A new approach to the determination of oxygen nonstoichiometry (δ) of MIEC oxides as a continuous function of pO2 at high temperatures was developed. The description of the model allowing one to distinguish the contribution of oxygen released from the samples to the partial pressure of oxygen at the outlet of the continuous-flow fixed-bed reactor after the stepwise change of the oxygen partial pressure of inlet gas from 0.2 to 10(-5) atm and to calculate the dependence of δ on pO2 is presented. The criterion for assessing the achievement of quasi equilibrium release of oxygen from the MIEC oxides is proposed. The adequacy of the method was confirmed by comparing the obtained and published data for well-studied SrCo0.8Fe0.2O3-δ and SrFeO3-δ MIEC oxides.

Alkali metal promoters have been widely employed for preparation of heterogeneous catalysts used in many industrially important reactions. However, the fundamentals of their effects are usually difficult to access. Herein, we unravel mechanistic and kinetic aspects of the role of alkali metals in CO2 hydrogenation over Fe‐based catalysts through state‐of‐the‐art characterization techniques, spatially resolved steady‐state and transient kinetic analyses. The promoters affect electronic properties of iron in iron carbides. These carbide characteristics determine catalyst ability to activate H2, CO and CO2. The Allen scale electronegativity of alkali metal promoter was successfully correlated with the rates of CO2 hydrogenation to higher hydrocarbons and CH4 as well as with the rate constants of individual steps of CO or CO2 activation. The derived knowledge can be valuable for designing and preparing catalysts applied in other reactions where such promoters are also used.

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In the present case study of tolazamide we illustrate how many seemingly contradictoryr esults that have been obtained from experimental observationsa nd theoretical calculationsc an finally startf ormingaconsistent picture: a" puzzle put together". For many years, tolazamide was considered to have no polymorphs. This made this drug substance unique amongt he large familyo fs ulfonylureas, which was known to be significantly more pronet op olymorphism than many other organic compounds. The present work employs ab road and in-deptha nalysist hat includest he use of optical microscopy,s ingle-crystal and powder X-ray diffraction,I Ra nd Ramans pectroscopies, DSC, semiempiricalP IXEL calculations and DFT of three polymorphs of tolazamide. This case study showsh ow the polymorphs of amolecular crystalc an be overlooked even if discovered serendipitously on one of numerous crystallizations, and how very different molecular packings can be practically isoenergetic but still crystallize quite selectively and transform one into anotherirreversibly upon heating.

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