The influence of solvent on the performance of Pt–Sn/θ-Al2O3 propane dehydrogenation catalyst prepared by co-impregnation method

The effect of the solvent used for the preparation of Pt–Sn/θ-Al2O3 catalysts via impregnation method on the properties of the catalyst was studied. The catalysts were prepared by co-impregnation of alumina support with the acidic solutions of H2PtCl6 and SnCl2 using water, ethanol and acetone as the solvents. The performance tests for propane dehydrogenation were carried out in a fixed-bed quartz reactor. It was found that the catalyst prepared in ethanol gives the highest propylene yield which can be attributed to the higher active metal dispersions. This could be explained in terms of the structure and boiling point of the solvent employed, as well as, the stability of complex formed in different solvents. The activity of the catalysts decreased in the order ethanol > water > acetone. However, regarding catalyst stability, the order was water > ethanol > acetone. A kinetic model was used to quantify and compare the activity and stability of the catalysts. The rate constants of reaction and deactivation of ethanolic catalyst were determined, respectively, as 9.3 m3/(kg.h) and 0.024 h− 1 at 620 °C. With a lower platinum content, the catalyst prepared in ethanol showed similar performance to that of the reference commercial catalyst.

► Pt–Sn/Al2O3 catalysts can be prepared by co-impregnation with different solvents. ► Solvent used strongly effects catalyst performance in propane dehydrogenation. ► The order of catalyst activity is ethanol > water > acetone. ► The order of catalyst stability is water > ethanol > acetone. ► The rate constant of ethanolic catalyst was determined as 9.3 m3/(kg.h) at 620 °C.