F:Flammable;
100-41-4Relevant articles and documents
Solubilities and Hydrophobic Interactions in Aqueous Solutions of Monoalkylbenzene Molecules
Ben-Naim, A.,Wilf, J.
, p. 583 - 586 (1980)
Solubilities of a series of monoalkylbenzene molecules in water were determined spectroscopically at several temperatures.The standard free energies of transferring these solutes from the gas into the liquid phase were calculated.From these data we have estimated hydrophobic interaction between a methane molecule and the various alkyl residues of these solutes.
NHC complexes of cobalt(II) relevant to catalytic C-C coupling reactions
Przyojski, Jacob A.,Arman, Hadi D.,Tonzetich, Zachary J.
, p. 723 - 732 (2013)
Alkyl compounds of cobalt(II) containing aryl-substituted N-heterocyclic carbene ligands have been prepared by reaction of the precursor chloro complexes [CoCl2(IMes)2] and [Co2Cl2(μ-Cl) 2(IPr)2] (IMes = 1,3-dimesityl-imidazol-2-ylidene; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with Grignard reagents. Examples of alkyl complexes possessing both four-coordinate and three-coordinate geometries are reported. The chloro complex [CoCl2(IMes) 2] adopts a pseudotetrahedral geometry displaying an S = 3/2 ground state, whereas the alkyl complex [Co(CH 3)2(IMes)2] adopts a square-planar geometry consistent with an S = 1/2 ground state. In contrast to [Co(CH3)2(IMes)2], [Co(CH2SiMe 3)2(IPr)] exhibits a three-coordinate trigonal-planar geometry displaying an S = 3/2 ground state. The catalytic efficacy of [CoCl2(IMes)2] in Kumada couplings is examined, as is the chemistry of the alkyl complexes toward CO. The structure and reactivity of these compounds is discussed in the context of C-C coupling reactions catalyzed by cobalt NHCs.
Ni/HZSM-5 catalyst preparation by deposition-precipitation. Part 2. Catalytic hydrodeoxygenation reactions of lignin model compounds in organic and aqueous systems
Barton,Carrier,Segura,Fierro,Park,Lamb,Escalona,Peretti
, p. 294 - 309 (2018)
Nickel metal supported on HZSM-5 (zeolite) is a promising catalyst for lignin depolymerization. In this work, the ability of catalysts prepared via deposition-precipitation (DP) to perform hydrodeoxygenation (HDO) on two lignin model compounds in organic and aqueous solvents was evaluated; guaiacol in dodecane and 2-phenoxy-1-phenylethanol (PPE) in aqueous solutions. All Ni/HZSM-5 catalysts were capable of guaiacol HDO into cyclohexane at 523 K. The role of the HZSM-5 acid sites was confirmed by comparison with Ni/SiO2 (inert support) which exhibited incomplete deoxygenation of guaiacol due to the inability to perform the cyclohexanol dehydration step. The catalyst prepared with 15 wt% Ni, a DP time of 16 h, and a calcination temperature of 673 K (Ni(15)/HZSM-5 DP16_Cal673), performed the guaiacol conversion with the greatest selectivity towards HDO products, with an intrinsic rate ratio (HDO rate to conversion rate) of 0.31, and 90% selectivity to cyclohexane. Catalytic activity and selectivity of Ni/HZSM-5 (15 wt%) in aqueous environments (water and 0.1 M NaOH solution) was confirmed using PPE reactions at 523 K. After 30 min reaction time in water, Ni/HZSM-5 exhibited ～100% conversion of PPE, and good yield of the desired products; ethylbenzene and phenol (～35% and 23% of initial carbon, respectively). Ni/HZSM-5 in NaOH solution resulted in significantly higher ring saturation compared to the Ni/HZSM-5 in water or the NaOH solution control.
Specific Inhibition of the Hydrogenolysis of Benzylic C?O Bonds Using Palladium Nanoparticles Supported on Nitrogen-Doped Carbon Nanofibers
Motoyama, Yukihiro,Morii, Koshi,Ishizuka, Shoya,Inomoto, Sou,Zhang, Zhenzhong,Yoon, Seong-Ho
, p. 505 - 509 (2018)
Palladium nanoparticles supported on 5 %-nitrogen-doped, herringbone-type carbon nanofibers (Pd/N-CNF-H), which are prepared by thermally decomposing [Pd2(dba)3?CHCl3] (dba=dibenzylideneacetone) in toluene in the presence of N-CNF-H, were found to be an efficient catalyst for the chemoselective hydrogenation of alkenyl and nitro moieties in benzyl-protected alcohols and carboxylic acid derivatives with high turnover frequencies: the hydrogenation reactions of these functional groups proceeded smoothly even at ambient temperature under atmospheric H2 pressure, and the benzyl protecting groups in the molecules remained intact. Moreover, the recovered Pd/N-CNF-H catalyst could be reused without loss of its catalytic activity or chemoselectivity. The Pd/N-CNF-H catalyst also acted as an effective hydrogenation catalyst for the reduction of aromatic ketones to the corresponding benzyl alcohol derivatives with good to high product selectivity.
Redox-active ligand-mediated oxidative addition and reductive elimination at square planar cobalt(III): Multielectron reactions for cross-coupling
Smith, Aubrey L.,Hardcastle, Kenneth I.,Soper, Jake D.
, p. 14358 - 14360 (2010)
Square planar cobalt(III) complexes with redox-active amidophenolate ligands are strong nucleophiles that react with alkyl halides, including CH 2Cl2, under gentle conditions to generate stable square pyramidal alkylcobalt(III) complexes. The net electrophilic addition reactions formally require 2e- oxidation of the metal fragment, but there is no change in metal oxidation state because the reaction proceeds with 1e - oxidation of each amidophenolate ligand. Although the four-coordinate complexes are very strong nucleophiles, they are mild outer-sphere reductants. Accordingly, addition of alkyl- or phenylzinc halides to the five-coordinate organometallic complexes regenerates the square planar starting materials and extrudes C-C coupling products. The net 2e- reductive elimination reaction also occurs without a oxidation state change at the cobalt(III) center. Together these reactions comprise a complete, well-defined cycle for cobalt Negishi-like cross-coupling of alkyl halides with organozinc reagents.
Supported palladium nanomaterials as catalysts for petroleum chemistry: 2. Kinetics and specific features of the mechanism of selective hydrogenation of phenylacetylene in the presence of carbon-supported palladium nanocatalyst
Berenblyum,Al-Wadhaf,Katsman
, p. 118 - 126 (2015)
The selective hydrogenation of phenylacetylene (PhA) into styrene (St) in the presence of a palladium nanocatalyst has been investigated. Salient features of this reaction have been revealed, such as independence of the PhA hydrogenation and St hydrogenat
Studies of the decomposition of the ethylene hydrophenylation catalyst TpRu(CO)(NCMe)Ph
Joslin, Evan E.,McKeown, Bradley A.,Cundari, Thomas R.,Gunnoe, T. Brent
, p. 289 - 293 (2017)
TpRu(CO)(NCMe)Ph is a catalyst for the conversion of benzene and ethylene to ethylbenzene. Previously, the formation of ethylbenzene has been shown to occur through a pathway that involves ethylene coordination to Ru, insertion of ethylene into the Ru–phe
Liquid-phase alkylation of benzene with ethylene over postsynthesized MCM-56 analogues
Zhang, Bin,Ji, Yongjun,Wang, Zhendong,Liu, Yueming,Sun, Hongmin,Yang, Weimin,Wu, Peng
, p. 103 - 110 (2012)
MCM-56 analogues were postsynthesized via a mild acid treatment technique from hydrothermally synthesized MCM-22 lamellar precursors with Si/Al ratios of 15-45. The physicochemical properties of MCM-56 were characterized by XRD, SEM, N2 adsorption, XPS, 29Si and 27Al MAS NMR, NH3-TPD and pyridine adsorption IR techniques. In comparison to MCM-22 with 3-dimensional MWW topology, the postsynthesized MCM-56 showed a broad X-ray diffraction of emerged 1 0 1 and 1 0 2 reflections and possessed a structural disorder along the layer stacking direction. Composed of partially delaminated MWW nanosheets, MCM-56 analogues had a larger external surface than MCM-22. The MCM-56 and MCM-22 catalysts were employed in the liquid-phase alkylation of benzene with ethylene. MCM-56 analogues exhibited a higher yield of ethylated benzenes and a higher catalytic stability than MCM-22, proving to serve as promising solid-acid catalysts for processing bulky molecules in petrochemical industry.
Reduced graphene oxide supported nickel-palladium alloy nanoparticles as a superior catalyst for the hydrogenation of alkenes and alkynes under ambient conditions
?etinkaya, Yasin,Metin, ?nder,Balci, Metin
, p. 28538 - 28542 (2016)
Addressed herein is the superior catalytic performance of reduced graphene oxide supported Ni30Pd70 alloy nanoparticles (rGO-Ni30Pd70) for the direct hydrogenation of alkenes and alkynes to alkanes, which surpasses the commercial Pd/C catalyst both in activity and stability. A variety of cyclic or aromatic alkenes and alkynes (a total of 17 examples) were rapidly reduced to the corresponding alkanes with high yields (>99%) via the presented direct hydrogenation protocol under ambient conditions. Compared to the commercially available Pd/C (10 wt%) catalyst, the rGO-Ni30Pd70 catalyst provided higher yields in shorter reaction times under the optimized conditions. Moreover, the rGO-Ni30Pd70 catalysts were more stable and durable than the commercial Pd/C catalysts by preserving their initial activity after five consecutive runs in the hydrogenation reactions.
Ketone Coupling on Reduced TiO2 (001) Surfaces: Evidence of Pinacol Formation
Pierce, Keith G.,Barteau, Mark A.
, p. 2405 - 2410 (1995)
Reductive coupling of acetone and acetophenone was investigated in temperature-programmed desorption (TPD) studies on both reduced (Ar(1+)-bombarded) and oxidized TiO2 (001) surfaces.The principal reaction product of either ketone on the reduced surface was a symmetric olefin with twice the carbon number of the reactant. 2,3-Diphenyl-2-butene comprised over 65percent of the volatile carbon-containing species desorbed from the reduced surface following acetophenone adsorption.The main side reactions which yielded products of the same carbon number as the reactants included deoxygenation to form olefins and deoxygenation plus hydrogenation to yield saturated species.The yield of reduction products was greatly diminished on the oxidized TiO2 (001) surface; the yield of 2,3-dimethyl-2-butene, the reductive coupling product of acetone, decreased 10-fold with respect to the yield from the reduced surface.This decrease in activity for reductive coupling is similar in scale to that observed for benzaldehyde coupling on the same surfaces, supporting the conclusion that both ketone and aldehyde coupling reactions occur at ensembles of Ti cations able to undergo a four-electron oxidation.Phenyl groups adjacent to the carbonyl carbon have the greatest effect on the carbonyl coupling reaction, giving significantly higher yield of the coupled olefin product.The observation of a small amount of the pinacol, 2,3-diphenyl-2,3-butanediol, during acetophenone TPD is the first direct evidence that the carbonyl coupling reaction on reduced TiO2 surfaces proceeds through a pinacolate intermediate, as it does for the McMurry reaction carried out in liquid-solid slurries.
