590-35-2Relevant articles and documents
Impact of the Spatial Organization of Bifunctional Metal–Zeolite Catalysts on the Hydroisomerization of Light Alkanes
Cheng, Kang,Harmel, Justine,Oenema, Jogchum,Sunley, Glenn,Yoshida, Hideto,Ze?evi?, Jovana,Zhang, Zhaorong,de Jong, Krijn P.,van der Wal, Lars I.
supporting information, p. 3592 - 3600 (2020/02/05)
Improving product selectivity by controlling the spatial organization of functional sites at the nanoscale is a critical challenge in bifunctional catalysis. We present a series of composite bifunctional catalysts consisting of one-dimensional zeolites (ZSM-22 and mordenite) and a γ-alumina binder, with platinum particles controllably deposited either on the alumina binder or inside the zeolite crystals. The hydroisomerization of n-heptane demonstrates that the catalysts with platinum particles on the binder, which separates platinum and acid sites at the nanoscale, leads to a higher yield of desired isomers than catalysts with platinum particles inside the zeolite crystals. Platinum particles within the zeolite crystals impose pronounced diffusion limitations on reaction intermediates, which leads to secondary cracking reactions, especially for catalysts with narrow micropores or large zeolite crystals. These findings extend the understanding of the ??intimacy criterion” for the rational design of bifunctional catalysts for the conversion of low-molecular-weight reactants.
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.
PROCESS FOR SELECTIVE RING OPENING OF CYCLIC HYDROCARBONS
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Paragraph 0078-0085, (2020/04/29)
PURPOSE: A process for ring opening is provided to obtain improved conversion ratio and selectivity in comparison with the case of using hydrogen as a reducing agent. CONSTITUTION: A cyclic hydrocarbon and a reducing agent are provided as supplying materials. The supplying materials are transferred into a reactor (5) and reacted under the presence of a catalyst. A product is separated from the effusion of reaction zone. The catalyst is a heterogeneous catalyst having both acid site and metallic component. The product is obtained by evaporating and heating a mixture containing 100 parts by weight of porous molecular sieve and 0.01-20 parts by weight of water soluble metallic salt. The cyclic hydrocarbon is a naphthene group cyclic hydrocarbon which is pentagonal or hexagonal compound, or an alkyl derivative thereof selected from cyclopentane and cyclohexane. The alkyl derivative is methyl, ethyl, profile, butyl, isopropyl or an isobutyl derivative.
Bis(imino)pyridine cobalt-catalyzed dehydrogenative silylation of alkenes: Scope, mechanism, and origins of selective allylsilane formation
Atienza, Crisita Carmen Hojilla,Diao, Tianning,Weller, Keith J.,Nye, Susan A.,Lewis, Kenrick M.,Delis, Johannes G. P.,Boyer, Julie L.,Roy, Aroop K.,Chirik, Paul J.
supporting information, p. 12108 - 12118 (2014/10/16)
The aryl-substituted bis(imino)pyridine cobalt methyl complex, ( MesPDI)CoCH3 (MesPDI = 2,6-(2,4,6-Me 3C6H2-N=CMe)2C5H 3N), promotes the catalytic dehydrogenative silylation of linear α-olefins to selectively form the corresponding allylsilanes with commercially relevant tertiary silanes such as (Me3SiO) 2MeSiH and (EtO)3SiH. Dehydrogenative silylation of internal olefins such as cis- and trans-4-octene also exclusively produces the allylsilane with the silicon located at the terminus of the hydrocarbon chain, resulting in a highly selective base-metal-catalyzed method for the remote functionalization of C-H bonds with retention of unsaturation. The cobalt-catalyzed reactions also enable inexpensive α-olefins to serve as functional equivalents of the more valuable α, ω-dienes and offer a unique method for the cross-linking of silicone fluids with well-defined carbon spacers. Stoichiometric experiments and deuterium labeling studies support activation of the cobalt alkyl precursor to form a putative cobalt silyl, which undergoes 2,1-insertion of the alkene followed by selective β-hydrogen elimination from the carbon distal from the large tertiary silyl group and accounts for the observed selectivity for allylsilane formation.
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.
Hydrocarbon separation
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Page/Page column 11, (2008/12/06)
Process for the separation of close boiling compounds comprising distilling a hydrocarbon mixture of said compounds in the presence of a high boiling diluent liquid and a solid adsorbent. The high boiling diluent is withdrawn from the bottom of the distillation column and recycled to the column. The process is particularly suitable for the separation of straight-chain isomers from isomerate mixtures, the separation of benzene from hydrocarbon mixtures and the separation of paraffins from olefins.
Process for the preparation of a paraffin isomerization catalyst
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Page/Page column 4-5, (2008/06/13)
A process for preparation of a paraffin isomerization catalyst comprising a mixture of a Group IVB metal oxide, a Group VIB metal oxide, a Group IIIA metal oxide and a Group VIII metal. The process includes the steps of: a) contacting a hydroxide of the Group IVB metal with an aqueous solution of an oxyanion of the Group VIB metal to provide a mixture, (b) drying the mixture to provide a dry powder, (c) kneading the powder with a Group IIIA hydroxide gel and a polymeric cellulose ether compound to form a paste, (d) shaping the paste to form a shaped material, (e) calcining the shaped material to form a calcined material, (f) impregnating the calcined material with an aqueous solution of a Group VIII metal salt to provide the catalyst, and (g) calcining the catalyst.
Isomerization of N-heptane in naphtha cuts
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Page/Page column 4, (2008/06/13)
A process for the isomerization of normal heptane contained within a naphtha stream, such as a C6-C8 naphtha, in which the naphtha stream is fractionated into a fraction substantially free of normal heptane and a fraction containing normal heptane. The fraction containing normal heptane is contacted with an isomerization catalyst in an isomerization zone operated as a singe pass fixed bed reactor having a single effluent to isomerize a portion of said normal heptane to branched heptane. The effluent is recovered from said isomerization zone and the effluent is fractionated to recover said branched heptane. The unconverted normal heptane is recovered and returned to the isomerization since it can be separated from the branded heptanes by fractionation.
Alkane metathesis catalyzed by a well-defined silica-supported Mo imido alkylidene complex: [(≡SiO)Mo(=NAr)(=CHtBu)(CH2tBu)]
Blanc, Frederic,Coperet, Christophe,Thivolle-Cazat, Jean,Basset, Jean-Marie
, p. 6201 - 6203 (2007/10/03)
A two-functions-in-one catalyst precursor allows an olefin metathesis catalyst to be turned into an alkane metathesis catalyst. A silica-supported alkyl alkylidene molybdenum complex containing an ancillary imido ligand is a highly active olefin metathesis catalyst and also acts as a catalyst precursor for alkane metathesis. This system involves a single metal with dual properties and shows that ancillary ligands are compatible with alkane metathesis reactions. (Chemical Equation Presented).
Disproportionation of hydrocarbons
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Page 2, (2010/02/07)
A novel hydrocarbon disproportionation process is provided and includes contacting a hydrocarbon feed comprising at least one paraffin with a disproportionation catalyst comprising a support component, a metal, and a halogen in a disproportionation reaction zone under disproportionation reaction conditions.
