Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with s...Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with sixty polystyrene-supported quaternary ammonium salt catalysts was synthesized. The reduction of acetophenone by NaBH, was used as the probing reaction to select out the most active catalyst in the library by using iterative method, which was the gel-type triethanolamine aminating strongly basic anion exchange resin with the crosslinking degree of 2% A hydrogen bonding assisted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.展开更多
The elution of WO ions by NaOH. NaNO3 NaCl and NH4Cl on strong basicanion exchange resins in quaternary ammonium form I and the adsorption properties after elution were studied. In addition, the elution curse, the per...The elution of WO ions by NaOH. NaNO3 NaCl and NH4Cl on strong basicanion exchange resins in quaternary ammonium form I and the adsorption properties after elution were studied. In addition, the elution curse, the permeation curveand the exchange capacities of operation were presented. The eluate containingtungsten with high content and excessive eluant of low content were obtained by employing the process of eluting using mixed solution of NaCl and NaOH. It's possible to obtain Na2WO4. 2H2O with high purity by evaporating and crystallizing theeluate. The results of mixed elution showed that the diffusion coefficients of Cl-.OH- and WO ions in solution or exchange agent varied due to the coexistence ofcounter ions and then the exchange velocity of WO→Cl- and WOe→OH- wasaccelerated.展开更多
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with sixty polystyrene-supported quaternary ammonium salt catalysts was synthesized. The reduction of acetophenone by NaBH, was used as the probing reaction to select out the most active catalyst in the library by using iterative method, which was the gel-type triethanolamine aminating strongly basic anion exchange resin with the crosslinking degree of 2% A hydrogen bonding assisted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.
文摘The elution of WO ions by NaOH. NaNO3 NaCl and NH4Cl on strong basicanion exchange resins in quaternary ammonium form I and the adsorption properties after elution were studied. In addition, the elution curse, the permeation curveand the exchange capacities of operation were presented. The eluate containingtungsten with high content and excessive eluant of low content were obtained by employing the process of eluting using mixed solution of NaCl and NaOH. It's possible to obtain Na2WO4. 2H2O with high purity by evaporating and crystallizing theeluate. The results of mixed elution showed that the diffusion coefficients of Cl-.OH- and WO ions in solution or exchange agent varied due to the coexistence ofcounter ions and then the exchange velocity of WO→Cl- and WOe→OH- wasaccelerated.
