Cyclization of pseudoionone (PI) to β-ionone is an important reaction used in the synthesis of vitamin A and in perfumery. Though the reaction is used for commercial production, its mechanism and kinetics are not known, and the same holds for the optimal performance of the process. This paper deals with experimental investigations of reaction mechanism and kinetics. The inherent characteristics of the reaction such as heat of reaction, thermal stability, and reactants/products distribution in biphasic (sulfuric acid-toluene) system was investigated experimentally. To overcome the mass transfer limitations, the intrinsic kinetics was studied in a batch reactor using a solvent (1-nitropropane) miscible with the reactant and the homogeneous catalyst. It was revealed that the reaction consists of two steps with the first being rapid, while the second is relatively slower. Therefore, the kinetics of only the second step was investigated which was observed to be first order with an activation energy of 65 kJ/mol.

Transient response method, temperature-programmed desorption (TPD), and a temporary analysis of products (TAP) reactor were used to study an inhibiting effect of water vapor in N2O decomposition to N2 and O2 over Fe−ZSM-5 catalysts with low iron content. The zeolites were activated in He at 1323 K for dehydroxylation and formation of active Fe(II) sites. At temperatures lower than 673 K the adsorbed water affects three main reaction steps involved in N2O decomposition, namely, N2O reversible adsorption, atomic oxygen (O)Fe loading from N2O, and oxygen desorption. The amounts of reversibly adsorbed N2O and (O)Fe loaded from N2O considerably decreased when water was preadsorbed on the zeolite. The oxygen recombination/desorption is the rate-determining step of N2O decomposition. During the TPD runs, oxygen desorption from the water-saturated catalyst as compared to the dry one took place at ∼300 K higher temperature. For the first time it was shown that water adsorption on the catalyst loaded with (O)Fe at 523 K induces the concomitant desorption of molecular oxygen. Moreover, the (O)Fe loaded on wet zeolite was shown to be inactive in CO oxidation, indicating transformation of active Fe(II) sites in the presence of N2O and H2O into an inactive Fe(III) hydroxylated form.

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Pressure and volume flow control is a non-trivial problem in the range of minute molar fluxes. Requirements with regard to precision, stability and flexibility go beyond the specifications of commercially available systems. The present concept offers a functional solution for flexible dosage of norm volume flows down into the lL flow range providing at the same time a suitable pressure control. Furthermore an opportunity for in situ calibration of capillaries concerning their length and inner diameter is introduced. The described setup, after calibration, provides the possibility to determine the unknown viscosity of gaseous mixtures, which are very sparsely found in literature.