Decarboxylation of Oleic Acid over Ordered Mesoporous Pt/SAPO-11

Ordered mesoporous SAPO-11 molecular sieves (OMSMS) with a single mesoporous structure were prepared via a one-step hydrothermal method. Metal-acid bifunctional Pt/SAPO-11 (Pt/OMSMS-700) catalysts with Pt loadings of 1% and 2% were synthesized by a deposition-precipitation method using OMSMS-700 as a carrier. The OMSMS and Pt/OMSMS-700 were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (N-2-BET) analysis, and X-ray powder diffraction (XRD). TEM and small-angle XRD results revealed that the degree of order in the OMSMS increased as the calcination temperature increased from 500 to 700 degrees C. The N-2-BET analysis revealed that the OMSMS had a mesoporous structure with an average pore diameter of 6.4-7.8 nm and a BET surface area of 149-171 m(2)/g. The sizes of the Pt nanoparticles supported on OMSMS-700 were in the range of 3 to 6 nm and displayed good dispersibility. The catalytic performance of Pt/OMSMS-700 during the decarboxylation of oleic acid to form C8-C17 alkanes under a CO2 atmosphere was investigated. As the reaction temperature increased from 320 to 360 degrees C, the total yield of C8-C17 alkanes initially increased and then decreased. Increasing the Pt loading led to an increased yield of C8-C17 alkanes. The total yield of C8-C17 alkanes reached 78% when 2 wt % Pt/OMSMS-700 was used at 340 degrees C for 3 h.