Four different types of shaped catalysts with controlled deposition of platinum and the same composition were prepared by extrusion of beta zeolite agglomerated with bentonite as an aluminosilicate clay binder. The catalysts were characterized using mechanical strength tests; scanning electron microscopy for morphology; transmission electron microscopy for porosity and periodicity; nitrogen physisorption for surface area, pore volume, and pore size distribution; and Fourier transform infrared spectroscopy using pyridine as a probe molecule to elucidate the presence, strength, and amount of Brønsted and Lewis acid sites. Elemental analysis was carried out using energydispersive X-ray microanalysis. Activity and selectivity of catalysts in the isomerization of n-hexane were evaluated using a fixed bed reactor at 200−350 °C. At low temperature, the performance of metal/acid bifunctional shaped catalysis was strongly affected by the metal-to-acid site ratio. This ratio and the total acidity were strongly influenced by the preparation method of the shaped catalysts, while the textural properties were comparable. The highest conversion of n-hexane and selectivity to C 6 isomers (comprising all branched isomers, such as methyl pentane and dimethylbutane) was obtained with extrudates prepared via in situ synthesis with platinum located on the zeolite. The extrudates prepared in this way have the highest metal-to-acid site ratio and their closest proximity, albeit the lowest mechanical strength.

Composite materials for shaped catalysts were prepared from three commercial beta zeolites using bentonite as an aluminosilicate clay binder.

Continuous cyclization of citronellal over zeolite-based extrudates was performed in a trickle-bed reactor at 35−70 °C and 10 bar of argon. Catalytic results were correlated with the physicochemical properties of the shaped catalyst prepared by extrusion of β or Y zeolites with binders. Rheological tests were used to elucidate the flow properties of a catalytic slurry and relate them with the extrusion performance. This study revealed that application of methylcellulose and bentonite binder modified the textural and acidic properties of the final extrudates. The main product was (−)-isopulegol at all temperatures with selectivity remaining quite constant with time-on-stream. The results illustrated that a binder such as bentonite cannot be considered inert. The mass-transfer limitations observed in extrudates did not significantly influence selectivity to the desired pulegols. This study also showed that a direct transfer of the batch reactor data to industrial continuous operation in citronellal cyclization is not straightforward.

One-pot menthol synthesis in a trickle bed reactor was investigated using Ru/H-beta-300 extrudates without any binder and Pt- and Ru/H-beta-25 extrudates containing 30 wt% bentonite binder using different methods of metal loading on the extrudates.