Desulfurization of Thiophenic Compounds by Ni(111):  Adsorption and Reactions of Thiophene, 3-Methylthiophene, and 2,5-Dimethylthiophene

Abstract

The adsorption and reactivity of thiophene, 2,5-dimethylthiophene, and 3-methylthiophene on Ni(111) have been examined. The saturation coverages of the three molecules are similar, about 0.13 monolayer (ML), and in all cases alkenes are the major hydrocarbon products. On initially clean surfaces, decomposition to sulfur, carbon and hydrogen is the major pathway, but the selectivity to hydrocarbon production can be enhanced by a factor of about 3 by predosing the surface with hydrogen. Sulfur is easily removed from the ring, and C-S bond scission is complete by 150 K. The rate-limiting step in alkene formation is hydrogenation of a highly unsaturated hydrocarbon intermediate. The hydrocarbon intermediates formed are difficult to unambiguously identify but are most likely cyclic structures, retaining the C 4 framework.

Chemistry of Thiophene, Pyridine, and Cyclohexylamine on Ni/MoSxand Ni/S/Mo(110) Surfaces: Role of Nickel in Hydrodesulfurization and Hydrodenitrogenation Processes

“…In recent years, many works have appeared investigating the surface chemistry of sulfur- and nitrogen-containing molecules on metallic Mo and Ni. − Metallic nickel is known to have an extremely high chemical affinity for sulfur- and nitrogen-containing molecules. − For example, the metal is able to break C−S bonds at temperatures as low as 100 K. , But, it is not clear how Ni will behave when in contact with molybdenum sulfide. In this article, we use synchrotron-based high-resolution photoemission to study the effects of Ni on the reactivity of MoS x and S/Mo(110) surfaces toward thiophene (C 4 H 4 S), pyridine (C 5 H 5 N), and cyclohexylamine (C 6 H 11 NH 2 , CHA).…”

“…In this article, we use synchrotron-based high-resolution photoemission to study the effects of Ni on the reactivity of MoS x and S/Mo(110) surfaces toward thiophene (C 4 H 4 S), pyridine (C 5 H 5 N), and cyclohexylamine (C 6 H 11 NH 2 , CHA). This type of study has not been done before, and here we take advantage of the sensitivity of photoemission for monitoring the rupture of C−S and C−N bonds. 4a,,,23b Thiophene and pyridine are frequently used as test molecules in HDS and hydrodenitrogenation (HDN) studies. ,,,− ,− These aromatic molecules are very stable, and it is difficult to break their C−S or C−N bonds. Cyclohexylamine derivatives are often observed during the HDN of large aromatic heterocyclic nitrogen compounds. ,, Compared to pyridine, cyclohexylamine is more susceptible to C−N bond cleavage. , Our studies show very interesting differences in the chemistry of these molecules on clean and Ni-promoted MoS x and S/Mo(110) surfaces.…”

Adsorption and thermal decomposition of 2-octylthieno[3,4-b]thiophene on Au(1 1 1)

“…This is probably due to fast desulfurization of thiophene on gold surfaces prior to desorption of monomers and dimerization of thiophenes during heating. It was also reported that desulfurization of thiophene derivatives on Ni(1 1 1) occurs around 150 K [35], Fig. 1.…”

Interaction between Ni and HZSM-5 in aromatization-enhanced reactive adsorption desulfurization catalysts for FCC gasoline upgrading

“…It also has good adsorption and hydrogenation abilities to olefins for unoccupied d orbitals [14, 15]. HZSM-5 zeolite, which has a particular 2-dimension pore structure, consists of Si–O tetrahedrons and Al–O tetrahedrons.…”