1 research outputs found
Temperature Tuning the Catalytic Reactivity of Cu-Doped Porous Metal Oxides with Lignin Models
Reported are the
temperature dependencies of the temporal product
evolution for lignin model compounds over copper-doped porous metal
oxide (CuPMO) in supercritical-methanol (sc-MeOH). These studies investigated
1-phenylethanol (PPE), benzyl phenyl ether (BPE), dihydrobenzofuran
(DHBF), and phenol over operating temperature ranges from 280 to 330
°C. The first three model compounds represent the β-O-4
and α-O-4 linkages in lignin as well as the furan group commonly
found in the β-5 linkage. Phenol was investigated due to its
key role in product proliferation as noted in earlier studies with
this Earth-abundant catalyst. In general, the apparent activation
energies for ether hydrogenolysis proved to be significantly lower
than that for phenol hydrogenation, a major side reaction leading
to product proliferation. Thus, temperature tuning is a promising
strategy to preserve product aromaticity as demonstrated by the more
selective conversion of BPE and PPE at lower temperatures. Rates of
methanol reforming over CuPMO were also studied over the temperature
range of 280–320 °C since it is this process that generates
the reducing equivalents for this catalytic system. In the absence
of substrate, the gaseous products H<sub>2</sub>, CO, and CO<sub>2</sub> were formed in ratios stoichiometrically consistent with catalyzed
methanol reformation and water gas shift reactions. The latter studies
suggest that the H<sub>2</sub> production ceases to be rate limiting
early in batch reactor experiments but also suggest that H<sub>2</sub> overproduction may contribute to product proliferation