Theoretical study on the mechanisms of cellulose dissolution and precipitation in the phosphoric acid-acetone process.
Theoretical study on the mechanisms of cellulose dissolution and precipitation in the phosphoric acid-acetone process.
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DOI：
10.1016/j.carbpol.2012.07.068
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发表时间：
2012-11
影响因子：
11.2
通讯作者：
Peng Kang;W. Qin;Zong-ming Zheng;C. Dong;Yongping Yang
中科院分区：
文献类型：
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作者：
Peng Kang;W. Qin;Zong-ming Zheng;C. Dong;Yongping Yang
采用磷酸-丙酮分级法对木质纤维素进行预处理，制备纤维素乙醇。模拟了纤维素在H2O、H3 PO 4和CH 3COCH 3中的溶解特性。原子几何和电子性质的计算采用密度泛函理论与局域密度近似。H3 PO 4分子吸附在两个纤维素链段之间，与EB形成4个氢键，电子伏特为− 1.61 eV。在H_3PO_4-纤维素体系中，纤维素的态密度出现离域，没有明显的峰。Egapof 4.46eV远小于其它系统中的Egapof。分子动力学模拟结果表明，在纤维素-H3 PO 4相互作用体系中，葡萄糖双环片段发生分离.冰冷的CH 3COCH 3加成导致分离的片段重新聚集。纤维素在三种溶剂中的反应能均在3.5eV左右，表明纤维素是化学稳定的。此外，理论结果与我们已经进行的实验相一致，表明纤维素溶解在H3 PO 4中，加入CH 3COCH 3后絮凝，最后变得更容易水解成葡萄糖。
Phosphoric acid–acetone fractionation was applied to pretreat lignocellulose for production of cellulosic ethanol. Cellulose solubility properties in H2O, H3PO4and CH3COCH3were simulated. Atomic geometry and electronic properties were computed using density functional theory with local-density approximation. H3PO4molecule is adsorbed between two cellulose segments, forming four hydrogen bonds with EBof −1.61eV. Density of state for cellulose in H3PO4–cellulose system delocalizes without obvious peak. Egapof 4.46eV is much smaller than that in other systems. Molecular dynamics simulation indicates that fragments of double glucose rings separate in the cellulose–H3PO4interaction system. Icy CH3COCH3addition leads to re-gathering of separated fragments. Reaction energy of cellulose in three solvents is around 3.5eV, implying that cellulose is chemically stable. Moreover, theoretical results correspond to the experiments we have performed, showing that cellulose dissolves in H3PO4, flocculates after CH3COCH3addition, and finally becomes more liable to be hydrolyzed into glucoses.