Pure and Applied Chemistry

Abstract: The catalysts that can efficiently hydro-reform higher n-paraffin to lower isoparaffins for environmentally friendly gasoline were studied. The catalysts were examined by the conversion of n-hexadecane, n-C₁₆H₃₄ to i-C₆H₁₄~i-C₁₂H₂₆. The tri-modally nanoporous (nanometer-size) catalysts composed of (Ni-Mo)/[γ-Al₂O₃], nano-oxide, and nanocrystalline zeolite have some active and selective performances because of the cooperation between (Ni-Mo)/[γ-Al₂O₃] and the composite of nano-oxide-nanozeolite. The (Ni-Mo)/[γ-Al₂O₃] component holding the skeletal isomerization activity enhances the cracking activity on the composite of nanoporous (np)-Al₂O₃-USY (ultra-stable Y-type zeolite) to result in i‑C₆H₁₄~i-C₁₂H₂₆ as the isomerization of n-hexadecane followed the cracking reaction. The catalyst composed of nanocrystalline BEA (beta-type zeolite) or MFI (ZSM-5-type zeolite) zeolite can be more activated with the nano-SiO₂ than with the nano-Al₂O₃. The catalyst composed of the dealuminated zeolite, USY (SiO₂/Al₂O₃ = 12) cannot be activated with the nano-SiO₂ but with the nano-Al₂O₃. This activation depends on the SiO₂/Al₂O₃ ratio of the USY. It is considered that the catalytic property of the three components is partially due to the novel active sites formed concertedly at the interface of the nano-oxides and the nanozeolites. The novel sites have a major role for the isomerization and cracking as the moderate and strong acids and are generated when Si-OH in the nanopores of the USY resulted from the dealumination catches Al-OH in the nano-Al₂O₃ to form Si-O-Al-O-Al-O-Si instead of Si-O-Al-O-Si-O-Si-O.