a silicon-aluminum ratio of 5-100, a pore size of 0.3-1nm; the specific surface area of ​​the micro-meso-multi-level pore molecular sieve is 150-500m 2 / g, a silicon-aluminum ratio of 5-100, and a pore size of 0.5-20nm; the microporous molecular sieve includes at least one of microporous Beta molecular sieve, microporous ZSM-5 molecular sieve, microporous Y molecular sieve and microporous mordenite; the micro-meso-multi-level pore molecular sieve includes at least one of micro-meso-multi-level pore Beta molecular sieve, micro-meso-multi-level pore ZSM-5 molecular sieve, micro-meso-multi-level pore Y molecular sieve and micro-meso-multi-level pore mordenite; The mass ratio of the microporous molecular sieve to the alkaline solution is 1: (10-50); the homogeneous reaction temperature is 50-150° C., and the time is 6-36 hours; the third calcination temperature is 300-600° C., and the time is 1-6 hours; The alkali in the alkali solution is at least one of sodium hydroxide, potassium hydroxide, tetrapropylammonium hydroxide and tetraethylammonium hydroxide; and the concentration of the alkali in the alkali solution is 0.5-5% by mass.

8. The catalyst prepared by the method according to any one of claims 3 to 7.

9. A method for preparing 1,3-propylene glycol, characterized in that: The method comprises: contacting glycerol with the catalyst according to claim 8 under hydrogenation conditions.

10. The method according to claim 9, wherein: The mass ratio of glycerol to the catalyst is 1:(0.01-0.3), preferably 1:(0.02-0.1); the hydrogenation conditions include: hydrogen pressure of 1-8Mpa, preferably 2-5Mpa, reaction temperature of 140-200°C, preferably 150-180°C, reaction time of 6-24h; Glycerin is used in the form of a 5 to 90% by mass glycerin aqueous solution, preferably in the form of a 10 to 50% by mass glycerin aqueous solution.

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