4292-75-5Relevant academic research and scientific papers
Carbazole hydrodenitrogenation over nickel phosphide and Ni-rich bimetallic phosphide catalysts
Bowker, Richard H.,Ilic, Boris,Carrillo, Bo A.,Reynolds, Michael A.,Murray, Brendan D.,Bussell, Mark E.
, p. 221 - 230 (2014)
Silica-supported nickel phosphide (Ni2P) and Ni-rich bimetallic phosphide catalysts were investigated for the hydrodenitrogenation (HDN) of carbazole with and without a benzothiophene co-feed. The Ni2P/ SiO2, Co0.1Ni1.9P/SiO2, and Fe 0.03Ni1.97P/SiO2 catalysts exhibited high carbazole HDN activities and out-performed a commercial sulfided Ni-Mo/Al 2O3 catalyst under the testing conditions employed. Co-feeding of benzothiophene inhibited carbazole HDN over the metal phosphides, but the Ni2P/SiO2 and Ni-rich bimetallic phosphide catalysts maintained higher activities than the sulfided Ni-Mo/Al 2O3 catalyst. The product selectivities of the metal phosphide and sulfide catalysts were similar, except that the sulfided Ni-Mo/Al2O3 catalyst yielded more hydrogenated carbazoles while the metal phosphide catalysts produced more of the partially hydrogenated hydrocarbon cyclohexylbenzene. The metal phosphide catalysts favored ring-opened (hexylcyclohexane) and ring-contracted ((2-methylcyclopentyl)cyclohexane) products, indicating the presence of metal and Br?nsted acid sites on the catalyst surfaces. The Ni2P/SiO2 and bimetallic phosphide catalysts exhibited excellent stabilities in the HDN conditions employed (carbazole-only and mixed feeds), as indicated by phase purity, average crystallite size and resistance to sulfur incorporation of the supported metal phosphide particles.
Facile arene hydrogenation under flow conditions catalyzed by rhodium or ruthenium on carbon
Hattori, Tomohiro,Ida, Takashi,Tsubone, Aya,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
supporting information, p. 2492 - 2497 (2015/04/22)
An efficient and practical protocol for the flow hydrogenation of aromatic rings was developed. The hydrogenation of a variety of aromatic compounds, such as benzene, furan, and pyridine derivatives, could be completed within only 20 s during a single pass through a catalyst cartridge containing 10 % rhodium on carbon (Rh/C) or 10 % ruthenium on carbon (Ru/C) under neutral conditions. The protocol was successfully applied to a 10 mmol scale reaction. Furthermore, the 10 % Rh/C and 10 % Ru/C did not deteriorate during the entire study.
Mechanistic Studies of Catalytic Carbon-Carbon Cross-Coupling by Well-Defined Iron NHC Complexes
Przyojski, Jacob A.,Veggeberg, Kevin P.,Arman, Hadi D.,Tonzetich, Zachary J.
, p. 5938 - 5946 (2015/10/12)
The mechanism of iron-catalyzed carbon-carbon cross-coupling reactions between Grignard reagents and alkyl halides has been investigated using well-defined N-heterocyclic carbene (NHC) compounds. The iron(II) precatalyst, [Fe2Cl2(μ-Cl)2(IPr)2], was employed in several C-C cross coupling reactions exhibiting the ability to efficiently couple primary and secondary alkyl halides with several aryl and alkyl Grignard reagents. For selected substrates, a 2 mol % catalyst loading (4 mol % Fe) afforded conversions of >99% and were achieved with 8% homocoupling of the electrophile. The mechanism of the coupling reaction was studied by means of radical clock, radical trap, and single-turnover experiments, which support a radical-based cycle involving an Fe(II/III) redox couple. The implications of this mechanism on the efficacy of iron-NHC-catalyzed cross-coupling reactions are discussed.
Cyclooctane metathesis catalyzed by silica-supported tungsten pentamethyl [(ΞSiO)W(Me)5]: Distribution of macrocyclic alkanes
Riache, Nassima,Callens, Emmanuel,Samantaray, Manoja K.,Kharbatia, Najeh M.,Atiqullah, Muhammad,Basset, Jean-Marie
supporting information, p. 15089 - 15094 (2015/02/19)
Metathesis of cyclic alkanes catalyzed by the new surface complex [(ΞSiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ring contraction or ring expans
Polyoxotungstate Photoinduced Alkylation of Electrophilic Alkenes by Cycloalkanes
Dondi, Daniele,Fagnoni, Maurizio,Molinari, Alessandra,Maldotti, Andrea,Albini, Angelo
, p. 142 - 148 (2007/10/03)
Alkyl radical obtained by irradiation of tetrabutylammonium decatungstate in acetonitrile in the presence of cycloalkanes (C5H10, C6H12, C7H14) are efficiently trapped by electrophilic alkenes (acrylonitrile, isopropylydenmalonitrile, isopropylydencyanoacetate) to give the corresponding alkylated aliphatic nitriles. The reaction can be carried out up to complete conversion of the alkene with reasonable (in most cases 60-65%) yields. Addition of the radicals to the alkene is followed by electron transfer from reduced decatungstate regenerating the sensitizer (turn over number up to 60). Steady-state measurements, EPR evidence, deuteration experiments and attempted intramolecular trapping of the adduct radical support the mechanistic proposal.
A highly selective arene hydrogenation catalyst that operates in ionic liquid
Boxwell, Clive J.,Dyson, Paul J.,Ellis, David J.,Welton, Thomas
, p. 9334 - 9335 (2007/10/03)
The synthesis and structural characterization of [Ru(η6-p-cymene)(η2-TRIPHOS)Cl][PF6] is described. The complex is a highly active, homogeneous arene hydrogenation catalyst that is selective toward the hydrogenation of aromatic rings in preference to alkenes, as demonstrated by the hydrogenation of allylbenzene to allylcyclohexane. The catalyst operates in both dichloromethane and ionic liquids and undergoes no decomposition in the latter solvent. Copyright
A Novel, Chemoselective, "One-pot" Procedure for the Simultaneous Denitration-Deoxygenation of 2-Nitroketones by TsNHNH2-NaBH4
Ballini, Roberto,Castagnani, Roberto,Marcantoni, Enrico
, p. 3161 - 3162 (2007/10/02)
Chemoselective conversion of both the carbonyl group and the carbon bearing the nitro group, of 2-nitro ketones, into two methylenes is performed in one-pot, under mild conditions.
NEW DEVELOPMENTS IN PALLADIUM CATALYSED CROSS COUPLING: THE COUPLING OF ALKYL IODIDES WITH ALKYL GRIGNARD REAGENTS
Castle, Paul L.,Widdowson, David A.
, p. 6013 - 6016 (2007/10/02)
The species generated by the in situ reduction of 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride is an effective catalyst for the cross coupling of alkyl iodides with alkyl Grignard regents.
Anodic Oxidation of Organoboranes
Schlegel, Guenter,Schaefer, Hans J.
, p. 1400 - 1423 (2007/10/02)
Organoboranes are converted into more easily oxidizable borates by reaction with nucleophiles and the alkyl groups are dimerized by anodic oxidation.The oxidation potentials (Ep) of the borates depend strongly on the nature of the complexing nucleophile, for instance Ep = +0.37 V (vs.SCE) with OH- or +1.65 V with tetrahydrofuran.The dimer yields are optimized with trioctylborane (5) by variation of the electrode material and the elctrolyte.At the platinum anode in sodium hydroxide-methanol/tetrahydrofuran yields of 80percent are obtained for acyclic alkyl groups, and lo wer ones for cycloalkyl groups.They exceed those obtained by the Kolbe electrolysis or the oxidation with neutral hydrogen peroxide and they are comparable to those of the AgNO3 oxidation. - The selective preparation of unsymmetrical products from borates with different alkyl groups is not possible, the dimerization proceeds likely via free radicals that couple statistically.Good yields of unsymmetrical coupling products are achieved, when one olefin is used in excess.With choro-, ethoxy-, acetoxy-, and aryl-substituted alkyl groups the dimers are obtained in 21 - 66percent yield, with bromide the yield are lower and with nitriles the dimerization fails.
Phenyl Effects in Radical Additions to Alkenes
Giese, Bernd,Kretzschmar, Gerhard
, p. 3267 - 3270 (2007/10/02)
Reactions of cyclohexylmercuric salts 4 with NaBH4 in the presence of alkenes 8 yield products 10.The main step of the reaction sequence, the addition of a cyclohexyl radical (7) to alkene 8, can be measured using a competition technique.The data show that styrene reacts 30 - 40 times faster than expected by the ?p--value.This phenyl effect decreases in going from monosubstituted alkenes 8 to disubstituted alkenes 3, 2 and 1 because the steric hindrance of a coplanar orientation of the ?-system increases in the same order.
