Hydrocarbons from ethanol using [Fe,Al]ZSM-5 zeolites obtained by direct synthesis

The search for new energy sources has impulsed hydrocarbon production from methanol and ethanol over ZSM-5 zeolites. Iron incorporation by different methods has led to a variety of chemical applications. Thus, hydrocarbon production from ethanol was evaluated using a [Fe,Al]ZSM-5 zeolite which was synthesized without nitrogenated templates, using ethanol and crystallization seeds and partially substituting iron for aluminium in the reaction mixture. Characterization was done by X-ray diffraction (XRD), Fourier-transform infra-red spectroscopy (FTIR), temperature programmed reduction (TPR), temperature programmed desorption of ammonia (TPD), nitrogen adsorption, electron paramagnetic resonance (EPR) and photoacoustic spectroscopies. Iron content in the synthesized samples varied from 0.02 to 1.82%. The obtained samples were used for the ethanol transformation, producing hydrocarbons from ethene to aromatics. Maximum production of liquid hydrocarbons was achieved with the zeolite with 0.5% iron. The procedure for obtaining the acid form of the zeolites, involving ammonium exchange and calcinations, has changed the iron species, probably with extraction from the structure, migration and agglomeration. (C) 2006 Elsevier B.V. All rights reserved.