Synthesis, Modification Of Mesoporous Sieve SBA-15 And Their Catalysis Properties

The mesoporous molecular sieve SBA-15 has been received much attention in the fields of catalytic chemistry and adsorption-separation, due to the advantages of high surface area, ordered and tunable pore structure, high thermal and hydwthermal stability and facile modification of surface properties. In spite of the weak acidicity, SBA-15 can still be used as acidic catalyst when some non-silicon atoms, such as Al, P, B, were introduced into its skeleton and, thus, some acid centers were obtained. In this thesis, SBA-15 was firstly prepared, and then SBA-15 has modified by Al doping and H3PO4 loading, and the catalytic activity of P-SBA-15 on the esterification reaction of acrylate and n-butanol was finally explored.Hydrothermal synthesis method was applied to prepare SBA-15 by using TEOS as silicate material and triblock copolymer P123 as the template in the acidic condition. The SBA-15 was characterized by XRD, FT-IR, TEM, and BET techniques. The results showed that the samples have long-range ordered hexagonal mesopores when crystallization time was three days and the molar ratio of reactants was n(P123):n(HCl):n(H2O):n(TEOS)=0.0138:4.8:139:1.Mesoporous molecular sieves Al/SBA-15 and Al-SBA-15 were prepared with aluminum isopropoxide as aluminum source by using in-situ and ex-situ grafting methods. The mechanisms of synthesizing Al/SBA-15 and Al-SBA-15 were compared and the resultant samples were analyzed by XRD and BET. It was found that SBA-15 maintained the highly ordered hexagonal structure after Al doping and the samples prepaced by the two synthetic methods had different pore sizes, pore volumes and specific surface areas for the Al/SBA-15 and Al-SBA-15 molecular sieves.The mesoporous molecular sieve catalyst P-SBA-15 for esterification reaction of acrylate and n-butanol was obtained by the impregnation method. The effects of reaction temperature, reaction time, molar ratio of acrylate to butanol, and catalyst content on the activity of the catalyst were investigated. It was found that mesoporous molecular sieve P-SBA-15 exhibited high catalytic activity for the esterification reaction, and the achieved highest yield of butyl acrylate was 52.1% under the following conditions: molar ratio of acrylate to butanol 1:1.3, catalyst content 5%, reaction temperature 120℃and reaction time 5 h.