Effect of urea on cellulose degradation under conditions of alkaline pulping
Effect of urea on cellulose degradation under conditions of alkaline pulping
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DOI：
10.1007/s10570-012-9791-4
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发表时间：
2012-09
期刊：
影响因子：
5.7
通讯作者：
O. Ershova;E. Costa;A. Fernandes;M. Domingues;D. Evtuguin;H. Sixta
中科院分区：
文献类型：
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作者：
O. Ershova;E. Costa;A. Fernandes;M. Domingues;D. Evtuguin;H. Sixta
以纤维素粉为原料，研究了尿素在碱法制浆条件下对纤维素降解的影响。在尿素存在下的纤维素产率的增加主要归因于氨基甲酸酯化反应，这是由元素分析，紫外-共振拉曼和固态13 C核磁共振光谱证实。基于动力学研究，提出了在制浆过程的加热期间尿素对纤维素剥离反应的稳定作用，并在使用纤维二糖的模型反应中进一步证实。通过串联电喷雾质谱分析了碱性尿素溶液中形成的反应产物，并证明了纤维二糖和尿素的还原端基之间发生Maillard型反应。认为美拉德型反应和还原性端基的氨基甲酸酯化反应是碱法制浆条件下纤维素保护机理的一部分。
The effect of urea on the cellulose degradation under conditions of alkaline pulping has been studied using purified cellulose powder. The increased cellulose yield in the presence of urea was assigned essentially to the carbamation reactions which were confirmed by elemental analysis, UV-resonance Raman and solid-state13C nuclear magnetic resonance spectroscopy. The stabilizing effect of urea on the cellulose peeling reactions during heating up period of pulping process was suggested based on kinetic studies and additionally confirmed in model reactions using cellobiose. The reaction products formed in alkaline urea solutions were analysed by tandem electrospray ionization mass spectrometry and the occurrence of Maillard type reactions between reducing end groups of cellobiose and urea were evidenced. Both Maillard type reactions and carbamation of reducing end groups were proposed to be a part of cellulose protection mechanism against peeling under the conditions of alkaline pulping.