Two new coordination compounds of rare earth chloride with N-acetyl-DL-alanine and imidazole have been prepared from absolute alcohol. The general formula RE(C5H8NO3)2(C3H5N2)2Cl3·4H2O (RE=Ce, Pr) of these compou...Two new coordination compounds of rare earth chloride with N-acetyl-DL-alanine and imidazole have been prepared from absolute alcohol. The general formula RE(C5H8NO3)2(C3H5N2)2Cl3·4H2O (RE=Ce, Pr) of these compounds were identified, by chemical and elemental analysis, FTIR spectra, UV spectra, 1H NMR and 13C NMR spectra, and molar conductance. The processes of thermal decomposition were identified by TG-DSC curves. The possible reaction mechanisms and the kinetics equation were investigated by comparing the kinetics parameters. The activation entropy of dehydration, as well as enthalpy values of dehydration and decomposition were obtained by DSC curve. The three-dimensional fluorescence spectra of liquid compounds were measured. The phenomenon of the up-conversion fluorescence is discussed.展开更多
文摘Two new coordination compounds of rare earth chloride with N-acetyl-DL-alanine and imidazole have been prepared from absolute alcohol. The general formula RE(C5H8NO3)2(C3H5N2)2Cl3·4H2O (RE=Ce, Pr) of these compounds were identified, by chemical and elemental analysis, FTIR spectra, UV spectra, 1H NMR and 13C NMR spectra, and molar conductance. The processes of thermal decomposition were identified by TG-DSC curves. The possible reaction mechanisms and the kinetics equation were investigated by comparing the kinetics parameters. The activation entropy of dehydration, as well as enthalpy values of dehydration and decomposition were obtained by DSC curve. The three-dimensional fluorescence spectra of liquid compounds were measured. The phenomenon of the up-conversion fluorescence is discussed.
文摘以聚醚多元醇和甲苯二异氰酸酯(TDI)为原料,选用氨基酰化酶I作为模型酶,采用一步发泡法,将酶固定在软质聚氨酯泡沫塑料(FPUF)上,并对其进行表征.研究结果表明,在发泡过程中加入一定量的惰性蛋白质,对酶蛋白有一定的屏蔽效果,降低了被TDI损伤的概率,客观上对酶分子起到保护作用,使固定化后的酶活力收率有所提高.测得FPUF对蛋白质的负载率高达100%,固定化酶活力收率为81.03%,该固定化酶的最适pH值为6.8,与最适pH值为7的酶液相比,略向酸性偏移;最适反应温度与游离酶相似,在50～70℃.将固定化酶用于拆分乙酰-DL-甲硫氨酸的试验,体现了较好的连续使用稳定性,其半衰期为404.3 min.
