43205-82-9Relevant articles and documents
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.
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.
