Alcohol and Saccharide Model-Compound Pyrolysis Experiments to Improve Understanding of Cellulose Pyrolysis.

摘要

The pyrolysis of model compounds was investigated for improved understanding of cellulose pyrolysis. These alcohol and saccharide/saccharide-like model-compound comparisons are important to the progress of obtaining organic chemicals form renewable biomass resources via pyrolysis. Understanding the reaction mechanisms of cellulose will enable vital modifications to biomass-pyrolysis processes. These vital process modifications should not simply be optimized reaction temperatures and residence times, but instead should be catalysts and co-reagents designed to augment cellulose's inherent reaction network.;The two main sets of model compounds employed were alcohols and saccharide/saccharide-like molecules. The set of alcohols included nine monols (methanol, ethanol, propan-1-ol, 2,2-dimethylpropan-1-ol, 5-hydroxymethylfurfural, propan-2-ol, butan- 2-ol, 2-methylpropan-2-ol, and phenol) three diols (ethan-1,2-diol, propan-1,2-diol, and propan-1,3-diol), and one triol (propan-1,2,3-triol), pyrolyzed in a pulse-injected gas-phase reactor operating at 200-400°C. Primary and secondary monols preferentially dehydrogenated to their respective aldehyde and ketone, but they also dehydrated to a very small extent. Phenol was the main exception, as it provided no reaction products. Tertiary monols dehydrated and showed no dehydrogenation. Products of carbon-carbon fragmentation were either undetected or provided only trace product quantities for all monols, with the exception being 5-hydroxymethylfurfural, which deformylated to a significant degree. Diols and triols dehydrogenated, dehydrated, and fragmented carboncarbon bonds but still did not combine to form larger products. Concerted mechanisms were proposed for dehydrogenation and dehydration based upon their success with previous studies [1], [2], and [3], and four- and six-center cyclic transition states were evaluated. (Abstract shortened by ProQuest.).