824-43-1Relevant articles and documents
METHODS FOR SELECTIVELY HYDROGENATING SUBSTITUTED ARENES WITH SUPPORTED ORGANOMETALLIC CATALYSTS
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Paragraph 0036, (2016/06/28)
Methods for selectively hydrogenating substituted arenes with a supported organometallic hydrogenating catalyst are provided. An exemplary method includes contacting a substituted arene-containing reaction stream with hydrogen in the presence of a supported organometallic hydrogenating catalyst under reaction conditions effective to selectively hydrogenate the substituted arenes to the cis isomer with high selectivity. In this method, the supported organometallic hydrogenating catalyst includes a catalytically active organometallic species and a Br?nsted acidic sulfated metal oxide support.
Influence of iridium content on the behavior of Pt-Ir/Al2O 3 and Pt-Ir/TiO2 catalysts for selective ring opening of naphthenes
Vicerich, María A.,Benitez, Viviana M.,Especel, Catherine,Epron, Florence,Pieck, Carlos L.
, p. 167 - 174 (2013/03/29)
The influence of Ir content on the properties of Pt-Ir/Al2O 3 and Pt-Ir/TiO2 catalysts for selective ring opening of naphthenes was studied. It was found that these catalysts display a strong Pt-Ir interaction but only a weak metal-support interaction. Catalyst acidities depend on the metal loading, but opposite effects were observed on alumina (decrease) or titania (increase) as the metal loading increased. The results obtained from test reactions (cyclohexane dehydrogenation and cyclopentane hydrogenolysis) showed that titania supported catalysts were less active than their alumina supported counterparts. This behavior could be due to the partial blockage of metallic sites by migrated TiOx species and the sinterization of metallic phase during the reduction step. The methylcyclopentane ring opening reaction was found to occur through a partially selective mechanism, and an increase in activity as the Ir loading increased was observed. The selective mechanism was favored by higher total metal loadings, possibly due to an increase in the size of metallic aggregates. Alumina supported catalysts present higher ring opening selectivities. The activity for decalin ring opening increased both with metal loading and reaction temperature level.
Ring opening of decalin via hydrogenolysis on Ir/- and Pt/silica catalysts
Haas, Andreas,Rabl, Sandra,Ferrari, Marco,Calemma, Vincenzo,Weitkamp, Jens
experimental part, p. 97 - 109 (2012/07/13)
The catalytic conversion of cis-decalin was studied at a hydrogen pressure of 5.2 MPa and temperatures of 250-410 °C on iridium and platinum supported on non-acidic silica. The absence of catalytically active Br?nsted acid sites was indicated by both FT-IR spectroscopy with pyridine as a probe and the selectivities in a catalytic test reaction, viz. the hydroconversion of n-octane. On iridium/silica, decalin hydroconversion starts at ca. 250-300 °C, and no skeletal isomerization occurs. The first step is rather hydrogenolytic opening of one six-membered ring to form the direct ring-opening products butylcyclohexane, 1-methyl-2-propylcyclohexane and 1,2- diethylcyclohexane. These show a consecutive hydrogenolysis, either of an endocyclic carboncarbon bond into open-chain decanes or of an exocyclic carboncarbon bond resulting primarily in methane and C9 naphthenes. The latter can undergo a further endocyclic hydrogenolysis leading to open-chain nonanes. All individual C10 and C9 hydrocarbons predicted by this direct ring-opening mechanism were identified in the products generated on the iridium/silica catalysts. The carbon-number distributions of the hydrocracked products C9- show a peculiar shape resembling a hammock and could be readily predicted by simulation of the direct ring-opening mechanism. Platinum on silica was found to require temperatures around 350-400 °C at which relatively large amounts of tetralin and naphthalene are formed. The most abundant primary products on Pt/silica are spiro[4.5]decane and butylcyclohexane which can be readily accounted for by the well known platinum-induced mechanisms described in the literature for smaller model hydrocarbons, namely the bond-shift isomerization mechanism and hydrogenolysis of a secondary-tertiary carboncarbon bond in decalin.
