Óxido de nióbio(v)/filossilicatos como catalisadores anfifílicos para a produção sustentável de biodiesel

Abstract

Biodiesel, a renewable biofuel produced from vegetable oils and animal fats, stands out as a sustainable alternative to fossil fuels. However, its production generates large volumes of glycerol as a by-product, the supply of which exceeds commercial demand, resulting in environmental and economic impacts. Materials with amphiphilic characteristics present themselves as efficient surfaces in different media, having additional advantages when incorporated into lamellar clay minerals. Among metal oxides, niobium has stood out for its catalytic properties and high availability. This work aimed to synthesize niobic acid compounds supported on vermiculite and bentonite, with amphiphilic properties, for application in the esterification of fatty acids and ketalization of glycerol. The compounds were prepared by the precipitation-deposition method, through three synthesis routes and using two different types of surfactants, cetyltrimethylammonium bromide and sodium dodecyl sulfate, and characterized by techniques such as Fourier transform infrared, Zero charge potential, Scanning electron microscopy, chemical composition analysis, hydrophobicity test, thermogravimetric analysis and dynamic light scattering. In esterification tests, conversion of up to 84% of oleic acid into butyl oleate was obtained, confirmed by FTIR and quantified by titration analysis. In the glycerol ketalization tests, the results reached 89.7% conversion. The best conversion percentages for both reactions occurred using catalysts oragnifilized with cetyltrimethylammonium bromide, via route 3. The results show that niobic acid compounds supported on amphiphilic clay minerals are promising for organic reactions of industrial interest, presenting environmental advantages such as the reuse of oils and fats, added value to glycerol residue, the replacement of mineral acids in addition to being produced with high-quality materials. low cost and high national availability.