β葡萄糖分子开环的计算研究:卤素轰击（英文）

Ring opening by breaking the C-O bond in β-glucose: halogen bombardment

生物质能源的主要来源纤维素,在工业上极易水解得到β葡萄糖。β葡萄糖是环状分子,很稳定,难以利用。卤素离子是低温等离子体技术中广泛使用的离子源,同时也是电负性很强且易与有机分子结合导致开环的元素。基于第一性原理分子动力学,我们采用卤素轰击β葡萄糖分子,导致开环形成链醇。在研究了各种初始反应构型后,我们发现开环过程中β葡萄糖和卤素之间发生了明显的电荷转移。结合电荷布局分析卤素的阴离子效应和水溶液效应发现β葡萄糖和卤素之间的电荷转移是开环反应发生的主要原因,而且电荷转移依赖于反应的条件。通过比较不同反应条件下的反应速率、产物寿命、所需能量以及产物燃烧热,我们发现溴离子在氧原子上方轰击β葡萄糖的成本最低,最利于实际的应用。对反应产物进一步加氢脱氧,将会得到液态的烷烃燃料。

β-glucose can be conveniently obtained from the dehydration of cellulose, which is the most abundant and available biomass resource. However, β-glucose is difficult to utilize due to its stable ring structure. As reported, halogen is a widely used plasmonic source implemented in the low-temperature plasma technique. Simultaneously, halogen characterizes a strong electronegativity and hence can be easily combined with organic molecules resulting in rings opening. Based on the first principle molecular dynamics, our work reports the study of ring opening in β-glucose molecule resulting from bombardment of halogen atoms. By investigating various initial configurations, a remarkable charge transfer is found to respond to the ring opening. The charge transfers occur not only in the β-glucose but between the β-glucose and the halogen. Combining with charge population, halogen anion effect as well as aqueous effect is analyzed, which demonstrates that the charge transfer between the β-glucose and the halogen is the main reason for ring opening reaction. Furthermore, charge transfer depends on the reaction conditions. By comparing the reaction rates, product life, energy required and combustion heat in different reaction conditions, we found that the required cost related to the reaction is the lowest in the case of bromide ion at the top of the oxygen atom bombarding β-glucose, which most favors the validity in the practical applications. Consequently, a direct method of selective ring opening in β-glucose is proposed and future studies on hydrogenation and deoxidization are expected to make the product of bombardment into liquid alkane.