Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques.

Complementary analytical methods have been used to study the effect of potassium on the pyrolysis mechanisms of cellulose and lignocellulosic biomasses. Thermogravimetry, calorimetry, high-temperature (1) H NMR spectroscopy (in situ and real-time analysis of the fluid phase formed during pyrolysis), and water extraction of quenched char followed by size-exclusion chromatography coupled with mass spectrometry have been combined. Potassium impregnated in cellulose suppresses the formation of anhydrosugars, reduces the formation of mobile protons, and gives rise to a mainly exothermic signal. The evolution of mobile protons formed from K-impregnated cellulose has a very similar pattern to the evolution of the mass loss rate. This methodology has been also applied to analyze miscanthus, demineralized miscanthus, miscanthus re-impregnated with potassium after demineralization, raw oak, and Douglas fir. Hydrogen mobility and transfer are of high importance in the mechanisms of biomass pyrolysis.

Experimental and theoretical study of carbohydrate-ionic liquid interactions.

With increasing interest in the use of lignocellulosic biomass for the production of renewable transportation fuels, new approaches for biomass pretreatment have been of considerable interest. The conversion of biomass cellulose to water-soluble sugars is currently one of the most intensive demands worldwide. The use of ionic liquids has been described as a new potentially viable development in this area. Indeed, previous work indicates that carbohydrates are soluble in some imidazolium based ionic liquids. For a better understanding of the behavior of such systems, theoretical quantum chemical calculation have become complementarities of experimental measurements. The goal of this work is to investigate the fundamental natures of the interaction between glucose or cellulose and imidazolium based ionic liquids using ab initio calculations and comparing these results with experimental data. Furthermore, a characterization study was made to investigate the changes in the cellulose structure during the process of solubility and regeneration with ionic liquids.