| Methyl N-phenylcarbamate (MPC) is an important organic raw material and intermediate. It can be used as a raw material for the synthesis of methylene diphenyl diisocyanate (MDI). The traditional method for the synthesis of MPC uses phosgene. Highly toxic phosgene, corrosive hydrogen chloride and a large amount of contaminative solution are inevitably involved in this process, which causes serious environmental pollution and equipment corrosion. The preparation of MPC by carbonylation reaction is considered to be the most promising non-phosgene approach, but the use of the expensive noble metals as homogeneous catalysts in this non-phosgene process leads to the difficulty of recycling catalyst and the high cost.In this thesis, a green process for the synthesis of MPC by the oxidative carbonylation of aniline over encapsulated Co (salen) was studied. Conclusions presented in this thesis were summarized as follows:1. Six salen ligands and six Co (salen) complexes were synthesized. Co (salen) complexes were successfully encapsulated in zeolite Y by"shipping-in-bottle"and flexible ligand method. The heterogeniged catalysts were characterized by AAS, BET, IR, UV-Vis TGA, XRD and XPS.2,The catalytic activities of the encapsulated catalysts and their homogeneous analogues were examined in the oxidative carbonylation of aniline to MPC. The effects of the electronic-effects of the substituent group, temperature, initial total pressure and CO initial pressure on the reaction were investigated. Under the conditions of aniline (11 mmol), encapsulated catalyst (0.5g), KI (0.365g), CO/O2 ratio 9:1, 4MPa, 170oC, 3h, Co(II)salophen(OH)2-Y catalyst shows the highest activity with the conversion of aniline 67.1% and selectivity of MPC 77.3%, respectively.3,The performance of recovered Co(II)salophen(OH)2-Y catalyst under the same conditions was studied, and we found that Co(II)salophen(OH)2-Y could be at least recycled for five times and no significant loss of catalytic activity was observed. |
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