CN113522345B - Ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material and preparation and application thereof - Google Patents

Ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material and preparation and application thereof Download PDF

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CN113522345B
CN113522345B CN202110830211.8A CN202110830211A CN113522345B CN 113522345 B CN113522345 B CN 113522345B CN 202110830211 A CN202110830211 A CN 202110830211A CN 113522345 B CN113522345 B CN 113522345B
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acid
sba
ordered mesoporous
mesoporous
zirconium
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CN113522345A (en
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潘大海
闫贝贝
于峰
任所财
陈树伟
闫晓亮
李瑞丰
王琰
王恒燕
史秀锋
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Taiyuan University of Technology
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/03—Catalysts comprising molecular sieves not having base-exchange properties
    • B01J29/0308—Mesoporous materials not having base exchange properties, e.g. Si-MCM-41
    • B01J35/615—
    • B01J35/617—
    • B01J35/635—
    • B01J35/638—
    • B01J35/647—
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0205—Impregnation in several steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0207—Pretreatment of the support
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/082—Decomposition and pyrolysis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/10—Heat treatment in the presence of water, e.g. steam
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L1/00—Liquid carbonaceous fuels
    • C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
    • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
    • C11C3/04—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fats or fatty oils
    • C11C3/10—Ester interchange
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
    • B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/20—After treatment, characterised by the effect to be obtained to introduce other elements in the catalyst composition comprising the molecular sieve, but not specially in or on the molecular sieve itself
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/37—Acid treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/40—Special temperature treatment, i.e. other than just for template removal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/10—Biofuels, e.g. bio-diesel

Abstract

The invention discloses an ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material, which is obtained by taking an ordered mesoporous Al-SBA-15 material rich in surface Al-OH species obtained by grafting Al on the surface of the pore wall of the ordered mesoporous SBA-15 material as a carrier and immobilizing sulfated zirconia. The solid acid material prepared by the invention has a highly regular and ordered mesoporous pore structure, a larger specific surface area and pore volume and higher structural stability, and the acid amount, acid center type, acid density and acid strength on the surface of the mesoporous pore wall are adjustable, so that the solid acid material can be used for catalyzing the transesterification reaction of soybean oil and methanol to synthesize biodiesel, and shows excellent biodiesel yield, catalytic stability and renewable reusability.

Description

Ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material and preparation and application thereof
Technical Field
The invention belongs to the technical field of preparation of inorganic porous solid acid catalytic materials, and relates to a sulfated zirconia-based solid acid material and a preparation method thereof. The solid acid material has a highly regular and ordered mesoporous pore channel structure, a higher specific surface area, a higher pore volume and a larger mesoporous pore diameter, and the surface acid amount, the acid density, the acid center type and the acid strength of the pore wall can be adjusted, so that the solid acid material can be used for catalyzing the transesterification reaction of synthesizing biodiesel from soybean oil and methanol.
Background
In the field of acid catalysis, with conventional liquid acids (e.g. H)2SO4HF and H3PO4) Compared with the prior art, the solid acid catalyst has the advantages of no corrosion, no pollution, easy separation, recycling and the like, and has wide application prospect in catalytic cracking, alkylation, isomerization, acylation, esterification and ester exchange reaction (theProg. Chem., 2011,23, 860；J. Mol. Catal. A-Chem2005, 237, 93), which is an important way to replace liquid acid catalysts to realize new environmentally friendly catalytic processes, is receiving widespread attention from technologists.
The catalytic function of the solid acid catalyst is mainly determined by acid centers on the surface of the solid acid, including Br ӧ nsted (B) acid and Lewis (L) acid centers.
Solid acids represented by sulfated zirconia whose surface acid center is derived from the induction of surface hydroxyl defects and S = O bonds of zirconia: (Catal. Today, 1994, 20, 295；Catal. Rev., 1996, 38, 329)。SO4 2-After coordination adsorption on the surface of zirconia, the S = O bond induces the electron cloud on the Zr-O bond to generate strong deviation, so that the Zr atom has the capability of accepting electron pairs and generates an L acid center; at the same time, the strong electron-withdrawing induction effect of S = O bond can reduce the electron cloud density in the Zr-OH, weaken the H-O bond function and generate the B acid center (B acid center) capable of providing protonJ. Catal., 1994, 150, 143)。
The specific surface area of the zirconia carrier is increased, and the coordination state, the electronic property and the Zr-OH content of Zr species on the surface of the zirconia carrier are changed, SO that the zirconia carrier and SO are hopefully enhanced4 2-On the basis of the inter-bonding effect, the aim of treating a large amount of SO is realized4 2-While stabilizing the solid support, the type, distribution and strength of the acid center on the surface of the material are modulated to obtain the sulfated zirconia solid acid catalytic material with more excellent catalytic performance (J. Phys. Chem. C, 2007, 111, 18731；Chem. Eng. J., 2019, 364, 111)。
However, the mesoporous zirconia carrier prepared by the conventional method is often disordered 'worm-shaped hole' structure, and has the defects of poor porosity, low specific surface area, small pore diameter, easy crystal phase transformation when heated and the like, SO that the carrier is loaded with SO4 2-The solid acid material obtained by the method generally has the defects of low acid content, poor structural thermal stability, difficult regulation and control of acid center type and distribution, easy loss and inactivation of active components in the catalytic process and the like, so that the practical application of the solid acid material in a plurality of catalytic reactions is severely limited.
Therefore, how to obtain a structure with high stability, large specific surface area and pore diameter and SO while introducing a regular ordered mesoporous structure to improve the diffusion rate of reactants and products through a simple and easily-repeated preparation process4 2-Carrying SO in the presence of strongly bonded zirconia-based carrier materials4 2-The method has the advantages that the surface acid center type, the acid density and the acid strength of the obtained solid acid material are adjusted while a large amount of solid carriers are stabilized, and the method has important research value and practical significance for development of high-performance sulfated zirconia-based solid acid catalytic materials with practical application values.
Disclosure of Invention
The invention aims to provide an ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material and a preparation method thereof, wherein zirconia is highly and uniformly coated on the mesoporous surface of the ordered mesoporous Al-SBA-15 material by means of a hydrothermal grafting method and a surface coating technology, and the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material is used for SO by taking the zirconia as a carrier4 2-The solid acid catalyst material of sulfated zirconia base, which has the advantages of regular and ordered mesoporous channel structure height, large specific surface area and pore diameter, high structure stability, adjustable surface acid amount, acid center type, acid density and acid strength, is prepared by the immobilization of the groups.
The ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material is prepared by the following method:
1) dissolving inorganic acid, organic carboxylic acid and triblock copolymer nonionic surfactant P123 in deionized water according to the molar ratio of silicon source, organic carboxylic acid, inorganic acid, deionized water and triblock copolymer nonionic surfactant P123= (50-150): (10-500): (150-500): (5000-13000): 1, slowly adding the silicon source, fully stirring for reaction, and drying to obtain the ordered mesoporous SBA-15 material wrapping the surfactant micelle;
2) adding the ordered mesoporous SBA-15 material into an aqueous solution of an aluminum source according to the Si/Al molar ratio of (5-100) to 1, adjusting the pH value of the solution to be 1-3, and performing hydrothermal treatment in a sealed high-pressure reaction kettle at 100-220 ℃ to prepare the ordered mesoporous Al-SBA-15 material which wraps the surfactant micelle and is grafted with Al atoms on the surface of the pore wall;
3) carrying out high-temperature treatment on the ordered mesoporous Al-SBA-15 material in an inert atmosphere to promote partial carbonization of surfactant micelles existing in the Al-SBA-15 mesoporous pore canals;
4) placing the ordered mesoporous Al-SBA-15 material subjected to high-temperature treatment in an aqueous solution of a zirconium source for dipping treatment, taking out the material, roasting the material in the air at 450-650 ℃, removing a part of carbonized surfactant micelles, and preparing the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall;
5) and placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into a sulfuric acid solution for dipping treatment, taking out the material and roasting the material at the temperature of 300-650 ℃ in the air to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
In the preparation method of the invention, the silicon source is one of methyl orthosilicate, ethyl orthosilicate, water glass or white carbon black, or a mixture of several of them in any proportion.
In the preparation method, the aluminum source is one of aluminum isopropoxide, aluminum tert-butoxide, aluminum isobutanolate, aluminum nitrate or aluminum chloride, or a mixture of several of the aluminum sources in any proportion.
In the above preparation method of the present invention, the zirconium source is one of zirconium oxychloride, zirconium isopropoxide, zirconium acetate or zirconium nitrate, or a mixture of several of them in any proportion.
In the above preparation method of the present invention, the inorganic acid is hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid.
In the preparation method of the invention, the organic carboxylic acid is citric acid, glacial acetic acid, oxalic acid or tartaric acid.
Wherein, in the step 1), the stirring reaction is carried out at normal temperature or slightly higher than the normal temperature.
Further, preferably, stirring reaction is carried out at the temperature of 20-45 ℃ for 6-24 hours to prepare the ordered mesoporous SBA-15 material wrapping the surfactant micelle.
In the step 2), the aqueous solution of the aluminum source is obtained by dissolving the aluminum source in deionized water according to a solid/liquid volume ratio of (0.02-0.2) to 1.
Further, the reaction time of the hydrothermal treatment is 6-48 h.
In the hydrothermal treatment process of the step 2), the pH value of the hydrothermal treatment solution is adjusted to be close to the isoelectric point of silicon oxide, the polymerization rate of silicon species in the pore wall of the SBA-15 material is low, a large amount of Si-OH can be reserved in the pore wall, and then the temperature is increased to carry out hydrothermal treatment so as to promote Al in the solution3+Ions generate forward reaction of hydrolysis to generate more Al-OH species, and the Al-OH species and Si-OH species in the hole wall of the SBA-15 material generate polymerization reaction to generate Si-O-Al bonds, so that Al is grafted to the hole wall of the mesopore of the SBA-15 material to obtain the ordered mesopore Al-SBA-15 material.
In the step 3), preferably, the ordered mesoporous Al-SBA-15 material is subjected to high-temperature treatment for 0.5-5 hours at 350-750 ℃ in an inert atmosphere, so that surfactant micelle existing in mesoporous channels of the Al-SBA-15 material is partially carbonized.
In the step 4), the ordered mesoporous Al-SBA-15 material subjected to high-temperature treatment is placed in a zirconium source water solution with the concentration of 0.1-1 mol/L for impregnation treatment according to the solid/liquid volume ratio of (0.05-1) to 1.
Further, the ordered mesoporous Al-SBA-15 material subjected to high-temperature treatment is preferably subjected to dipping treatment for 10-60 min in an aqueous solution of a zirconium source under stirring.
Furthermore, the product of the dipping treatment in the aqueous solution of the zirconium source is preferably roasted in the air for 3-8 h.
The high-temperature treatment under the inert atmosphere ensures that the surfactant micelle existing in the mesoporous pore channel of the Al-SBA-15 material still exists in the mesoporous pore channel of the Al-SBA-15 material although being partially carbonized, and a certain gap exists between the surfactant micelle and the pore wall, so that zirconium species can be impregnated on the surface of the pore wall of the Al-SAB-15 material, namely, a layer of zirconium oxide is coated on the surface of the pore wall of the Al-SBA-15 material; and then roasting in the air to remove the partially carbonized surfactant micelle in the mesoporous pore channel, and finally obtaining the Al-SBA-15 material which has an ordered mesoporous pore channel structure and a layer of zirconia uniformly coated on the surface of the pore wall.
If the surfactant micelle is directly removed, the zirconia is directly impregnated after the mesoporous pore channel is completely exposed, and the zirconia often forms nano particles in the pore channel, so that the pore channel is partially blocked, the utilization rate of zirconium species for bonding with sulfate radicals is reduced, and the acid content of the obtained solid acid is reduced.
In the step 5), the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall is placed in a sulfuric acid solution with the concentration of 0.1-2 mol/L for dipping treatment according to the solid/liquid volume ratio of (0.01-0.5) to 1.
Further, preferably, the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall is soaked in a sulfuric acid solution for 20-80 min under stirring.
Furthermore, the product of the dipping treatment in the sulfuric acid solution is preferably roasted in the air for 3-8 h.
The method comprises the steps of firstly, introducing an ordered mesoporous SBA-15 material which wraps a surfactant micelle and is rich in Si-OH on the surface of a pore wall into a precursor solution in which an aluminum source is dissolved, and carrying out high-temperature hydrothermal treatment on the material under the condition of a pH value close to the isoelectric point of silicon oxide. At the moment, the surfactant micelle existing in the SBA-15 mesoporous pore channel can effectively support the silicon oxide mesoporous framework and prevent the collapse of the ordered mesoporous structure caused by serious shrinkage in the high-temperature hydrothermal treatment process; meanwhile, a large amount of Si-OH reserved on the surface of the SBA-15 pore wall can be subjected to polymerization reaction with Al-OH obtained by high-temperature hydrolysis of an aluminum source in a solution to generate Si-O-Al bonds, so that Al atoms are highly and uniformly grafted on the surface of the pore wall of the SBA-15 mesopores.
And then, carrying out high-temperature partial carbonization treatment on the surfactant micelle in the Al-SBA-15 mesoporous pore canal in an inert atmosphere, so that an obvious gap exists between the surfactant micelle after carbonization and shrinkage and the Al-SBA-15 mesoporous pore wall, and the method can be used for uniformly coating zirconium oxide on the surface of the Al-SBA-15 mesoporous pore wall in the subsequent dipping treatment process.
Finally, through air roasting treatment, surfactant micelles partially carbonized in mesoporous pore canals can be removed, Al-OH species on the surface of the wall of the Al-SBA-15 pore and coated Zr-OH species are promoted to perform high-temperature polymerization reaction, and ZrO containing a large number of Zr-O-Al bonds and coated with a zirconia layer on the surface of the mesoporous pore wall is obtained2Al-SBA-15 material and use thereof as a support for SO4 2-A large amount of stable immobilization.
Based on the preparation method, the obtained ZrO is regulated and controlled by regulating and controlling the hydrothermal grafting treatment condition, the surfactant micelle carbonization shrinkage heat treatment condition, the zirconium oxide dipping treatment condition and the air roasting treatment condition2The specific surface area, pore volume and pore diameter of the/Al-SBA-15 carrier are simultaneously realized, the grafting amount of Al atoms on the surface, the coating degree of zirconia and the electronic property of the carrier are finely adjusted, and finally the purpose of introducing SO is achieved4 2-After the group is formed, the surface acid amount, the acid density, the acid type and the acid strength of the obtained ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material are effectively regulated and controlled.
The preparation method of the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material provided by the invention is simple and feasible, and has high reproducibility. The obtained solid acid material has a highly regular and ordered two-dimensional hexagonal mesoporous channel structure, high structural stability, large specific surface area and mesoporous aperture, zirconium and aluminum atoms on the surface of the pore wall can be uniformly dispersed at the atomic level, and the surface acidity is adjustable.
Through determination, the ordered mesoporous Al-SBA-15 load sulfated zirconia solid acid material prepared by the method of the inventionThe specific surface area of the material is 350-800 m2Per g, pore volume of 0.5-1.5 cm3The pore diameter is 6.0-25.0 nm, the molar ratio of zirconium to aluminum atoms on the surface of the mesoporous pore wall is adjusted within the range of 0.2-10, and the acid amount, the acid density, the ratio of B acid center to L acid center and the content of super acid center on the surface of the pore wall are respectively 1.5-5.2 mmol/g and 0.0001-0.02 mmol/m20.01 to 2.1 and 0 to 1.0 mmol/g.
The ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material prepared by the method is used as a catalyst, and has extremely high catalytic activity, stability and renewable reusability.
The ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material prepared by the method is used as a catalyst in the transesterification reaction of soybean oil and methanol to synthesize biodiesel, not only can realize the complete conversion of the soybean oil at 140 ℃ and ensure that the yield of the biodiesel is not lower than 99.0 percent, but also can ensure that the yield of the biodiesel is not lower than 73.0 percent after the biodiesel is repeatedly used for 8 times.
Meanwhile, the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material prepared by the invention is roasted and regenerated after being repeatedly used for many times, and the structure, the texture, the surface acidity and the catalytic performance of the material are not obviously changed.
Drawings
FIG. 1 is an XRD spectrum of an ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared in example 1.
FIG. 2 is an element mapping chart of ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared in example 1.
FIG. 3 is a diagram of example 1 for preparing an ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material with N2Adsorption-desorption isotherms (A) and corresponding pore size distribution curves (B).
FIG. 4 is NH of ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared in example 13TPD desorption profile.
FIG. 5 is a pyridine-infrared spectrum of ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared in example 1.
FIG. 6 is a graph of the effect of the number of reuses of the ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared in example 1 on the yield of biodiesel.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are only for more clearly illustrating the technical solutions of the present invention so as to enable those skilled in the art to better understand and utilize the present invention, and do not limit the scope of the present invention.
The names and abbreviations of the experimental methods, production processes, instruments and equipment involved in the examples and comparative examples of the present invention are those commonly known in the art and are clearly and clearly understood in the relevant fields of use, and those skilled in the art can understand the conventional process steps and apply the corresponding equipment according to the names and perform the operations according to the conventional conditions or conditions suggested by the manufacturers.
The various starting materials or reagents used in the examples of the present invention and comparative examples are not particularly limited in their sources, and are all conventional products commercially available. They may also be prepared according to conventional methods well known to those skilled in the art.
Example 1.
Adding 3.25g of tetraethoxysilane into 50mL of 2.0mol/L hydrochloric acid solution dissolved with 1.6g P123 and 0.82g of citric acid under strong stirring at 38 ℃, maintaining the temperature, continuing stirring for reaction for 24 hours, carrying out suction filtration and washing on reaction liquid, and preparing the white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species.
Adding the white solid obtained by self-assembly into 30mL of 0.5mol/L aluminum isopropoxide aqueous solution, adjusting the pH value of a reaction mixture to 2.0 by using dilute hydrochloric acid, stirring at room temperature for 30min, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 180 ℃ for hydrothermal treatment for 24h, taking out a reaction product, and performing suction filtration, washing and drying to obtain the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
In N2And heating the obtained white solid to 550 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2h to promote the carbonization shrinkage of the surfactant micelle in the mesoporous pore canal.
And then, placing the carbonized material in 15mL of 0.2mol/L zirconium oxychloride aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into 30mL of 1mol/L sulfuric acid solution, stirring for 30min at room temperature, carrying out suction filtration, drying for 12h at 100 ℃, heating to 550 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
As can be seen from the small angle XRD spectrum of fig. 1 (fig. 1A), the sample shows three distinct diffraction peaks at 2 θ =1.06, 1.68 and 1.92 °. The reciprocal of the interplanar spacing corresponding to the three diffraction peaks is calculated to find that the ratio is 1: 1.73: 2, so that the three diffraction peaks can be respectively identified as belonging top6mmThe diffraction of the crystal faces of (100), (110) and (200) of the space group shows that the obtained solid acid material has a highly regular and ordered two-dimensional hexagonal mesoporous channel structure. In addition, as can be seen from a large-angle XRD spectrogram (figure 1B), no crystal phase diffraction peak of zirconia or alumina is detected in the sample with the 2 theta of 10-80 degrees, which indicates that Zr and Al species on the surface of the mesoporous pore wall of the sample can be highly uniformly dispersed.
The elemental mapping analysis results (fig. 2) further demonstrate that Si, Al, Zr, and S species can achieve a highly uniform dispersion at the atomic level throughout the sample. By calculation, the Si/Al atomic ratio in the sample was 15.6, the Zr/Al atomic ratio was 1.03, and the Zr/S atomic ratio was 2.32.
From N of FIG. 32As can be seen from the adsorption-desorption isotherm (A) and the corresponding pore size distribution curve (B), the sample shows a typical IV-type adsorption isotherm of columnar pores and an H1-type hysteresis loop, and shows a very steep capillary condensation curve (as shown in FIG. 3A) in the range of relative pressure of 0.7-1.0, indicating that the sample has a high degree of order regularity and regularityMesoporous structure and larger and uniformly distributed mesoporous aperture (e.g. 3B). The specific surface area and the pore volume of the sample were respectively 478m as calculated2G and 0.89cm3The mesoporous aperture is 14.1 nm.
From sample NH3The TPD spectrum (fig. 4) shows that the sample shows four distinct ammonia desorption peaks at 207, 316, 410 and 578 ℃, corresponding to the desorption of the chemisorbed ammonia molecules at the weak, medium, strong and super acid centers on the sample surface. The total acid amount of the sample is 2.46mmol/g after calculation of the peak area of each desorption peak, wherein the acid amounts of the weak acid, the medium acid, the strong acid and the super acid on the surface are respectively 0.70, 0.43, 1.23 and 0.10 mmol/g.
From the pyridine adsorption-desorption infrared spectrum (FIG. 5) of the sample, it can be seen that the sample was at 1543, 1490 and 1454cm when pyridine was desorbed at 150, 250 and 350 deg.C, respectively-1All shows three obvious absorption peaks, which indicates that B acid and L acid centers exist on the surface of the pore wall of the sample. By desorbing 1543 and 1454cm in the infrared curve with pyridine at different temperatures-1The acid amount ratio of the total B acid center and the total L acid center of the sample was found to be 1.12 by calculation from the adsorption peak area, wherein the acid amount ratio of the B acid to the L acid in the strong acid center to the strong acid center was 2.07 and 1.36, respectively.
The prepared sample is used as a solid acid catalyst for preparing biodiesel through transesterification of soybean oil and methanol, and the catalytic performance of the catalyst is examined.
According to the molar ratio of soybean oil to methanol of 1: 20, 40g of reactants and 1.2g of catalyst are put into a closed reaction kettle with a stirrer, and the reaction is started at 140 ℃ under the condition of stirring speed of 600rpm for 5 hours.
After the reaction, solid-liquid separation was carried out by a centrifuge. The liquid reaction mixture was first distilled under reduced pressure to remove unreacted methanol, then left to stand until the mixed solution was layered up and down, and a quantitative upper layer solution was taken, diluted with pyridine, and subjected to product composition analysis on a gas chromatograph equipped with a hydrogen Flame Ionization Detector (FID).
The separated solid acid catalyst was washed with methanol and hexane, dried, and then put into use again to examine the catalytic stability of the catalyst.
The catalytic evaluation result (figure 6) shows that the catalytic material can realize the complete conversion of the soybean oil after the reaction is carried out at the low temperature of 140 ℃ for 5 hours, and the yield of the biodiesel in the product can reach 99.8 percent, which indicates that the catalyst has excellent transesterification reaction activity of the biodiesel synthesized from the soybean oil and methanol.
In addition, as can be seen from the trend that the yield of the biodiesel is changed along with the repeated use times of the catalyst, the catalyst can realize 100 percent conversion of soybean oil in the repeated use process of 4 times, and the yield of the biodiesel is kept above 99.7 percent. Even though the conversion rate of the catalyst to the soybean oil is gradually reduced from the 5 th repeated use, the catalyst can still realize the conversion of 80.9 percent of the soybean oil into the biodiesel (the yield of the biodiesel is 80.5 percent) after the 8 th repeated use.
More importantly, after the catalyst after 8 times of repeated use is calcined and regenerated for 2 hours at 550 ℃, the structure, texture and surface acidity of the catalyst are not obviously changed compared with those of a fresh catalyst, the complete conversion of soybean oil at 140 ℃ can be realized again, and the yield of the biodiesel reaches 99.6%.
Therefore, the catalyst shows excellent catalytic activity, stability and regeneration performance in the process of biodiesel transesterification reaction synthesized from soybean oil and methanol.
Example 2.
Adding 3.02g of methyl orthosilicate into 45mL of 2.0mol/L hydrochloric acid solution dissolved with 2.0g P123 and 1.65g of glacial acetic acid under strong stirring at 32 ℃, maintaining the temperature, continuing stirring and reacting for 12h, carrying out suction filtration and washing on reaction liquid, and preparing the white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species.
Adding the white solid obtained by self-assembly into 25mL of 1.0mol/L aluminum nitrate aqueous solution, adjusting the pH value of the reaction mixture to 2.4 by using dilute hydrochloric acid, stirring for 30min at room temperature, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 150 ℃ for hydrothermal treatment for 24h, taking out a reaction product, and performing suction filtration, washing and drying to obtain the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
In N2And heating the obtained white solid to 550 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2h to promote the carbonization shrinkage of the surfactant micelle in the mesoporous pore canal.
And then, putting the carbonized material into 15mL of 0.3mol/L zirconium nitrate aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into 10mL of 1.2mol/L sulfuric acid solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 100 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
XRD, EDX and N2The adsorption-desorption and other characteristic results prove that the prepared sample has a highly regular ordered two-dimensional hexagonal mesoporous channel structure and uniform mesoporous aperture, and Si, Al, Zr and S atoms on the surface of the pore wall of the sample can be uniformly dispersed on the level of near atoms in the whole sample range. By calculation, the specific surface area and the pore volume of the sample were 536m, respectively2G and 0.83cm3(ii)/g, the mesoporous pore diameter was 8.6 nm, the atomic ratio of Si/Al in the sample was 10.2, the atomic ratio of Zr/Al was 2.12, and the atomic ratio of Zr/S was 2.81.
NH3The infrared characterization results of TPD and pyridine adsorption-desorption prove that weak acid, medium acid, strong acid and super acid centers exist on the surface of the sample at the same time, and the contents are 0.62, 0.50, 1.35 and 0.12mmol/g respectively. The acid amount ratio of the total B acid center and L acid center on the surface of the sample was 1.15, wherein the acid amount ratio of the B acid to the L acid in the strong acid center to the strong acid center was 1.84 and 1.12, respectively.
The transesterification reaction of soybean oil and methanol was carried out under the reaction conditions of example 1, and the sample of this example was examined for its catalytic performance as a catalyst. The sample can realize the complete conversion of the soybean oil in the process of repeated use for 3 times, and the yield of the biodiesel is kept above 99.8 percent. Although the conversion rate of the sample to the soybean oil gradually decreases from the 4 th reuse, the yield of the biodiesel is kept above 80.2% in the 8 times of reuse.
After the used sample is roasted at 550 ℃ for regeneration for 2 hours, the structure, texture and surface acidity of the sample are not obviously changed compared with those before reaction, 100 percent of complete conversion of soybean oil can be realized again, and the yield of the biodiesel reaches 99.5 percent.
Example 3.
Adding 0.72g of white carbon black into 40mL of 1.0mol/L hydrochloric acid solution dissolved with 2.1g P123 and 0.62g of tartaric acid under strong stirring at 40 ℃, maintaining the temperature, continuing stirring and reacting for 24 hours, carrying out suction filtration and washing on reaction liquid, and preparing the white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species.
Adding the white solid obtained by self-assembly into 30mL of 1.5mol/L aluminum tert-butoxide aqueous solution, adjusting the pH value of the reaction mixture to 2.5 by using dilute hydrochloric acid, stirring at room temperature for 30min, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 160 ℃ for hydrothermal treatment for 24h, taking out a reaction product, and performing suction filtration, washing and drying to prepare the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
In N2And heating the obtained white solid to 650 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2h to promote the surfactant micelle in the mesoporous pore canal to be carbonized and shrunk.
And then, placing the carbonized material into 15mL of 0.3mol/L zirconium isopropoxide aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into 15mL of 1.5mol/L sulfuric acid solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 100 ℃ for 12h, heating to 600 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
XRD, EDX and N2The adsorption-desorption and other characteristic results prove that the prepared sample has a highly regular ordered two-dimensional hexagonal mesoporous channel structure and uniform mesoporous aperture, and Si, Al, Zr and S atoms on the surface of the pore wall of the sample can be uniformly dispersed on the level of near atoms in the whole sample range. The specific surface area and the pore volume of the sample were respectively 451m by calculation2G and 0.76cm3(ii)/g, the mesoporous pore diameter was 7.3nm, the atomic ratio of Si/Al in the sample was 8.7, the atomic ratio of Zr/Al was 1.12, and the atomic ratio of Zr/S was 2.51.
NH3The infrared characterization results of TPD and pyridine adsorption-desorption prove that weak acid, medium acid, strong acid and super acid centers exist on the surface of the sample at the same time, and the contents are 0.80, 0.62, 1.05 and 0.10mmol/g respectively. The acid amount ratio of the total B acid center and the L acid center on the surface of the sample was 1.55, wherein the acid amount ratio of the B acid to the L acid in the strong acid center and the strong acid center was 1.62 and 1.35, respectively.
The transesterification reaction of soybean oil and methanol was carried out under the reaction conditions of example 1, and the sample of this example was examined for its catalytic performance as a catalyst. The sample can realize the complete conversion of the soybean oil in the process of repeated use for 3 times, and the yield of the biodiesel is kept above 99.7 percent. Although the conversion rate of the sample to the soybean oil gradually decreases from the 4 th reuse, the yield of the biodiesel is kept above 80.8% in the 8 times of reuse.
After the used sample is roasted at 550 ℃ for regeneration for 2 hours, the structure, texture and surface acidity of the sample are not obviously changed compared with those before reaction, 100 percent of complete conversion of soybean oil can be realized again, and the yield of the biodiesel reaches 99.5 percent.
Example 4.
Under the condition of strong stirring at 35 ℃, 4.58g of tetraethoxysilane is added into 40mL of 2.0mol/L hydrochloric acid solution dissolved with 2.2g P123 and 1.2g of oxalic acid, the temperature is maintained, the stirring reaction is continued for 24 hours, the reaction solution is filtered and washed, and the white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species is prepared.
Adding the white solid obtained by self-assembly into 30mL of 1.5mol/L aluminum nitrate aqueous solution, adjusting the pH value of the reaction mixture to 1.8 by using dilute hydrochloric acid, stirring for 30min at room temperature, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 120 ℃ for hydrothermal treatment for 24h, taking out a reaction product, and performing suction filtration, washing and drying to prepare the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
In N2And heating the obtained white solid to 550 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2h to promote the carbonization shrinkage of the surfactant micelle in the mesoporous pore canal.
And then, placing the carbonized material into 15mL of 0.5mol/L zirconium oxychloride aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into 15mL of 1.2mol/L sulfuric acid solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 100 ℃ for 12h, heating to 500 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
XRD, EDX and N2The adsorption-desorption and other characteristic results prove that the prepared sample has a highly regular ordered two-dimensional hexagonal mesoporous pore structure and uniform mesoporous aperture, and Si, Al, Zr and S atoms on the surface of the pore wall of the sample can be uniformly dispersed on the level of near atoms in the whole sample range. By calculation, the specific surface area and the pore volume of the sample were 502m, respectively2G and 1.05cm3(ii)/g, the mesoporous pore diameter is 8.1nm, the atomic ratio of Si/Al in the sample is 11.2, the atomic ratio of Zr/Al is 3.11, and the atomic ratio of Zr/S is 3.08.
NH3The infrared characterization results of TPD and pyridine adsorption-desorption prove that weak acid, medium acid, strong acid and super acid centers exist on the surface of the sample at the same time, and the contents are 0.66, 0.58, 1.15 and 0.14mmol/g respectively. The acid amount ratio of the total B acid centers to the L acid centers on the surface of the sample was 1.48, which isIn the strong acid center and the medium strong acid center, the acid amount ratio of the B acid to the L acid was 1.82 and 1.28, respectively.
The transesterification reaction of soybean oil and methanol was carried out under the reaction conditions of example 1, and the sample of this example was examined for its catalytic performance as a catalyst. The sample can realize the complete conversion of the soybean oil in the process of repeated use for 3 times, and the yield of the biodiesel is kept above 99.8 percent. Although the conversion rate of the sample to soybean oil gradually decreases from the 4 th reuse, the yield of the biodiesel is kept above 78.2% in the 8 times of reuse.
After the used sample is roasted at 550 ℃ for 2 hours for regeneration, the structure, texture and surface acidity of the sample are not obviously changed compared with those before reaction, 100% complete conversion of soybean oil can be realized again, and the yield of the biodiesel reaches 99.8%.
Example 5.
Under the condition of strong stirring at 35 ℃, 2.81g of methyl orthosilicate is added into 40mL of 1.5mol/L hydrochloric acid solution dissolved with 2.2g P123 and 2.08g of glacial acetic acid, the temperature is maintained, stirring is continued for reaction for 24 hours, reaction liquid is subjected to suction filtration and washing, and white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species is prepared.
Adding the white solid obtained by self-assembly into 30mL of 0.8mol/L aluminum iso-butoxide aqueous solution, adjusting the pH value of the reaction mixture to 2.2 by using dilute hydrochloric acid, stirring at room temperature for 30min, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 160 ℃, carrying out hydrothermal treatment for 24h, taking out a reaction product, carrying out suction filtration, washing and drying to prepare the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
In N2And heating the obtained white solid to 550 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2 hours to promote the surfactant micelle in the mesoporous pore canal to be carbonized and shrunk.
And then, placing the carbonized material into 15mL of 1.2mol/L zirconium isopropoxide aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 550 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into 18mL of 1.6mol/L sulfuric acid solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 100 ℃ for 12h, heating to 500 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
XRD, EDX and N2The adsorption-desorption and other characteristic results prove that the prepared sample has a highly regular ordered two-dimensional hexagonal mesoporous channel structure and uniform mesoporous aperture, and Si, Al, Zr and S atoms on the surface of the pore wall of the sample can be uniformly dispersed on the level of near atoms in the whole sample range. By calculation, the specific surface area and the pore volume of the sample were 455m2G and 1.05cm3The mesoporous diameter is 15.1nm, the atomic ratio of Si/Al in the sample is 10.7, the atomic ratio of Zr/Al is 8.01, and the atomic ratio of Zr/S is 2.28.
NH3The infrared characterization results of TPD and pyridine adsorption-desorption prove that weak acid, medium acid, strong acid and super acid centers exist on the surface of the sample at the same time, and the contents are 0.90, 0.61, 0.99 and 0.10mmol/g respectively. The acid amount ratio of the total B acid center and the L acid center on the surface of the sample was 2.02, wherein the acid amount ratio of the B acid to the L acid in the strong acid center and the strong acid center was 1.71 and 1.31, respectively.
The transesterification reaction of soybean oil and methanol was carried out under the reaction conditions of example 1, and the sample of this example was examined for its catalytic performance as a catalyst. The sample can realize the complete conversion of the soybean oil in the process of repeated use for 4 times, and the yield of the biodiesel is kept above 99.8 percent. Although the conversion rate of soybean oil of the sample is gradually reduced from the 5 th repeated use, the yield of the biodiesel is kept above 80.0 percent in the 8 repeated use processes.
After the used sample is roasted at 550 ℃ for regeneration for 2 hours, the structure, texture and surface acidity of the sample are not obviously changed compared with those before reaction, 100 percent of complete conversion of soybean oil can be realized again, and the yield of the biodiesel reaches 99.8 percent.
Example 6.
Adding 4.58g of tetraethoxysilane into 50mL of 2.0mol/L hydrochloric acid solution dissolved with 2.5g P123 and 2.56g of glacial acetic acid under strong stirring at 38 ℃, maintaining the temperature, continuing stirring for reaction for 24 hours, carrying out suction filtration and washing on reaction liquid, and preparing the white solid of the ordered mesoporous SBA-15 material which wraps the surfactant micelle and has the pore wall rich in Si-OH species.
Adding the white solid obtained by self-assembly into 30mL of 2.0mol/L aluminum nitrate aqueous solution, adjusting the pH value of the reaction mixture to 2.8 by using dilute hydrochloric acid, stirring for 30min at room temperature, placing the reaction mixture in a closed high-pressure reaction kettle, heating to 180 ℃ for hydrothermal treatment for 24h, taking out a reaction product, and performing suction filtration, washing and drying to obtain the ordered mesoporous Al-SBA-15 material white solid which wraps the surfactant micelle and is uniformly grafted with Al atoms on the surface of the pore wall.
At N2And heating the obtained white solid to 550 ℃ under the atmosphere, and carrying out high-temperature heat treatment for 2h to promote the carbonization shrinkage of the surfactant micelle in the mesoporous pore canal.
And then, placing the carbonized material into 15mL of 1.5mol/L zirconium isopropoxide aqueous solution, stirring at room temperature for 30min, carrying out suction filtration, drying at 60 ℃ for 12h, heating to 600 ℃ under an air atmosphere, and carrying out roasting treatment for 5h to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall.
And (2) placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with zirconia into 20mL of 1.5mol/L sulfuric acid solution, stirring for 30min at room temperature, carrying out suction filtration, drying for 12h at 100 ℃, heating to 500 ℃ under an air atmosphere, and roasting for 5h to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
XRD, EDX and N2The adsorption-desorption and other characteristic results prove that the prepared sample has a highly regular ordered two-dimensional hexagonal mesoporous channel structure and uniform mesoporous aperture, and Si, Al, Zr and S atoms on the surface of the pore wall of the sample can be uniformly dispersed on the level of near atoms in the whole sample range. The specific surface area and the pore volume of the sample were calculated to be 461m2G and 1.15cm3G, the mesoporous aperture is 13.6nm, and the Si/Al atomic ratio in a sampleWas 12.6, the Zr/Al atomic ratio was 5.05 and the Zr/S atomic ratio was 4.02.
NH3TPD and pyridine adsorption-desorption infrared characterization results prove that weak acid, medium strong acid, strong acid and super strong acid centers exist on the surface of the sample at the same time, and the contents of the centers are 1.76, 0.81, 1.02 and 0.11mmol/g respectively. The acid amount ratio of the total B acid center and the total L acid center on the surface of the sample was 1.99, wherein the acid amount ratio of the B acid to the L acid in the strong acid center and the strong acid center was 1.63 and 1.46, respectively.
The transesterification reaction of soybean oil and methanol was carried out under the reaction conditions of example 1, and the sample of this example was examined for its catalytic performance as a catalyst. The sample can realize the complete conversion of the soybean oil in the process of repeated use for 3 times, and the yield of the biodiesel is kept above 99.8 percent. Although the conversion rate of the sample to soybean oil gradually decreases from the 4 th reuse, the yield of the biodiesel is kept above 76.7% in the 8 times of reuse.
After the used sample is roasted at 550 ℃ for regeneration for 2 hours, the structure, texture and surface acidity of the sample are not obviously changed compared with those before reaction, 100 percent of complete conversion of soybean oil can be realized again, and the yield of the biodiesel reaches 99.6 percent.
The above embodiments of the present invention are not intended to be exhaustive or to limit the invention to the precise form disclosed. Various changes, modifications, substitutions and alterations to these embodiments will be apparent to those skilled in the art without departing from the principles and spirit of this invention.

Claims (9)

1. A preparation method of an ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material comprises the following steps:
1) dissolving inorganic acid, organic carboxylic acid and triblock copolymer nonionic surfactant P123 in deionized water according to the molar ratio of silicon source, organic carboxylic acid, inorganic acid, deionized water and triblock copolymer nonionic surfactant P123= (50-150): (10-500): (150-500): (5000-13000): 1, slowly adding the silicon source, fully stirring for reaction, and drying to obtain the ordered mesoporous SBA-15 material wrapping the surfactant micelle;
2) adding the ordered mesoporous SBA-15 material into an aqueous solution of an aluminum source according to the Si/Al molar ratio of (5-100) to 1, adjusting the pH value of the solution to be 1-3, and performing hydrothermal treatment in a sealed high-pressure reaction kettle at 100-220 ℃ to prepare the ordered mesoporous Al-SBA-15 material wrapping the surfactant micelle and grafted with Al atoms on the surface of the pore wall;
3) carrying out high-temperature treatment on the ordered mesoporous Al-SBA-15 material in an inert atmosphere to promote partial carbonization of surfactant micelles existing in the Al-SBA-15 mesoporous pore canals;
4) placing the high-temperature treated ordered mesoporous Al-SBA-15 material in a water solution of a zirconium source for dipping treatment, taking out the material, roasting the material in the air at the temperature of 450-650 ℃, and removing partially carbonized surfactant micelles to prepare the ordered mesoporous Al-SBA-15 material with the zirconia coated on the surface of the pore wall;
5) and placing the ordered mesoporous Al-SBA-15 material with the pore wall surface coated with the zirconia into a sulfuric acid solution for dipping treatment, taking out the material and roasting the material at the temperature of 300-650 ℃ in the air to prepare the ordered mesoporous Al-SBA-15 loaded sulfated zirconia solid acid material.
2. The preparation method of claim 1, wherein the silicon source is one or a mixture of methyl orthosilicate, ethyl orthosilicate, water glass or white carbon black in any proportion; the aluminum source is one of aluminum isopropoxide, tert-butyl alcohol aluminum, isobutyl alcohol aluminum, aluminum nitrate or aluminum chloride, or a mixture of several of the aluminum source and the tert-butyl alcohol aluminum; the zirconium source is one of zirconium oxychloride, zirconium isopropoxide, zirconium acetate or zirconium nitrate, or a mixture of several of the zirconium oxychloride, the zirconium isopropoxide and the zirconium acetate in any proportion.
3. The method according to claim 1, wherein the inorganic acid is hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid.
4. The method according to claim 1, wherein the organic carboxylic acid is citric acid, glacial acetic acid, oxalic acid or tartaric acid.
5. The preparation method of claim 1, wherein the ordered mesoporous Al-SBA-15 material is subjected to high temperature treatment at 350-750 ℃ for 0.5-5 h under an inert atmosphere.
6. The preparation method of claim 1, wherein the high-temperature treated ordered mesoporous Al-SBA-15 material is immersed in a zirconium source aqueous solution with a concentration of 0.1-1 mol/L according to a solid/liquid volume ratio of (0.05-1) to 1.
7. The preparation method of claim 1, wherein the ordered mesoporous Al-SBA-15 material with zirconia coated on the surface of the pore wall is immersed in a sulfuric acid solution with a concentration of 0.1-2 mol/L according to a solid/liquid volume ratio of (0.01-0.5) to 1.
8. The ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material prepared by the preparation method of claim 1 has a highly ordered two-dimensional hexagonal mesoporous channel structure with a specific surface area of 350-800 m2Per g, pore volume of 0.5-1.5 cm3The pore diameter is 6.0-25.0 nm, the molar ratio of zirconium to aluminum atoms on the surface of the mesoporous pore wall is adjusted within the range of 0.2-10, and the acid amount, the acid density, the ratio of B acid center to L acid center and the content of super acid center on the surface of the pore wall are respectively 1.5-5.2 mmol/g and 0.0001-0.02 mmol/m20.01 to 2.1 and 0 to 1.0 mmol/g.
9. The use of the ordered mesoporous Al-SBA-15 supported sulfated zirconia solid acid material of claim 8 as a catalyst for transesterification of biodiesel synthesis from soybean oil and methanol.
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CN111215131B (en) * 2018-11-26 2023-05-16 中国科学院大连化学物理研究所 Preparation method of shape selective isomerism catalyst based on MTW type structure molecular sieve
CN111097497B (en) * 2019-12-24 2022-09-02 湘潭大学 Method for producing hydrogen by catalyzing direct conversion of methane, catalyst and preparation method thereof
CN111229305B (en) * 2020-02-17 2023-07-18 江苏大学 Molybdenum modified Fe-ZSM5 molecular sieve catalyst and preparation method and application thereof

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