Neste trabalho são apresentados a preparação de novos materiais obtidos da co-precipitação de alumina e óxidos de estanho e zinco e seu uso como sistemas catalíticos ativos para alcoólise de óleos vegetais. Foi observado que estes óxidos metálicos do tipo (Al 2 O 3 ) X (SnO) Y (ZnO) Z são ativos para a alcoólise do óleo de soja usando diversos álcoois, incluindo ramificados. Os melhores resultados foram observados utilizando metanol, sendo atingidas conversões acima de 80% em 4 horas. Foi também possível reciclar estes materiais sem perda aparente de sua atividade catalítica.The preparation of new materials obtained from the co-precipitation of aluminum, tin and zinc oxides and their use as catalytic system activities for vegetable oils alcoholysis are reported herein. It was observed that these metal-oxides of the type (Al 2 O 3 ) X (SnO) Y (ZnO) Z are active for soybean oil alcoholysis, uzing several alcohols, including branched ones. Best result was achieved using methanol, with conversion yields up to 80% in 4 h. It was also possible to recycle the catalysts without apparent loss of activity.

2 O have been investigated as catalysts for the transesterification, esterification and pyrolysis of vegetable oils. The compounds were characterized by thermal analysis (DTA-TGA), spectroscopy (DRX, FT-IR and FT-Raman), surface area (BET) and the acidity (Ho) determined by n-butylamine titration using the Hammet´s indicator method. It was observed that after the acid treatment both the surface area and the acidity decreased as compared to the starting Nb 2 O 5 •xH 2 O. The only exception was a higher acidity verified when nitric acid was used. Among the catalyst investigated, the Nb 2 O 5 /H 3 PO 4 presented the highest activity in the alcoholysis of soybean oil with different mono-alcohols (methanol, ethanol, 2-propanol, n-butanol

The pyrolysis of vegetable oils consists of cracking triglycerides to produce smaller molecules. A mixture of hydrocarbons and oxygenated compounds, such as carboxylic acids and aldehydes, is obtained as the product and which can be separated by fractional distillation. When the reaction is carried out in the absence of catalysts (thermal cracking), a great quantity of these oxygenated compounds is obtained. Thus, the presence of those oxygenated compounds in the products results in a high level of acidity, which can be a problem when using them as fuels in combustion engines. The aim of this work was to study the composition of the products obtained by cracking of vegetable oils assisted by c-alumina doped with zinc and tin oxides. The products were analyzed by FT-IR, GC-MS and GC-FID and the acid number was determined by titration with alcoholic KOH solution. The acid number, infrared spectra and chromatograms of the resulting hydrocarbon mixtures indicated a significant reduction in oxygenated compounds when compared with the mixtures obtained by the thermal cracking process, thus decreasing the acidity of the mixture.