Produção de biocombustíveis por craqueamento fotoquímico de óleos vegetais utilizando imidas aromáticas suportadas em sílicas mesoporosas como sensitizadores

Resumo

Catalytic cracking is a key reaction in the petrochemical industry, allowing the conversion of high molecular weight hydrocarbons into low molecular weight fuel. Up to the years 1930, the cracking reaction was performed by thermal methods, but since then, with the introduction of the zeolites, which are microporous heterogeneous catalysts, catalytic cracking has become the most widely used method. More recently, it has been recognized that catalytic cracking of vegetable oils could be used to obtain biofuel, as an alternative to the transesterification reaction. The use of photochemistry in cracking reactions, however, has remained largely unexplored. In the present proposal, the development of photochemical catalysis as a method for the cracking of vegetable oils will be pursued, using principles of nanotechnology to design nanostructured photocatalytic systems. For this goal, aromatic imides, such phthalimides, 1,8-naphthalimides, 1,4,5,8-naphthalenediimides and 3,4,9,10-perylenediimides, will be employed as photosensitizers. Our group has great expertise in the photochemistry of these compounds. When excited by light, these compounds generate a variety of free radicals, which are expected to stimulate the cracking reaction, which is a radical chain reaction. The imides will be immobilized by covalent grafting onto the surface of silicates MCM-41 and SBA-15, which are mesoporous nanostructured materials synthesized in the presence of surfactant micelles. The modified particles will be irradiated with a UV lamp and with natural sun light, in the presence of different vegetable oils. Mesoporous materials with different loads of the organic dye will be tested, containing either a single imide or a mixture of different imides. (AU)