Catalyst for preparing ethylene glycol from biomass as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for preparing ethylene glycol from biomass as well as a preparation method and application of the catalyst. The catalyst for preparing ethylene glycol from biomass comprises a carrier and a noble metal active component loaded on the carrier, and the carrier is a bismuth element bulk phase doped SBA-15 molecular sieve. The catalyst prepared by the invention has high activity for preparing ethylene glycol from biomass, and can be used in a catalytic reaction for preparing ethylene glycol from biomass.

Description

Technical Field

[0001] The invention belongs to the field of catalysts, and in particular relates to a biomass-to-ethylene glycol catalyst and a preparation method and application thereof. Background Art

[0002] The development of the world's economy and society today is highly dependent on fossil resources, but fossil resources are non-renewable resources. The fossil resources on the earth will one day be exhausted by humans. Therefore, it is very important to seek a renewable resource to replace fossil resources for the sustainable development of mankind. Biomass is a renewable carbon-containing resource with abundant reserves in nature. According to statistics, the carbon fixed by plant photosynthesis reaches 200 billion tons per year. The annual production of plants on the earth alone is equivalent to 20 times the mineral energy consumed by humans. The potential for resource development and utilization is huge. Biomass synthesized by photosynthesis is generally a precursor of sugar-containing compounds, such as cellulose. In addition to providing food for humans, these compounds cannot be used directly as chemicals. Therefore, converting biomass such as cellulose into commonly used chemicals is a major scientific problem and difficulty facing mankind. What kind of chemicals can biomass be converted into to more reasonably utilize biomass resources is a problem that must be faced in biomass utilization. Cellulose hydrolysis can produce glucose and fructose, etc. Sugar is a polyol, which can be decomposed into low-alcohols from the analysis of molecular structure. Ethylene glycol is an important basic organic raw material, mainly used in the production of polyethylene terephthalate (PET), automotive antifreeze, unsaturated polyester resin, nonionic surfactant, plasticizer, etc., and has a wide range of uses. At present, the industrial production of ethylene glycol mainly comes from fossil resources. If ethylene glycol can be prepared from biomass, it can enrich the source of ethylene glycol production at present, and in the future it can replace fossil resources to produce synthetic ethylene glycol, which has broad application prospects.

[0003] At present, human beings are still in the early development stage of biomass utilization, and the technology is not mature. The same is true for the preparation of ethylene glycol from biomass. The use of biomass to produce small molecule diols can be traced back to 1933. However, due to the difficulty in controlling the reaction selectivity, the technology has developed slowly in the following decades. For example, the Ni-Mo-Cu / diatomaceous earth catalyst reported in 2005 can catalyze the hydrogenolysis of sucrose to obtain glycerol, ethylene glycol and propylene glycol, but the mass yields are only 28%, 22% and 13%, respectively. It was not until 2008 that a significant breakthrough was achieved in this field: Zhang Tao's research group at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, used tungsten carbide catalysts for cellulose conversion reactions and obtained a high yield of ethylene glycol for the first time (61%, mass fraction). Therefore, tungsten-based catalysts have been widely studied by the scientific community. For example, nickel-tungsten, iridium-tungsten, and ruthenium-tungsten catalysts have all been developed for cellulose conversion to ethylene glycol catalysts. Of course, other transition metal catalysts have also been used for cellulose to prepare ethylene glycol catalysts. For example, nickel-tin, nickel-lanthanum, and chromium-copper catalysts have also been developed for cellulose conversion to ethylene glycol catalysts. Summary of the invention

[0004] One of the technical problems to be solved by the present invention is that the catalyst for preparing ethylene glycol from biomass in the prior art has low activity and poor stability. The prepared catalyst has the advantages of high activity and good stability. The second technical problem to be solved by the present invention is a method for preparing the catalyst corresponding to the first technical problem. The third technical problem to be solved by the present invention is the application of the catalyst corresponding to the first technical problem in preparing ethylene glycol from biomass.

[0005] In the first aspect, the present invention provides a biomass-to-ethylene glycol catalyst, comprising a carrier and a noble metal active component loaded on the carrier, wherein the carrier is a bismuth-doped SBA-15 molecular sieve. The bismuth active component of the catalyst of the present invention is introduced during the hydrothermal synthesis of the mesoporous molecular sieve, and the noble metal active component is loaded on the mesoporous molecular sieve by an impregnation method, which can effectively improve its catalytic activity and stability.

[0006] In some embodiments, the mass content of the bismuth element is 0.3%-2.5% based on the mass of the catalyst. In some embodiments, the mass content of the bismuth element is 0.4%, 0.6%, 0.7%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, 1.5%, 1.55%, 1.6%, 1.65%, 1.7%, 1.75%, 1.8%, 1.85%, 1.9%, 1.95%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4% or any value therebetween. In some embodiments, the mass content of the bismuth element is 0.8%-2% based on the mass of the catalyst.

[0007] In some embodiments, the mass content of the precious metal is 0.01%-0.15% based on the mass of the catalyst. In some embodiments, the mass content of the precious metal is 0.02%, 0.03%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085%, 0.09%, 0.095%, 0.1%, 0.105%, 0.11%, 0.115%, 0.12%, 0.13%, 0.14% or any value therebetween. In some embodiments, the mass content of the precious metal is 0.04%-0.12% based on the mass of the catalyst.

[0008] In some embodiments, the noble metal active components are platinum and palladium. In some embodiments, the molar ratio of platinum to palladium is (0.015-12):1. In some embodiments, the molar ratio of platinum to palladium is 0.05:1, 0.2:1, 0.5:1, 0.7:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 9:1, 10:1, 11:1 or any value therebetween. In some embodiments, the molar ratio of platinum to palladium is (0.1-8):1.

[0009] In some embodiments, the specific surface area of ​​the catalyst is 500 m 2 / g-900m 2 / g

[0010] In a second aspect, the present invention provides a method for preparing a biomass-to-ethylene glycol catalyst, comprising:

[0011] S1: mixing a silicon source, a bismuth source, a template, an acid and water, and performing a crystallization reaction to obtain a crystallization reaction product;

[0012] S2: drying and first calcining the crystallization reaction product in S1 to obtain a bismuth-doped SBA-15 molecular sieve;

[0013] S3: The bismuth-doped SBA-15 molecular sieve in S2 is impregnated in a solution containing a noble metal source, followed by drying, a second calcination and reduction to obtain the catalyst.

[0014] In some embodiments, the molar ratio of the bismuth source to the silicon source is (0.01-0.06):1, for example, 0.015:1, 0.02:1, 0.025:1, 0.03:1, 0.035:1, 0.04:1, 0.045:1, 0.05:1 or 0.055:1. In some embodiments, the molar ratio of the bismuth source to the silicon source is (0.02-0.04):1, based on the bismuth element and the silicon element.

[0015] In some embodiments, the molar ratio of the template to the silicon source is (0.01-0.025):1, for example, 0.013:1, 0.015:1, 0.017:1, 0.02:1, or 0.023:1. In some embodiments, the molar ratio of the acid to the silicon source is (1.0-1.3):1, for example, 1.05:1, 1.1:1, 1.15:1, 1.2:1, or 1.25:1. In some embodiments, the molar ratio of the water to the silicon source is (195-215):1, for example, 198:1, 200:1, 203:1, 205:1, 207:1, 209:1, 210:1, 211:1, or 213:1.

[0016] In some embodiments, the silicon source is selected from at least one of tetraethyl silicate, tetramethyl silicate, and methacryloxypropyltrimethoxysilane.

[0017] In some embodiments, the bismuth source is selected from at least one of bismuth nitrate, bismuth acetate, and bismuth oxalate.

[0018] In some embodiments, the template is selected from at least one of P123 and hexadecyltrimethylammonium bromide.

[0019] In some embodiments, the acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid and acetic acid.

[0020] In some embodiments, based on the mass of the bismuth-doped SBA-15 molecular sieve, the mass content of the precious metal element in the precious metal source is 0.01%-0.15%, for example, 0.02%, 0.03%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085%, 0.09%, 0.095%, 0.1%, 0.105%, 0.11%, 0.115%, 0.12%, 0.13%, 0.14% or any value therebetween. In some embodiments, the mass content of the precious metal element in the precious metal source is 0.04%-0.12%.

[0021] In some embodiments, the noble metal source includes a platinum source and a palladium source.

[0022] In some embodiments, the molar ratio of the platinum source to the palladium source is (0.015-12): 1, for example, 0.05: 1, 0.2: 1, 0.5: 1, 0.7: 1, 1: 1, 1.5: 1, 2: 1, 2.5: 1, 3: 1, 3.5: 1, 4: 1, 4.5: 1, 5: 1, 5.5: 1, 6: 1, 6.5: 1, 7: 1, 7.5: 1, 8: 1, 9: 1, 10: 1 or 11: 1. In some embodiments, the molar ratio of the platinum source to the palladium source is (0.1-8): 1, for example, 0.05: 1, 0.2: 1, 0.5: 1, 0.7: 1, 1: 1, 1.5: 1, 2: 1, 2.5: 1, 3: 1, 3.5: 1, 4: 1, 4.5: 1, 5: 1, 5.5: 1, 6: 1, 6.5: 1, 7: 1, 7.5: 1, 8: 1, 9: 1, 10: 1 or 11: 1.

[0023] In some embodiments, the noble metal source is selected from a soluble acid of a noble metal or a soluble salt of a noble metal, such as chloroplatinic acid and palladium chloride.

[0024] In some embodiments, the temperature of the crystallization reaction in S1 is 110° C.-130° C. In some embodiments, the time of the crystallization reaction in S1 is 15 h-30 h.

[0025] In some embodiments, the temperature of the first calcination in S2 is 500° C.-600° C. In some embodiments, the time of the first calcination in S2 is 4 h-10 h.

[0026] In some embodiments, the temperature of the second calcination in S3 is 500°C-600°C. In some embodiments, the time of the second calcination in S3 is 1h-15h. In some embodiments, the reduction in S3 is carried out under a mixed atmosphere of hydrogen and nitrogen. In some embodiments, the temperature of the reduction in S3 is 300°C-400°C. In some embodiments, the volume concentration of hydrogen in the mixed gas is 5%-25%.

[0027] In some embodiments, the method for preparing a biomass-to-ethylene glycol catalyst of the present invention comprises the following specific steps:

[0028] 1) Synthesis of bismuth-doped SBA-15 molecular sieve: Dissolve the template such as P123 in water, add the required acid such as hydrochloric acid, then add the silicon source and bismuth source solution, and stir at 25°C-45°C for 10h-30h. Then crystallize at a certain temperature such as 110°C-130°C. Finally, filter to obtain the solid, dry and calcine it to obtain the SBA-15 molecular sieve doped with metallic bismuth.

[0029] 2) The noble metal platinum and palladium are dissolved in water to obtain an aqueous solution, which is impregnated onto the above-mentioned SBA-15 molecular sieve doped with metal bismuth by an impregnation method, and then dried and calcined to obtain a catalyst.

[0030] 3) The above catalyst is reduced with hydrogen at a certain temperature, for example, 300°C-400°C.

[0031] In a third aspect, the present invention provides use of the catalyst described in the first aspect or the catalyst prepared by the preparation method described in the second aspect in the production of ethylene glycol from biomass.

[0032] In the fourth method, the present invention provides a method for preparing ethylene glycol from biomass, which comprises contacting a biomass raw material with the catalyst described in the first aspect or the catalyst prepared by the preparation method described in the second aspect, and introducing hydrogen at 200°C-250°C and 0.2MPa-10MPa to convert cellulose into ethylene glycol.

[0033] In some embodiments, the biomass raw material is selected from at least one of cellulose, starch, hemicellulose and sugars. The cellulose may include microcrystalline cellulose and cellulose in lignocellulosic biomass.

[0034] The catalyst provided by the present invention is a mesoporous molecular sieve catalyst loaded with dual active components of platinum palladium noble metal and non-noble metal bismuth. The catalyst active component bismuth is introduced during the hydrothermal synthesis of the mesoporous molecular sieve, and the noble metal active component is loaded onto the mesoporous molecular sieve by an impregnation method. The catalyst prepared by the present invention has high activity for preparing ethylene glycol from biomass, and can be used in the catalytic reaction of preparing ethylene glycol from biomass. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] The present invention will be described in detail below through examples.

[0038] Unless otherwise specified, all operations in the Examples and Comparative Examples were carried out at room temperature.

[0039] In the present invention, the reaction product is quantitatively determined by high performance liquid chromatography (Waters Alliance e2695), and the signal detection is completed by a differential refractive index detector (RID). The chromatographic column used is an SC1011 column, with water as the mobile phase, a flow rate of 0.7 mL / min, and a column temperature of 80°C.

[0040] The biomass conversion rate and ethylene glycol selectivity were calculated according to the following formula:

[0041]

[0042]

[0043] Example 1-Example 12

[0044] Step 1) Synthesis of bismuth-doped SBA-15 molecular sieve:

[0045] P123 (the molar ratio of P123 to tetraethyl tetrasilicate added later is 0.020) is dissolved in water (the molar ratio of water to tetraethyl silicate added later is 200) to obtain a solution, and then the required dilute hydrochloric acid (the molar ratio of hydrochloric acid to tetraethyl silicate added later is 1.20) is added, and stirred for 0.5 hours. Then a certain amount of tetraethyl silicate and the required amount of bismuth nitrate (the molar ratio of bismuth nitrate to tetraethyl silicate is shown in Table 1) solution are added, and stirred at 40°C for 20 hours. Then it is transferred to a stainless steel hydrothermal autoclave lined with polytetrafluoroethylene and crystallized at 100°C for 20 hours. Finally, filter, wash with deionized water to obtain a solid, dry it at 110°C, and roast it at 550°C for 8 hours to obtain a SBA-15 molecular sieve doped with metallic bismuth.

[0046] Step 2) Loading of precious metals platinum and palladium: The required amount of chloroplatinic acid and palladium chloride are prepared into an aqueous solution according to the amount given in Table 1, and then an equal amount of them are impregnated onto the above bismuth-doped SBA-15 molecular sieve carrier. Then, the catalyst precursor is obtained by drying at 110° C. for 5 hours and calcining at 550° C. for 5 hours.

[0047] Step 3) The catalyst precursor is reduced in a 10% hydrogen (the rest is nitrogen) atmosphere at 350° C. for 5 hours.

[0048] Performance Test:

[0049] 2 grams of cellulose and 100 grams of water were mixed and placed in a stainless steel reactor, 0.5 grams of the above catalyst was added, and the mixture was stirred at 250°C, hydrogen was introduced, and the pressure was increased to 6 MPa, and the reaction was carried out for 2.5 hours. The reaction results are shown in Table 1.

[0050] Embodiment 13

[0051] Except for the following differences, the remaining steps are the same as those in Example 3: In step 2), only the required amount of chloroplatinic acid is added.

[0052] Performance Test:

[0053] 2 grams of cellulose and 100 grams of water were mixed and placed in a stainless steel reactor, 0.5 grams of the above catalyst was added, and the mixture was stirred at 250°C, hydrogen was introduced, and the pressure was increased to 6 MPa, and the reaction was carried out for 2.5 hours. The reaction results are shown in Table 1.

[0054] Embodiment 14

[0055] The remaining steps are the same as those in Example 3 except for the following differences: In step 2), only the required amount of palladium chloride is added.

[0056] Performance Test:

[0057] 2 grams of cellulose and 100 grams of water were mixed and placed in a stainless steel reactor, 0.5 grams of the above catalyst was added, and the mixture was stirred at 250°C, hydrogen was introduced, and the pressure was increased to 6 MPa, and the reaction was carried out for 2.5 hours. The reaction results are shown in Table 1.

[0058] Comparative Example 1

[0059] Loading of precious metals platinum and palladium and metal bismuth: Bismuth nitrate, chloroplatinic acid and palladium chloride were prepared into aqueous solution according to the amounts given in Table 1, and then impregnated onto the alumina carrier. The catalyst was then dried at 110°C for 5 hours and calcined at 550°C for 6 hours to obtain the catalyst. Performance test:

[0060] 2 grams of cellulose and 100 grams of water were mixed and placed in a stainless steel reactor, 1.0 grams of the above catalyst was added, and the mixture was stirred at 250°C, hydrogen was introduced, and the pressure was increased to 6 MPa, and the reaction was carried out for 4 hours. The reaction results are shown in Table 1.

[0061] Comparative Example 2

[0062] Except for the following differences, the remaining steps are the same as in Example 3:

[0063] In step 1), a certain amount of tetraethyl silicate and a required amount of sodium tungstate (the molar ratio of sodium tungstate to tetraethyl silicate is shown in Table 1) solution are then added.

[0064] Performance Test:

[0065] 2 grams of cellulose and 100 grams of water were mixed and placed in a stainless steel reactor, 0.5 grams of the above catalyst was added, and the mixture was stirred at 250°C, hydrogen was introduced, and the pressure was increased to 6 MPa, and the reaction was carried out for 2.5 hours. The reaction results are shown in Table 1.

[0066] Table 1

[0067]

[0068]

[0069] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A biomass-to-ethylene glycol catalyst, comprising a carrier and a noble metal active component supported on the carrier, wherein: The carrier is a SBA-15 molecular sieve doped with bismuth element.

2. The catalyst according to claim 1, characterized in that Based on the mass of the catalyst, the mass content of the bismuth element is 0.3%-2.5%, preferably 0.8%-2%.

3. The catalyst according to claim 1 or 2, characterized in that Based on the mass of the catalyst, the mass content of the noble metal is 0.01%-0.15%, preferably 0.04%-0.12%.

4. The catalyst according to any one of claims 1 to 3, characterized in that The noble metal active components are platinum and palladium. Preferably, the molar ratio of platinum to palladium is (0.015-12):1, preferably (0.1-8):

1.

5. The catalyst according to any one of claims 1 to 4, characterized in that The specific surface area of ​​the catalyst is 500 m 2 / g-900m 2 / g.

6. A method for preparing a biomass-to-ethylene glycol catalyst, comprising: S1: mixing a silicon source, a bismuth source, a template, an acid and water, and performing a crystallization reaction to obtain a crystallization reaction product; S2: drying and first calcining the crystallization reaction product in S1 to obtain a bismuth-doped SBA-15 molecular sieve; S3: The bismuth-doped SBA-15 molecular sieve in S2 is impregnated in a solution containing a noble metal source, followed by drying, a second calcination and reduction to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that: Calculated on the basis of bismuth element and silicon element, the molar ratio of the bismuth source to the silicon source is (0.01-0.06):1, preferably (0.02-0.04):1; and / or The molar ratio of the template to the silicon source is (0.01-0.025):1, the molar ratio of the acid to the silicon source is (1.0-1.3):1, and the molar ratio of the water to the silicon source is (195-215):

1. Preferably, the silicon source is selected from at least one of tetraethyl silicate, tetramethyl silicate and methacryloxypropyltrimethoxysilane, the bismuth source is selected from at least one of bismuth nitrate, bismuth acetate and bismuth oxalate, the template is selected from at least one of P123 and hexadecyltrimethylammonium bromide, and the acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid and acetic acid.

8. The preparation method according to claim 6 or 7, characterized in that: The mass content of the precious metal element in the precious metal source is 0.01%-0.15%, preferably 0.04%-0.12%, based on the mass of the bismuth-doped SBA-15 molecular sieve; and / or The noble metal source comprises a platinum source and a palladium source. Preferably, the molar ratio of the platinum source to the palladium source is (0.015-12):1, preferably (0.1-8):1, calculated as platinum element and palladium element. Preferably, the noble metal source is selected from a soluble acid of a noble metal or a soluble salt of a noble metal, such as chloroplatinic acid and palladium chloride.

9. The preparation method according to any one of claims 6 to 8, characterized in that: In S1, the temperature of the crystallization reaction is 110° C.-130° C., and the time of the crystallization reaction is 15 h-30 h; and / or In S2, the temperature of the first calcination is 500° C.-600° C., and the time of the first calcination is 4 h-10 h; and / or In S3, the temperature of the second calcination is 500° C.-600° C., and the time of the second calcination is 1 h-15 h; and / or In S3, the reduction is performed in a mixed atmosphere of hydrogen and nitrogen, the reduction temperature is 300° C.-400° C., and preferably, the volume concentration of hydrogen in the mixed gas is 5%-25%.

10. Use of the catalyst according to any one of claims 1 to 5 or the catalyst prepared by the preparation method according to any one of claims 6 to 9 in the production of ethylene glycol from biomass.

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