Authors:Nataly Santos, Marileide Tavares, R. Rosenhaim, F. Silva, V. Fernandes Jr, Iêda Santos, and A. Souza
The growing petroleum deficit
requires the development of alternative fuel sources. Biodiesel is a good
alternative, as it is a biodegradable and renewable product, which obeys the
carbon cycle. In this work, the biodiesel from babassu was synthesized using
the methanol route, and characterized by physico-chemical analyses in order
to make able the investigated biodiesel to fulfill with its properties the
requirements of Brazilian National Agency for Petroleum, Natural Gas and Biofuel
(ANP). Besides gas chromatography, IR spectroscopy experiments and thermoanalytical
measurements in air and in nitrogen were done to determine the main thermal
decomposition processes and calorimetric events. The evaporation temperature
of babassu biodiesel was similar in both atmospheres, started around 52 in
air and around 60C in nitrogen.
Authors:A. Vasconcelos, M. Dantas, M. Filho, R. Rosenhaim, E. Cavalcanti, N. Antoniosi Filho, F. Sinfrônio, I. Santos, and A. Souza
The influence of drying processes in the biodiesel oxidation was investigated by means of the oxidative induction time obtained
from differential scanning calorimetry data. For this purpose, corn biodiesel was dried by different methods including: chemical
(anhydrous sodium sulfate) and thermal (induction heating, heating under vacuum and with microwave irradiation). The drying
efficiency was evaluated by monitoring IR absorption in the 3,500–3,200 cm−1 range and by the AOCS Bc 2-49 method. In general, the oxidative induction times increased inversely to the heating degree,
except that of microwave irradiation, which was selective to water evaporation and caused low impact over the unsaturation
of biodiesel. The DSC technique was shown to be a powerful tool to evaluate with high level of differentiation the influence
of the drying process on the oxidative stability of biodiesel.
Authors:M. L. S. De Melo, N. A. Santos, R. Rosenhaim, A. G. Souza, and P. F. Athayde Filho
Biodiesel has the advantage of being renewable and clean and for these reasons has been studied recently both academically and in industry. Research in this area is focused on developing new synthetic routes to obtain a purer product or to find new alternative sources of food to replace conventional oils. Papaya biodiesel is obtained from oily residues with a fatty acid composition similar to olive oil. It is generally discarded by the ton, considering that Brazil is the world’s largest producer of papaya with an annual output of 1,811 million tons, productivity of 52 t/hectare and domestic consumption at 86.5%. This study was designed by means of thermal analysis (TG, DSC, P-DSC, and MT-DSC), to verify the possibility of achieving high quality biodiesel, with oxidative stability and flow properties previously indicated by composition analysis of its fatty esters, physical–chemical properties (including oxidative stability) using classical methodology, recommended by ASTM D 6756.
Authors:D. Gouveia, R. Rosenhaim, M. de Maurera, S. Lima, C. Paskocimas, E. Longo, A. Souza, and I. Santos
With the aim of obtaining materials with applications in pigments, CoxZn7-xSb2O12 spinels were synthesized using the Pechini method. This method consists in the formation of a polymeric net, where the metallic
cations are homogeneously distributed. In this work, two types of alcohol (ethyl glycol and ethylene glycol) were used for
the synthesis of a zinc antimoniate spinel, CoxZn7-xSb2O12 (x=0-7). The materials were characterized by termogravimetry (TG) and differential thermal analysis (DTA). TG results indicated
a decrease in total mass loss when cobalt was added to the solution substituting zinc, for samples prepared using the two
different alcohols. Decomposition temperatures, obtained by TG and DTA, presented a decreasing behavior as cobalt was added
to the material. In relation to the alcohols, all results indicated a better polymerization of the resin when ethylene glycol
was used, being the most indicated one for cation immobilization. X-ray diffraction did not show differences between the two
alcohols - both presented the spinel phase (Co, Zn)2.33Sb0.67O4. Samples with higher quantity of cobalt also presented ilmenite phase (Co, Zn)Sb2O6.
Authors:M. Dantas, Marta Conceição, V. Fernandes Jr, Nataly Santos, R. Rosenhaim, Aldalea Marques, Iêda Santos, and A. Souza
This work evaluates the thermal and kinetic
behaviour of corn biodiesel obtained by the methanol and ethanol routes. As
to the TG curves, in air three thermal decomposition steps are for the methanol
biodiesel and two steps are for the ethanol biodiesel. These steps are related
to the evaporization and/or combustion of the methyl and ethyl esters, respectively.
The corn oil presented four thermal decomposition steps in air, and only one
step in nitrogen. These steps were attributed to the evaporization and/or
decomposition of triglycerides. The TG and DTA profiles of the biodiesel approach
the mineral diesel oil ones.
Authors:N. A. Santos, R. Rosenhaim, M. B. Dantas, T. C. Bicudo, E. H. S. Cavalcanti, A. K. Barro, I. M. G. Santos, and A. G. Souza
Biodiesel is an increasingly attractive alternative to diesel fuel. The main component of Babassu biodiesel is lauric acid (C12:0), which is a saturated fatty acid with a high melting point. Controlling flow properties, such as viscosity and the cold filter plugging point, is critical because viscosity affects atomization, and crystal formation resulting from decreases in temperature can negatively affect engine starting and performance. To evaluate its flow characteristics more fully, the rheological properties of babassu biodiesel were analyzed, taking into account variations in temperature. The crystallization temperature was determined by modulated temperature differential scanning calorimetry (MT-DSC). The curve of biodiesel viscosity as a function of the biodiesel refrigeration temperature contained an inflection point (corresponding to a steep increase in viscosity) that was coincident with both the transition from a Newtonian-type flow to a pseudoplastic-type flow and the crystallization temperature obtained by MT-DSC, indicating that the appearance of crystals in the biodiesel increased its viscosity. The rheological properties of fatty acid methyl and ethyl mixtures (FAME and FAEE) with metropolitan diesel were also evaluated; a higher FAME percentage reduced viscosity in blends up to B100.
Authors:G. A. A. Teixeira, A. S. Maia, R. Rosenhaim, I. M. G. Santos, A. L. Souza, A. G. Souza, and N. Queiroz
Biodiesel can be obtained from various fatty acid sources. Each raw material has a different chemical composition that leads to different properties. Owing to these properties, the mixture of different proportions of raw materials can lead to biodiesels with best features in relation to physicochemical parameters such as viscosity, oxidative stability and flow properties, generating a fuel whose characteristics meet the requirements of the current legislation of the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP). The objective of this study was to determine the physicochemical properties of biodiesel samples produced from mixtures of beef tallow, babassu oil, and soybean oil. The thermo-oxidative stability was evaluated using thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC). The results showed that all samples were in accordance to the ANP specifications. The biodiesel obtained from a mixture containing 50% of babassu oil had lower values of pour point, cold filter plugging point, and freezing point. This biodiesel also showed a higher thermo-oxidative stability in synthetic air and in oxygen atmospheres.
Authors:L. Freire, T. Bicudo, R. Rosenhaim, F. Sinfrônio, J. Botelho, J. Carvalho Filho, I. Santos, V. Fernandes, N. Antoniosi Filho, and A. Souza
Biodiesel is susceptible to autoxidation if exposed to air, light and temperature, during its storage. Physic nut (Jatropha curcas L.) seeds show potential application for biodiesel production since its oil yields high quality biodiesel. This work aims
to evaluate the thermal behavior of the physic nut oil and biodiesel, from several Brazilian crops, by means of thermoanalytical
techniques. Thermogravimetry (TG) and pressurized-differential scanning calorimetry (PDSC) were used in order to determine
the applicability of physic nut biodiesel as fuel. Results suggest that physic nut biodiesel is a practical alternative as
renewable and biodegradable fuel able to be used in diesel motors.
Authors:P. S. Epaminondas, K. L. G. V. Araújo, J. A. Nascimento, M. C. D. Silva, R. Rosenhaim, L. E. B. Soledade, N. Queiroz, A. L. Souza, I. M. G. Santos, and A. G. Souza
Physico-chemical properties, spectroscopy, and thermal analyses were used aiming at evaluating the influence of toasting and of the flaxseed variety on thermo-oxidative behavior of flaxseed oils. Thermogravimetry (TG) and differential scanning calorimetry (DSC) were associated to gas chromatography, infrared spectroscopy and UV–Vis spectroscopy, as well as to physico-chemical analyses to characterize the oils obtained from raw and toasted flaxseeds. No meaningful differences in the thermal and oxidative stabilities were noticed comparing oils obtained from the brown and the golden flaxseeds. Nevertheless, the UV–Vis spectra indicated that both flaxseed oils were at the beginning of the oxidation process. The previous toasting of the seeds led to a higher oxidation for both varieties being harmful to the flaxseed oil quality.
Authors:K. L. G. V. Araújo, P. S. Epaminondas, M. C. D. Silva, A. E. A. de Lima, R. Rosenhaim, A. S. Maia, L. E. B. Soledade, A. L. Souza, I. M. G. Santos, A. G. Souza, and N. Queiroz
Physicochemical and thermal analyses were undertaken to evaluate the influence of the temperature on the oxidation of sea fish oil once its polyunsaturated fatty acids deteriorate rapidly. Fish oil displayed four decomposition steps in synthetic air atmosphere and only one step in nitrogen atmosphere. The first step started at 189 and 222 °C for oxidizing and inert atmospheres, respectively. An OIT value of 53 min was measured at 100 °C. After the degradation process the peroxide index and the iodine index reduced from 35.38 to 9.85 meq × 1000 g−1 and from 139.79 to 120.19 gI2 × 100 g−1, respectively. An increase of the free fatty acids amount from 0.07 to 0.17% was observed while viscosity increased from 57.2 to 58.0 cP. Absorption at 272 nm also increased. The thermogravimetric and spectroscopic techniques are reproducible and versatile being an option for characterization of edible oil oxidation.