Studies On The Baeyer-Villiger Oxidation Of Cycloketones Catalyzed By Liquid And Solid Acids

Straight chain ketones and Cycloketones can convert into more complicated and valuable Straight chain esters and lactones by Baeyer-Villiger oxidation(abbreviated for B-V hereinafter), which play important roles in the synthesis of fine chemicals, flavors and medical intermediates . Using low concentration of hydrogen peroxide (30%) instead of peroxide organic acid as oxidant in B-V reaction is friendly to environment and with higher atom economy. The solution of hydrogen peroxide is a kind of middling active inorganic oxidant, which forms two phases when react with some organic solvents directly and results to low oxidation efficiency and low yield of products. Therefore, it is a goal for many researchers to get solid catalysts which can activate hydrogen peroxide efficiently with high steric selectivity and good chemical selectivity to produce expected lactones.In this paper, the research object was focused on the B-V oxidation of 1-indanone by using 30% hydrogen peroxide as oxidant and some liquid and solid acids as catalysts in solvent of 2, 2, 3, 3-tetrafluoro-1-propanol. At the same time, some new solid acid catalysts were also synthesized. A new resin with weak acidity and ion exchange ability were prepared from Cross-linked Polystyrene . The synthesis condition for Beta zeolite containing transition metal tin were explored. The main contents and results are as follows:in the first chapter, The research proceeding on B-V oxidation of cycloketones especially indanones was summarized. So far, this research is focused on making oxidations and catalysts heterogenized to get security and green processes. The character of trifluoromethanesulfonic acid, triflate and Beta zeolite, the preparation methods of Beta zeolite and Beta zeolites containing trasitional metal were summarized. The application of Beta Zeolite and Triflates in organic reaction especially B-V oxidation were also reviewed. Finally, the research object and content of this paper were described.In the second chapter, the research was focused on the oxidation of 1-indanonecatalyzed by trifluoromethanesulfonic acid. The products were separated and confirmed by GC-MS, IR and NMR. The effect of reaction conditions were discussed detailedly. The results indicated that the optimal catalyst is HOTf and the best reaction condition was O.lg 1-indanone, 0.5ml HOTf, 0.32ml 30%H2O2, 2ml 2,2,3,3-tetrafluoro-propanol (TFP), under 60"C for 4h. Under this condition, the conversion of 1-indanone was 86%, while the selectivity of o-hydroxyl-phenylpropyl acid reached 98%. The possible reaction mechanism is supposed to go through two parallel routes, in which an intermediate is formed from actived H2O2 by HOTf. The lactone produced via the two parallel routes is hydrolyzed into o-hydroxyl-phenylpropyl acid under aqueous acid condition. Another product was produced and separated in general ethanols solvents reaction system. It was confirmed as indan-l,2-dione by GC-MS, IR and NMR. The reaction mechanism of producing indan-l,2-dione was also speculated.l/i the third chapter, metal triflates were prepared and characterized by IR. They are applied in the B-V oxidation of 1-indanone and cyclohexanone. The results show that scandium triflate is the best catalyst among all selected metal triflates in the reaction. Some cation exchanged resins and metal oxides were also tesed in the reaction. A new resin with weak acidity and ion exchange ability were prepared by grafted a function group of -CH2CH2CH2COOH from y-butyrolactone to the cross-linked Polystyrene successfully by Friedel-Crafts reaction.In the final chapter. The preparation of Beta Zeolite and Beta Zeolite containing transitional metal was explored. The influence of templates , silicon resources , the kinds of metal ions, the alkalinity of solution by hydrothermal synthesis were reviewed. The samples were characterized by using powder XRD, FT-IR and UV-Raman. The results indicated that beta zeolite was synthesized, but other crystal phases were detected by using TRABr as template, SiO? as silicon resource , sodium hydroxide and sodium aluminate as the adjusting agent for the alkalinity of solution. This method will decrease the cost for synthesizing beta zeolite. It is found that UV-Raman is a useful technique to confirm Beta zeolite phase during its synthesis process. The interactive mechanism between the activation center of Beta zeolite with transitional metal anddifferent reaction reactants need to be studied further.