Preparação de catalisadores de cobalto suportados sobre material mesoporoso da família M41S.

Abstract

The Fischer-Tropsch Synthesis (FTS) permits the synthesis of hydrocarbons by catalysis at elevated temperatures and pressures by passing synthesis gas through an adequate reactor. Actually mesoporous materials such as MCM-41 and MCM-48 are available, wich possess elevated porous surfaces able to accommodate metal catalysis for the FTS. The preparation of these mesoporous structures in the form of silica spheres can be done by a modified Stober synthesis, wich permits to control the medium sphere diameter. The synthesis of this material follows the steps: reaction, drying, calcination, besides a further inoculation of cobalt nitrate dissolved in ethanol, mediated by ultra-sound. After the calcination the samples were cooled in desiccator over silica. The characterization of the catalysis were done by XRD, EDX laser granulometry and physisorption of nitrogen for the determination of the surface area (BET) and permits us the conclusion, that the method allows the successful preparation of catalysis of the MCM-48 type containing five, ten and fifteen weight percent(5%,10% and 15%) of cobalt finely dispersed on the catalyst surface. Anyway, the same charaterization has show that the preparation of the equivalent MCM-41 type has not occurred and that the incorporation of cobalt contents lower than 15% results in the decrease of the mesoporous material organization.