Estudo da reação de desoxigenação do ácido esteárico em meio aquoso sob catalisadores Pd-Ni suportado em NbOPO4

Abstract

The main objective of this work was to evaluate monometallic and bimetallic catalysts Nickel (Ni) and Palladium (Pd) on the support Niobium Phosphate (NbOPO4) in the deoxygenation reaction of Stearic Acid (AE) in aqueous-phase. The catalysts were prepared by wet impregnation. The NbOPO4 support was calcined (500 °C, 4 h) and subsequently impregnated with the metals under study using a rotoevaporator. The precursors used were Nickel Chloride (NiCl2.6H2O), Palladium Chloride (PdCl2) and Tetraaminapalladium (II) Nitrate [Pd(NH3)4].(NO3)2. After impregnation the catalysts underwent vacuum drying (120 °C, 40 min) and calcination (300 °C, 4 h). Textural properties as surface area by N2 isotherms (BET) and mainly surface characteristics by temperature programmed reduction and temperature programmed desorption at CO were analyzed. The catalytic deoxygenation tests of stearic acid were carried out in a 500 ml batch reactor at 250 °C and under 50 bar pressure for 3 h and 30 min after in situ activation of the catalyst. The conversion of stearic acid varied from 17.75 to 35.24% and followed the following order: 1%Pd10%Ni/NbOPO4 > 1%Pd/NbOPO4 - PdCl2 > 1%Pd/ NbOPO4 - Pd(NH3)4.(NO3)2 > 10%Ni/NbOPO4 demonstrating that the catalyst activity can be improved using a bimetallic catalyst.