CAVALCANTE, J. C.; http://lattes.cnpq.br/3333644619173869; CAVALCANTE, Jéssica Caroline Freitas.
Résumé:
The Industrial Revolution in the 18th century brought rapid development of production
techniques and new technologies. However, increased production and natural resource
consumption led to negative impacts such as air pollution and global warming. In this
context, countries are seeking to diversify their energy sources and reduce dependence
on fossil fuels for both environmental and energy security reasons. Among renewable
energy sources, biodiesel is considered the prime option. The most commonly used
technology for biodiesel production is transesterification, involving the reaction
between triglycerides and alcohol in the presence of a catalyst. Among heterogeneous
solid catalysts, molybdenum oxide (MoO3) incorporated into the mesoporous molecular
sieve MCM-41 stands out. The aim of this work is to evaluate biodiesel production via
methylation transesterification of corn oil using catalyst x_MoO3/MCM-41, determining
optimal reaction conditions through a 22+3PtCt factorial design. Initially, MCM-41
molecular sieve was obtained through a hydrothermal process and subsequently
activated by calcination to remove the structural template. Subsequently, the ammonium
heptamolybdate precursor was incorporated into the MCM-41 structure by pore volume
saturation, at percentages (by mass) of 10, 15, and 20%. MoO3 under the MCM-41
molecular sieve was obtained through calcination activation. Thermograms
demonstrated removal of the structural template and precursor salt decomposition.
Diffractograms identified MCM-41 structural phases and formation of the catalyst
structure with excessive MoO3. Adsorption/desorption isotherms revealed a
characteristic type IV profile of mesoporous materials, and textural properties indicated
MoO3 dispersion in MCM-41, affecting pore diameter. TPD demonstrated ammonia silica-molybdenum interaction, impacting catalyst acidity. The factorial design revealed
that using the 10% MoO3 catalyst at 175°C converted 86.9% of triglycerides in corn oil
into methyl esters. Density, viscosity, and acidity tended to align within established
parameters at temperatures above 150°C. Statistical analysis confirmed that the reactive
temperature variable significantly influenced the response factor (% of methyl esters),
being the most influential factor on the response variable.