二苯并噻吩类硫化物在非负载型NiMoW催化剂上加氢脱硫反应机理  

Mechanism of hydrodesulfurization of dibenzothiophenes on unsupported NiMoW catalyst

作　　者：殷长龙[1] 翟西平[1] 赵蕾艳[1] 刘晨光[1] 

机构地区：[1]中国石油大学(华东)重质油国家重点实验室CNPC催化重点实验室,山东青岛266580

出　　处：《燃料化学学报》2013年第8期991-997,共7页Journal of Fuel Chemistry and Technology

基　　金：国家重点基础研究发展规划(973计划;2010CB226905)

摘　　要：研究了二苯并噻吩(DBT)、4-甲基二苯并噻吩(4-MDBT)和4,6-二甲基二苯并噻吩(4,6-DMDBT)在非负载型NiMoW催化剂上的加氢脱硫反应产物分布及反应机理,给出了它们在非负载型催化剂上加氢脱硫反应网络。研究发现,由于甲基的空间位阻效应,二苯并噻吩类化合物加氢脱硫转化率顺序为4,6-DMDBT≈4-MDBT<DBT,而非负载型NiMoW催化剂具有很高的芳环加氢活性,有利于烷基取代的芳环加氢,减弱空间位阻效应,使烷基取代的二苯并噻吩类化合物得到有效脱除。DBT的脱硫产物会被进一步加氢,其产物分布与联苯加氢产物相似。4-MDBT有两种预加氢脱硫反应路径,甲基取代的苯环由于甲基的供电子效应会被优先加氢。非负载型催化剂存在的L酸中心会使部分4-MDBT和4,6-DMDBT通过脱甲基反应生成DBT再进行脱硫反应。Hydrodesulfurization （ HDS ） of dibenzothiophene （ DBT）, 4-methyldibenzothiophene （ 4-MDBT ） and 4,6-dimethyldibenzothiophene （4,6-DMDBT） on unsupported NiMoW catalyst was studied. Moreover, mechanisms and reaction networks were revealed on the basis of GC and GC-MS analyses of the reaction products. The result shows that, the HDS rate of dibenzothiophenes is in the order of 4,6-DMDBT ≈4-MDBT〈 DBT for the spatial restraining effect of the methyl group. Unsupported NiMoW catalyst has high hydrogenation activity in aromatics saturation, it favours the hydrogenation of alkyl-substituted aromatic ring, weakens the spatial restraining effect, leads to the effectively removing of alkyl-substituted dibenzothiophenes. The hydrodesulfurization products of DBT could be hydrogenated further and its distribution is similar to the hydrogenation products of biphenyl（BP）. The hydrogenation route of the hydrodesulfurization of 4-MDBT have two reaction pathways, the electron donor induction of the methyl group could promote the hydrogenation of the adjacent phenyl. On the lewis acid sites of catalyst, part of 4-MDBT and 4,6-DMDBT transformed into DBT through the demethylation reaction in their hydrodesulfurization process.

关 键 词：二苯并噻吩 4-甲基二苯并噻吩 4 6-二甲基二苯并噻吩 加氢脱硫 反应网络 非负载型NiMoW催化剂 

分 类 号：O643[理学—物理化学] TQ53[理学—化学]