Catalytic conversion of lactic acid to 2,3-pentanedione over
sodium salts and base on low surface
area silica support has been studied. Yield and selectivity toward
2,3-pentanedione are optimal
at around 300 °C, 3−4 s residence time, and 0.5 MPa total pressure.
Anions of initial salt
catalysts used do not participate in lactic acid condensation to
2,3-pentanedione once steady-state conditions have been achieved; instead, sodium lactate has been
identified by postreaction
FTIR spectroscopy as the primary, stable species on the support during
reaction. Sodium lactate
is believed to be an intermediate in 2,3-pentanedione formation.
Conversion of a sodium salt to
sodium lactate is greatest when the salt used has a low melting point
and a volatile conjugate
acid; the extent of conversion depends weakly on reaction time and
temperature within
experimental conditions. At high temperature (∼350 °C), sodium
lactate decomposes to sodium
propanoate and sodium acetate, which may explain reduced
2,3-pentanedione yields at higher
temperatures.
A new method for fabrication of metal-cermet anodes in solid-oxide fuel cells (SOFCs) has been developed. Highly porous, yttriastabilized zirconia (YSZ) films were prepared using a mixture of zircon fibers (YSZp, Si-stabilized, and <0.3% Si) and normal YSZ powders (YSZd). The films remained highly porous following calcination up to 1550ЊC, after which either Cu or Ni could be incorporated by impregnation with the nitrate salts. For Cu cermets, the performance increased with metal loading to at least 40% Cu. At 800ЊC using H 2 as the fuel and a 230 m, YSZ electrolyte, the current-voltage (I-V) curves for either a Cu-or Ni-cermet anode formed using this new method were found to be identical to the I-V curve for a Ni cermet formed using traditional methods. Scanning electron microscopy showed that the anode films remained porous even with addition of Cu, so that additional modification was possible. Tests of this concept through the addition of ceria by impregnation with the Ce(NO 3 ) 3 led to an additional increase in the cell performance.
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