43205-82-9Relevant academic research and scientific papers
Use of Raman spectroscopy to characterize hydrogenation reactions
Tumuluri, Venkat S.,Kemper, Mark S.,Sheri, Anjaneyulu,Choi, Seoung-Ryoung,Lewis, Ian R.,Avery, Mitchell A.,Avery, Bonnie A.
, p. 927 - 933 (2006)
Raman spectroscopy was used to characterize hydrogenation reactions involving single-step and two-step processes. The Raman technique was shown to be well-suited for endpoint determination as well as process optimization. In this investigation, hydrogenation of cyclohexene to produce cyclohexane was used as a model system. Conditions were varied to determine the effect of catalyst loading, solvent ratios, and reactant concentrations. Four catalysts were evaluated. The kinetic profiles of each reaction process were determined for each of the catalysts. In one case, a side reaction leading to an intermediate was observed for the hydrogenation reaction when run under hydrogen-starved conditions. After these cyclohexene hydrogenations were characterized, Raman spectroscopy was applied to the conversion of carvone to tetrahydrocarvone and the hydrogenation of 2-(4-hydroxyphenyl) propionate. Raman was used to characterize the kinetics of these reactions and was also used to prove that two-step hydrogenation mechanisms occurred in each. Raman was shown to be useful for process understanding, process optimization, process monitoring, and endpoint determination. Accomplishment of these goals leads to better process controls upon transfer of the procedure to a process environment. This ultimately leads, in turn, to the mitigation of risk of making out-of-specification product in manufacturing.
METHOD FOR PREPARING ORTHO-SUBSTITUTED AMINOFERROCENES
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Page/Page column 22, (2010/06/16)
The present disclosure relates to a method for preparing an ortho-substituted aminoferrocene comprising reacting an aminoferrocene with a Lewis acid and a lithiating reagent in the presence of an electrophile to form the ortho-substituted aminoferrocene.
A recyclable nanoparticle-supported rhodium catalyst for hydrogenation reactions
Dell'Anna, Maria Michela,Gallo, Vito,Mastrorilli, Piero,Romanazzi, Giuseppe
experimental part, p. 3311 - 3318 (2010/09/15)
Catalytic hydrogenation under mild conditions of olefins, unsaturated aldeydes and ketones, nitriles and nitroarenes was investigated, using a supported rhodium complex obtained by copolymerization of Rh(cod)(aaema) [cod: 1,5-cyclooctadiene, aaema-: deprotonated form of 2-(acetoacetoxy)ethyl methacrylate] with acrylamides. In particular, the hydrogenation reaction of halonitroarenes was carried out under 20 bar hydrogen pressure with ethanol as solvent at room temperature, in order to minimize hydro-dehalogenation. The yields in haloanilines ranged from 85% (bromoaniline) to 98% (chloroaniline).
Highly selective hydrogenation of carbon-carbon multiple bonds catalyzed by the cation [(C6Me6)2Ru2(PPh 2)H2]+: Molecular structure of [(C 6Me6)2Ru2(PPh2)(CHCHPh)H] +, a possible intermediate in the case of phenylacetylene hydrogenation
Tschan, Mathieu J.-L.,Suess-Fink, Georg,Cherioux, Frederic,Therrien, Bruno
, p. 292 - 299 (2007/10/03)
The dinuclear cation [(C6Me6)2Ru 2(PPh2)H2]+ (1) has been studied as the catalyst for the hydrogenation of carbon-carbon double and triple bonds. In particular, [1][BF4] turned out to be a highly selective hydrogenation catalyst for olefin functions in molecules also containing reducible carbonyl functions, such as acrolein, carvone, and methyljasmonate. The hypothesis of molecular catalysis by dinuclear ruthenium complexes is supported by catalyst-poisoning experiments, the absence of an induction period in the kinetics of cyclohexene hydrogenation, and the isolation and single-crystal X-ray structure analysis of the tetrafluoroborate salt of the cation [(C6Me6)2Ru2(PPh 2)-(CHCHPh)H]+ (2), which can be considered as an intermediate in the case of phenylacetylene hydrogenation. On the basis of these findings, a catalytic cycle is proposed which implies that substrate hydrogenation takes place at the intact diruthenium backbone, with the two ruthenium atoms acting cooperatively in the hydrogen-transfer process.
α- and β-thujone radical rearrangements and isomerizations. A new radical clock
He, Xiang,Ortiz De Montellano, Paul R.
, p. 5684 - 5689 (2007/10/03)
Radical clocks have been extensively used in chemical and biochemical mechanistic studies. The C4 radicals of α- and β-thujone can undergo two distinct rearrangement reactions that could, in principle, serve as simultaneous but independent radical clocks. We have therefore generated these C4 radicals by photolysis of the corresponding N-hydroxypyridine-2-thione ester precursors and have investigated their fates and lifetimes. Photolysis of either α- or β-thujone generates the same 6:100 mixture of α- and β-thujone when the radicals are quenched by thiophenol. Hydrogen atom transfer from thiophenol to the radical thus occurs preferentially from the less sterically hindered α-face to give β-thujone. The third product formed in the photolysis via opening of the cyclopropyl ring is 2-methyl-5-isopropylcyclopent-2-enone. The ratio of ring opened to unopened products gives very similar values of krα = 4.4 × 10 7 S-1 and krβ = 1.0 × 108 S-1 for ring opening of the radicals generated from α- and β-thujone, respectively. If the C4 cation rather than radical is generated, it is converted to carvacrol, a phenol that is not obtained in the radical reactions. Thujone therefore differentiates between radical and cation pathways and provides a measure of the radical lifetime.
Aerobic Oxidation of Secondary Alcohols via Ruthenium-catalysed Hydrogen Transfer Involving a New Triple Catalytic System
Wang, Guo-Zhi,Andreasson, Ulrika,Baeckvall, Jan-E.
, p. 1037 - 1038 (2007/10/02)
Aerobic oxidation of secondary alcohols was performed employing a new triple catalytic system (Ru-catalyst 1, 2,6-di-tert-butylbenzoquinone 2, and Co-macrocycle 3) under a low concentration of molecular oxygen (air:nitrogen is between 1:3 and 1:20) at ambient pressure.
New Trialkylsilyl Enol Ether Chemistry: New Regiospecific Methodology for the Synthesis of α,β-Unsaturated Cyclic Ketones
Magnus, Philip,Evans, Andrew,Lacour, Jerome
, p. 2933 - 2936 (2007/10/02)
Treatment of TIPS enol ethers with PhIO/TMSN3 followed by desilylation/elimination with fluoride ion gives good yields of the α,β-unsaturated ketone.
Electrocatalytic Hydrogenation Using Precious Metal Microparticles in Redox-Active Polymer Films
Coche, Liliane,Ehui, Bernadette,Limosin, Daniele,Moutet, Jean-Claude
, p. 5905 - 5910 (2007/10/02)
Glassy carbon felt electrodes have been modified by electrodeposition of poly(pyrrole-viologen) films (derived from N,N'-dialkyl-4,4'-bipyridinium salts), followed by electroprecipitation of precious metal (Pt, Pd, Rh, or Ru) microparticles.The resulting electrodes have been proved to be active for the electrocatalytic hydrogenation of conjugated enones (2-cyclohexen-1-one, cryptone, carvone, isophorone), styrene, and benzonitrile in aqueous media (pH 1).Despite low loading of metal catalysts, high electric and product yields and a long term stability of these cathodes have been observed.The influence of the metal loading and the polymer structure on the catalytic efficiency as well as the selectivity obtained according to the metal catalyst used have been studied.Comparision with results previously reported for other catalytic cathodes like Pt/Pt, Pd/C, or Raney nickel electrodes proves the high efficiency of these microparticles within redox polymer film based electrodes.
ENANTIOSELECTIVE ROUTES TO 2,5-DISUBSTITUTED- AND 4-SUBSTITUTED-2-CYCLOHEXENONES
Asaoka, Morio,Aida, Toshiaki,Sonoda, Syuzo,Takei, Hisashi
, p. 7075 - 7078 (2007/10/02)
Starting with 5-trimethylsilyl-2-cyclohexenone, widely applicable enantioselective routes to the title compounds are established.
