Isomerization of n-alkanes derived from jatropha oil over bifunctional catalysts

Several Pt catalysts with various solid acid supports (SAPO-11, Al-SBA-15, and Al2O3) and various SAPO-11 supported active metal (Pd, Ni, Ru, Pt) catalysts were prepared and characterized using BET, XRD, XRF, CO pulse adsorption, and NH3-TPD techniques. Their catalytic performances in isomerization of hydrodeoxygenated jatropha oil were carried out using a fixed bed flow reactor system. All Pt/SAPO-11, Pt/Al-SBA-15, and Pt/Al2O3 catalysts showed high catalytic activity for isomerization of n-alkanes with long carbon chain. Especially over Pt/SAPO-11 catalyst, a high yield of iso-C10–18 up to 79.4% was obtained, which was attributed to the absence of strong acidic sites of Pt/SAPO-11 catalyst. With an increase in reaction temperature, Pt/SAPO-11 catalyst still showed a high ratio of monobranched iso-C10–18 to multibranched iso-C10–18, presumably because of its ordered microporous structure, which suppresses formation of multibranched product. The catalytic activity of SAPO-11 catalysts containing various active metals decreased in the order of Pt/SAPO-11 > Pd/SAPO-11 > Ni/SAPO-11 > Ru/SAPO-11, which might be attributable to the difference of hydrogenation–dehydrogenation activity of these metals.

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► Catalytic activity of support decreased in the order of SAPO-11 > Al2O3 > Al-SBA-15.
► Catalytic activity of metal decreased in the order of Pt > Pd > Ni > Ru.
► High performance of SAPO-11 support was due to its weak acids and shape selectivity.