Transformation Of 1,4-Butanediol Monoacetate Over Modified APT Catalyst

1,4-butanediol monoacetate can selectively synthesis of 3-buten-1-ol (BTO),3-buten-1-ol acetate, tetrahydrofuran (THF),1,4-butanediol (BDO) and other important organic chemical raw materials. Preparation and application of solid acid and base catalysts is the key to realize the value of transformation of 1,4-butanediol monoacetate to such target object. Therefore, it has important theory and application value to discuss the technology of preparing catalysts and reveal the inner relationship between catalytic structure, surface acid-base properties and catalytic properties on transformation of 1,4-butanediol monoacetate.The supported solid acid and base catalysts are made up by acid and base active ingredient and the support which has high catalytic activity, easy to control,stability in a variety of chemical reactions.At present, the research on the prepration of solid acid and base catalysts with APT as supports has always been the hot issue in the research field, because of it has more advantages than other supports,such as cheaper, easier aviailable, big surface area and environment friendly.Based on the above discussion, we used APT as support and prepared a series of modified APT catalysts by the impregnation method and characterized by FT-IR, NH3-TPD, CO2-TPD, XRD, N2 physisorption techniques. With the results of catalytic activities for transformation of 1,4-butanediol monoacetate.,we investigated the impact on catalyst texture, surface properties and catalytic esterification of modified APT caused by different alkaline earth metal and its amount as variables. In order to build the relationship between the preparation method and the acid-base properties, catalytic performance. The main research results included the following aspects:1.The effect on the performance of CaO/APT catalysts in transformation reaction of 1,4-butanediol monoacetate caused by catalyst texture, surface acid and base properties. The result indicated that the CaO/APT maintained the main structure of APT with the CaO loadings. The surface area has decreased; pore volume, pore size showed an increasing trend.When the CaO loading was less than 20%, CaO entered the crystal lattice of APT and destroied the crystal structure that made the sample surface acidic sites showed a gradual increasing trend, and the sample surface basic sites increase over the body APT.The synergistic effect of the CaO/APT shows the high BTO and 3-buten-1-ol acetate selectivity. With the further increasing of CaO content, the CaO begins to aggregate and then the total amount of acidic and basic sites showed an decreasing trend. And the selectivity of 1,4-butanediol gradually increase. Combined with the characterization results and catalytic performance of catalyst samples,we concluded that high acid sites in favor of THF formation, and the higher basic sites help BDO product formation, and the CaO/APT which had appropriate content of CaO helped to produce 3-buten-1-ol and 3-buten-1-ol acetate, it showed the acid-base synergism.2. Based on the above work, a series of MgO/APT catalysts loaded with different amount of MgO were prepared by the impregnation method. The obtained results showed that the MgO/APT maintained the main structure of APT. The result indicates that with raising MgO loadings, The surface area has decreased; pore size as a whole showed an increasing trend, and pore volume showed a first increasing and then decreasing trend. And with the increasing of MgO content, the acid sites of MgO/APT showed a increasing first then decreasing trend, but the basic sites showed a growing trend. Comparison of MgO/APT and CaO/APT, MgO/APT had more acid sites,so it helped to produce THF in transformation of 1,4-butanediol monoacetate. We speculated:the MgO-SiO2 composite oxides was generated when MgO was introduced to APT. When the content of CaO,MgO was higher, both of MgO/APT and CaO/APT had the same acid-base sites,The reaction product distribution was similar on transformation of 1,4-butanediol monoacetate.3. Based on the the catalytic performance of CaO、MgO、CaO/APT and MgO/APT. A three-pathway reaction mechanism was proposed to describe the catalytic transformation of 1,4-butanediol monoacetate based on the acid-base properties and the reaction results of the catalysts.