110-71-4Relevant articles and documents
X-ray crystal structure of the tetra(tert-butyl)erbate anion and attempts to prepare tetravalent organolanthanide complexes
Noh, Wontae,Girolami, Gregory S.
, p. 3865 - 3870 (2007)
The new [Li(DME)3+] salt of the previously-known tetra(tert-butyl)erbate(III) anion [Er(t-Bu)4-] has been prepared and structurally characterized. The erbium(III) center is ligated by four tert-butyl groups in an approximately tetrahedral arrangement. The C-Er-C angles between the tert-butyl groups range from 108.8(3)° to 111.2(3)° and the Er-C distances range from 2.352(6) to 2.395(6) A?. The lithium cation is surrounded by three DME molecules, which form a distorted octahedral coordination sphere. Attempts to oxidize the analogous terbate complex [Li(DME)3][Tb(t-Bu)4] and its cerium analog to electrically neutral tetra(alkyl)lanthanide(IV) compounds are described.
Reactions of diols with dimethyl carbonate in the presence of W(CO) 6 and Co2(CO)8
Khusnutdinov,Shchadneva,Mayakova
, p. 948 - 952 (2014)
Dimethoxyalkanes and dimethyl alkanediyl biscarbonates were synthesized by reactions of diols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of dimethoxyalkanes or dimethyl alkanediyl biscarbonates.
Niobia-modified aluminas prepared by impregnation with niobium peroxo complexes for dimethyl ether production
Rocha, Angela S.,Da S. Forrester, Aline M.,Lachter, Elizabeth R.,Faro Jr., Arnaldo C.,Sousa-Aguiar, Eduardo F.
, p. 104 - 111,8 (2012)
Use of a water-soluble niobium peroxo complex allowed the preparation of niobium-modified aluminas containing up to 90% of the theoretical niobia monolayer in one impregnation step. There was a maximum in the density of surface Lewis acid sites at 45% of the theoretical monolayer. FTIR of adsorbed pyridine and adsorbed CO2 suggest the vertical growth of the Nb 2O5 layer for the largest niobium contents. The addition of 22.5% of the theoretical monolayer eliminated about 80% of the basic surface hydroxyls, inhibiting the adsorption of gas phase CO2 by the samples. The niobia/alumina catalysts suffered less inhibition by CO2 than the pure alumina in the methanol dehydration reaction, confirming that Nb 2O5 is mainly deposited on sites where the CO2 adsorption is stronger, leaving free sites that are active in catalytic dehydration and less inhibited by CO2, however none of the niobia/aluminas was more active than the pure alumina. Nevertheless, in the direct syngas to DME conversion using a mixed catalyst system comprised of a CuZnAl methanol synthesis catalyst and a methanol dehydration component, the activity was significantly larger with a niobia/alumina as a dehydrating component than with the pure alumina.
Organometallic compounds of the lanthanides. 42. Bis(dimethoxyethane)lithium bis(cyclopentadienyl)bis(trimethylsilyl)lanthanide complexes
Schumann, Herbert,Nickel, Siegbert,Loebel, J?rg,Pickardt, Joachim
, p. 2004 - 2009 (1988)
The trichlorides of Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu react with NaC5H5 in tetrahydrofuran in the presence of dimethoxyethane (dme) with formation of bis(cyclopentadienyl)lanthanide chloride complexes of the types (C5H5)2Ln(μ-Cl)2Na(dme). The reactions of these organolanthanide halide complexes with (trimethylsilyl)lithium in dme yield compounds of the type [Li(dme)2][(C6H5)2Ln(SiMe 3)2] (Ln = Sm, Dy, Ho, Er, Tm, Lu). (C5H5)2Sm(μ-Cl)2Na(dme) reacts with (trimethylgermyl)lithium in dme/pentane with formation of [Li(dme)3][(C5H5)3SmClSin(C 5H5)3] (7a). The new compounds have been characterized by elemental analyses and IR and NMR spectra. The structure of [Li(dme)3][(C5H5)3SmClSm(C 5H5)3] (7a) has been elucidated through complete X-ray analysis. The crystals are monoclinic with a = 14.00 (1) A?, b = 13.38 (2) A?, c = 23.49 (3) A?, β = 93.37 (9)°, space group P21/n, Z = 4, and R = 0.0411 for 4671 reflections. The [Cp3SmClSmCp3]- anion consists of two Cp3Sm unite bridged by a chlorine atom with Sm-Cl distances of 2.827 (2) and 2.798 (2) A?.
Carbonylation of methanol to acetic acid using homogeneous Ru complex catalyst
Kelkar, Ashutosh A.,Kolhe, Devidas S.,Chaudhari, Raghunath V.
, p. 111 - 116 (1992)
Carbonylation of methanol to give acetic acid catalysed by Ru complexes such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2 and H2Ru(CO)(PPh3)3 is reported.The highest activity and selectivity were obtained with H2Ru(CO)(PPh3)3 as the catalyst precursor.Hydrogen increases the activity and selectivity of catalysts such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2, but has no influence on the activity and selectivity in the case of H2Ru(CO)(PPh3)3.
Mechanistic Studies on Initial C-C Bond Formation in the Zeolite ZSM-5 Catalysed Methanol Conversion Reaction: Evidence against a Radical Pathway
Hunter, Roger,Hutchings, Graham J.,Pickl, Wolfgang
, p. 843 - 844 (1987)
The behaviour of the methoxymethyl radical in the gas phase has been studied and the results provide strong evidence against a radical mechanism for the title reaction.
C-C Bond Formation from Dimethil Ether via a Radical Mechanism in the Presence of Strong Acid
Choukroun, Henri,Brunel, Daniel,Germain, Alain
, p. 6 - 7 (1986)
The selective radical dimerization of dimethyl ether by peroxodisulphuryl difluoride in fluorosulphuric acid, suggests that a radical intermediate for initial C-C bond formation in the conversion of methanol into hydrocarbons is a possibility.
Synthesis, characterization and properties of carbon nanotubes microspheres from pyrolysis of polypropylene and maleated polypropylene
Zhang, Junhao,Du, Jin,Qian, Yitai,Xiong, Shenglin
, p. 15 - 20 (2010)
Microspheres assembled from carbon nanotubes (MCNTs), with the diameters ranging from 5.5 to 7.5 μm, were synthesized by means of pyrolysis of polypropylene and maleated polypropylene in an autoclave. The characterization of structure and morphology was carried out by X-ray diffractometer (XRD), field-emission scanning electron microscopy (FESEM), (high resolution) transmission electron microscope [(HR)TEM)], selected-area electron diffraction (SAED) and Raman spectrum. As a typical morphology, the possible growth process of MCNTs was also investigated and discussed. The results of nitrogen adsorption-desorption indicate that the Brunauer-Emett-Teller (BET) surface area (140.6 m2/g) of the MCNTs obtained at 600 °C is about twice as that (74.5 m2/g) of carbon nanotubes obtained at 700 °C. The results of catalytic experiment show that MCNTs based catalyst has higher catalytic activity than the carbon nanotubes based catalyst for the preparation of methanol and dimethoxy-ethane by oxidation of dimethyl ether.
Visualizing Element Migration over Bifunctional Metal-Zeolite Catalysts and its Impact on Catalysis
Cheng, Kang,Wang, Genyuan,Wang, Ye,Wang, Yuhao,Zhang, Qinghong,de Jong, Krijn P.,van der Wal, Lars I.
, p. 17735 - 17743 (2021)
The catalytic performance of composite catalysts is not only affected by the physicochemical properties of each component, but also the proximity and interaction between them. Herein, we employ four representative oxides (In2O3, ZnO, Cr2O3, and ZrO2) to combine with H-ZSM-5 for the hydrogenation of CO2 to hydrocarbons directed by methanol intermediate and clarify the correlation between metal migration and the catalytic performance. The migration of metals to zeolite driven by the harsh reaction conditions can be visualized by electron microscopy, meanwhile, the change of zeolite acidity is also carefully characterized. The protonic sites of H-ZSM-5 are neutralized by mobile indium and zinc species via a solid ion-exchange mechanism, resulting in a drastic decrease of C2+ hydrocarbon products over In2O3/H-ZSM-5 and ZnO/H-ZSM-5. While, the thermomigration ability of chromium and zirconium species is not significant, endowing Cr2O3/H-ZSM-5 and ZrO2/H-ZSM-5 catalysts with high selectivity of C2+ hydrocarbons.
Decomposition of Methanol to Syngas over AlPO4-Supported Nickel Catalyst
Tada, Akio,Yoshino, Takumi,Itoh, Hidenobu
, p. 419 - 422 (1987)
An AlPO4-supported nickel catalyst exhibited significantly higher activity and selectivity for the title reaction than such conventional catalysts as Ni/Al2O3, Ni/SiO2, Ni/TiO2, and CuO-ZnO-Cr2O3.The effects of Ni loading and temperatures of reduction and reaction on its catalytic property were also investigated.
