Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. T...Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. The effects of the ratio of d-glucose/l-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored. The optimum conditions were as follows: n(d-glucose):n(l-leucine) = 4, temperature 150 °C, reaction time 3 h, pH 5. The highest yield of isovaleraldehyde obtained was about 32%.展开更多
The effect of rare earths （Sm, Pr, Ce, Nd and La） on the hydrogenation properties ofp-chloronitrobenzene （CNB） over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that ...The effect of rare earths （Sm, Pr, Ce, Nd and La） on the hydrogenation properties ofp-chloronitrobenzene （CNB） over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that the hydrogenation of p-CNB could be carried out over PtMOx/CNTs catalysts. Both catalytic activities and yields ofp-chloroaniline （CAN） were all improved. PtCeOx/ CNTs catalyst exhibited the best catalytic activity （TOF was 0.47 s^-1） and the highest yield of p-CAN （97.5 mol%）. PtCeOx/CNTs （1.0 wt%） catalyst exhibited good stability on the hydrogenation of p-CNB.展开更多
The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation ofcinnamaldehyde over Pt/ZrO_2 catalysts was studied in ethanol at 343K under 2.0MPa H_2 pressure.PtCo/ZrO_2 and PtFe/ZrO_2 catalysts exhibi...The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation ofcinnamaldehyde over Pt/ZrO_2 catalysts was studied in ethanol at 343K under 2.0MPa H_2 pressure.PtCo/ZrO_2 and PtFe/ZrO_2 catalysts exhibit high selectivity and activity of hydrogenation for C=O(93.8% at 87.3% conversion and 83.6% at 88.6% conversion, respectively), and PtNi/ZrO_2 exhibitshigh selectivity of hydrogenation for C=C (64.3% at 70.6% conversion). In the presence of traceH_2O and NaOH, over the PtNi/ZrO_2 (0.4wt%Ni) catalyst the selectivity to hydrocinnamaldehydereaches 90.6% and the conversion of cinnamaldehyde is 90.5%.展开更多
文摘Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. The effects of the ratio of d-glucose/l-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored. The optimum conditions were as follows: n(d-glucose):n(l-leucine) = 4, temperature 150 °C, reaction time 3 h, pH 5. The highest yield of isovaleraldehyde obtained was about 32%.
文摘The effect of rare earths （Sm, Pr, Ce, Nd and La） on the hydrogenation properties ofp-chloronitrobenzene （CNB） over Pt/CNTs catalyst was studied in ethanol at 303 K and normal pressure. The results exhibited that the hydrogenation of p-CNB could be carried out over PtMOx/CNTs catalysts. Both catalytic activities and yields ofp-chloroaniline （CAN） were all improved. PtCeOx/ CNTs catalyst exhibited the best catalytic activity （TOF was 0.47 s^-1） and the highest yield of p-CAN （97.5 mol%）. PtCeOx/CNTs （1.0 wt%） catalyst exhibited good stability on the hydrogenation of p-CNB.
文摘The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation ofcinnamaldehyde over Pt/ZrO_2 catalysts was studied in ethanol at 343K under 2.0MPa H_2 pressure.PtCo/ZrO_2 and PtFe/ZrO_2 catalysts exhibit high selectivity and activity of hydrogenation for C=O(93.8% at 87.3% conversion and 83.6% at 88.6% conversion, respectively), and PtNi/ZrO_2 exhibitshigh selectivity of hydrogenation for C=C (64.3% at 70.6% conversion). In the presence of traceH_2O and NaOH, over the PtNi/ZrO_2 (0.4wt%Ni) catalyst the selectivity to hydrocinnamaldehydereaches 90.6% and the conversion of cinnamaldehyde is 90.5%.
