A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventiona...A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.展开更多
在乙醇与环氧乙烷的醚化反应中,系统地研究了杂多酸化合物的催化性能。实验结果表明,PMo_(12),PW_(12),SiMo_(12),SiW_(12)对乙醇与环氧乙烷的醚化反应具有较高的催亿活性。Mo 和 W 混合配位的 PMO_(12-n)Wn 杂多酸具有相近的催化活性,...在乙醇与环氧乙烷的醚化反应中,系统地研究了杂多酸化合物的催化性能。实验结果表明,PMo_(12),PW_(12),SiMo_(12),SiW_(12)对乙醇与环氧乙烷的醚化反应具有较高的催亿活性。Mo 和 W 混合配位的 PMO_(12-n)Wn 杂多酸具有相近的催化活性,而 PMO_(12-n)V_n 的催化活性则随 V 取代数的增加而降低。同时,还考查了各种因素,如环氧乙烷和催化剂的浓度、反应温度和反应时间对乙二醇乙醚收率的影响。展开更多
Polyelectrolytes have a high hydrophilicity and can be used in pervaporation(PV) dehydration of alcohol. Chitosan(CS) used as polycation polysaccharide and carboxymethyl cellulose(CMC) used as polyanion polysaccharide...Polyelectrolytes have a high hydrophilicity and can be used in pervaporation(PV) dehydration of alcohol. Chitosan(CS) used as polycation polysaccharide and carboxymethyl cellulose(CMC) used as polyanion polysaccharide were chosen as PV membrane materials. CS membrane cross linked with oxalic acid or citric acid and CS CMC polyelectrolyte membrane were prepared. The results showed that the polyelectrolyte membranes had an excellent PV performance for alcohol dehydration. For example, when the separation factor gone up to 2 300, the total flux of CS CMC polyelectrolyte membrane was above 800 g/(m 2·h) in 95% EtOH and at 72 ℃. The nature and content of crosslinking agents affected the separation properties of cross linked CS membrane. The total flux of the cross linked CS membrane increased with operating temperature increasing and corresponded to the Arrhenius equation.展开更多
文摘A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.
文摘在乙醇与环氧乙烷的醚化反应中,系统地研究了杂多酸化合物的催化性能。实验结果表明,PMo_(12),PW_(12),SiMo_(12),SiW_(12)对乙醇与环氧乙烷的醚化反应具有较高的催亿活性。Mo 和 W 混合配位的 PMO_(12-n)Wn 杂多酸具有相近的催化活性,而 PMO_(12-n)V_n 的催化活性则随 V 取代数的增加而降低。同时,还考查了各种因素,如环氧乙烷和催化剂的浓度、反应温度和反应时间对乙二醇乙醚收率的影响。
文摘Polyelectrolytes have a high hydrophilicity and can be used in pervaporation(PV) dehydration of alcohol. Chitosan(CS) used as polycation polysaccharide and carboxymethyl cellulose(CMC) used as polyanion polysaccharide were chosen as PV membrane materials. CS membrane cross linked with oxalic acid or citric acid and CS CMC polyelectrolyte membrane were prepared. The results showed that the polyelectrolyte membranes had an excellent PV performance for alcohol dehydration. For example, when the separation factor gone up to 2 300, the total flux of CS CMC polyelectrolyte membrane was above 800 g/(m 2·h) in 95% EtOH and at 72 ℃. The nature and content of crosslinking agents affected the separation properties of cross linked CS membrane. The total flux of the cross linked CS membrane increased with operating temperature increasing and corresponded to the Arrhenius equation.
