Synthesis, Characterization And Catalytic Performance Of Sn-Containing Catalyst For Baeyer-Villiger Oxidation Of Cyclohexanone

ε-Carprolactone is an very important organic intermediate and monomer in synthesizing many chemical products,which has an extremely wide range of applications. At present, ε-Carprolactone is produced by Baeyer-Villiger oxidation of cyclohexanone with peroxide organic acid as oxidant. However, this process is high explosive and produce organic acid as byproduct. So,using low concentration and environmentally friendly H2O₂（30%） instead of peroxide organic acid as oxidant can meet the requirement of green chemistry’s philosophy. Therefore, development of efficient catalysts become the key technology of preparation ε-carprolactone through the Baeyer-Villiger oxidation of cyclohexanone.At the first part of this thesis, Sn-NaY is synthesized by ion exchange method with NaY as the carrier and SnCl₄?5H₂O as tin source. The influence of the amout of SnCl₄?5H₂O, the exchange temperature and exchange time is researched. Otherwise, the structure of catalysis is characterized by means of FT-IR, UV-Vis, XRD and N₂ physical adsorption-desorption. The results show that more extra-framework SnO₂ are produced with the increase of the amount of tin source. In addition, the increased acidity can destroy the structure of NaY molecular sieve. Along with the prolonging of exchange time, more four coordinated Sn⁴⁺ are generated. The exchange reached equilibrium when the exchange time exceeds 8h and the amout of Sn will not increase. Using the Baeyer-Villiger oxidation of cyclohexanone as probe reaction, the optimal condition of ion exchange method to prepare Sn-NaY is as follow: the ratio of carried and tin source is 3:1 under 80℃ for 8h.Secondly, Sn/NaY are synthesized by chemical vapor deposition（CVD） with NaY as the carrier. Three different methods such as hydrochloric acid dealuminum, hydrothermal dealumination and isomorphous substitution dealumination by（NH4_）2SiF₆ solution are carried out and the effect on structure and catalytic performance are studied. The surface ares, pore volume, pore diameter, skeleton pore structure are characterized by a variety of characterization means. The catalyst activity is evaluated by the Baeyer-Villiger oxidation of cyclohexanone with hydrogen peroxide as oxidant. The results show that NaY molecular sieve modified by hydrothermal dealuminated is the best. After loading metal Sn,the conversion of cyclohexanone is 43.7% and the selectivity of caprolactone is 41.5%.Finally, Sn-containing SiO₂ is synthesized by chemical vapor deposition（CVD）with amorphous silica as carrier and SnCl₄ as tin source. The effects of the pretreatment, CVD temperature, CVD time, calcinations atmosphere and calcinations temperature on catalyst’s structure are systematicly discussed with FT-IR, UV-Vis, N₂ physical adsorption-desorption ICP and NH3-TPD. Results show that the amount of Si-OH will increase after hydrothermal pretreatment,which is good for form more framework Sn in the CVD process. Calcination in N2 atmosphere can prevent extre-framework of Sn group oxidizing into SnO₂. Further, the catalytic profermance are tested by using the Baeyer-Villiger oxidation of cyclohexanone with H2O₂ as the oxygen. The optimal conditions of CVD is as follow: calcinatd treatment is carried out for the carrier and the CVD temperature is 540℃ for 1.5h with calcination in N₂ atmosphere under 300℃。...