(35d) Comparing Pyrolysis of D-Arabinose and L-Fucose to D-Xylose

To understand the rates and selectivity of hemicellulose pyrolysis, we have probed the differences between pyrolysis of xylose, fucose and arabinose. Hemicellulose pyrolysis is an important part of making bio-oil from lignocellulosic biomass pyrolysis. Xylose is the monomer of xylan, arabinose occurs in hemicellulose but has different hydroxyl group stereochemistry at carbon-4 (fifth atom in the ring with oxygen numbered first) and fucose substitutes a methyl for an H onto xylose’s carbon-5 (sixth atom in the ring with oxygen numbered first).

Samples of D-arabinose (Fisher Scientific), L-fucose (Acros), and D-xylose (Sigma Aldrich) were flash-pyrolyzed (Pyroprobe 5200, CDS) at 250°C and 350°C. Product gases were analyzed by two-dimensional gas chromatography with time-of-flight mass spectrometry (Pegasus 4D, LECO).

The yield of furan compounds in pyrolysis of D-xylose was more than from pyrolysis of L-fucose. Isomerization of D-arabinose to xylose was observed in arabinose pyrolysis. The dominant products in D-arabinose and D-xylose pyrolyses were water and glycolaldehyde. In the presentation we will discuss the possible mechanisms.