2825-86-7Relevant academic research and scientific papers
Probing the synergistic effect of Mo on Ni-based catalyst in the hydrogenation of dicyclopentadiene
Fang, Zhuqing,Shi, Daxin,Lin, Na,Li, Airu,Wu, Qin,Wang, Qiqi,Zhao, Yun,Feng, Caihong,Jiao, Qingze,Li, Hansheng
, p. 60 - 70 (2019/02/07)
Mo promoted Ni/γ-Al2O3 catalysts were synthesized by an incipient wetness co-impregnation method. The micro-structure, surface composition and adsorption characteristics of these catalysts were investigated by N2 adsorption-desorption isotherms, XRD, HRTEM, XPS, TPR and dicyclopentadiene-TPD. The hydrogenation of dicyclopentadiene (DCPD) to endo-tetrahydrodicyclopentadiene (endo-THDCPD) was selected to evaluate the catalytic performance. The results showed Mo species improved dispersity of nickel oxide on the support surface and inhibit formation of spinel NiAl2O4. The nickel oxide could be reduced to Ni nanoparticles at relatively lower temperature because of its excellent dispersity and weakened interaction with the support. Meanwhile, the aggregation of metallic Ni on catalysts were markedly inhibited with the increasing of Mo content. Mo species also changed the adsorption mode of DCPD on Ni-based catalysts, and hence improved DCPD adsorption strength and capacity on catalysts and further changed hydrogenation mechanism of DCPD. The catalytic properties of NiMoX/γ-Al2O3 catalysts showed that the hydrogenation activity was increased by adding Mo to Ni-based catalyst within limits. When the ratio of Mo to Ni was 0.2, the NiMo0.2/γ-Al2O3 catalyst displayed the highest activity (TOF = 134.2 h?1) and the best selectivity (99.7%). Compared with Ni/γ-Al2O3 catalyst, the hydrogenation time reduced from 6 h to 3 h and the amount of by-product C5 fraction significantly decreased from 2.4% to 0.3%.
Palladium nanoparticles encapsulated in a dendrimer networks as catalysts for the hydrogenation of unsaturated hydrocarbons
Karakhanov, Edward A.,Maksimov, Anton L.,Zakharian, Elena M.,Kardasheva, Yulia S.,Savilov, Sergey V.,Truhmanova, Nadezhda I.,Ivanov, Andrey O.,Vinokurov, Vladimir A.
, p. 1 - 18 (2015/02/19)
A novel method has been proposed for encapsulating palladium nanoparticles up to 5 nm in the matrix of polymeric support networks based on polyamidoamine dendrimers. The shape of the particle size distribution and the catalytic activity of the materials obtained during the hydrogenation of unsaturated compounds depend strongly on the support structure. High activity (TOF up to 86,000 h-1) has been observed during the hydrogenation of styrene.
Palladium-catalyzed and samarium-promoted coupling of stereochemically-biased allylic acetates with carbonyl compounds
Jacquet, Olivier,Bergholz, Timm,Magnier-Bouvier, Caroline,Mellah, Mohamed,Guillot, Régis,Fiaud, Jean-Claude
experimental part, p. 222 - 226 (2010/03/01)
Stereochemically-biased bicyclic allylic acetates endo- and exo-1 were shown as being allyl donors for Pd-catalyzed carbonyl allylation using stoichiometric quantities of samarium diodide. Cyclopentenyl acetate and bicyclic derivatives 1 react with cyclic ketones in the presence of SmI2 without requirement of palladium catalysis. Use of enantiomerically enriched substrate suggests that the reaction goes through a π-allyl samarium complex. However, this reactivity appears to be restricted to strained cyclopentenyl acetates since other linear and cyclic allylic acetates do not give the carbonyl allylation product.
The Adamantane Rearrangement of syn- and anti-Tricyclo2,5>decane. Part II. Rearrangements Initiated by Regioselective Formation of Carbocations at C(3) and C(9)
Brossi, Marco,Ganter, Camille
, p. 848 - 858 (2007/10/02)
The endo- and exo-alcohols 5-12 of syn- (1) and anti-tricyclo2,5>decane (2) were treated with BF3/Et3SiH (ionic hydrogenation) in order to study the behaviour of the corresponding regioselectively generated carbocations at C(3) (a (syn), b (anti) and C(9) (c (syn), d (anti)).The anti-hydrocarbon 2 is practically the sole product obtained starting with the four 3-alcohols (via a -> b from 5 and 6 (syn) and via b from 9 and 10 (anti)).The four 9-alcohols in each case yield a mixture of 2-endo,3-endo- (3) and 2-exo,3-exo-trimethylene-8,9,10-trinorbornane (4) (via c -> e from 7 and 8 (syn) and via d -> f from 11 and 12 (anti)), but no hydrocarbon 2, i.e. none of the 1,3-H shifts c -> a and d -> b is involved.
Light-promoted catalytic hydrogenation of olefins with nickel complexes: the formation of nickel hydrides from the reaction of Ni(I) complexes with hydrogen
Chow, Yuan L.,Li, Huali,Yang, Meng-Su
, p. 2920 - 2927 (2007/10/02)
The conditions pertaining to triplet excited state ketone-sensitized photoreduction of Ni(acac)2 under hydrogen were show to serve as a method for light-promoted hydrogenation of olefins with clean chemospecificity.For example, the double bond in the bicyclic system was preferentially hydrogenated over the other double bond in dicyclopentediene and in 5-methylenebicycloheptene.This photohydrogenation could be run under a wide range of conditions and was apparently a homogeneous catalytic process; in a late stage of photohydrogenation, concurrence of heterogeneous catalytic processes was not ruled out.The Ni(I) complexes of tetrahydrofuran and olefins generated from the photoreduction of Ni(acac)2 were shown to react with hydrogen to give nickel hydride complexes.By analogy with the generally accepted reaction pattern, coordinated olefins in these nickel hydride complexes probably spontaneously undergo intramolecular addition to give Ni-alkyl complexes.It is suggested, that these Ni-alkyl complexes are photoexcited to generate a vacant coordination site so that the reaction with hydrogen can proceed to give products and regenerate a nickel hydride catalyst.
New Method for the Classification of Nucleophiles in the Palladium-Catalyzed Substitution of Allylic Acetates
Fiaud, Jean-Claude,Legros, Jean-Yves
, p. 1907 - 1911 (2007/10/02)
Palladium-catalyzed reactions of nucleophiles were carried out on cyclopent-2-enyl acetate (1), 3a,4,5,6,7,7a-hexahydro-(1α,3aα,4α,7α,7aα)-4,7-methano-1H-inden-1-yl acetate (3b), and 3a,4,5,6,7,7a-hexahydro-(1β,3aα,4α,7α,7aα)-4,7-methano-1H-inden-1-yl acetate (5b) to give indications on the mechanism of the reaction and the mode of attack of the nucleophiles.The lack of reactivity of 3b confirmed that a trans relationship between the approaching Pd(O) complex and the departing acetate is required in the η3-allyl-forming step.Examination of the reactivity of the nucleophiles with 5b compared to 1 allowed a decision as to whether the primary attack of the intermediate (η3-allyl)palladium complex by the nucleophile is directed to η3-allylic ligand (Nu1 nucleophiles: sodium dimethyl malonate, sodium cyclopentadienide, lithium thioxodiphenylphosphide, morpholide) or to the metal (Nu2 nucleophiles: phenylzinc chloride, sodium indenide, ammonium formate).
Synthesis and Reactions of Tricyclo2,6>dec-2(6)-ene
Takaishi, Naotake,Takahashi, Hitoshi,Yamashita, Osamu,Inamoto, Yoshiaki
, p. 4862 - 4865 (2007/10/02)
The synthesis and some addition reactions of the novel strained olefin, tricyclo2,6>dec-2(6)-ene (5), are described.The stability and reactivity of 5 are discussed with regard to molecular mechanics calculations (MM2).
