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Fast pyrolysis of lignocellulosic materials is a promising research area to produce renewable fuels and chemicals. Dehydration is known to be among the most important reaction families during cellulose pyrolysis; water is the most important product. Together with water, dehydration reactions also form a range of poorly known oligomer species of varying molecular sizes, often collected as part of the bio-oil water-soluble (WS) fraction. In this work, we used electronic structure calculations to evaluate the relative thermodynamic stabilities of several oligomer species from cellulose depolymerization intermediates undergoing three consecutive dehydration events. A library of the thermodynamically favored candidate molecular structures was compiled. Results revealed that most of the water molecules are eliminated from the non-reducing end, forming thermodynamically more stable conjugated compounds. This is consistent with results reported in literature where dehydration reactions occur preferably at the non-reducing ends of oligomers. The theoretical Fourier-Transform Infrared Spectroscopy and NMR spectra of these proposed sugar oligomers conform qualitatively to the experimental result of pyrolytic sugars. Understanding their chemical structure could help to develop rational strategies to mitigate coke formation as sugars are often blamed to cause coke formation during bio-oil refining. The estimated physical–chemical properties (boiling point, melting point, Gibbs free energy of formation, enthalpy of formation, and solubility parameters among others) are also fundamental to conducting first-principles engineering calculations to design and analyze new pyrolysis reactors and bio-oil up-grading units. 

A novel miniaturized, transparent reactor system for use as either a research or educational tool was developed for investigating biomass char gasification with oxygen to determine the kinetic parameters. Parametric temperature and pressure data taken can be used to distinguish the validity of assumptions inherent in the Avrami, the random pore (RPM), the unreacted core shrinking (UCSM), and a UCSM hybrid models (HM). The results demonstrate the UCSM for spherical and cylindrical geometries, and an HM variation with a best-fit exponent, that yields residual sums of squares 2 to 4 orders of magnitude lower than other models. An Arrhenius evaluation yielded an activation energy of 84.8 kJ/mol and pre-exponential factor of 1.34  103 s-1. An O2 reaction order of 0.85 indicates O2 adsorption on the char surface is the primary rate-controlling step. Data are consistent with a rapidly decreasing surface area as the reaction nears completion, suggesting available corresponding active sites for rapid chemisorption decrease as the reaction progresses. More importantly, the design of the system is safe to take into the classroom while simultaneously allowing students to view real-time reactions and produce repeatable data; this pushes the bounds on classroom interventions and learning.