(276h) Effect of Redox Properties of LaCoO3 Perovskites on Production of Lactic Acid from Cellulosic Biomass

Effect of Redox Properties of LaCoO₃
Perovskites on Production of Lactic Acid from Cellulosic Biomass

Xiaokun
Yang, Lisha Yang, Hongfei Lin*

Department
of Chemical and Materials Engineering, University of Nevada,

1664
N. Virginia St., Reno, NV 89557, USA

E-mail:
HongfeiL@unr.edu

Cost-effective conversion of cellulosic
biomass to value-added lactic acid with heterogeneous catalysts has attracted
much attention recent years.  While both
solid Lewis acids and bases are extensively studied, which exhibit good
catalytic performance but are unfortunately unstable in hydrothermal media, the
role of redox catalysts for the production of lactic acid is barely
understood.  Herein, the LaCoO₃
perovskite metal oxides with strong redox properties and a good stability in
hydrothermal media were used as the catalyst for the conversion of a variety of
cellulosic biomass to lactic acid. 
Different gas atmosphere including oxidative, inert and reductive gases
had the profound effect on the yield of lactic acid.  The effects of reaction conditions such as
reaction temperature and catalyst loading were also investigated.  At the optimum conditions, the yields of
~40%, 38%, and 24% lactic acid were obtained from glucose, xylose and
cellulose, respectively.  The key
intermediates and final products were used as the probe reactants to explore
the reaction mechanism.  Unlike Lewis acid
or base catalysed biomass conversion reaction pathways, our proposed redox
reaction pathway has the distinct characteristic that lattice oxygen atoms in
the LaCoO₃ perovskite structure participate the redox cycles in the
sugar conversion to lactic acid.   The
stability of the LaCoO₃ catalyst was also discussed.