化工学报2018，Vol.69Issue(2)：725-732,8.DOI:10.11949/j.issn.0438-1157.20170962
Brønsted酸强度对正碳离子转化方向影响的分子模拟
Influence of Br?nsted acid strength on conversion of carbenium ion by molecular simulation
摘要
Abstract
The influence of Br?nsted acid strength on catalytic reactivity of carbenium ion was systematically studied by density functional theory (DFT) calculations. Four typical reactions of C4carbenium ion as model compound, including hydrogen transfer, isomerization, β scission, and dehydrogenation, were simulated in five solid acid models with various acid strengths from weak-, strong-, even close to super-acid. The calculation results revealed that the reaction energy barrier decreased exponentially for hydrogen transfer reaction but decreased linearly for other three reactions with the increase of Br?nsted acid strength. In weak-acid range, the sensitivities of reactions to acid strength from high to low was: hydrogen transfer > isomerization > β scission >dehydrogenation. Hydrogen transfer reaction had the lowest sensitivity in the strong-acid range. Calculation on ionic character of the organic fragments in transition states showed that reaction sensitivity to acid strength could be related to Mulliken charges of the transition state. The transition state with more Mulliken charge lead to stronger interaction with acid such that the activation energy barrier could be effectively reduced by increasing acid strength. The calculation was consistent with experimental conclusion and explained acid strength on production yield at the atomic level, which is of great significance to the development of new catalytic materials and modification of current catalysts.关键词
Brønsted酸强度/正碳离子/分子模拟/Mulliken电荷/催化/化学反应Key words
Brønsted acid strength/carbenium ion/molecular simulation/Mulliken charge/catalysis/chemical reaction分类
化学化工引用本文复制引用
付佳,冯翔,刘熠斌,杨朝合..Brønsted酸强度对正碳离子转化方向影响的分子模拟[J].化工学报,2018,69(2):725-732,8.基金项目
国家自然科学基金项目(U1462205,21606254) （U1462205,21606254）
山东省自然科学基金项目(ZR2016BB16) （ZR2016BB16）
青岛市应用基础研究源头创新计划项目(17-1-1-18-jch) （17-1-1-18-jch）
山东省重点研发计划项目(2017GSF17126) （2017GSF17126）
研究生创新工程基金项目(YCX2017037).supported by the National Natural Science Foundation of China(U1462205,21606254),the Natural Science Foundation of Shandong Province(ZR2016BB16),the Applied Fundamental Research of Qingdao(17-1-1-18-jch),the Key Research and Development Program of Shandong(2017GSF17126)and the Graduate Innovation Project(YCX2017037). （YCX2017037）
