SILVA, A. S.; http://lattes.cnpq.br/4286135071988899; SILVA, Adriano Sant'Ana.
Resumo:
Biodiesel is a biofuel produced from renewable sources such as vegetable oils and
animal fat, which was proposed as an alternative to petroleum diesel. Typically, this
biofuel is made from soybean oil, by transesterification with alkaline homogeneous
catalysts that at the end of the reaction are not reused and still require refined oil.
Thus, the use of heterogeneous catalysts has been increasingly in industry by the
possibility of its reuse and for allowing the use of different lipid sources. Furthermore,
the search for low cost lipid sources, such as cottonseed oil, has become the current
focus of several studies. Therefore, the objective of this thesis was to synthesize,
characterize and evaluate the catalysts M0O3-MCM-41 and NiO-MCM-41 in ethyl and
methyl, transesterification and esterification reactions of cottonseed oil, using a static
reaction system. The support MCM-41 was obtained by synthesis at room
temperature. The catalysts were synthesized by the method of physical dispersion in
three different concentrations (1, 3 and 5% in weight) and were characterized by
XRD, FTIR, EDX and textural analysis. Through a 23 factorial design the effects of
independent variables: temperature, molar ratio of oil: the percentage of alcohol and
catalyst on the dependent variables éster and triglycerides in the transesterification
reaction, were evaluated. In the esterification reaction the effects of these variables
on the conversion of free fat acid was evaluated. The characterization results
indicated that the hexagonal phase of MCM-41 was obtained and the procedure of
physical dispersion of the oxides was viable for the synthesis of the catalysts under
study. In the catalytic tests the catalyst 5%Mo03-MCM-41 showed the best results for
the methyl and ethyl transesterification and for methyl esterification, with conversion
of about 53, 48.1 and 78.7%, respectively. For the reaction of ethyl esterification, the
catalyst 3%MoC«3-MCM-41 showed the highest conversion, about 67.9%. The
catalyst NiO-MCM-41 showed no catalytic activity. The temperature, according to the
experimental design, was the variable that most influenced the reactions.