Heterogeneous Catalysis with Zeolites, Sulphides and Metals

Abstract

Zeolitic materials with sufficiently narrow pores for shape-selective reactions are developed which do not suffer from the diffusional side effects of narrow pores, such as a high Thiele modulus, a low effectiveness factor, and pore blocking by side reactions. The diffusional limitations are remedied by the creation of mesopores through dealumination and desilylation of the zeolites by acids and complexing agents. The removal of nitrogen from N-containing aromatics takes place via a complex network of hydrogenation, hydrogenolysis and N-elimination reaction steps. To investigate the catalytic sites at which these steps take place, the kinetics of the hydrodenitrogenation of model compounds such as pyridine, piperidine, quinoline, decahydroquinoline and aniline is studied at elevated temperature and pressure in plug flow reactors. The mechanism of the formation of methanol from carbon monoxide and hydrogen at medium high pressure is studied in a plug flow reactor, as well as in a combination of a medium high pressure reactor with a surface science apparatus comprising X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Experiments in plug flow equipment have shown that the methanol formation is only formed over Pd and Rh catalysts when the catalyst is doped with earth alkali metals.