The oxidative dehydrogenation (ODH) of isobutane over Cr_2O_3/La_2(CO_3)_3 has been investigated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reaction steps can be accurat...The oxidative dehydrogenation (ODH) of isobutane over Cr_2O_3/La_2(CO_3)_3 has been investigated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reaction steps can be accurately determined. By heating the catalyst at a constant rate from 150-300℃, temperature fluctuations due to non-equilibrium adsorption are minimized. The evolved gas profiles show that ODH to isobutene and water is a primary reaction pathway, while carbon dioxide, which forms from the catalyst during reaction, is the only other product. This CO2 evolution may enhance the activity of the catalyst. Isobutene formation proceeds with the participation of lattice oxygen from the Cr2O3/La2(CO3)3 catalyst. The intrinsic Arrhenius rate constant for the ODH of isobutane isk(s-1) = 1011.5±2.2exp{-((55±5) -ΔHads kJmol-1)/RT}The small pre-exponential factor is expected for a concerted mechanism and for such a catalyst with a small surface area and limited porosity.展开更多
6-(bromomethyl)-2-methylquinazolin-4(3H)-one is the important intermediate which is first-line drugs for treating colon and rectal cancers.In order to investigate the Raltitrexed better,to optimizeby production method...6-(bromomethyl)-2-methylquinazolin-4(3H)-one is the important intermediate which is first-line drugs for treating colon and rectal cancers.In order to investigate the Raltitrexed better,to optimizeby production method,we designed a synthetic route based related literature by cycling,ammoniation and bromination.The process provided high yield,synthetic methodology.The yield of 6-(bromomethyl)-2-methylquinazolin-4(3H)-one was up to 64.8%展开更多
文摘The oxidative dehydrogenation (ODH) of isobutane over Cr_2O_3/La_2(CO_3)_3 has been investigated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reaction steps can be accurately determined. By heating the catalyst at a constant rate from 150-300℃, temperature fluctuations due to non-equilibrium adsorption are minimized. The evolved gas profiles show that ODH to isobutene and water is a primary reaction pathway, while carbon dioxide, which forms from the catalyst during reaction, is the only other product. This CO2 evolution may enhance the activity of the catalyst. Isobutene formation proceeds with the participation of lattice oxygen from the Cr2O3/La2(CO3)3 catalyst. The intrinsic Arrhenius rate constant for the ODH of isobutane isk(s-1) = 1011.5±2.2exp{-((55±5) -ΔHads kJmol-1)/RT}The small pre-exponential factor is expected for a concerted mechanism and for such a catalyst with a small surface area and limited porosity.
文摘6-(bromomethyl)-2-methylquinazolin-4(3H)-one is the important intermediate which is first-line drugs for treating colon and rectal cancers.In order to investigate the Raltitrexed better,to optimizeby production method,we designed a synthetic route based related literature by cycling,ammoniation and bromination.The process provided high yield,synthetic methodology.The yield of 6-(bromomethyl)-2-methylquinazolin-4(3H)-one was up to 64.8%
