Effect of drying methods on the structure and catalytic combustion activity of Mn-substituted hexaaluminate catalysts

Conventional oven drying (COD) and supercritical drying (SCD) methods were applied to the preparation of Mn-substituted hexaaluminate (BaMnA(11)O(19-alpha)) catalysts. The effect of drying methods on phase composition, specific surface area, pore structure and combustion activity of the samples was investigated. The samples obtained by SCD have higher surface area, narrower pore size distribution, and higher combustion activity than those obtained by COD.

N-arylamides from selenium-catalyzed reactions of nitroaromatics and amides in the presence of carbon monoxide and mixed organic bases

N-Arylamides were exclusively obtained in moderate to good yields from selenium-catalyzed reactions of nitroaromatics with amides in the presence of CO and mixed organic bases Et3N and DBU.

Separation of peptides on mixed mode of reversed-phase and ion-exchange capillary electrochromatography with a monolithic column

The mixed mode of reversed phase (RP) and strong canon-exchange (SCX) capillary electrochromatography (CEC) based on a monolithic capillary column has been developed. The capillary monolithic column was prepared by in situ copolymerization of 2-(sulfooxy)ethyl methacrylate (SEMA) and ethylene dimethacrylate (EDMA) in the presence of porogens. The sulfate group provided by the monomer SEMA on the monolithic bed is used for the generation of the electroosmotic flow (EOF) from the anode to the cathode, but at the same time serves as a SCX stationary phase. A mixed-mode (RP/SCX) mechanism for separation of peptides was observed in the monolithic column, comprising hydrophobic and electrostatic interaction as well as electrophoretic migration at a low pH value of mobile phase. A column efficiency of more than 280000 plates/m for the unretained compound has been obtained on the prepared monoliths. The relative standard deviations observed for to and retention factors of peptides were about 0.32% and less than 0.71% for ten consecutive runs, respectively. Effects of mobile phase compositions on the EOF of the monolithic column and on the separation of peptides were investigated. The selectivity on separation of peptides in the monolithic capillary column could be easily manipulated by varying the mobile phase composition.