In this study,a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O3)reactor has been developed.Using 1-phenylethanol as a model reactant,the performance of RPB...In this study,a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O3)reactor has been developed.Using 1-phenylethanol as a model reactant,the performance of RPB-O3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O3).Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O3 process,with 78%yield after 30 min.In a parallel STR-O3 experiment,the yield of acetophenone was50%.Other experimental variables,i.e.O3 concentration,reaction time,high-gravity factor and liquid flow rate were also optimized.The highest yield of acetophenone was obtained using O3 concentration of 80 mg·L-1,reaction time of 30 min,high gravity factor of 40 and liquid flow rate of 120 L·h-1.Under the optimized reaction conditions,a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%)yield.The ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR)spectroscopy,monitoring the radical species formed upon self-decomposition of O3.The characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH)was observed in the electron paramagnetic resonance(EPR)spectrum,indicating an indirect oxidation mechanism of alcohols via·OH radical.展开更多
[Objecdve] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes. [Method] Based on national stand- ards, the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed. In the m...[Objecdve] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes. [Method] Based on national stand- ards, the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed. In the meantime, by dint of simultaneous distillation and extraction equip- ment coupled to GC and GC/MS, the puff-by-puff transfer ratios to TPM of smoke were expounded and compared. [ Result] The puff-by-puff deliv- ery profiles of NFDPT,nicotine and carbon monoxide increased with increasing puff number. This trend was similar to that of particulate matters. The transfer ratio of flavored tobacco was increasing in general, but partial flavors augmented to the maximum value and then decreased slowly. [ Conclusion] The study provided reference for the application of carbonyl compounds in tobacco.展开更多
基金supported by the Specialized Research Fund for Sanjin Scholars Program of Shanxi Province(201707)Key Research&Development Plan of Shanxi Province(201903D321059)+1 种基金Shanxi Scholarship Council of China(2019032)Shanxi Graduate Education Innovation Project(2019BY106)。
文摘In this study,a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O3)reactor has been developed.Using 1-phenylethanol as a model reactant,the performance of RPB-O3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O3).Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O3 process,with 78%yield after 30 min.In a parallel STR-O3 experiment,the yield of acetophenone was50%.Other experimental variables,i.e.O3 concentration,reaction time,high-gravity factor and liquid flow rate were also optimized.The highest yield of acetophenone was obtained using O3 concentration of 80 mg·L-1,reaction time of 30 min,high gravity factor of 40 and liquid flow rate of 120 L·h-1.Under the optimized reaction conditions,a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%)yield.The ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR)spectroscopy,monitoring the radical species formed upon self-decomposition of O3.The characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH)was observed in the electron paramagnetic resonance(EPR)spectrum,indicating an indirect oxidation mechanism of alcohols via·OH radical.
文摘[Objecdve] The aim was to observe the puff-by-puff transfer ratios of some flavors in cigarettes. [Method] Based on national stand- ards, the puff-by-puff transfer of tobacco of carbonyl flavors was analyzed. In the meantime, by dint of simultaneous distillation and extraction equip- ment coupled to GC and GC/MS, the puff-by-puff transfer ratios to TPM of smoke were expounded and compared. [ Result] The puff-by-puff deliv- ery profiles of NFDPT,nicotine and carbon monoxide increased with increasing puff number. This trend was similar to that of particulate matters. The transfer ratio of flavored tobacco was increasing in general, but partial flavors augmented to the maximum value and then decreased slowly. [ Conclusion] The study provided reference for the application of carbonyl compounds in tobacco.
