ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Gravimetric Study of the Dynamics of Adsorption and Desorption of Ammonia on  γ-Alumina

A. Gáliková and A. Gálik

Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, CZ-165 02 Prague

E-mail: galikova@icpf.cas.cz

Abstract: In the earlier study of the adsorption of propylamines on alumina it was suggested that the catalytic decomposition of propylamines on gamma-alumina accompanied by stop-effect involves the blockage of the adsorbing centres by ammonia and by propylene formed. The present work contributes to the elucidation of this complex phenomenon by the study of the adsorption of ammonia on γ-alumina, using electronic recording microbalances CAHN D-200. The kinetic model was suggested, taking into account that the ammonia molecule may be bound to basic centres by one, two, and even by three hydrogen bonds consecutively, and to the acidic centres by its lone electron pair on the nitrogen atom. This model has been used for the evaluation of the experimental data. The fitting of the model to the isothermal parts of the adsorption-desorption curves was joined with the deconvolution of the temperature-programmed desorption data. The results suggest that ammonia occupies both acidic and basic sites during the desorption stage, so supporting the previous assumptions.

Full paper in Portable Document Format: 544a210.pdf

Chemical Papers 54 (4) 210–214 (2000)