MARINHO, J. C.; http://lattes.cnpq.br/1029505875404349; MARINHO, Janaína Constantino.
Resumo:
The present study aimed to prepare mesoporous molecular sieves SBA-15 and AlSBA-15
with Si/Al ratios of 10, 25, 50, 75 and 100 and use them in the
transesterification of soybean oil with ethanol for production biodiesel. The
catalysts SBA-15 and Al-SBA-15 (Si/Al=10) were selected and tested on reaction
to produce ethyl ester, monoglycerides, diglycerides and glycerol. The
hydrothermal method under static conditions, was used to synthesize the
molecular sieve SBA-15. The mesoporous sieve Al-SBA-15 was prepared by
direct synthesis method in SBA-15, and the alumina source used was
pseudoboehmite (AlOOH). All samples were characterized in concerning to its
structure and texture by XRD and N2 physical adsorption. Moreover, they were
characterized by TG/DTA, SEM, FTIR. The acidity generated from aluminum
incorporation into the structure of SBA-15 was evaluated by TPD-NH3. The
transesterification reaction of soybean oil was carried out in a batch reactor,
without stirring, for reaction times of 6, 12, 24 and 48 hours at 200 °C using a 12:1
oil/ethanol relation and 5% of the catalyst (SBA-15 e Al-SBA-15 (10)). The reaction
products were characterized by Kinematic Viscosity and Gas Chromatography.
The success of the synthesis of molecular sieves SBA-15 and Al-SBA-15 were
observed for all the techniques used. All the materials were obtained with a high
hexagonal ordering degree, demonstrated by XRD, showed aspects of vermicular
type with intertwined necklace appearance, visualized by SEM and showed
isotherm with type IV profile, which is a characteristics of mesoporous material.
The result of the kinematic viscosity obtained for SBA-15 with 48 hours of reaction
(6.49 mm2/s) is close to the range of values obtained by the National Petroleum
standard, Natural Gas and Biofuels (ANP) and the international standards of
biodiesel ASTM D6751-02 and EN 14214. And the value of kinematic viscosity for
Al-SBA-15 (10) with 48 hours of reaction (10.43 mm2/s) is out of the standards
range. The selected catalysts (SBA-15 and Al-SBA-15 (10)) was subjected to
transesterification reaction of soybean oil with ethanol and the Al-SBA-15 (10)
catalyst was more efficient than the SBA-15. The conversion value for the Al-SBA15
catalyst (10) was 96.50%.