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Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10~(-2)(DS)~(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved. 相似文献
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反相高效液相色谱法的多波长同时测定预混合饲料中的脂溶性维生素A,α-E,D_3,K_3 总被引:5,自引:0,他引:5
The assay of lipo-soluble-vitamins is considered as a difficult analysis item by all analysts. This paper putsforward a method to simultaneously determine lipo-soluble-vitamins by multiwavelength reversed-phase high performance liquid chromatography,that have not found in references. Under normal conditions samples must bepretreated and then injected separately for each vitamin in analysis. Our method with multiwave length variableprogram and simultaneous determination can assay all lipo-soluble-vitamins on 相似文献
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用电位滴定法测定了在不同溶剂中生成的羧甲基纤维素(CMC)完全酶降解和酸水解后的还原端基数,计算出反映CMC一条分子链上取代基分布的参数,如取代及未取代葡萄糖单元(AGU)的链段长度、单取代及双取代百分数等,并考察了这些CMC耐酸性,表明熔剂种类与取代基沿CMC分子链的分布密切相关,研究了在异丙醇-水体系内生成的CMC,醇和水的比例对取代基分布的影响,发现在异丙醇含量为75-95%范围内,随用量增大,CMC取代度升高,取代基沿分子链分布更均一。 相似文献
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在苯-乙醇介质中生成的羧甲基纤维素取代基分布的研究 总被引:5,自引:0,他引:5
以三组份两相液体苯 乙醇 水为介质合成羧甲基纤维素(CMC),应用1H NMR谱图分析了CMC中羧甲基在葡萄糖单元(AGU)的C2、C3及C6位上对羟基的取代分布.结果表明,取代基的分布顺序是C6>C2>C3;当取代度(DS)低于10时,C2∶C3∶C6近似于145∶1∶215;DS高于10以后,分布趋于相同,通过对CMC的X 衍射分析解释了取代基分布规律.同时研究了苯的影响,证实相同取代度下,在苯 乙醇 水中生成的CMC试样,其C6位取代基分布多于在乙醇 水中生成的试样. 相似文献
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