CARACTERIZAÇÃO E ATIVIDADE CATALÍTICA DE K₂CO₃/AL₂O₃ NA TRANSESTERIFICAÇÃO DO ÓLEO DE GIRASSOL COM AQUECIMENTO CONVENCIONAL E MICRO-ONDAS

CHARACTERIZATION AND CATALYTIC ACTIVITY OF K₂CO₃/Al₂O₃ IN THE TRANSESTERIFICATION OF SUNFLOWER OIL IN CONVENTIONAL AND MICROWAVE HEATING

Commercial and synthetic mesoporous aluminas impregnated with potassium carbonate were characterized by X-ray diffraction (XRD), nitrogen physisorption, infrared spectroscopy and ²⁷Al MAS NMR. The activities in the transesterification reaction of sunflower oil with methanol for biodiesel production were evaluated. ²⁷Al MAS NMR spectra evidenced the presence of Al^IV and Al^VI in the samples, and also of Al^V sites in the mesoporous synthesized alumina, which disappeared after impregnation with potassium salt followed by calcination. All aluminas containing potassium were active for biodiesel production from sunflower seed oil, with high conversions by both conventional heating and microwave irradiation.