(338g) Direct Conversion of Cellulosic Biomass to Alkyl Lacatate on Mesoporous Zr-Silicates

Direct
Conversion of Cellulosic Biomass to Alkyl Lacatate on
Mesoporous Zr-Silicates

Lisha
Yang¹, Xiaokun Yang¹, and
Hongfei Lin¹*

¹
Department of
Chemical and Materials Engineering,

University
of Nevada, Reno

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

Fax:
(+1) 775-327-5059;

*E-mail:
HongfeiL@unr.edu

Abstract

Biomass-derived lactic acid esters are "green" solvents that are not only
biodegradable but also non-toxic. In this study, a variety of Zr-SBA-15
materials, which possess strong Lewis acid sites and weak Brønsted
sites, were synthesized with tunable structures and pore sizes. The optimized
Zr-SBA-15 catalyst showed excellent performance for the conversion of sugars to
lactic acid esters in a "one-pot" reaction system. The effects of reaction
conditions, including temperature, reaction time, and catalyst loading amount,
on the conversions of carbohydrates and the corresponding yields of lactate
were investigated.  The carbon
yields of methyl lactate, up to 41 % and 44%, were produced from pentose and
hexose, respectively. The key intermediates such as glyceraldehyde, glycolaldehyde and pyruvaldehyde
were used as probe reactants to understand the mechanism.  The role of the catalyst in the retro-aldol condensation of carbohydrates, as well as the
catalyst stability, has been discussed.  Furthermore, the carbon yield of ethyl
lactate, up to 33% was produced directly from cellulose with the hydrophobic Zr-SBA-15
catalyst in the water-ethanol mixed solvents.