22900-08-9Relevant academic research and scientific papers
Trans-Selective and Switchable Arene Hydrogenation of Phenol Derivatives
Bergander, Klaus,Glorius, Frank,Heusler, Arne,Wollenburg, Marco
, p. 11365 - 11370 (2020/11/24)
A trans-selective arene hydrogenation of abundant phenol derivatives catalyzed by a commercially available heterogeneous palladium catalyst is reported. The described method tolerates a variety of functional groups and provides access to a broad scope of trans-configurated cyclohexanols as potential building blocks for life sciences and beyond in a one-step procedure. The transformation is strategically important because arene hydrogenation preferentially delivers the opposite cis-isomers. The diastereoselectivity of the phenol hydrogenation can be switched to the cis-isomers by employing rhodium-based catalysts. Moreover, a protocol for the chemoselective hydrogenation of phenols to cyclohexanones was developed.
Cobalt-Nanoparticles Catalyzed Efficient and Selective Hydrogenation of Aromatic Hydrocarbons
Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Alshammari, Ahmad S.,Altamimi, Rashid M.,Kreyenschulte, Carsten,Pohl, Marga-Martina,Lund, Henrik,Jagadeesh, Rajenahally V.,Beller, Matthias
, p. 8581 - 8591 (2019/09/12)
The development of inexpensive and practical catalysts for arene hydrogenations is key for future valorizations of this general feedstock. Here, we report the development of cobalt nanoparticles supported on silica as selective and general catalysts for such reactions. The specific nanoparticles were prepared by assembling cobalt-pyromellitic acid-piperazine coordination polymer on commercial silica and subsequent pyrolysis. Applying the optimal nanocatalyst, industrial bulk, substituted, and functionalized arenes as well as polycyclic aromatic hydrocarbons are selectively hydrogenated to obtain cyclohexane-based compounds under industrially viable and scalable conditions. The applicability of this hydrogenation methodology is presented for the storage of H2 in liquid organic hydrogen carriers.
FUNGICIDAL COMPOSITIONS
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Paragraph 1330-1332, (2014/11/27)
The present invention provides a composition comprising a combination of components A) and B), wherein component A) is a compound of formula (I) and the component (B) is a further fungicide, insecticide or herbicide.
Kinetic analysis of 4-isopropylphenol hydrogenation over activated carbon-supported rhodium catalysts in supercritical carbon dioxide solvent
Hiyoshi, Norihito,Sato, Osamu,Yamaguchi, Aritomo,Rode, Chandrashekhar V.,Shirai, Masayuki
experimental part, p. 633 - 638 (2012/05/04)
Hydrogenation behavior of 4-isopropylphenol to 4-isopropylcyclohexanol over activated carbon-supported rhodium catalysts in supercritical carbon dioxide (scCO2) at 313 K was studied in a batch reactor and the results were compared with those in 2-propanol. Higher yields of cis-4-isopropylcyclohexanol were obtained in scCO2 than in 2-propanol, and the formation of a byproduct, isopropylcyclohexane, was suppressed in scCO2. The catalyst modification with hydrochloric or phosphoric acid enhanced the yield of cis-4-isopropylcyclohexanol in both scCO2 and 2-propanol solvents. Kinetic analyses of the reaction profiles revealed higher reaction rates in scCO2 than those in 2-propanol for the 4-isopropylcyclohexanol formation both by the direct hydrogenation of 4-isopropylphenol and by the consecutive hydrogenation of 4-isopropylcyclohexanone, and also revealed that the addition of hydrochloric acid increased the consecutive hydrogenation rate of 4-isopropylcyclohexanone to cis-4-isopropylcyclohexanol, which reduced the total reaction time needed for the complete hydrogenation of 4-isopropylphenol to 4-isopropylcyclohexanol. The Royal Society of Chemistry 2012.
Raney Ni-Al alloy-mediated reduction of alkylated phenols in water
Tan, Song-Liang,Liu, Guo-Bin,Gao, Xiang,Thiemann, Thies
experimental part, p. 5 - 7 (2009/09/06)
Raney Ni-Al alloy in a dilute aqueous alkaline solution has been shown to be a very powerful reducing agent in the hydrogenation of phenol and alkylated phenols to the corresponding cyclohexanol derivatives.
The Interaction of π orbitals with a carbocation over three σ bonds
Lambert, Joseph B.,Ciro, Sol M.
, p. 1940 - 1945 (2007/10/03)
The semi-π analogue of double hyperconjugation ("hyperconjugation/conjugation") has been examined in 4-isopropylidenecyclohexyl mesylate (4-OMs) by comparison with the saturated analogue, trans-4-isopropylcyclohexyl mesylate (5-OMs). The unsaturated substrate reacts in 97% trifluoroethanol only four times faster than the saturated substrate. Raber-Harris plots indicate that both substrates react by ks mechanisms; i.e., solvolysis occurs with solvent assistance rather than carbocation formation. These results are consistent with the absence of a direct, through-bond interaction of the double bond with the reactive center. The absence is caused at least in part by less than ideal overlap of the γ,δ π orbitals with the α,β σ orbitals. In contrast, an electron-rich tin atom attached to the 4-position provides a large rate enhancement and changes the mechanism to carbocation formation through double hyperconjugation.
ENZYMATIC "IN VITRO" REDUCTION OF KETONES. Part 10. Study of 3-Acetylpyridine Adenine Dinucleotide in a Co-enzyme Recycling System Ethanol-Ketone-3-AcPyAD+-HLAD
Lemiere, Guy L.,Jaco, Jan,Merckx, Erik M.,Lepoivre, Josef A.,Alderweireldt, Frank C.
, p. 747 - 752 (2007/10/02)
The NAD+ analogue 3-acetylpyridine adenine dinucleotide (3-AcPyAD+) has been studied in the co-enzyme recycling system ethanol-ketone-3-AcPyAD+-HLAD.All reaction parameters are tested in analogous conditions as for the NAD+-recycling system.The stereospecificity of the new system is investigated for the reduction of 4-, 3- and 2-alkylcyclohexanones.The new recycling system is kinetically and stereochemically very similar to the NAD+ system, but 3.2 times slower.
ENZYMATIC "IN VITRO" REDUCTION OF KETONES. VI.(1) Reduction rates and stereochemistry of the HLAD-catalyzed reduction of 3-alkyl- and 4-alkylcyclohexanones.
Osselaer, T. A. Van,Lemiere, G. L.,Lepoivre, J. A.,Alderweireldt, F. C.
, p. 133 - 150 (2007/10/02)
Reaction rate constants for the catalytic step HLAD-NADH + ketone * HLAD-NAD+ + alcohol in the HLAD-catalyzed reduction of 3-alkyl- and 4-alkylcyclohexanones are determined from initial rate measurements in the coenzyme recycling system ketone-ethanol-NAD+-HLAD.By rate measurements at several temperatures, activation parameters were determined and isokinetic relationships tracked down.Two different isokinetic relationships show that the 3-alkylcyclohexanones pass through an other type of transition state than cyclohexanone and the 4-alkylcyclohexanones, which means that they have a different arrangement on the HLAD-NADH complex.The results are rationalized in view of the most recent principles on nucleophilic additions to carbonyl functions.The resulting model for the HLAD-catalyzed reduction adequately explains the observed rate accelerating and decelerating effects and the stereochemistry of the reduction as well.
