F:Flammable;
142-82-5Relevant articles and documents
Synthesis of metal complexes of polyalkylene(arylene) phosphorous amides
Teleshev,Te, Van,Mishina,Abrashina,Nifant'ev
, p. 1334 - 1337 (2008)
Reactions of phosphorous triamides with symmetrical diols in equimolar ratio were studied. These reactions result in formation of unique poly(oligo)amidophosphorous systems. The products obtained are used as ligands for the synthesis of metal complexes of a new type.
Platinum Hydroformylation Catalysts containing Diphenylphosphine Oxide Ligands
Leeuwen, Piet W. N. M. van,Roobeek, Cornelis F.,Wife, Richard L.,Frijns, John H. G.
, p. 31 - 33 (1986)
Platinum complexes of the general formula Pt(H)(Ph2PO)(Ph2POH)(PPh3) (1a) catalyse the hydroformylation of hept-1-ene and, more significantly, hept-2-ene, yielding products of high linearity (90 and 60percent, respectively); the intermediate alkyl and acyl complexes (1c-e) which most often escape direct observation in a catalytic system, have been successfully isolated and identified.
REACTION OF HCo(CO)4 WITH OLEFINS, EFFECT OF Co2(CO)8
Ungvary, Ferenc,Marko, Laszlo
, p. 397 - 400 (1981)
Dicobalt octacarbonyl catalyzes the formation of acylcobalt tetracarbonyls and paraffins from olefins and cobalt tetracarbonyl hydride, presumably by generating radical species.The relative reactivities of CO and HCo(CO)4 towards an alkylcobalt carbonyl determine the carbonylation/hydrogenation ratio.
Catalytic testing of TiO2/platinum/silicalite-1 composites
Van Der Puil, Nelleke,Creyghton, Edward J.,Rodenburg, Elise C.,Sie, Tjong S.,Van Bekkum, Herman,Jansen, Jacobus C.
, p. 4609 - 4615 (1996)
The synthesis, characterisation and testing of a composite catalyst, consisting of TiO2-supported platinum catalyst particles covered with a 0.8-1.3 μm thick silicalite-1 layer, are described. The composite shows mass transport selectivity, which is demonstrated by the high ratios of the initial conversion rates in the competitive hydrogenation of a linear and a dibranched alkene, reaching average values of 35 at 100°C. At the temperatures applied, adsorption of the alkene is dominant and hydrogen supply to the catalytic sites is relatively small. As a result the double-bond migration is more pronounced than with an uncovered platinum catalyst. At the catalytic sites of the composites steric constraints are observed, which lead to regioselectivity in the hydrogenation of long-chain alkenes. A linear alkene with a terminal double bond is converted preferentially over an isomer with an internal double bond.
The effect of TiO2 particle size on the characteristics of Au-Pd/TiO2 catalysts
Kittisakmontree, Prathan,Yoshida, Hiroshi,Fujita, Shin-Ichiro,Arai, Masahiko,Panpranot, Joongjai
, p. 70 - 75 (2015)
The nanocrystalline TiO2 materials with average crystallite sizes of 9 and 15 nm were synthesized by the solvothermal method and employed as the supports for preparation of bimetallic Au/Pd/TiO2 catalysts. The average size of Au-Pd alloy particles increased slightly from sub-nano (2 crystallite size from 9 to 15 nm. The catalyst performances were evaluated in the liquid-phase selective hydrogenation of 1-heptyne under mild reaction conditions (H2 1 bar, 30 °C). The exertion of electronic modification of Pd by Au-Pd alloy formation depended on the TiO2 crystallite size in which it was more pronounced for Au/Pd on the larger TiO2 (15 nm) than on the smaller one (9 nm), resulting in higher hydrogenation activity and lower selectivity to 1-heptene on the former catalyst.
Catalytic deoxygenation of octanoic acid over supported palladium: Effects of particle size and alloying with gold
Sun, Keyi,Wilson, Adria R.,Thompson, Simon T.,Lamb, H. Henry
, p. 1939 - 1948 (2015)
Catalytic deoxygenation of octanoic acid (OA) to n-heptane was investigated over silica-supported Pd and PdAu catalysts at 260 °C and 1 atm in a fixed-bed microreactor. Pd/SiO2 catalysts were prepared by incipient wetness (IW) and ion exchange (IE). Bimetallic catalysts were prepared using an IE procedure that is known to produce supported PdAu nanoparticles. The Pd nanoparticles (7.5 nm average size) in the Pd/SiO2 (IW) catalyst exhibit well-defined (100) and (111) facets, as evidenced by high-resolution electron microscopy (HREM) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed CO. As expected, the smaller nanoparticles (1.5 nm average size) in the Pd/SiO2 (IE) catalyst display strong linear and bridging CO DRIFTS bands. The PdAu/SiO2 (1/1 atomic ratio) catalyst contains 5 nm alloy nanoparticles with Pd-rich surfaces, as evidenced by HREM with energy-dispersive X-ray (EDX) analysis and in situ EXAFS spectroscopy. DRIFTS thermal desorption experiments demonstrated that alloying with Au reduced the CO adsorption energy on surface Pd sites. The Pd/SiO2 (IE) catalyst initially exhibited OA decarboxylation and decarbonylation activity but lost decarboxylation activity rapidly with time on stream (TOS). In contrast, the Pd/SiO2 (IW) catalyst had only decarbonylation activity, deactivated less rapidly with TOS, and could be regenerated by heating in H2 to remove OA residues. Alloying Pd with Au was found to improve catalyst stability without significantly affecting decarbonylation activity, as evidenced by the equivalent OA turnover frequencies of the Pd/SiO2 (IW) and PdAu/SiO2 (2/3) catalysts. The geometric and electronic effects of alloying reduce the CO adsorption energy and mitigate self-poisoning by OA and related species.
HYDROGENATION OF ALKENES AND ALKYNES ON Pd-POLYHETEROARYLENE CATALYSTS TREATED WITH SODIUM BOROHYDRIDE
Belyi, A. A.,Chigladze, L. G.,Rusanov, A. L.,Vol'pin, M. E.
, p. 1801 - 1806 (1989)
As a result of treatment with sodium borohydride, Pd(0)-polyheteroarylene catalysts for the hydrogenation of unsaturated compounds acquire the capability for selective hydrogenation of alkynes as a result of suppressing processes of hydrogen addition to the double bond of the olefins and dienes that are obtained by reduction of the alkynes.
Highly dispersed Pd nanoparticles supported on nitrogen-doped graphene with enhanced hydrogenation activity
Liu, Ping,Li, Gen,Chang, Wan-Ting,Wu, Meng-Yao,Li, Yong-Xin,Wang, Jun
, p. 72785 - 72792 (2015)
Pd nanoparticles supported on nitrogen-doped graphene (NG) were prepared as hydrogenation catalysts. Different nitrogen sources (ethylenediamine, ammonia, and urea) were employed to synthesize NG using hydrothermal treatment under mild conditions. The as-made samples were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, elemental analysis, nitrogen adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. Remarkably improved dispersion of Pd nanoparticles was observed when nitrogen was introduced into the graphene structure. These NG-supported Pd catalysts showed enhanced catalytic hydrogenation activities owing to the superior dispersion of Pd. In the hydrogenation of different olefins, perfect turnover frequencies were obtained over the NG-supported Pd catalyst with urea as the nitrogen source.
Mechanism of autocatalysis in the thermal dehydrochlorination of poly(vinyl chloride)
Starnes Jr., William H.,Ge, Xianlong
, p. 352 - 359 (2004)
Autocatalysis during the thermal dehydrochlorination of poly(vinyl chloride) (PVC) is shown to be a free-radical process that converts the ordinary monomer units of the polymer into chloroallylic structures that have low thermal stabilities. In the first stage of dehydrochlorination, conjugated polyene sequences are created by a nonfree-radical route. They react with HCl to give cation monoradicals and/or excited cation diradicals. One or both of these species, or other radicals formed them, can then abstract methylene hydrogen in order to produce new radicals that are also carbon-centered. These are converted by chlorine-atom β scission into the chloroallylic segments, which start the growth of new polyenes in the usual (nonradical) way. At 180°C in solid PVC, autocatalysis was inhibited by free-radical scavengers (a hindered phenol, triphenylmethane, and metallic mercury) but greatly enhanced by an increased concentration of HCl when all-trans-β-carotene, a model for PVC polyene sequences, was introduced simultaneously. When the were subjected to autocatalytic conditions, other model compounds gave products that apparently resulted from the abstraction of hydrogen by free-radical intermediates.
Fabricating nickel phyllosilicate-like nanosheets to prepare a defect-rich catalyst for the one-pot conversion of lignin into hydrocarbons under mild conditions
Cao, Meifang,Chen, Bo,He, Chengzhi,Ouyang, Xinping,Qian, Yong,Qiu, Xueqing
supporting information, p. 846 - 857 (2022/02/09)
The one-pot conversion of lignin biomass into high-grade hydrocarbon biofuels via catalytic hydrodeoxygenation (HDO) holds significant promise for renewable energy. A great challenge for this route involves developing efficient non-noble metal catalysts to obtain a high yield of hydrocarbons under relatively mild conditions. Herein, a high-performance catalyst has been prepared via the in situ reduction of Ni phyllosilicate-like nanosheets (Ni-PS) synthesized by a reduction-oxidation strategy at room temperature. The Ni-PS precursors are partly converted into Ni0 nanoparticles by in situ reduction and the rest remain as supports. The Si-containing supports are found to have strong interactions with the nickel species, hindering the aggregation of Ni0 particles and minimizing the Ni0 particle size. The catalyst contains abundant surface defects, weak Lewis acid sites and highly dispersed Ni0 particles. The catalyst exhibits excellent catalytic activity towards the depolymerization and HDO of the lignin model compound, 2-phenylethyl phenyl ether (PPE), and the enzymatic hydrolysis of lignin under mild conditions, with 98.3% cycloalkane yield for the HDO of PPE under 3 MPa H2 pressure at 160 °C and 40.4% hydrocarbon yield for that of lignin under 3 MPa H2 pressure at 240 °C, and its catalytic activity can compete with reported noble metal catalysts.
