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壳聚糖钙/锌配位降解产物的GFC及清除O-·2研究   总被引:3,自引:0,他引:3  
分别将Ca(Ⅱ)和Zn(Ⅱ)加入到壳聚糖溶液中,调节pH值使壳聚糖与金属配位.加入H2O2并升高温度对处于配位缔合状态的壳聚糖进行氧化降解,测定了降解产物寡糖的数均相对分子质量和相对分子质量分布.结果表明壳聚糖在与Ca和Zn配位的情况下,可被H2O2迅速降解;降解从大相对分子质量范围开始,降解产物寡糖相对分子质量分布较窄,且聚合度(DP数)越小,寡糖相对分子质量分布指数越小.同时对两者的降解产物进行了清除超氧阴离子自由基(O2-.)的研究,研究发现两者的降解产物均对O2-.有一定的清除作用,清除率随降解产物数均相对分子质量的减小而增大.但用完全降解产物氨基葡糖形成配合物时,清除作用几乎完全消失.  相似文献   
2.
壳聚糖铜(Ⅱ)配位与氧化控制降解寡糖的GFC色谱研究   总被引:3,自引:0,他引:3  
在壳聚糖溶液中加入铜离子使形成壳聚糖铜配合物,通过IR ,UV ,元素分析及热重分析等对壳聚糖铜配合物进行表征。用H2 O2 对形成的壳聚糖Cu(Ⅱ)配合物进行氧化降解,测定了降解产物寡糖的平均数均分子量和分子量分布。结果表明壳聚糖铜配合物在升高温度时,在过氧化氢的存在下降解迅速,降解从大分子量范围开始,降解寡糖分子量分布在温度和降解时间相同条件下大大窄于目前常用的盐酸和纯过氧化氢氧化降解方法。分子量分布指数与降解寡糖的平均数均分子量有关,当高于10个寡聚糖数(DP)时,DP越小,分子量分布指数越小。  相似文献   
3.
壳聚糖锰(Ⅱ)配位与氧化控制降解寡糖的分子量分布   总被引:4,自引:0,他引:4  
Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Mn(Ⅱ) complex, and the molecular distribution of degraded products were investigated after eliminating Mn(Ⅱ) ions using the cation exchange resin column. The result suggested that the Chitosan could be degraded rapidly, the degradation started from higher molecular weight range, the molecular weight distribution of oligosaccharides was much more narrower than that of degradated products from common methods such as hydrolysis, acidic and oxidizing methods. The index of molecular weight distribution was changed with the average degradability. When exceeding 10 oligosaccharides, the smaller of the DP, the smaller of the index.  相似文献   
4.
The compound [Mn2(CO)10] reacts with 2-(Methylthio)thiophene (C5H6S2) while refluxing in xylene to afford a methylthio-tetramanganese product [MnS(CO)3]4, in which C5H6S2 is cleaved with loss of thiophene. The crystal structure of [MnS(CO)3]4 has been studied by direct method. Based on the 21 685 unique reflections collected using Mo of X-ray radiation and a CCD-based detector, it is refined to an agreement index (R1) of 0.079 0. The cell is triclinic with dimensions: a=1.719 49 nm, b=1.959 2 nm, c=2.632 6 nm and α=79.733°, β=71.407°, γ=89.387°. There are 12 unit cells of [MnS(CO)3]4 in the cell, with space group P1.  相似文献   
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