Preparation method and application of supported tin-based single / double-metal catalyst
By dealuminizing and metal loading on commercial Al-β zeolites, a supported tin-based single and bimetallic catalyst was prepared, which solved the problems of long tin synthesis time and tin oxide formation in the prior art, and achieved the effect of efficient catalytic conversion of glucose to lactic acid.
Patent Information
- Application Number
- CN202510247824.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2025-06-06
Smart Images
Figure CN120094633A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical engineering, and in particular to a preparation method of a supported tin-based monometallic and bimetallic catalyst and application thereof. Background Art
[0002] Lactic acid is a versatile molecule with hydroxyl and carboxyl groups that is widely used in the pharmaceutical, food and cosmetic industries. The global demand for lactic acid has increased significantly over the past few years and will continue to grow, especially due to its successful application as a monomer in the production of bioplastics (polylactic acid). The catalytic conversion of carbohydrates into lactic acid is currently one of the most promising pathways, due to the abundance of renewable biomass resources and the easy availability of catalysts suitable for large-scale industrial applications.
[0003] Sn-Beta is considered to be a representative catalyst for the conversion of glucose to lactic acid, in which the Lewis acidic tin sites are particularly effective for cascade reactions such as glucose isomerization, retro-aldol condensation of fructose, dehydration of dihydroxyacetone, and rehydration of methylglyoxal to produce lactic acid. Although Sn-Beta exhibits good catalytic performance in the production of lactic acid, the direct addition of tin to the molecular sieve framework during the hydrothermal synthesis process is cumbersome and time-consuming. This is due to the need to add tin precursors to the gel when synthesizing Beta zeolite molecular sieves, which largely hinders the nucleation and crystal growth processes, resulting in prolonged synthesis time (up to 40 days). On the other hand, how to obtain a large number of isolated active sites without forming tin oxides remains a challenge.
[0004] The post-synthesis method has attracted widespread attention because of its relatively short synthesis time and the absence of harmful reagents such as hydrofluoric acid. In general, this process can be described as first removing the metal from the original zeolite framework and then adding tin cations to the vacant zeolite framework to form more open tin sites [(HO)-Sn-(OSi) 3 ], these sites have higher activity, which can promote the isomerization and retro-aldol condensation of sugars. However, this is usually accompanied by the formation of more Si-OH defects because tin cannot fully occupy the vacancies, resulting in the formation of Brønsted acid sites and causing side reactions. Some studies have used the addition of alkali to [1] / Alkaline Earth Metals [2] or metal ions [3,4] To stabilize the open tin sites, however, there are some defects such as low lactic acid / methyl lactate yield or long catalyst synthesis time.
[0005] Therefore, in order to solve the above problems, this paper proposes a preparation method and application of a supported tin-based mono- and bimetallic catalyst. Summary of the invention
[0006] The purpose of the present invention is to provide a tin-based molecular sieve catalyst with a simple preparation method and strong reusability, so as to realize the efficient and green preparation of lactic acid from sugars.
[0007] In order to achieve the above technical effects, the present invention is implemented by the following technical scheme: A method for preparing a supported tin-based single and double metal catalyst, characterized in that it comprises the following steps:
[0008] S1, dealuminizing the commercial Al-β zeolite at a ratio of 20 mL of concentrated nitric acid solution per gram of commercial Al-β zeolite;
[0009] S2. Use a Buchner funnel and a water pump to filter the dealuminated zeolite, and wash it with deionized water until the pH value of the filtrate is neutral. Collect the dealuminated zeolite on the Buchner funnel filter paper, and then dry it at 100° C. until it is dry.
[0010] S3, loading the dried dealuminated zeolite with metal to obtain an initial catalyst body;
[0011] S4. The obtained catalyst precursor is calcined to prepare a supported tin-based monometallic and bimetallic catalyst.
[0012] Furthermore, in S1, the dealumination treatment step is as follows: 10 g of zeolite molecular sieve is put into a round-bottom flask, and then 100 mL of concentrated nitric acid solution is added, and a reaction reflux device is installed in an oil bath at 90-110° C. to carry out dealumination operation for 10 hours;
[0013] Furthermore, in S1, the concentration of the concentrated nitric acid solution is 65-68%.
[0014] Furthermore, in S3, the step of loading the dealuminated molecular sieve with a metal is as follows: a dried dealuminated β molecular sieve zeolite carrier is taken, tin tetrachloride is used as a base, and tin tetrachloride and chromium chloride, indium chloride, niobium oxalate, magnesium chloride, ammonium tungstate and ammonium heptamolybdate metal salts are used as precursors, and an initial impregnation method is used to prepare a metal-loaded β molecular sieve zeolite catalyst to prepare an initial catalyst body.
[0015] Furthermore, in S4, the heating rate in the muffle furnace is 2°C / min.
[0016] Another object of the present invention is to provide an application of a supported tin-based single and double metal catalyst, characterized in that the supported tin-based single and double metal catalyst is used in catalyzing the preparation of lactic acid from glucose.
[0017] Further, the steps of preparing lactic acid by catalyzing glucose with a supported tin-based single and bimetallic catalyst are as follows:
[0018] A. Take 80-360 mg of glucose and add it to 10 mL of deionized water solvent to prepare an initial reaction substrate system with different concentration gradients;
[0019] B. Place the initial reaction substrate system in a closed high-temperature and high-pressure reactor and fill it with 0.5 MPa of N 2 , heat and stir at 110-160°C for 15-540 min to carry out the reaction of converting glucose into lactic acid.
[0020] The beneficial effects of the present invention are:
[0021] The supported tin-based single and double metal catalysts designed by the present invention have a simple preparation method and can efficiently catalyze the reverse aldol condensation reaction of glucose to produce lactic acid; the product lactic acid has a high carbon yield and high selectivity, and has great practical application value; at the same time, the supported tin-based single and double metal catalysts can also catalyze a variety of sugar substrates to produce high-yield lactic acid, have extremely strong substrate adaptability, and present a good industrial application prospect. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.
[0023] Figure 1 It is a preparation flow chart of the supported tin-based mono- and bi-metallic catalyst of the present invention;
[0024] Figure 2 It is a schematic diagram of preparing lactic acid from glucose by catalyzing the supported tin-based monometallic and bimetallic catalysts of the present invention. DETAILED DESCRIPTION
[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0026] Example 1
[0027] A method for preparing a supported tin-based monometallic and bimetallic catalyst, characterized in that it comprises the following steps:
[0028] S1. Take 10g of zeolite molecular sieve and put it into a round-bottom flask, then add 100mL of concentrated nitric acid solution with a concentration of 65-68%, and place it in an oil bath at 100°C with a reaction reflux device for dealumination operation for 10 hours;
[0029] S2. Filter the dealuminated zeolite using a Buchner funnel and a water pump, wash with deionized water until the pH value is neutral, and then dry at 100°C;
[0030] S3. Take a dried dealuminated β molecular sieve zeolite carrier, use tin tetrachloride as a base, and then use tin tetrachloride and one of chromium chloride, indium chloride, niobium oxalate, magnesium chloride, ammonium tungstate and ammonium heptamolybdate as precursors to prepare a metal-loaded β molecular sieve zeolite catalyst using an initial impregnation method to prepare a catalyst initial body.
[0031] S4. The obtained catalyst precursor is placed in a muffle furnace at 550° C. and calcined for 6 hours to prepare a supported tin-based monometallic and bimetallic catalyst with a tin loading of 5 wt%.
[0032] Example 2
[0033] This example aims to illustrate the use of an impregnation method to load the metal salt tin tetrachloride on a dealuminated β zeolite carrier, with a tin loading of 5 wt %, denoted as Sn-deAl-β, and to explore the reaction effect of a single metal tin-loaded catalyst at different temperatures.
[0034] First, the catalyst prepared with the zeolite carrier was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0035] The reactor was sealed, heated and stirred at 110-160°C for 3 hours. After the reaction was completed, the reaction was cooled to room temperature, filtered, and the filtrate was tested for glucose conversion rate and lactic acid yield by liquid chromatography; the data table of the Sn-deAl-β catalyst catalytic reaction shown in Table 1 was obtained.
[0036]
[0037] Table 1
[0038] Example 3
[0039] This example aims to illustrate the use of an impregnation method to load the metal salt tin tetrachloride on a dealuminated β zeolite carrier, with a tin loading of 5 wt %, denoted as Sn-deAl-β, and to explore the reaction effect of a single metal tin-loaded catalyst at 160° C. at different reaction times.
[0040] First, the catalyst prepared with the zeolite carrier was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0041] The reactor was sealed, heated and stirred at 160°C for 15 to 180 minutes. After the reaction was completed, it was cooled to room temperature and filtered. The filtrate was tested for glucose conversion rate and lactic acid yield by liquid chromatography. The data table of the Sn-deAl-β catalyst catalytic reaction was obtained as shown in Table 2.
[0042]
[0043]
[0044] Table 2
[0045] Example 4
[0046] This example aims to illustrate the use of an impregnation method to load a metal salt tin tetrachloride and another metal salt at a metal molar ratio of 1:1 on a dealuminated β zeolite carrier, with a tin loading of 5 wt%, denoted as SnM-deAl-β, where M represents other metal elements, and to explore the reaction effect of the bimetallic SnM-deAl-β catalyst at 160°C at different reaction times.
[0047] The metal salts chromium chloride and tin tetrachloride are loaded on the dealuminated zeolite and recorded as SnCr-deAl-β.
[0048] The metal salts indium chloride and tin chloride are loaded on the dealuminated zeolite and recorded as SnIn-deAl-β.
[0049] The combination of metal salts niobium oxalate and tin chloride loaded on dealuminated zeolite is recorded as SnNb-deAl-β.
[0050] The metal salt magnesium chloride and tin chloride combined and loaded on the dealuminated zeolite is recorded as SnMg-deAl-β.
[0051] The combination of metal salts ammonium tungstate and tin chloride loaded on dealuminated zeolite is recorded as SnW-deAl-β.
[0052] The combination of metal salt ammonium heptamolybdate and tin chloride loaded on dealuminated zeolite is recorded as SnMo-deAl-β.
[0053] First, the catalyst prepared with the zeolite carrier was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0054] The reactor was sealed and heated and stirred at 160°C for 180 minutes. After the reaction was completed, it was cooled to room temperature and filtered. The filtrate was tested for glucose conversion rate and lactic acid yield by liquid chromatography. The data table of the catalytic reaction of the Sn-based bimetallic zeolite molecular sieve catalyst shown in Table 3 was obtained.
[0055]
[0056] Table 3
[0057] Example 5
[0058] This example aims to illustrate the catalytic performance of preparing lactic acid from glucose using SnMo-deAl-β as the best catalyst to explore the catalytic performance of preparing lactic acid from glucose under different ratios of Mo and Sn; the catalyst is denoted as Sn x Mo-deAl-β, the subscript x represents the metal molar ratio of Mo to Sn.
[0059] Firstly, the catalyst loaded with Mo and Sn in different metal molar ratios was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0060] Sn 0.2 Mo-deAl-β was used as catalyst, and the amount of catalyst was 40 mg;
[0061] Sn 0.5 Mo-deAl-β was used as catalyst, and the amount of catalyst was 40 mg;
[0062] Sn 1 Mo-deAl-β was used as catalyst, and the amount of catalyst was 40 mg;
[0063] Sn 1.5 Mo-deAl-β was used as catalyst, and the amount of catalyst was 40 mg;
[0064] Sn 2 Mo-deAl-β was used as catalyst, and the amount of catalyst was 40 mg;
[0065] The reactor was sealed and heated and stirred at 160°C for 3 hours. After the reaction was completed, it was cooled to room temperature, diluted and filtered, and the filtrate was tested for mannose yield by liquid chromatography to obtain the data table of the catalytic reaction of Mo and Sn loaded on the dealuminated zeolite in different metal ratios as shown in Table 4.
[0066]
[0067] Table 4
[0068] Example 6
[0069] The purpose of this example is to use SnMo-deAl-β with a molar ratio of Sn to Mo of 1:1 as the best catalyst to explore the effect and influence of different temperatures on the preparation of lactic acid from glucose.
[0070] First, the catalyst SnMo-deAl-β was added into a reaction kettle with a volume of 10 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0071] The reactor was sealed and heated and stirred at 110-180°C for 180 minutes. After the reaction was completed, the mixture was cooled to room temperature, diluted and filtered, and the filtrate was tested for lactic acid yield by liquid chromatography to obtain the reaction data table shown in Table 5 when the reaction temperature was changed within the range of 110-180°C.
[0072]
[0073] Table 5
[0074] Example 7
[0075] The purpose of this example is to use SnMo-deAl-β as a catalyst to explore the effect and influence of different reaction times on the preparation of lactic acid from glucose.
[0076] First, the catalyst SnMo-deAl-β was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added, and the amount of catalyst was 40 mg.
[0077] The reactor was sealed, heated and stirred at 160°C for 15 to 540 minutes. After the reaction was completed, the mixture was cooled to room temperature, diluted and filtered, and the filtrate was tested for lactic acid yield by liquid chromatography; the data within the range of 15 to 540 minutes as shown in Table 6 were obtained.
[0078]
[0079] Table 6
[0080] Example 8
[0081] This example aims to use SnMo-deAl-β as a catalyst to explore the effect and influence of different glucose substrate concentrations on the preparation of lactic acid.
[0082] First, the catalyst SnMo-deAl-β was added into a reactor with a stirrer and a volume of 10 mL, and then different masses of glucose (80-360 mg) and 10 mL of water were added. The mass concentration of glucose was 8-36 g / L, and the ratio of the amount of catalyst used to the amount of glucose added was 1:2.
[0083] The reactor was sealed and heated and stirred at 160°C for 180 minutes. After the reaction was completed, the mixture was cooled to room temperature, diluted and filtered, and the filtrate was tested for mannose yield by liquid chromatography; the reaction data table in the range of substrate concentration of 8 to 36 g / L was obtained as shown in Table 7.
[0084]
[0085]
[0086] Table 7
[0087] Example 9
[0088] The purpose of this example is to use SnMo-deAl-β as a catalyst to explore the effect and influence of different catalyst dosages on the preparation of lactic acid from glucose.
[0089] First, the catalyst SnMo-deAl-β was added into a reaction kettle with a volume of 25 mL and equipped with a stirrer, and then 80 mg of glucose and 10 mL of water were added. The amount of the catalyst was 0 to 160 mg.
[0090] The reactor was sealed and heated and stirred at 160°C for 180 minutes. After the reaction was completed, the mixture was cooled to room temperature, diluted and filtered, and the filtrate was tested for mannose yield by liquid chromatography; the reaction data table in the range of catalyst dosage of 0 to 160 mg was obtained as shown in Table 8.
[0091]
[0092] Table 8
[0093] Example 10
[0094] The purpose of this example is to use SnMo-deAl-β as a catalyst to explore the effects and influences of different sugars as substrates on the preparation of lactic acid from glucose.
[0095] The selected carbohydrate compounds mainly include fructose, mannose, xylose, arabinose, sucrose and cellobiose.
[0096] First, the catalyst MoSn-deAl-β was added into a reaction kettle with a volume of 25 mL and an agitator, and then 80 mg of glucose and 10 mL of water were added. The mass concentration of glucose was 8 g / L, and the amount of catalyst was 0 to 160 mg.
[0097] The reactor was sealed and heated and stirred at 160° C. for 180 minutes. After the reaction was completed, the mixture was cooled to room temperature, diluted and filtered, and the filtrate was tested for mannose yield by liquid chromatography; the reaction data table shown in Table 9 was obtained.
[0098]
[0099] Table 9.
Claims
1. A method for preparing a supported tin-based monometallic and bimetallic catalyst, characterized in that: The following steps are involved: S1, dealuminizing the commercial Al-β zeolite at a ratio of 20 mL of concentrated nitric acid solution per gram of commercial Al-β zeolite; S2. Use a Buchner funnel and a water pump to filter the dealuminated zeolite, and wash it with deionized water until the pH value of the filtrate is neutral. Collect the dealuminated zeolite on the Buchner funnel filter paper, and then dry it at 100° C. until it is dry. S3, loading the dried dealuminated zeolite with metal to obtain an initial catalyst body; S4. The obtained catalyst precursor is placed in a muffle furnace at 550-600° C. and calcined for 6 hours to prepare a supported tin-based monometallic and bimetallic catalyst.
2. The method for preparing a supported tin-based single and double metal catalyst according to claim 1, characterized in that: In S1, the dealumination treatment steps are as follows: 10 g of zeolite molecular sieve is put into a round-bottom flask, and then 100 mL of concentrated nitric acid solution is added, and a reaction reflux device is installed in an oil bath at 90-110° C. for dealumination operation for 10 hours.
3. The method for preparing a supported tin-based single and double metal catalyst according to claim 1, characterized in that: In S1, the concentration of the concentrated nitric acid solution is 65-68%.
4. The method for preparing a supported tin-based single and double metal catalyst according to claim 1, characterized in that: In S3, the step of metal loading on the dealuminated molecular sieve is as follows: take a dried dealuminated β molecular sieve zeolite carrier, use tin tetrachloride as a basis, and then combine tin tetrachloride and other metal salts as precursors, and adopt an initial impregnation method to prepare a metal-loaded β molecular sieve zeolite catalyst to prepare an initial catalyst body.
5. The method for preparing a supported tin-based single and double metal catalyst according to claim 4, characterized in that: The other metal salt is one of chromium chloride, indium chloride, niobium oxalate, magnesium chloride, ammonium tungstate and ammonium heptamolybdate.
6. The method for preparing a supported tin-based monometallic and bimetallic catalyst according to claim 1, characterized in that: In S4, the heating rate in the muffle furnace is 2°C / min; the loading amount of tin in the mono / bimetallic supported zeolite molecular sieve catalyst is 5 wt%.
7. An application of a supported tin-based monometallic and bimetallic catalyst, characterized in that: The supported tin-based single and double metal catalysts are used in catalyzing the preparation of lactic acid from glucose.
8. The use of a supported tin-based monometallic and bimetallic catalyst according to claim 7, characterized in that: The steps of preparing lactic acid from glucose using a supported tin-based single and bimetallic catalyst are as follows: A. Take 80-360 mg of glucose and add it to 10 mL of deionized water solvent to prepare an initial reaction substrate system with different concentration gradients; B. Place the initial reaction substrate system in a sealed high-temperature and high-pressure reactor, fill it with 0.5MPa of N2, heat and stir at 110-160°C for 15-540 min Carry out the reaction of converting glucose into lactic acid.