In Situ X-Ray Diffraction Studies of Heterogeneous Reactions¹

Abstract

Dec., 19511% Situ X -R A Y DIFFRACTION STUDIES OF HETEROGENEOUS KEACTIONS 5635 lakes. The lakes formed by additlg a drop of a solution containing at least 0.2 mg./ml. of the respective dyes to a little solid palladium(I1) cyanide on a piece of filter paper are dark blue and red-pink, respectively. Hence it is easy to differentiate between drops of solutions which contain at least approximately 0.2 mg. of dye par milliliter.Palladium( 11) cyanide also forms adsorption complexes with many alkaloids. Dilute hydrochloric acid solutions of caffeine, theobromine, quinine, ephedrine and berberine were prepared which gave a turbidity on the addition of phosphomolybdic acid. About 5 ml. of these solutions was shaken with palladium(I1) cyanide and filtered. On the addition of phosphomolybdic acid, the solution remained clear, showing that the alkaloids were completely adsorbed by the palladium(I1) cyanide. Some of the caffeine adsorption complex with palladium( 11) cyanide was prepared by heating a suspension of the cyanide in an aqueous solution of caffeine. After drying the residue a t 110' the palladium content was found to be 52.5%. Thus in spite of its large molecular volume, caffeine forms the same type of adsorption complex as do the amines which have a smaller molecular volume. It is thus possible to concentrate alkaloids by forming adsorption complexes with palladium( 11) cyanide and decomposing the complex in a suitable manner.

The Reduction of Iron Ores

“…This diagram should be compared with the corresponding one, Fig. The more gradual increase of the critical partial pressure of the CO with increasing temperature given by 119. Fig.…”

Reduction Process of Iron Catalyst Precursors for Ammonia Synthesis Doped with Lithium Oxide

“…The authors' views on the direct reduction of magnetite to metallic iron are divided. Authors of the work [1], on the basis of "in situ" examinations carried out in a reaction chamber, made with the aid of XRD method, confirmed the presence of wustite after the reduction at a temperature of 413 • C. Other authors on the ground of chemical analysis and Mössbauer investigations [37,38] made the wustite formation impossible during the reduction of the magnetite precursor. Results of our research confirmed that magnetite was reduced to iron through the wustite phases.…”

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

“…The formation of wustite under conditions where wustite is metastable has been reported from magnetic measurements during reduction [106][107][108] and from X-ray powder diffraction [109] during reduction. Evidence against the formation of wustite has been reported from chemical analysis [110] and Mossbauer spectroscopic studies [27,111].…”