109-66-0Relevant articles and documents
Synthesis of a Highly Active Superacid of Platinum-supported Zirconia for Reaction of Butane
Hino, Makoto,Arata, Kazushi
, p. 789 - 790 (1995)
A highly active superacid of 8 masspercent Pt-supported ZrO2 for the skeletal isomerization of butane to isobutane is obtained by impregnating zirconia gel with 0.5 mol dm-3 H2SO4 followed by drying, impregnating the sulfated gel with a solution of H2PtCl6, and finally calcining in air at 600 deg C.
Kurras,Otto
, p. 479 (1965)
LE COMPLEXE 2> CATALYSEUR HOMOGENE D'HYDROGENATION ET D'HYDROSILYLATION D'OLEFINES ET D'ALDEHYDES ET CETONES α,β-INSATURES
Rumin, R.
, p. 351 - 356 (1983)
The chloro-bridged platinum(II) complex dichlorobis(2,4,6-trimethylpyridine)platinum was found to be an active catalyst for homogeneous hydrogenation and hydrosilylation of olefins and α,β-unsaturated aldehydes and ketones at room temperature and under atmospheric pressure.Hydrosilylation of terminal olefins can be achieved with dimethylphenylsilane and a catalyst/reactant ratio of 10-6/1.This complex is the first example of a platinum(II) compound containing pyridine ligands having good catalytic activity possibilities.
Some Diels-Alder reactions of trimethoxysilylpropylcyclopentadiene and the synthesis of a silica-supported 4,5-dicyanonorbornenepalladium complex
Adeleke, J. A.,Booth, B. L.
, p. 223 - 230 (1988)
Trimethoxysilylpropylcyclopentadiene reacts with the electron-deficient acetylenes, RO2CC2CO2R (R=Me, Et) and olefins R1CH=CHR2 (R1=H, R2=SOPh; R1=R2=P(O)Ph2, R1=R2=CN) to give the corresponding Diels-Alder adducts.The compounds CHCl=CHCl and E-Ph2P(S)CH=CHP(S)Ph2 failed to react under similar conditions.The adduct from fumarodinitrile has been used to synthesise a silica-anchored bis-nitrile palladium chloride complex, which catalyses the isomerisation of pent-1-ene.
Understanding ketone hydrodeoxygenation for the production of fuels and feedstocks from biomass
King, Amanda E.,Brooks, Ty J.,Tian, Yong-Hui,Batista, Enrique R.,Sutton, Andrew D.
, p. 1223 - 1226 (2015)
Although we can efficiently convert bioderived furans into linear alkanes, the most energy-intensive step in this approach is the hydrodeoxygenation of the intermediate polyketone. To fully understand this process, we have examined the hydrodeoxygenation of a model compound, 3-pentanone, which allows us to follow this process stepwise using Pd/C, H2 (200 psi), and La(OTf)3 in acetic acid to remove the oxygen atom at temperatures between 25 and 200 C. We have found that ketone reduction to an alcohol is followed by acetoxylation, which provides a more facile route to C-O bond cleavage relative to the parent alcohol. (Chemical Presented).
Oligomerisation of alkenes by radical initiation
Cowley, Michele
, p. 286 - 288 (2007)
The use of di-tert-butyl peroxide (DTBP) as initiator for the radical oligomerisation of 1-octene and pentene, typical Fischer-Tropsch-derived products, was studied in the temperature range 100-200°C. Using this approach, the favourable product distributi
Laser photocatalytic isomerization and hydrogenation of olefins in the gas phase
Whetten, Robert L.,Fu, Ke-Jian,Grant, Edward R.
, p. 3769 - 3770 (1982)
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Rare-earth metal allyl and hydrido complexes supported by an (NNNN)-type macrocyclic ligand: Synthesis, structure, and reactivity toward biomass-derived furanics
Abinet, Elise,Martin, Daniel,Standfuss, Sabine,Kulinna, Heiko,Spaniol, Thomas P.,Okuda, Jun
, p. 15014 - 15026 (2011)
The preparation and characterization of a series of neutral rare-earth metal complexes [Ln(Me3TACD)(η3-C3H 5)2] (Ln=Y, La, Ce, Pr, Nd, Sm) supported by the 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane anion (Me3TACD -) are reported. Upon treatment of the neutral allyl complexes [Ln(Me3TACD)(η3-C3H5) 2] with Bronsted acids, monocationic allyl complexes [Ln(Me3TACD)(η3-C3H5)(thf) 2][B(C6X5)4] (Ln=La, Ce, Nd, X=H, F) were isolated and characterized. Hydrogenolysis gave the hydride complexes [Ln(Me3TACD)H2]n (Ln=Y, n=3; La, n=4; Sm). X-ray crystallography showed the lanthanum hydride to be tetranuclear. Reactivity studies of [Ln(Me3TACD)R2]n (R=η3-C3H5, n=0; R=H, n=3,4) towards furan derivatives includes hydrosilylation and deoxygenation under ring-opening conditions.
Catalytic consequences of particle size and chloride promotion in the ring-opening of cyclopentane on Pt/Al2O3
Shi, Hui,Gutiérrez, Oliver Y.,Yang, Hao,Browning, Nigel D.,Haller, Gary L.,Lercher, Johannes A.
, p. 328 - 338 (2013)
Ring-opening of cyclopentane on alumina-supported Pt particles was studied as a function of Pt particle size in the presence of different Cl contents. With catalysts prepared from a Cl-free precursor, measured turnover rates increased monotonically with increasing Pt particle size (1-15 nm). On catalysts derived from a Cl-containing precursor, the turnover rates fell into two separate trends with the change of Pt particle size, depending on the extent of Cl removal by increasing thermal treatment temperature. In both cases, catalytic activity increased with increasing particle size in the examined ranges of dispersions (D = 0.7-1.0 and 0-0.6) and for both series of catalysts, the apparent activation energies were higher on large Pt particles than on small ones, with only small differences in the reaction orders for H2 and cyclopentane on particles of widely varying average sizes. Therefore, the effect of particle size on the turnover rates stems mainly from intrinsic rate constants, rather than from coverage effects. The relative adsorption coefficients of toluene and benzene indicated lower electron densities at the surface Pt atoms in the catalysts prepared from the Cl-containing precursor than in those from the Cl-free precursor. This subtle electron deficiency, which seems not to stem from the local Cl enrichment near Pt, affects both the concentration of chemisorbed hydrogen under reaction conditions and the barrier for C-C bond cleavage. The Cl postintroduced to the catalyst, in contrast, does not induce a similarly positive effect.
Activation of alkyl C-F Bonds by B(C6F5)3: Stoichiometric and catalytic transformations
Caputo, Christopher B.,Stephan, Douglas W.
, p. 27 - 30 (2012)
The Lewis acid B(C6F5)3 is shown to activate a series of alkyl fluorides. In stoichiometric reactions, treatment of sterically demanding phosphines with B(C6F5) 3/alkyl fluorides gives phosphonium fluoroborate salts while treatment of B(C6F5)3/alkyl fluorides with the salts [tBu3PX][XB(C6F5)3] (X = H, PhS) gives the alkane and the salt byproduct [tBu3PX][FB(C 6F5)3]. These fluoroalkanes are also catalytically converted to the corresponding alkanes by reaction of the fluoroalkane and Et3SiH using B(C6F5)3 as the catalyst.
Direct Observation of Ion-Pair Dynamics
Masnovi, J. M.,Kochi, J. K.
, p. 7880 - 7893 (1985)
The intimate ion pair is spontaneously generated by the change-transfer excitation of the electron donor-acceptor complex of anthracene donors (A) and tetranitromethane (TNO2) with a 25-ps laser pulse.The kinetics of the subsequent ion-pair decay to the adduct (i.e., -> AT) is followed spectroscopically over the separate picosecond, nanosecond, and microsecond time domains, each with a different laser-flash system.Three distinctive rate profiles are observed: (a) the picosecond decay following first-order kinetics (kI), the nanosecond decay also following first-order but slower kinetics (kII), and the microsecond decay following second-order kinetics (kIII).The experimental rate constants kI, kII, and kIII are associated with the relaxation of the intimate or tight ion pair , the solvent-separated or loose ion pair , and the free ions , respectively, as originally formulated by Winstein and co-workers for solvolysis mechanisms.These kinetics data together with the measurements of the fractional partitioning of ion pairs allow all the microscopic rate constsnts relevant to ion pair dynamics to be separately evaluated.The Winstein ion-pair formulation is substantiated by the observation and quantitative treatment of the "common-ion" and "special" salt effects.The role of solvent is underscored by the unique kinetics responses of reactive and persistent cations derived from various 9-substituted and 9,10-disubstituted anthracenes, respectively, with changes in the polarity of the medium from benzene and dichloromethane to acetonitrile.The overall importance of charge annihilation and separation in the microdynamics of transient ion pairs is underscored by a comparison with the bimolecular kinetics of radical-radical interaction measured under comparable conditions.
Push-pull mechanism of hydrodenitrogenation over silica-supported MoP, WP, and MoS2 hydroprocessing catalysts
Clark,Wang,Deck,Oyama
, p. 116 - 126 (2002)
The mechanism of liquid-phase catalytic hydrodenitrogenation at 3.1 MPa on silica-supported molybdenum phosphide, MoP/SiO2, and tungsten phosphide, WP/SiO2, was studied using a series of pentylamines of different structures. The reactivity pattern suggested that removal of nitrogen occurred primarily by an E2 elimination mechanism involving acidic and base sites on the catalyst surfaces in a push-pull process. Infrared spectroscopy and temperature-programmed reaction studies of ethylamine indicated that alkyl ammonium species formed on Bronsted acid sites were intermediates in the reaction. Similar results were obtained with a reference MoS2/SiO2 sample tested at the same conditions. This suggested that sulfur was probably present on the active surface and assisted in the removal of sulfur.
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Craig
, p. 1006,1011 (1943)
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Correlating heat of adsorption of CO to reaction selectivity: Geometric effects vs electronic effects in neopentane isomerization over Pt and Pd catalysts
Childers, David,Saha, Arindom,Schweitzer, Neil,Rioux, Robert M.,Miller, Jeffrey T.,Meyer, Randall J.
, p. 2487 - 2496 (2013)
Silica-supported Pt and Pd nanoparticles from 1 to 10 nm in diameter were evaluated for neopentane conversion (hydrogenolysis and isomerization). Characterization of the catalysts was conducted utilizing scanning transmission electron microscopy (STEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed CO, X-ray absorption spectroscopy (XAS), and isothermal calorimetry of CO adsorption to determine how geometric or electronic structure effects can explain changes in reactivity. Isomerization selectivity of Pt was much higher than Pd for all particle sizes. There is a pronounced effect of particle size on selectivity, with the highest isomerization selectivity achieved over catalysts containing the largest particle size for both Pt (57%) and Pd (26%) catalysts. For both Pd and Pt catalysts, DRIFTS showed a decrease in the ratio of linear-to-bridge bonded CO with particle size, while isothermal calorimetry of CO adsorption shows that both Pt and Pd enthalpies of adsorption decrease with increasing particle size. The isomerization selectivity was found to correlate inversely with the strength of CO adsorption for all catalysts suggesting that the chemisorption energy and not the particle size, coordination geometry, or ensemble size is the most important factor for increasing the isomerization selectivity.
Kinetic and FTIR studies of 2-methyltetrahydrofuran hydrodeoxygenation on Ni2P/SiO2
Cho, Ara,Kim, Hosoo,Iino, Ayako,Takagaki, Atsushi,Ted Oyama
, p. 151 - 161 (2014)
The hydrodeoxygenation of 2-methyltetrahydrofuran (2-MTHF) at a medium pressure of 0.5 MPa is studied over a Ni2P/SiO2 catalyst. Contact time studies show the formation of n-pentanal, 1-pentanol, 2-pentanone, 2-pentanol, and 2-pentene, as reaction intermediates and the production of pentane and butane as major products. The results are consistent with adsorption of 2-MTHF followed by rate-determining ring-opening to form either 1-pentoxide or 2-pentoxide alkoxide intermediates. Subsequent hydrogen-transfer steps produce the various intermediates, a decarbonylation step of the pentanal forms n-butane and CO, and further hydrodeoxygenation steps result in n-pentane. Fitting of the results using a rake mechanism that considers adsorbed intermediates gives excellent agreement with experimental data, and agrees with a simulation with a simpler first-order model. The more detailed rake analysis indicates that the surface species from the 1-pentoxide intermediate are ten-fold more plentiful than those produced from the 2-pentoxide intermediate. In situ infrared measurements support this reaction mechanism.
The hydrogenation of 1,3-pentadiene over an alumina-supported palladium catalyst: An FTIR study
Opara, Elaine,Lundie, David T.,Lear, Timothy,Sutherland, Iain W.,Parker, Stewart F.,Lennon, David
, p. 5588 - 5595 (2004)
The hydrogenation of a mixture of cis- and trans-1,3-pentadiene over a 1% Pd/Al2O3 catalyst at 303 K has been studied using infrared spectroscopy to monitor the changes in the composition of the gas phase over the catalyst as a function of time. The reaction is seen to occur as a consecutive process, with the terminal double bond hydrogenated in advance of the internal double bond. Vibrational assignments have been confirmed through ancillary calculations for a number of C5 molecules. The reaction profile is consistent with the catalyst presenting two distinct reaction sites: hydrogenation of the terminal double bond occurs at Site α, whilst Site β is responsible for hydrogenation of the internal double bond. Trans-pent-2-ene is identified as the only reaction intermediate. From comparative studies of the hydrogenation of pentenes over the catalyst, the absence of any cis-pent-2-ene in the reaction mixture is tentatively attributed to cis-1,3-pentadiene isomerising at Site α to form trans-1,3-pentadiene. The effect of toluene-d8 to act as a chemical modifier was also investigated and shown to selectively poison Site β Site α being unperturbed.
HYDROGENATION OF PENTYNES AND OF PENTADIENES CATALYSED BY Ru3(CO)12, Fe3(CO)12 AND MIXED METAL Ru-Fe DODECACARBONYLS SUPPORTED ON γ-Al2O3
Lausarot, P. Michelin,Vaglio, G. A.,Valle, M.
, p. 233 - 238 (1984)
Hydrogenation under mild conditions of 1- and 2-pentyne and of 1,3-cis- and 1,3-trans-pentadiene catalysed by Ru3(CO)12, FeRu2(CO)12, Fe2Ru(CO)12 and Fe3(CO)12 in toluene solutions or anchored on γ-Al2O3 has been studied.For all the systems examined, catalytic activity was highest for Ru3(CO)12-containing catalysts and lowest for Fe3(CO)12-containing ones.For mixed metal catalysts, activity decreased with increasing number of Fe atoms in the dodecacarbonyls.Anchorage of the clusters to γ-Al2O3 produced catalysts which were less active towards hydrogenation of 1- and 2-pentyne and more active towards hydrogenation of 1,3-cis- and 1,3-trans-pentadiene, but had no effect on product distribution.
Using modifiers to specify stereochemistry and enhance selectivity and activity in palladium-catalysed, liquid phase hydrogenation of alkynes
Garcia, Paloma E.,Lynch, Ailsa S.,Monaghan, Andy,Jackson, S. David
, p. 548 - 551 (2011)
Enhancing selectivity is a key parameter in green chemistry. In this study, we have examined the liquid phase hydrogenation of alkynes over a palladium catalyst and used modifiers to enhance selectivity and activity. The reactions studied were the hydrogenation of 1-pentyne and 2-pentyne. Five modifiers were used, pentane nitrile and its respective amine, pentyl amine, 3-phenyl propionitrile and its respective amine, 3-phenyl propylamine and trans-cinnamonitrile. These modifiers were not hydrogenated under reaction conditions. It was possible to obtain high (>90%) selectivities to 1-pentene and cis-2-pentene at high conversion. The effect on rate was dependent upon the modifier and the alkyne. The effect of the modifier was the same whether added with or before the reactants. Competitive reactions confirmed that terminal alkynes and internal alkynes are hydrogenated on separate sites and do not interfere and that the modifier influences each separately.
Preparation of the Ru/HZSM-5 catalyst and its catalytic performance for the 2-pentanone hydrodeoxygenation reaction
An, Hualiang,Wang, Yanji,Xi, Xi,Yang, Ye,Zhao, Xinqiang
, p. 17692 - 17698 (2021)
Levulinic acid is an ideal model compound for complex oxygenated components in bio-oil. To assist the understanding of its hydrodeoxygenation (HDO) performance, it is necessary to investigate separately the HDO property of the ketonic carbonyl group and carboxyl group. Herein, 2-pentanone was selected as a model to study the HDO property of the ketonic carbonyl group. The Ru/HZSM-5 catalyst was prepared by an excessive impregnation method and its structure and acidity were characterized by H2-TPR, NH3-TPD, HRTEM, SEAD, Py-IR, TG-DSC, and ICP analyses. The effect of preparation conditions on the catalytic performance of Ru/HZSM-5 was studied; the suitable preparation conditions were determined as follows: a calcination temperature of 450 °C, a calcination time of 3 h, a reduction temperature of 350 °C, and a reduction time of 4 h. The catalytic performance of Ru/HZSM-5 for the 2-pentanone HDO reaction was evaluated; pentane selectivity of 77.7% at a 2-pentanone conversion of 91.8% was achieved under the conditions of a reaction pressure of 5 MPa, a reaction temperature of 190 °C, a catalyst amount of 6 wt% and a reaction time of 6 h. 2-Pentanone HDO follows the reaction path of 2-pentanone hydrogenation to 2-pentanol and then 2-pentanol dehydration and hydrogenation to the target product pentane. The acidity of the catalyst plays a certain role in influencing its catalytic performance: Lewis acid sites show high activity for activating C-O bonds and Br?nsted acid sites are the key to accelerate the further dehydration of 2-pentanol and hydrogenation to alkanes.
MECHANISMS OF THE FORMATION OF ISOMERS OF ISOAMILENES IN SELECTIVE HYDROGENATION OF ISOPRENE ON A PALLADIUM-LEAD CATALYST
Beisembaeva, Z. T.,Gudkov, B. S.,Kiperman, S. L.
, p. 481 - 485 (1984)
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Dessing et al.
, p. 880 (1972)
Palladium metal nanoparticles stabilized by ionophilic ligands in ionic liquids: Synthesis and application in hydrogenation reactions
Leal, Brbara C.,Consorti, Crestina S.,Machado, Giovanna,Dupont, Jairton
, p. 903 - 909 (2015)
The reduction of [Pd(acac)(COD)]BF4 (acac = acetylacetonate; COD = 1,5-cyclooctadiene), dissolved in BMI·BF4, in the presence of P- or N-containing ionophilic ligands by H2 yields "soluble" and stable [Pd(0)]n nanoparticles (NPs). These ionic liquid soluble NPs are active and selective catalysts for the hydrogenation of 1,3-dienes and alkynes under mild reaction conditions. Selectivities up to 87% to cis-2-pentene and 95% conversion were obtained using Pd NPs modified with 1-(3-(diphenylphosphino)propyl)-2,3-dimethyl-1H-imidazol-3-ium N-bis(trifluoromethylsulfonyl)imide in 1-n-butyl-3-methylimidazolium tetrafluoroborate.
Hydrogen storage using heterocyclic compounds: The hydrogenation of 2-methylthiophene
Zhao,Oyama,Naeemi
, p. 172 - 184 (2010)
Alkyl substituted thiophenes are promising candidates for hydrogen carriers, as their dehydrogenation reactions are known to occur under mild conditions. Four types of catalysts, including supported noble metals, bimetallic noble metals, transition metal
Radical reactions in the radiolysis of cyclopentane
Wojnarovits,LaVerne
, p. 3168 - 3172 (1995)
The end products produced in the γ-radiolysis of cyclopentane have been measured at very low total doses (25-50 krad). Iodine scavenging techniques in solutions of 0.1-30 mM were used to elucidate radical yields and reaction mechanisms. The yields of the main radical species were found to be as follows: cyclopentyl, 4.9; 1-pentyl, 0.2; 3-cyclopentenyl, 0.07; H atom, 1.3 radical/100 eV. The change in yields from neat cyclopentane to 0.1 mM iodine solution suggests that about 79% of the cyclopentyl radicals escape the spur and react in the bulk medium with a disproportionation to combination ratio of 0.97. Radical precursors account for about 50% of the total end product yield, which is much smaller than found in the radiolysis of cyclohexane or cyclooctane. The radiolysis mechanism for cyclopentane is discussed and compared to those for cyclohexane and cyclooctane.
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Vogel
, (1948)
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Mechanisms of Methylenecyclobutane Hydrogenation over Supported Metal Catalysts Studied by Parahydrogen-Induced Polarization Technique
Salnikov, Oleg G.,Burueva, Dudari B.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Kovtunov, Kirill V.,Koptyug, Igor V.
, (2022/03/15)
In this work the mechanism of methylenecyclobutane hydrogenation over titania-supported Rh, Pt and Pd catalysts was investigated using parahydrogen-induced polarization (PHIP) technique. It was found that methylenecyclobutane hydrogenation leads to formation of a mixture of reaction products including cyclic (1-methylcyclobutene, methylcyclobutane), linear (1-pentene, cis-2-pentene, trans-2-pentene, pentane) and branched (isoprene, 2-methyl-1-butene, 2-methyl-2-butene, isopentane) compounds. Generally, at lower temperatures (150–350 °C) the major reaction product was methylcyclobutane while higher temperature of 450 °C favors the formation of branched products isoprene, 2-methyl-1-butene and 2-methyl-2-butene. PHIP effects were detected for all reaction products except methylenecyclobutane isomers 1-methylcyclobutene and isoprene implying that the corresponding compounds can incorporate two atoms from the same parahydrogen molecule in a pairwise manner in the course of the reaction in particular positions. The mechanisms were proposed for the formation of these products based on PHIP results.
Mechanism change of (+)-nonlinear effect in a phase separation system in a CuII-catalyzed asymmetric friedel-crafts reaction using a C2-chiral dioxolane-containing-bisamidine ligand, Naph-diPIM-dioxo-iPr
Kitamura, Masato,Le, Thien Phuc,Tanaka, Shinji,Yoshimura, Masahiro
supporting information, p. 1319 - 1333 (2020/11/30)
A CuII complex of bisamidine ligand LS, chirally modified naphtho[1,2-b:7,8-b′]dipyrroloimidazole (Naph-diPIM), catalyzes the enantioselective Friedel-Crafts (FC) reaction of indole (1a) with ethyl trifluoropyruvate (2) to give quantitatively the FC adduct 3a with a 98:2 S/R enantiomer ratio (er). The reaction shows no nonlinear effect (NLE) under the standard conditions of [1a] = [2] = 100mM; [Cu(OTf)2] = [LS + LR] = 0.10 mM; CPME; and 0 °C irrespective of the catalyst aging temperature. A five-fold increase in the catalyst concentration (0.50mM) changes the situation, leading to a strong (+)-NLE with phase separation of a white solid. The NLE is expressed by the Noyori-type mechanism: Aggregate of heterochiral dimer CuLSCuLR is separated from the reaction system (Khetero > 1 > Khomo). Furthermore, a strong (+)-NLE is observed via a purple solid liberation even with [CuII] = 0.10mM after the catalyst aging at 100 °C in the presence of an excess amount of chiral ligand. A mechanistic study has revealed i) that the sterically disfavored homochiral 1:2 complex CuLSLS is more stabilized by an intramolecular n-π? interaction than the sterically favored heterochiral 1:2 complex CuLSLR and ii) that the (+)-NLE originates from the phase separation of heterochirally interacted (CuLSLSCuLRLR).