617-78-7Relevant articles and documents
Silica-immobilized ionic liquid Br?nsted acids as highly effective heterogeneous catalysts for the isomerization of: N -heptane and n -octane
Al-Fatesh, Ahmed S.,Dhar, Abhishek,Fakeeha, Anis H.,Ibrahim, Ahmed A.,Khimani, Mehul,Patel, Hiren,Siva Kumar, Nadavala,Vekariya, Rohit L.
, p. 15282 - 15292 (2020/05/05)
Metal-free imidazolium-based ionic liquid (IL) Br?nsted acids 1-methyl imidazolium hydrogen sulphate [HMIM]HSO4 and 1-methyl benzimidazolium hydrogen sulphate [HMBIM]HSO4 were synthesized. Their physicochemical properties were investigated using spectroscopic and thermal techniques, including UV-Vis, FT-IR, 1H NMR, 13C-NMR, mass spectrometry, and TGA. The ILs were immobilized on mesoporous silica gel and characterized by FT-IR spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis, ammonia temperature-programmed desorption, and thermogravimetric analysis. [HMIM]HSO4?silica and [HMBIM]HSO4?silica have been successfully applied as promising replacements for conventional catalysts for alkane isomerization reactions at room temperature. Isomerization of n-heptane and n-octane was achieved with both catalysts. In addition to promoting the isomerization of n-heptane and n-octane (a quintessential reaction for petroleum refineries), these immobilized catalysts are non-hazardous and save energy.
Synthesis and functionalization of ordered mesoporous carbons supported Pt nanoparticles for hydroconversion of n-heptane
Said
, p. 14517 - 14529 (2018/08/28)
A comprehensive study was performed on the spectroscopic and textural properties of ordered mesoporous carbon (OMC) of the CMK-3 type modified by acid oxidation using K2S2O8 as a benign oxidant and nitrogen-doping by the aid of the polymerization of ethylenediamine and carbon tetrachloride inside the pore channels of SBA-15 hard template. The pristine, nitrogen-doped, and oxidized-ordered mesoporous carbons were used as supports to prepare 10 wt% platinum nanoparticles-loaded catalysts using ethylene glycol as a reducing agent. The catalytic behavior, mechanism, and influence of the surface functionalization of the ordered mesoporous carbon bifunctional catalysts toward the hydroconversion of n-heptane using a fixed-bed flow system operated under atmospheric pressure were investigated. The synthesized samples were characterized by various analytical and spectroscopic techniques. The mesostructural regularity corresponding to the hexagonal P6mm symmetry of the OMC-CMK-3 type was well-reserved even after surface modifications replicated from an SBA-15 template. H2 pulse chemisorption and EDX mapping images confirmed differences in the Pt NPs contents and dispersion depending on the support composition. The catalytic activity results achieved were hand in hand with the proper balance between the acidity strength and Pt NPs dispersion degree.
Influence of chlorine on the catalytic properties of supported rhodium, iridium and platinum in ring opening of naphthenes
Samoila,Epron,Marécot,Especel
, p. 207 - 219 (2013/07/26)
Pt, Ir and Rh were deposited on SiO2 or Al2O 3 using chlorinated precursors and various amounts of HCl in the impregnation medium. The Br?nsted and Lewis acidities increased with the chlorine content of the alumina supported catalysts. The silica-supported catalysts only presented Lewis acid sites. The catalysts were evaluated in methylcyclopentane (MCP) and methylcyclohexane (MCH) ring-opening (RO) under pressure (2.85 and 3.95 MPa, respectively), from 200 to 425 C. For MCP conversion, the acidity of the alumina support had no sensitive effect on the activity and selectivity to RO products, and few effects on the distribution of RO products. No isomerization or hydrocracking products were observed, confirming that these reactions occurred mainly on the metal function, which was not modified by the presence of chlorine. The nature of the support, SiO 2 or Al2O3, had a strong effect on both the activity (1.9 against 0.5 mol h-1 g-1metal for Ir/Al2O3 and Ir/SiO2, respectively at 225 C) and selectivity to RO products (99.6% against 97.5% for Ir/Al2O 3 and Ir/SiO2, respectively, at 80% of MCP conversion) for Ir catalysts only. Interestingly, the Rh/SiO2 exhibited a high selectivity for converting MCP to RO products, similar to Ir/Al 2O3, i.e. 99.6% at 80% of conversion. Depending on the metal and the supports, three types of behavior were observed for MCH ring-opening: (i) a direct ring-opening on the metal function whatever the support for Ir, (ii) a first step of isomerization, and then a need of a sufficiently acidic support, for Pt and (iii) an intermediate behavior for Rh, which was able to either directly convert MCH in absence of acidic support or favor a bifunctional mechanism on chlorinated alumina.
