Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Polish Journal of Chemical Technology

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Effect of alkali metal promoters on catalytic performance of Co-based catalysts in selective hydrogenation of aniline to cyclohexylamine

Valeš Roman, Zapletal Martin, Krupka Jiří

Polish Journal of Chemical Technology

2023

Vol. 25, nr 1

1--7

In this study, a series of Co-based catalysts with alkali metal carbonate promoters were prepared to investigate the interrelation between promotion effect of these carbonates and catalytic performance for aniline hydrogenation to cyclohexylamine in vapour phase. The chemical promoters Li2CO3 and Na2CO3 leading to decrease in catalytic activity of cobalt catalysts for aniline hydrogenation. Catalysts with K2CO3 and Cs2CO3 loadings have practically no catalytic activity for hydrogenation of aniline. Results of TPD of aniline proved that presence of alkali metals carbonates restricts the adsorption of aniline on the surface of cobalt catalysts. Further, it was found that the addition of Na2CO3 greatly enhances the catalytic selectivity towards the cyclohexylamine and inhibits the consecutive reactions of cyclohexylamine leading to formation of by-products such as dicyclohexylamine and N-phenylcyclohexylamine.

Thermodynamic analysis on disproportionation process of cyclohexylamine to dicyclohexylamine

Valeš Roman, Dvořák Bohumír, Krupka Jiří

Polish Journal of Chemical Technology

2021

Vol. 23, nr 3

43--48

This work deals with a study of the effect of temperature on the cyclohexylamine disproportionation to dicyclohexy-lamine, conjointly with the thermodynamic analysis of this process. The laboratory experiments were carried out in a glass tubular continuous-flow reactor in a gaseous phase at the reaction temperature 433–463 K over a nickel catalyst. The results show, that the temperature has a trifing effect on equilibrium conversion of cyclohexylamine. However, temperature affects the formation of hydrocarbons, benzene and cyclohexane, and dehydrogenation products of dicyclohexylamine, i.e. N-cyclohexylidenecyclohexanamine and N-phenylcyclohexylamine. The latter one is the dominant product of dicyclohexylamine dehydrogenation. The disproportionation of cyclohexylamine has slightly exothermic character. At the experimental reaction temperature range, the cyclohexylamine disproportionation is spontaneous reaction and other reactions of this process are non-spontaneous.