Some Characteristic Features of Dilute Aqueous Alkali Solutions of Specific Alkali Concentration (2.5 mol l−1) Which Possess Maximum Solubility Power against Cellulose
Some Characteristic Features of Dilute Aqueous Alkali Solutions of Specific Alkali Concentration (2.5 mol l−1) Which Possess Maximum Solubility Power against Cellulose
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DOI：
10.1295/polymj.20.447
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发表时间：
1988-06
期刊：
影响因子：
2.8
通讯作者：
Takashi Yamashiki;K. Kamide;K. Okajima;K. Kowsaka;Toshihiko Matsui;Hiroko Fukase
中科院分区：
文献类型：
--
作者：
Takashi Yamashiki;K. Kamide;K. Okajima;K. Kowsaka;Toshihiko Matsui;Hiroko Fukase
水（aq.）通过电导率、1 H和2 3 Na NMR、溶剂化和拉曼光谱分析，研究了纤维素在特定浓度（2.5 mol l-1）的碱溶液中的溶胀和溶解。碱，尤其是aq.氢氧化钠纤维二糖水溶液还对碱进行1H NMR和比旋角测量以阐明纤维素的溶解状态。发现在特定碱浓度下，电导率、1H和23 Na化学位移和1H弛豫时间变得更小，并且每1摩尔碱金属氢氧化物的溶剂化水分子的数目变得比在特定碱浓度范围之外从它们的碱浓度依赖性简单地预期的那些更大。拉曼光谱表明，在特定的水溶液浓度下，给出最大强度的OH-变形的峰在能量上最弱。碱当将纤维二糖加入到aq.在碱溶液中，体系的质子化学位移在整个碱浓度范围内都变大，特别是在4°C时，其变化与碱浓度几乎呈线性关系。基于这些实验事实，提出了水溶液的结构模型。提出了特定浓度的碱溶液以及纤维素在碱溶液中的溶解状态。
Some structural features of aqueous (aq.) alkali solutions with specific concentration (2.5 mol l−1), in which cellulose shows maximum swelling or dissolution, were investigated by analysing electrical conductivity, 1H and 23Na NMR, solvation and Raman spectra of aq. alkali, especially aq. sodium hydroxide. Cellobiose solution in aq. alkali was also subjected to 1H NMR and specific rotatory angle measurements to elucidate the dissolved state of cellulose. It was found that in the specific alkali concentration, electrical conductivity, 1H and 23Na chemical shifts and 1H relaxation time became smaller and the number of solvated water molecules per 1 mole of alkali hydroxide became larger than those simply expected from their alkali concentration dependence in the outside range of specific alkali concentration. Raman spectra revealed that the peak giving maximum intensity of OH-deformation is energetically weakest at the specific concentration of aq. alkali. When cellobiose was added to the aq. alkali solution it was found that proton chemical shift of the system becomes larger especially at 4°C over the all alkali concentration range and its dependence on alkali concentration was almost linear. Based on these experimental facts some structure models of aq. alkali solution with specific concentration and the dissolved state of cellulose in the alkali solution were proposed.