Mechanism of dibenzofuran hydrodeoxygenation on the Ni (111)surface

• 作者: Zi-Zheng Xie Meng Zhang Xing-Bao Wang Liang Guo Zhen-Yi Du Wen-Ying Li
• 来源期刊: 中国化学工程学报（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: Catalysis, Kinetics and Reaction Engineering
• 页码范围: 204-210
• 页数: 7页
• 语种: 英文

摘要

The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygena-tion of dibenzofuran,as a model compound of coal tar,on the Ni (111) surface.The obtained results indi-cate that dibenzofuran can be firstly hydrogenated to tetrahydrodibenzofuran and hexahydrodibenzofuran.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran (Ea =0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of 2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcyclo-hexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxy-genation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodiben-zofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.