This study presented results on reduction of alumina
supported chromium and platinum–chromium catalysts using temperature
programmed reduction method (TPR). It has been shown that catalysts after
earlier oxidation step but without calcinations one undergo reduction in lower
temperature in comparison to calcined only catalysts. Moreover, addition platinum
to Cr/Al2O3 catalysts also caused
decrease of reduction temperature. It has been observed that over the examined
catalysts oxidation CO to CO2 and reduction CO to CH4
occurs. However, on Pt–Cr catalysts both reactions proceed at lower
temperature compare to Cr catalysts.
Alumina supported Mo and Pt-Mo catalysts was subject to temperature
programmed reduction (TPR) using H2 and CO. After earlier
oxidation step TPR–H2 profiles shows different
surface species, which depends on the composition of the catalysts and reduction
temperature. Change in reducing gas from H2 into CO
results in significant changes in catalyst system. Hydrogen causes a decrease
in oxidation number of metals, while carbon monoxide reacts with chemisorbed
Authors:M. Gadzikowska, G. W. Jóźwiak, and M. Waksmundzka-Hajnos
The effect of conditioning the silica layer by mobile phase vapour or ammonia vapour on the retention of alkaloids eluted with non-aqueous mobile phases was examined. The effect of vapour phase composition on system efficiency, peak symmetry, and separation selectivity were also investigated. The most effective and selective systems were used for separation of the alkaloid fraction of Datura innoxia.
Authors:E. Styczeń, W. Jóźwiak, M. Gazda, D. Wyrzykowski, and Z. Warnke
Thermal decomposition of compounds consisting of tetrahalogenocuprate(II), [CuBrnCl4−n]2− (n=0–4) anions and a tetraethylammonium cation has been studied using TG-FTIR, TG-MS, DTA and DTG techniques. The measurements
were carried out in an argon and air atmospheres over the temperature range 293-1073 K. The products of the thermal decomposition
were identified by IR and Far Infrared (FIR) spectroscopy as well as X-ray powder diffractometry.