Results 131 to 140 of about 614 (173)

Crystal and magnetic structure of copper chromite

Acta Crystallographica, 1957
Copper chromite, CuCr~O 4, is a tetragonally distorted normal spinel with a c/a ratio, as referred to a face-centered unit cell, of about 0.91. A structure which is physically reasonable, belonging to the space group D~-I42d, is based on an environment for the copper ions which is distorted from a tetr~hedron toward a square, and also slightly rotated ...
openaire   +1 more source

Study of copper chromite catalysts, III. Structure and catalytic activity of copper chromite catalyst in reductive alkylation reaction

Reaction Kinetics and Catalysis Letters, 1986
The catalytic activity of copper chromite catalysts prepared by thermal decomposition reaction of basic copper(II) ammonium chromate, CuCrO4[Cu(OH)2]0.17−(NH4OH)0.78, and copper(II) chromate CuCrO4, has been studied. The catalysts with highly disordered structure, prepared from basic copper(II) ammonium chromate at 270–320 °C, show the highest ...
F. Hanic, G. Plesch, P. Dolezel, J. Ovecková   +3 more
openaire   +1 more source

Characterization of copper chromite catalysts for methanol dehydrogenation

Applied Catalysis, 1984
Abstract Copper chromite catalysts have been characterised by total and metal surface areas. X-ray powder diffraction, thermal gravimetric analysis and selective extraction of copper oxide in order to investigate the nature of the active catalyst for methanol dehydrogenation.
S.P. Tonner, M.S. Wainright, D.L. Trimm, N.W. Cant   +3 more
openaire   +1 more source

Nanometer size copper particles in copper chromite catalysts

1995
Publisher Summary It is difficult to obtain copper in atomic state on the surface of an oxide catalyst. Therefore, the task of achieving metallic copper with a large surface area becomes crucial. Highly dispersed copper can be obtained on the surface via the reduction of copper-containing oxides.
openaire   +1 more source

A study of the preactivation of a copper chromite catalyst

Catalysis Letters, 1994
Copper chromite was studied for the reductive alkylation of aniline with acetone to N-isopropylaniline as a function of the catalyst prereduction conditions. In order to optimize prereduction conditions the catalyst was reduced in an atmosphere of hydrogen at different temperatures: 100, 150, 200, 250, 300, 350, 400 and 450°C and for different ...
openaire   +1 more source

Sintering of lanthanum chromite doped with zinc or copper

Journal of Materials Science Letters, 1988
La substitution de Zn ou Cu a Cr dans LaCrO 3 permet l'obtention de ceramiques denses sans controle de la pression d'oxygene lors du ...
Shinsuke Hayashi, Kenji Fukaya, Hajime Saito   +2 more
openaire   +1 more source

Synthesis and Characterization of Magnesium Copper Chromite Spinels

International Journal of Scientific Research, 2012
Various composition of copper magnesium chromite spinels (Cu1-x MgxCr2O4 with x=0, 0.25, 0.5, 0.75, 1.0) were synthesized by co-precipitation method. The catalysts were characterized by various Physico-chemical methods XRD, nitrogen adsorption studies, FT-IR spectroscopy, Thermogravimetric analysis (TG), UV-DRS and Temperature Pro- grammed Desorption ...
Reni George, Sankaran Sugunan
openaire   +1 more source

Methane combustion over copper chromite catalysts

Catalysis Letters, 1997
A study of the activity and durability of two different copper chromite catalysts in methane combustion is presented. The catalysts, a massive (CAT-E) and a supported (CAT-I) copper chromite, were characterized by different techniques in order to investigate morphological properties (N2 adsorption), crystalline structure (X-ray diffraction, XRD) and ...
G. Comino, A. Gervasini, V. Ragaini, Z. Ismagilov   +3 more
openaire   +1 more source

Properties of Copper Chromite Catalysts in Hydrogenation Reactions

Journal of Catalysis, 1997
Abstract A pretreatment involving a 4-h reduction under H2at 573 K, compared to either 473 or 673 K, gave the highest specific activity for furfural and crotonaldehyde hydrogenation over an unpromoted copper chromite catalyst. Both H2and CO chemisorption declined monotonically with increasing reduction temperature, but turnover frequencies also ...
R. Rao, A. Dandekar, R.T.K. Baker, M.A. Vannice   +3 more
openaire   +1 more source

Crystal Distortion in Copper Ferrite-Chromite Series

Journal of the Physical Society of Japan, 1961
The cation distributions in copper ferrite-chromite series and the copper ferrite quenched from high temperatures are measured by X-ray diffraction method. The lattice parameters are also measured as a function of chromium ion content and of temperature.
Haruyuki Ohnishi, Teruo Teranishi
openaire   +1 more source