Carboxymethylcellulose synthesis in organic media containing ethanol and/or acetone
Carboxymethylcellulose synthesis in organic media containing ethanol and/or acetone
复制标题
在含有乙醇和/或丙酮的有机介质中合成羧甲基纤维素
DOI：
10.1002/(sici)1097-4628(19980118)67:3
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发表时间：
1998
影响因子：
3
通讯作者：
Daniel Ţi˘mpu
中科院分区：
文献类型：
--
作者：
N. Olaru;L. Olaru;A. Stoleriu;Daniel Ţi˘mpu
研究了木浆纤维素和棉短绒纤维素在不同有机介质（即乙醇、丙酮和乙醇-丙酮混合物）中的羧甲基化。此前，发现用作反应介质的乙醇-丙酮1:1（w/w）混合物比单独的纯溶剂具有更高的取代度（DS）。在本工作中，在乙醇-丙酮3:7（w/w）混合物以及丙酮作为反应介质中进行了纤维素羧甲基化的动力学研究，并且观察到了溶剂混合物的相同协同效应。数据表明伪一级动力学行为可以通过以下方程令人满意地描述：ln(1.11 − DS) = −kt。观察到的两个反应步骤分别与具有较高反应速率的较少有序区域和具有较小反应速率的较多有序区域的转变有关。考虑到 X 射线衍射和量热法测定所揭示的乙醇-丙酮 3:7 (w/w) 混合物、乙醇和丙酮产生的纤维素结晶度和可及性的不同结构变化，给出了这种行为的可能解释。 © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 481–486, 1998
A study of the carboxymethylation of wood pulp cellulose and cotton linters cellulose in different organic media, namely, ethanol, acetone, and ethanol-acetone mixtures, is performed. Previously, the ethanol-acetone 1 : 1 (w/w) mixture used as reaction medium was found to give a higher degree of substitution (DS) than the pure solvents separately. In the present work, the kinetic investigation of cellulose carboxymethylation was carried out in ethanol-acetone 3 : 7 (w/w) mixture, as well as in acetone as reaction media, and the same synergistic effect of the solvents mixture was observed. The data suggested a pseudo-first-order kinetic behavior satisfactorily described by the following equation: ln(1.11 − DS) = −kt. The two reaction steps observed are related to the transformations of less ordered regions with higher reaction rate and more ordered regions with smaller reaction rates, respectively. A possible explanation for this behaviour is given, taking into account the different structural changes of cellulose crystallinity and accessibility produced by ethanol-acetone 3 : 7 (w/w) mixture, ethanol, and acetone, as revealed by X-ray diffraction and calorimetry determinations. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 481–486, 1998