4534-76-3Relevant academic research and scientific papers
Ductile Pd-Catalysed Hydrodearomatization of Phenol-Containing Bio-Oils Into Either Ketones or Alcohols using PMHS and H2O as Hydrogen Source
Di Francesco, Davide,Subbotina, Elena,Rautiainen, Sari,Samec, Joseph S. M.
supporting information, p. 3924 - 3929 (2018/09/14)
A series of phenolic bio-oil components were selectively hydrodearomatized by palladium on carbon into the corresponding ketones or alcohols in excellent yields using polymethylhydrosiloxane and water as reducing agent. The selectivity of the reaction was governed by the water concentration where selectivity to alcohol was favoured at higher water concentrations. As phenolic bio-oil examples cardanol and beech wood tar creosote were studied as substrate to the developed reaction conditions. Cardanol was hydrodearomatized into 3-pentadecylcyclohexanone in excellent yield. From beech wood tar creosote, a mixture of cyclohexanols was produced. No hydrodeoxygenation occurred, suggesting the applicability of the reported method for the production of ketone-alcohol oil from biomass. (Figure presented.).
Selective nickel-catalyzed conversion of model and lignin-derived phenolic compounds to cyclohexanone-based polymer building blocks
Schutyser, Wouter,Van Den Bosch, Sander,Dijkmans, Jan,Turner, Stuart,Meledina, Maria,Van Tendeloo, Gustaaf,Debecker, Damien P.,Sels, Bert F.
, p. 1805 - 1818 (2015/06/02)
Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (>250°C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (≈80 %) and tin-containing beta zeolite to form 4-alkyl-ε-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2O2.
Selective activation of secondary C-H bonds by an iron catalyst: Insights into possibilities created by the use of a carboxyl-containing bipyridine ligand
Cheng, Shi,Li, Jing,Yu, Xiaoxiao,Chen, Chuncheng,Ji, Hongwei,Ma, Wanhong,Zhao, Jincai
, p. 3267 - 3273 (2013/10/01)
In this work, we report the discovery of a carboxyl-containing iron catalyst 1 (FeII-DCBPY, DCBPY = 2,2′-bipyridine-4,4′- dicarboxylic acid), which could activate the C-H bonds of cycloalkanes with high secondary (2°) C-H bond selectivity. A turnover number (TN) of 11.8 and a 30% yield (based on the H2O2 oxidant) were achieved during the catalytic oxidation of cyclohexane by 1 under irradiation with visible light. For the transformation of cycloalkanes and bicyclic decalins with both 2° and tertiary (3°) C-H bonds, 1 always preferred to oxidise the 2° C-H bonds to the corresponding ketone and alcohol products; the 2°/3° ratio ranged between 78/22 and >99/1 across 7 examples. 18O isotope labelling experiments, ESR experiments, a PPh3 method and the catalase method were used to characterize the reaction process during the oxidation. The success of 1 showed that, in addition to using a bulky catalyst, high 2° C-H bond selectivity could also be achieved using a less bulky molecular iron complex as the catalyst.
Efficient stereo- and regioselective hydroxylation of alkanes catalysed by a bulky polyoxometalate
Kamata, Keigo,Yonehara, Kazuhiro,Nakagawa, Yoshinao,Uehara, Kazuhiro,Mizuno, Noritaka
scheme or table, p. 478 - 483 (2010/09/17)
Direct functionalization of alkanes by oxidation of C-H bonds to form alcohols under mild conditions is a challenge for synthetic chemistry. Most alkanes contain a large number of C-H bonds that present difficulties for selectivity, and the oxidants employed often result in overoxidation. Here we describe a divanadium-substituted phosphotungstate that catalyses the stereo- and regioselective hydroxylation of alkanes with hydrogen peroxide as the sole oxidant. Both cyclic and acyclic alkanes were oxidized to form alcohols with greater than 96% selectivity. The bulky polyoxometalate framework of the catalyst results in an unusual selectivity that can lead to the oxidation of secondary rather than the weaker tertiary C-H bonds. The catalyst also avoids wasteful decomposition of the stoichiometric oxidant, which can result in the production of hydroxyl radicals and lead to non-selective oxidation and overoxidation of the desired products.
Regioselective radical ring-opening reaction of bicyclo[4.2.0]octan-2-ones promoted by samarium(II) iodide
Kakiuchi, Kiyomi,Minato, Koichi,Tsutsumi, Ken,Morimoto, Tsumoru,Kurosawa, Hideo
, p. 1963 - 1966 (2007/10/03)
Radical ring-opening reactions of bicyclo[4.2.0]octanones, its C6 alkyl derivatives, and tricyclic ketones promoted by SmI2 gave cyclohexanones via fission of the external cyclobutane bond. The CO2Me, CN, and phenyl derivatives led t
Observation of Ethyl-Substituted Cyclohexanone and Cyclopentanone Rotamers Using Resonance-Enhanced Multiphoton Ionization Spectroscopy
Nesselrodt, Dale R.,Potts, Alan R.,Baer, Tomas
, p. 4458 - 4465 (2007/10/02)
The various rotamer conformations associated with the hindered ethyl group rotor in ethyl-substituted cyclohexanones and cyclopentanones have been trapped in a supersonic expansion and spectroscopically analyzed by 2 + 1 resonance-enhanced multiphoton ionization via the 3s - n Rydberg transition.The rapid cooling in the supersonic expansion effectively freezes many of the conformations at their room temperature equilibrium concentrations.The various rotamers, including some in the axial orientation, were identified by comparing peak intensities with those calculated by both molecular mechanics and ab initio MO methods.Excellent agreement between the calculations and the experimental results is noted.
