Li Tianshuang, Li Jie, Zhang Hongliang, Sun Kena, Xiao Jin
School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China.
J Phys Chem A. 2019 Jan 31;123(4):796-810. doi: 10.1021/acs.jpca.8b09882. Epub 2019 Jan 22.
Thiophene sulfur is the most stable organic sulfur species in petroleum coke, among which benzothiophene accounts for a significant portion. Removal of benzothiophene will help to gain ultralow desulfurization. In this work, a density function theory (DFT) method was adopted to investigate benzothiophene pyrolysis mechanism. It was found that the most possible pyrolysis reaction of benzothiophene is triggered by α-H migration to β-position. The dominating products are S radical and ethenethione, which could explain benzothiophene pyrolysis experiments well. Converting thiophene fused on aromatic to a thiol group could help to promote desulfurization. As a contrast, the thiophene pyrolysis reaction was also calculated at the same level. The initial pyrolysis temperature of benzothiophene and thiophene may be close, but the pyrolysis rate of thiophene is higher than that of benzothiophene. The implication of the benzothiophene pyrolysis mechanism may be beneficial for the development of new desulfurization technology.
噻吩硫是石油焦中最稳定的有机硫物种，其中苯并噻吩占很大一部分。脱除苯并噻吩将有助于实现超低脱硫。在这项工作中，采用密度泛函理论（DFT）方法研究苯并噻吩的热解机理。发现苯并噻吩最可能的热解反应是由α-H迁移至β位引发的。主要产物是S自由基和乙烯硫酮，这可以很好地解释苯并噻吩的热解实验。将稠合在芳烃上的噻吩转化为硫醇基团有助于促进脱硫。作为对比，也在相同水平上计算了噻吩的热解反应。苯并噻吩和噻吩的初始热解温度可能相近，但噻吩的热解速率高于苯并噻吩。苯并噻吩热解机理的研究结果可能有利于新型脱硫技术的开发。
