Thermogravimetry has been widely used for the characterization of several biomasses but the most useful information given
by this technique has been normally concerned to the relative amounts of humidity, hemi-cellulose, cellulose and lignin present
in the biomass. TG-FTIR has been used to yield qualitative data about the pyrolysis products, in an exploratory way, by some
authors. In the present paper, this technique was employed to reach comparative data about the products of pyrolysis of biomasses
that are potentially available at economic bases for the production of biofuels. Agricultural residues such as coconut shell,
sugarcane bagasse, corn stalks and peanut shell were chosen to be investigated. For all samples, the thermogravimetric curves
showed a mass loss between 35 and 400 °C changed up to 73%, while that the loss between 400 and 800 °C changed up to 26%.
TG-FTIR indicated tendencies in the rate of the formation of important species during the pyrolysis process of the four biomasses
studied. The interpretation of the spectra allowed the proposition of characteristic absorbance ratios and the comparison
of these values allowed inferences about the relative abundances of components formed in the pyrolysis of the biomasses. As
an example of the possible inferences reached, among the species formed in the pyrolysis condensate, called bio-oil, the formation
of carboxylic acids has to be specially considered due to their corrosivity. Thus, the data produced indicated that a bio-oil
derived from peanut shell should be a little less acidic while the one derived from sugarcane bagasse should be showed more
acidic among the biomasses studied.