Matias Kangas

On the way to improve cetane number in diesel fuels: Ring opening of decalin over Ir-modified embedded mesoporous materials

Embedded materials prepared from MCM-41 together with BE or TON were synthesized, characterized and tested in the ring opening of decalin in a temperature range of 523–623 K. The characterization results revealed that both microporous and mesoporous phases were present in the catalyst. Ir-modification did not change the phase purity, affecting, however, the acidity due to metal-support interactions. The parameters studied in ring opening of decalin were support structure, presence of Ir and temperature. The detailed analysis of 2D/3D isomers and ring opening products showed that the main ring opening products contained ethyl side chain. The Ir-modified embedded mesoporous catalysts were active and relatively selective in the ring opening of decalin, giving 35% selectivity to the ring opening products at 98% conversion at 573 K and 6 MPa.

Lipase-catalyzed acylation in a continuous down-flow fixed-bed reactor

The kinetic resolution of racemic 1-phenylethanol with ethyl acetate was investigated in a down-flow fixed-bed reactor operated in a continuous mode mainly at the molar ratio of 1: 3 in 400 mL toluene at 70°C. The catalytic activity of the immobilized lipase was studied by: (i) changing the flow rates, (ii) utilizing different substrate concentrations, (iii) applying step changes using ethyl acetate, ethyl benzene, acetic acid, acetophenone etc., (iv) investigating the inhibitory effect of either the desired or the stoichiometric products (R)-1-phenylethyl acetate and ethanol, respectively), (v) elucidating the effect of water on the activity and stability of the immobilized lipase. The residence time distribution and the reactor hydrodynamics were also discussed along with kinetic modelling. The results were linked to the one-pot reactions.

An integrated approach to modelling of chemical transformations in chemical reactors

An integrated approach to the modelling of chemical reactors, particularly catalytic ones is presented. The modelling approach starts from quantum-chemical calculations, mechanistic hypothesis, derivation of kinetic expressions in order to achieve an appropriate kinetic model. The model parameters are determined by regression analysis and the complex behaviour of fixed bed reactors, including catalyst deactivation is described in an adequate manner. A general flowsheet for the procedure is proposed.

Kinetics and phase equilibria of competing aldolization and elimination in a three-phase reactor

Abstract Butyraldehyde was aldolized with formaldehyde over a weakly basic anion-exchange resin catalyst in aqueous solvent in a batch reactor operating at atmospheric pressure and at temperatures 50–70°C. The reaction mixture was a liquid–liquid–solid system, an emulsion, the phase equilibria of which were studied through chemical analysis of the organic and aqueous phase as well as of the mixed emulsion. Simplified rate equations were derived starting from molecular reaction mechanisms on the catalyst surface. A liquid–liquid reactor model for the fitting of the experimental results was developed on the basis of the rate equations and the phase equilibria. The model described very well the experimental data.

A Chemical Engineering Approach to Cellulose Substitution Kinetics

A general kinetic model for the substitution of cellulose was developed. The model assesses the differences in the reactivity of the cellulose hydroxyl groups and a decrease in the reactivity as the substitution proceeds. The model predicts the detailed distribution of the different mono (2, 3, 6)-, di (23, 26, 36) – and trisubstituted (236) units as a function of the reaction time. The classical Spurlin distribution is obtained as a special case of the general model. Numerical strategies were developed for the solution and computer simulation of the model. Simulation results were shown to be valid for various reactivity ratios of the hydroxyl groups. The modelling concept was verified with experimental data obtained for carboxymethylation of cellulose in a slurry reactor. The detailed data, which revealed the non-uniform reactivities of the different hydroxyl groups and the decline of the substitution rate with time, were successfully described by the mathematical model.