Alkoxylation Of Alkyl Anhydrides By Direct Insertion Of Epoxides

The thesis studied the one-step alkoxylation (ethoxylation or propoxylation) of alkylanhydrides to synthesize 1, 2-ethanediol (propanediol) diesters, catalyzed by Mg-Alcomposite oxide catalyst. The details of experiments and the main conclusions are listed asfollows:A synthesis routine of the aforementioned 1, 2-ethanediol diesters was described byinserting a ring-opening ethylene oxide molecule into alkyl anhydrides (acetic anhydride,propionic anhydride, n-butyric anhydride, i-butyric anhydride, n-pentanoic anhydride,n-hexanoic anhydride). The products were characterized by FT-IR, ESI-MS,GC-MS, 1H-NMR,13C-NMR and elemental analysis. The experimental results showed that the one-step approachprovided more than 93% yields of targeted diesters based on stoichiometry and higher than98% excellent product selectivities. Furthermore, the technological parameters wereoptimized using acetic anhydride and ethylene oxide as model reactants. Under the optimizedreaction conditions: 1 wt% Mg-Al composite oxide, n (EO) : n (AA) = 1:1, T = 140 oC, t = 4hours, high yield (94.0%) of 1, 2-ethanediol diacetate and up to 98.4% of mono-adductselectivity were obtained in stoichiometry without solvent.A synthesis routine of 1, 2-propanediol diesters was described by inserting aring-opening propylene oxide molecule into alkyl anhydrides(acetic anhydride, propionicanhydride, n-butyric anhydride, i-butyric anhydride, n-pentanoic anhydride, trimethylaceticanhydride, n-hexanoic anhydride). The products were characterized by FT-IR, ESI-MS,GC-MS, 1H-NMR, 13C-NMR and elemental analysis. Taking acetic anhydride and propyleneoxide as model reactants, more than 95% yields of target diesters based on stoichiometry andhigher than 98% excellent product selectivities were obtained under following optimizedconditions: 1 wt% Mg-Al composite oxide, n (PO) : n(anhydride) = 1:1, T = 160 oC, t = 4hours.Moreover, the effect of anhydride structure on the alkoxylation was investigated. Inaccordance with the one-step inserting mechanism by Hama and the hypothesis of theethoxylation kinetics, a model was presented for the study of thermodynamics and kinetics ofone-step propoxylation catalyzed by Mg-Al composite oxide. According to the kinetic andthermodynamic data of the propoxylation of acetic anhydride, propionic anhydride, i-butyricanhydride, it could be concluded that the electron-donating group was contributing to theone-step inserting alkoxylation for the ability to reduce the reaction activation energy. Thepropoxylation of anhydride followed the one-step inserting mechanism...