The kinetics of sugar cane bagasse cellulose saccharification and the decomposition of glucose under extremely low acid (ELA) conditions, (0.07%), 0.14%, and 0.28% H 2 SO 4 , and at high temperatures were investigated using batch reactors. The first-order rate constants were obtained by weight loss, remaining glucose, and fitting glucose concentration profiles determined with HPLC using the Saeman model. The maximum glucose yields reached 67.6% (200°C, 0.07% H 2 SO 4 , 30 min), 69.8% (210°C, 0.14% H 2 SO 4 , 10 min), and 67.3% (210°C, 0.28% H 2 SO 4 , 6 min). ELA conditions produced remarkable glucose yields when applied to bagasse cellulose. The first-order rate constants were used to calculate activation energies and extrathermodynamic parameters to elucidate the reaction mechanism under ELA conditions. The effect of acid concentration on cellulose hydrolysis and glucose decomposition was also investigated. The observed activation energies and reaction orders with respect to hydronium ion for cellulose hydrolysis and glucose decomposition were 184.9 and 124.5 kJ/mol and 1.27 and 0.75, respectively.

This paper describes the organosolv delignification of depithed bagasse using glycerol-water mixtures without a catalyst. The experiments were performed using two separate experimental designs. In the first experiment, two temperatures (150 and 190°C), two time periods (60 and 240 min) and two glycerol contents (20% and 80%, v/v) were used. In the second experiment, which was a central composite design, the glycerol content was maintained at 80%, and a range of temperatures (141.7-198.3°C) and time (23-277 min) was used. The best result, obtained with a glycerol content of 80%, a reaction time of 150 min and a temperature of 198.3°C, produced pulps with 54.4% pulp yield, 7.75% residual lignin, 81.4% delignification and 13.7% polyose content. The results showed that high contents of glycerol tend to produce pulps with higher delignification and higher polyoses content in relation to the pulps obtained from low glycerol content reactions. In addition, the proposed method shows potential as a pretreatment for cellulose saccharification.

Sugarcane bagasse cellulose was subjected to the extremely low acid (ELA) hydrolysis in 0.07% H 2 SO 4 at 190, 210 and 225 • C for various times. The cellulose residues from this process were characterized by TGA, XRD, GPC, FTIR and SEM. A kinetic study of thermal decomposition of the residues was also carried out, using the ASTM and Kissinger methods. The thermal studies revealed that residues of cellulose hydrolyzed at 190, 210 and 225 • C for 80, 40 and 8 min have initial decomposition temperature and activation energy for the main decomposition step similar to those of Avicel PH-101. XRD studies confirmed this finding by showing that these cellulose residues are similar to Avicel in crystallinity index and crystallite size in relation to the 110 and 200 planes. FTIR spectra revealed no significant changes in the cellulose chemical structure and analysis of SEM micrographs demonstrated that the particle size of the cellulose residues hydrolyzed at 190 and 210 • C were similar to that of Avicel.

The analytical methods currently used for chemical characterization of lignocellulosic materials were developed for wood and are applied with minor modifications for sugar cane bagasse and straw analysis. The lack of specific methodology for these materials leads to inadequate results and hamper both the planning and the interpretation of results. Thus, the main aim of this work is to develop specific analytical methodologies to the chemical characterization of sugar cane bagasse and straw. The determination of lignin was studied by the hydrolysis and dissolution of the polysaccharide fraction in sulfuric acid solution. The insoluble fraction was analyzed by elemental analysis, Fourier Transform Infrared (FT-IR), Carbon-13 nuclear magnetic resonance spectroscopy (13 C NMR), Gel permeation chromatography (GPC) and Thermogravimetric analysis (TGA). The sugars and derivatives of these hydrolysates were analyzed by High performance liquid chromatography (HPLC). It was also performed a complementary analysis from the holocellulose content determinations in order to check the values obtained by the klason procedure. The results showed the dependence of sulfuric acid concentration on lignin content determinations and the role of condensation reactions in the lignin characteristics. Despite the similarities in chemical composition, klason lignins obtained from straw exhibited very low molar masses. Preliminary results obtained from holocellulose determinations showed also the need for optimized oxidation procedures in order to be successful applied to sugar cane bagasse analysis.

This paper describes a study of the variability of measured composition for a single bulk sugarcane bagasse conducted across eight laboratories using similar analytical methods, with the purpose of determining the expected variation for compositional analysis performed by different laboratories. The results show good agreement of measured composition within a single laboratory, but greater variability when results are compared among laboratories. These interlaboratory variabilities do not seem to be associated with a specific method or technique or any single piece of instrumentation. The summary censored statistics provide mean values and pooled standard deviations as follows: total extractives 6.7% (0.6%), whole ash 1.5% (0.2%), glucan 42.3% (1.2%), xylan 22.3% (0.5%), total lignin 21.3% (0.4%), and total mass closure 99.4% (2.9%).