Preparation And Catalytic Performance Of Hetero-atom Modified SBA-15 Materials

Mesoporous molecular sieves SBA-15,as a new nanostructured material,have a narrow pore size distribution and a large specific surface area in the adsorption of macromolecules.Separation and catalysis have important applications.SBA-15 active center has weak catalytic activity,which can be modified on the surface to improve catalytic active center.In this paper,mesoporous material SBA-15（SBA-15）was prepared by using P123 template as raw material and tetraethyl orthosilicate（TEOS）as silicon source.AlCl₃、FeCl₃、I₂、ZnCl₂、NiCl₂、KF with SBA-15 as the main material A variety of supported mesoporous molecular sieves catalysts were derived from hetero-atomic sources,and the modified molecular sieves were characterized by X-ray diffraction,scanning electron microscope,nitrogen adsorption and desorption,infrared,thermogravimetric and so on.The catalytic performance of the catalyst was investigated by esterification,Knoevenagel reaction and heterocycle synthesis.According to the structural characteristics of SBA-15,the preparation and modification methods of SBA-15 were combed and analyzed by scholars at home and abroad.On this basis,the research direction of this paper is selected,and the research methods and technical routes are determined.This paper has carried out the research from the following aspects to study:Reference synthesis SBA-15、X-SBA-15（X=Al、Fe、I、Ni、Zn、K）was prepared with SBA-15 as carrier,and the structure was confirmed by IR、BET、TG、XRD、SEM.K-SBA-15 was used to catalyze the Knoevenagel condensation of benzaldehyde and malononitrile.The effects of catalyst dosage,molar ratio of raw material and type of catalyst on the yield were investigated.The optimum conditions were as follows:the molar ratio of aromatic aldehyde to malononitrile was 1:1,and the yield was 80.3%⁹5.8%at room temperature for 10 mmol%,with benzaldehyde as catalyst.The heterocyclic reaction was catalyzed by Al、Fe、I、Zn、Ni supported on SBA-15 under ultrasonic conditions.The effects of catalyst type,molar ratio of raw material and amount of catalyst on the yield were investigated.The optimum conditions were selected as follows:The molar ratio of benzoyl to o-phenylenediamine is 1:1,catalyst dosage of 10 mmol%,ultrasonic reaction at 70℃for 5 min,the yield was 94.7%.Six kinds of derived SBA-15 catalysts were prepared by using SBA-15as support.The structures of SBA-15 and Al-SBA-15 were confirmed by IR、BET、TG、SEM.The effects of catalyst type and dosage,molar ratio of alcohol to acid,reaction time and temperature on the yield of esterification were investigated.The optimum reaction conditions were as follows:reaction at 135℃for 3 h,and Al-SBA-15 was 8 mmol%,of p-hydroxybenzoic acid（p-hydroxybenzoic acid）.The esterification rate was up to 96.8%when Al-SBA-15:TsOH was 2:1 and the molar ratio of alcohol to acid was 3:1.