106-98-9Relevant articles and documents
Isolation and Direct Observation of Intramolecular Hydroacylation of a cis-Hydridopent-4-enoylrhodium(III) Complex
Milstein, David
, p. 1357 - 1358 (1982)
A stable cis-hydridopentenoylrhodium(III) trimethylphosphine complex, isolated from oxidative addition of pent-4-enal to RhCl(PMe3)3, undergoes intramolecular hydroacylation to cyclopentanone.
Silver(I) and Nickel(II) Complexes with Oxygen- or Nitrogen-Functionalized NHC Ditopic Ligands and Catalytic Ethylene Oligomerization
Ren, Xiaoyu,Wesolek, Marcel,Bailly, Corinne,Karmazin, Lydia,Braunstein, Pierre
, p. 1073 - 1087 (2020)
Potentially bidentate ditopic ligands containing a N-heterocyclic carbene (NHC) donor associated with an ether or an amine have been prepared and coordinated to NiII centers. The influence of the length of the alkyl chain, –(CH2)2– or –(CH2)3– connecting the ether or the amine group to the heterocycle was examined. In the analogous AgI complexes [Ag{Im(Dipp)(C3OMe)-κ1CNHC}2]Cl (8), 9 and 10, in the neutral NiII complexes with a C3 spacer trans-[NiCl2{Im(Dipp)(C3OMe)-κ1CNHC}2] (5a), 6, and 7, and in the cationic cis-[Ni{Im(Dipp)(C3OMe)-κ1CNHC}2(NCMe)2](PF6)2 (15) and cis-[Ni{Im(Mes)(C3OMe)-κ1CNHC}2(NCMe)2](PF6)2 (16), the ligand is monodentate. [(ImH)(Dipp)(C3OMe)][NiX3{Im(Dipp)(C3OMe)-κ1CNHC}] (14a, X = Cl) and (14b, X = Br) are rare examples of complexes of the type [NiX3(NHC)]–. For comparison, [NiBr2{(Im)(Dipp)(C2NMe2)-κ2,CNHC,Namine}] (24) and [NiBr2{(Im)(Dipp)(C3NMe2)-κ2,CNHC,Namine}] (25) contain a six- or a seven-membered κ2CNHC,Namine chelate, respectively. Various NiII complexes were evaluated as precatalysts for ethylene oligomerization. The structures of the carbene (Dipp)(C3OMe)imidazole-ylidene (4) and of the complexes 5a, 7, 8, [(ImH)(Dipp)(C3OMe)]2[NiCl4] (11a), [(ImH)(Dipp)(C3OMe)]2[NiBr4] (11b), [(ImH)(Me)(C3OMe)]2[NiCl4] (13), 14b, 16·NCMe, [Im(H){C(Me)(=NDipp)}(C3OMe)]2 [NiCl4] (18), [AgCl{Im[C(Me)=NDipp](C3OMe)}-κ1CNHC] (19), [AgCl{Im(Dipp)(C3NMe2)-κ1CNHC}] (23), 24, 25 and trans-[NiCl2{Im(Dipp){CH2CH2C(O)OEt}}2] were analyzed by X-ray diffraction.
Hierarchically porous Nb-TiO2 nanomaterials for the catalytic transformation of 2-propanol and n-butanol
Franco Finol,Rooke,Siffert,Cousin,Carniti,Gervasini,Giraudon,Su,Lamonier
, p. 1988 - 1995 (2014)
Nb-TiO2 nanomaterials with hierarchical porosity (macro, meso and micropores) have been successfully synthesized using a simple self-assembly method without the need for a surfactant. Improved textural and structural properties were obtained after incorporation of Nb within a TiO2 framework. High Nb dispersion and Nb-Ti interaction were achieved at the Nb-TiO2 nanomaterial surface. With Nb addition to TiO2, the balance of Lewis to Br?nsted acid sites was maintained however the acidity increased in strength. The catalytic transformation of 2-propanol and n-butanol was favoured at very low temperatures with a change in selectivity; the dehydration reaction of alcohols into alkenes was promoted by the increase in acidity of the Nb-TiO2 nanomaterials.
Selective dimerization of ethylene to but-1-ene under the conditions of industrial process. I. Influence of temperature and pressure on the rate of the process in a bubbling type reactor
Zhukov,Val'kovich,Skorik,Petrov,Belov
, p. 1195 - 1200 (2007)
Analysis of mass and heat balance in the reaction node of the process of ethylene dimerization into but-1-ene under the industrial conditions is performed. It is found that ethylene concentration in the reactor liquid phase by a complex way depends on the reactor temperature, pressure and but-1-ene concentration in the liquid phase. Optimal process temperature is 80-90°C, operating pressure in the reactor is 0.6-0.8 MPa. Increase in pressure above 1 MPa practically excludes heat withdraw via but-1-ene evaporation and makes the system of heat withdrawing ineffective.
Product distribution of CO2 hydrogenation by K- and Mn-promoted Fe catalysts supported on N-functionalized carbon nanotubes
Kangvansura, Praewpilin,Chew, Ly May,Saengsui, Worasarit,Santawaja, Phatchada,Poo-arporn, Yingyot,Muhler, Martin,Schulz, Hans,Worayingyong, Attera
, p. 59 - 65 (2016)
An iron based catalyst supported on an N-functionalized carbon nanotube (NCNT) was promoted with potassium and manganese as follows: Fe/NCNT, K/Fe/NCNT, Mn/Fe/NCNT, and K/Mn/Fe/NCNT for CO2 hydrogenation. Time-resolved reduction X-ray absorption near edge spectroscopy (XANES) showed mixed phases of Fe, FeO, Fe3O4, and Fe2O3 resulting from K/Fe/NCNT, and of FeO and Fe3O4 resulting from Mn/Fe/NCNT. The product distributions and growth probability of n-alkanes during CO2 hydrogenation indicated that the potassium-promoted iron catalysts performed Fischer-Tropsch (FT) synthesis under steady state at 60?h. 1-Alkenes desorbed from the FT sites with the potassium-promoted catalysts, (K/Fe/NCNT and K/Mn/Fe/NCNT), with low methane formation. Small amounts of 1-alkene, along with high methanation, were produced from the potassium-unpromoted catalysts, (Fe/NCNT and Mn/Fe/NCNT), indicating high local H2:CO ratios on the catalyst surfaces. K/Fe/NCNT and K/Mn/Fe/NCNT catalysts also produced ethanol. Thus, potassium is a key promoter providing active species of the catalysts for alkene and ethanol formation. Reduced surrounding of the NCNT support, potassium as an electronic promoter together with manganese as a structural promoter made the iron-active phase well suitable for CO2 hydrogenation producing mainly alkenes and ethanol.
HYDROGENOLYSIS AND HOMOLOGATION OF LINEAR AND BRANCHED PENTENES ON Ru/SiO2 CATALYSTS: IMPLICATION IN THE MECHANISM OF C-C BOND FORMATION AND CLEAVAGE ON METAL SURFACES.
Rodriguez,Leconte,Basset,Tanaka,Tanaka
, p. 275 - 278 (1988)
Hydrogenolysis and homologation of 1-pentene to butenes and hexenes take place simultaneously and at the same rate over a Ru/SiO//2 catalyst at 110 degree C, suggesting that these two reactions are mechanistically related. **1**3C labeling experiments indicate that C-C cleavage occurs at the double bond of 1-pentene-1-**1**3C leading to unlabeled 1-butene and labeled hexenes. The product distribution in the hydrogenolysis of 1-pentene, 2-pentenes, 3-methyl-1-butene, 2-methyl-2-butene, and 2-methyl-1-butene is accounted for by a carbene-olefin mechanism, which can therefore be considered as a reasonable common path for the formation and cleavage of carbon-carbon bonds on metal surfaces.
Leaving group effects in gas-phase substitutions and eliminations
Gronert, Scott,Fagin, Adelaide E.,Okamoto, Keiko,Mogali, Sudha,Pratt, Lawrence M.
, p. 12977 - 12983 (2004)
Using a methodology recently developed for studying the product distributions of gas-phase SN2 and E2 reactions, the effect of the leaving group on the reaction rate and branching ratio was investigated. Using a dianion as the nucleophile, reactions with a series of alkyl bromides, iodides, and trifluoroacetates were examined. The alkyl groups in the study are ethyl, n-propyl, n-butyl, isobutyl, isopropyl, sec-butyl, and tert-butyl. The data indicate that leaving group abilities are directly related to the exothermicities of the reaction processes in both the gas phase and the condensed phase. Gas-phase data give a reactivity order of iodide > trifluoroacetate > bromide for SN2 and E2 reactions. Previous condensed phase data indicate a reactivity order of iodide > bromide > trifluoroacetate for substitution reactions; however, the basicities of bromide and trifluoroacetate are reversed in the condensed phase so this reactivity pattern does reflect the relative reaction exothermicities. Aside from this variation, the gas-phase data parallel condensed phase data indicating that the substituent effects are rooted in the nature of the alkyl substrate rather than in differences in solvation. The experimental data are supported by calculations at the MP2/6-311+G(d,p)//MP2/6-31+(d) level.
Protonation of an internal alkyne produces a terminal alkene: Reactivity of [Mo(η2-MeCCMe)(Ph2PCH2CH 2PPh2)2]
Davies, Sian C.,Henderson, Richard A.,Hughes, David L.,Oglieve, Kay E.
, p. 2039 - 2040 (1996)
Structurally defined [Mo(η2-MeCCMe)-(Ph2PCH2CH 2PPh2)2] reacts with anhydrous HCl in thf to give predominantly trans-[MoCl2(Ph2PCH2CH2PPh 2)2] with but-1-ene (69 ± 6%) and cis-but-2-ene (10 ± 2%); in addition, some [MoH2Cl2(Ph2PCH2CH 2PPh2)2] and but-2-yne (21 ± 5%) are produced; the mechanistic features by which protonation of an internal alkyne yields a terminal alkene are enumerated.
Selective Catalytic Dimerisation of Ethylene to But-1-ene by 2-CHPMe2)>
Gibson, Vernon C.,Kee, Terence P.,Poole, Andrew D.
, p. 1720 - 1722 (1990)
2-CHPMe2)> reacts with an excess of ethylene at 70 deg C to give but-1-ene cleanly and selectively.
Preparation of highly active NiW hydrotreating model catalysts with 1,2- cyclohexanediamine-N,N,N'N'-tetraacetic acid (CyDTA) as a chelating agent
Kishan,Coulier,De Beer,Van Veen,Niemantsverdriet
, p. 1103 - 1104 (2000)
Changing the order in which oxidic W and Ni convert to sulfides by adding 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CyDTA) as a chelating agent for nickel in the preparation of NiWS-SiO2 catalysts is the key ingredient in obtaining a high activity for thiophene hydrodesulfurization.
