Hydroisomerization of n-butane over Pd/HZSM-5 and Pd/hmordenite with and without binder

The influence of a clay binder (bentonite) on the acid properties and performance of Pd/HZSM-5 and Pd/HM catalysts with different Si/Al ratios for the hydroisomerization of n-butane has been studied. Temperature-programmed desorption of ammonia, atomic absorption spectroscopy, chemisorption and surface area measurements were used to characterize the catalysts. After agglomeration, some zeolite protons are neutralized by clay sodium and, consequently, a lower n-butane conversion is obtained. However, the decrease in conversion will be compensated by a much higher isobutane selectivity. The product selectivity is also strongly influenced by the binder due to the fact that zeolite hydrogen transfer activity, metal/acid site balance, and diffusion of products are modified. The isomerization activity for Pd/HZSM-5 samples were higher than for Pd/HM catalysts due to mordenite is expected to be more sensitive to the increased in the length of the effective diffusional pathway due to its one-dimensional pore structure.