Síntese do catalisador ácido molibdofosfórico suportado em zircônia sulfatada e magneticamente recuperável visando a valorização de compostos derivados da biomassa lignocelulósica

Abstract

The impacts associated with excessive use of energy derived from non-renewable sources transcend the discussion of possible exhaustion and are strongly aligned with the possibility of an environmental imbalance. In this way, the interest in the production of fuels from natural and renewable sources grows strongly throughout the globe. In this directenvironmentalsting paths for sustainable fuel growth and development is through the use of lignocellulosic biomass as the raw material. Lignocellulosic biomass represents a high interest due to the possibility of being converted into sugars which, in turn, proceeds through reactions catalyzed by acid - Lewis and Brønsted - to provide products such as furfural (FUR), 5-hydroxymethylfurfural (HMF), levulinic acid (LA), alkyl levulinate, gamma-valerolactone (GVL) and derivatives thereof. These compounds are considered platforms molecules of great industrial and academic interest. Therefore, it is of great importance the research of new materials with acidic characteristics, which are able to promote these transformations.The molybdophosphoric acid (MoP) is a heteropolyacid that has associated protons, presenting high Brønsted acidity and, consequently, emerges as an interesting catalyst in the valorization of compounds derived from lignocellulosic biomass. In this work, a catalyst composed of molybosphoric acid supported in magnetically recoverable sulfated zirconia was synthesized, which should be characterized by techniques such as X-ray diffraction (XRD), programmed temperature desorption of ammonia (TPD-NH3), transform infrared spectroscopy of Fourier with adsorption of pyridine (FTIR-py), quantum interference superconducting device (SQUID), X-ray photoelectron spectroscopy (XPS), 31P nuclear magnetic resonance, transmission electron microscopy (TEM), and high transmission electron microscopy resolution (HR-TEM). Properly characterized, they were evaluated the conversions of the compound derived from lignocellulosic biomass to alkyl levulinates. In the catalytic evaluation, it was necessary to optimize the catalyst through the influence of fundamental parameters such as temperature, catalyst mass, molar ratio between the substrate and solvent, and water influence in order to obtain the ideal conditions and the products of this reaction analyzed by gas chromatography coupled with mass spectrometry (GC-MS).