Síntesis y caracterización fisicoquímica de circonia promovida con ácido tungstofosfórico y ácido bórico utilizada como catalizador en la isomerización de n-pentano

In this work it is presented the preparation, characterization and evaluation of the catalytic activity of materials such as ZrO₂ promoted with tungstophosphoric and boric acids. Zr(OH)₄ was synthesized by the sol-gel method using precursors such as zirconium n-butoxide and 1-butanol maintaining a pH = 8 during the synthesis. Zr(OH)₄ was impregnated with 15 wt % of the acid agents, calcined at 600°C and impregnated again with 0,5 wt% of platinum. It was observed that the [PW ₁₂O₄0]^3- and [BO₃]^3- ions remained firmely attached to the ZrO₂ surface inhibiting the particle growth and delaying the syntherization of the material and the apparition of the monoclinic phase. Also, with the incorporation of these dopping agents, the total acidity of the material increased specially the amount of strong acid sites being this type of sites the most abundant in the acidified samples. Acidity developed by the materials was adequate to catalyse the isomerization reaction of n-pentane with conversions above 20% and selectivities toward isopentane in the order of 90%.