二苯并噻吩和吲哚在NiMoS/γ-Al2O3上加氢脱硫和加氢脱氮反应的相互影响

在固定床高压微反装置上考察了预硫化型NiMoS/γ-Al2O3催化剂上二苯并噻吩（DBT）加氢脱硫（HDS）反应和吲哚加氢脱氮（HDN）反应之间的相互影响。结果表明，吲哚对DBT的加氢脱硫反应具有抑制作用，其中对加氢路径（HYD）比对氢解路径（DDS）的抑制作用强，温度升高后，吲哚的抑制作用减弱。吲哚对DBT加氢脱硫反应的抑制作用源于吲哚及其HDN反应的中间产物在活性位上的竞争吸附。DBT和原位生成的H2S促进了催化剂表面硫阴离子空穴（CUS）向B酸位的转化，从而提高1,2-二氢吲哚（HIN）分子中C(sp3)—N键的断裂能力，使得吲哚的转化率和产物中邻乙基苯胺（OEA）的相对含量增大。HDN活性相的形成虽然需要硫原子的参与，但是活性相的保持并不需要大量的硫原子，较高含量硫化物存在时加氢活性位减少，不利于脱氮反应。

Mutual influences of hydrodesulfurization of dibenzothiophene and hydrodenitrogenation of indole over NiMoS/y-Al2O3 catalyst

The influence of indole on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and the influence of DBT on the hydrodenitrogenation (HDN) of indole were investigated over a presulfided NiMoS/γ-Al₂O₃ catalyst in a fixed-bed high-pressure microreactor. A significant negative effect of indole on the HDS of DBT was observed. The inhibitory effect of indole on the hydrogenation route (HYD) was stronger than on the direct desulfurization route (DDS). Indole and its HDN intermediate products suppressed HDS of DBT through the competitive adsorption on active sites of the catalyst. DBT and H₂S produced in situ promoted the conversion of coordinatively unsaturated sites (CUS) to Brønsted acid sites on the catalyst surface, which in turn facilitated the cleavage of C(sp³)—N bond in indoline; the conversion of indole and the relative concentration of o-ethylanline (OEA) then increased. Although the presence of sulfur atoms is essential for the formation of active sites on the catalyst for HDN, a small amount of sulfur species is sufficient to maintain the HDN active sites; higher content of sulfides may bring on a negative influence on the HDN of indole.