One step conversion of lignin from intact biomass to two phenol products, improving access to aromatics and fuels.

A fast-pyrolysis probe/tandem mass spectrometer combination was utilized to determine the initial fast-pyrolysis products for four different selectively (13)C-labeled cellobiose molecules. Several products are shown to result entirely from fragmentation of the reducing end of cellobiose, leaving the nonreducing end intact in these products. These findings are in disagreement with mechanisms proposed previously. Quantum chemical calculations were used to identify feasible low-energy pathways for several products. These results provide insights into the mechanisms of fast pyrolysis of cellulose.

The effects of three metal chlorides including FeCl 3 , CuCl 2 , and AlCl 3 on corn stover biomass pretreatment and enzymatic hydrolysis were studied under lower severity conditions (reaction temperature of 150−160 °C, salt concentration of 0.075−0.125M, and reaction time of 10 min). The results were compared with dilute sulfuric acid pretreatment at the same conditions. The maximum monomeric xylose yields were observed to be 93 and 94 wt % when CuCl 2 and FeCl 3 were used in the pretreatment at 160 °C for 10 min at 0.125 M concentrations, which were higher than the sulfuric acid pretreatment yields at the same reaction conditions. However, monomeric xylose yield for corn stover pretreated with AlCl 3 was observed to be 8 wt % at the same condition. This could be explained by isomerization of xylose to xylulose and subsequent dehydration into furfural. However, enzymatic digestibility yields for the three metal chloride pretreated samples at 160 °C were greater than 92 wt % . These yields were higher than sulfuric acid pretreated samples at the same reaction conditions. The overall formation of fermentation inhibitor products for samples pretreated with CuCl 2 and FeCl 3 was observed to be similar to the control samples (pretreated with sulfuric acid at the same conditions).

A lab-scale, high-pressure, continuous-flow fast-hydropyrolysis and vapor-phase catalytic hydrodeoxygenation (HDO) reactor has been successfully designed, built and tested with cellulose as a model biomass feedstock. We investigated the effects of pyrolysis temperature on high-pressure cellulose fastpyrolysis, hydrogen on high-pressure cellulose fast-hydropyrolysis, reaction pressure (27 bar and 54 bar) on our reactor performance and candidate catalysts for downstream catalytic HDO of cellulose fasthydropyrolysis vapors. In this work, a liquid chromatography-mass spectrometry (LC-MS) method has been developed and utilized for quantitative characterization of the liquid products. The major compounds in the liquid from cellulose fast-pyrolysis (27 bar, 520 °C) are levoglucosan and its isomers, formic acid, glycolaldehyde, and water, constituting 51 wt%, 11 wt%, 8 wt% and 24 wt% of liquid respectively.Our results show that high pressures of hydrogen do not have a significant effect on the fast-hydropyrolysis of cellulose at 480 °C but suppress the formation of reactive light oxygenate species like glycolaldehyde and formic acid at 580 °C. The formation of permanent gases (CO, CO 2 , CH 4 ) and glycolaldehyde and formic acid increased with increasing pyrolysis temperature in the range of 480 °C-580 °C in highpressure cellulose fast-pyrolysis, in the absence of hydrogen. Candidate HDO catalysts Al 2 O 3 , 2% Ru/Al 2 O 3 and 2% Pt/Al 2 O 3 resulted in extents of deoxygenation of 20%, 22% and 27%, respectively, but led to carbon loss to gas phase as CO and CH 4 . These catalysts provide useful insights for other candidate HDO catalysts for improving the extent of deoxygenation with higher carbon recovery in the liquid product. † Electronic supplementary information (ESI) available. See