1. Selective Dehydration of Lactic Acid to
Acrylic Acid in the Gas Phase
Jonathan Hunt, Centre College
Methods
• Zeolite catalysts were prepared through wetimpregnation of a standardized Na-Y zeolite.
Background
• In order to reduce global reliance on fossil fuels
(especially petroleum), research has been conducted on
the conversion of biorenewable feedstocks into products
typically produced through petroleum cracking [1].
• Lactic acid, the most prevalent product of the
fermentation process, has been dehydrated to acrylic
acid – a precursor for plastics – over a variety of salts
and catalysts. Because of acrylic acid’s current industrial
source as a product of petroleum cracking, the
conversion of renewable lactic acid into acrylic acid is of
particular interest to green chemists [2].
• The highest selectivity to acrylic acid ever achieved
[S(AA)=72.3%] was accomplished through modification
of zeolite Na-Y [3]. Therefore, investigations into the
modification of zeolite Na-Y and the effects of these
modifications are currently being undergone
• The evaporation of aqueous lactic acid is carried out
using a glass reactor. The liquid feed is pumped into
an evaporation zone located above the catalyst and
the vapor is driven through the catalyst bed by
nitrogen. Zeolite catalyst is utilized in a fixed-bed flow
reactor with integrated evaporator. Products are
collected in a cooling trap utilizing a dry ice-acetone
bath.
Ph.D candidate Gregor Nafe with reactor
used for selective dehydration of lactic
acid in the gas phase
Flow apparatus for evaporation inside the vapourphase reactor.
Acrylic acid A can be produced by dehydration of lactic acid, with propionic
acid B, acetaldehyde C, 2,3-pentanedione D and polylactic acid (PLA) E
being the main side products.
Purpose
• To investigate the effects of different forms of Na-Y
zeolite [impregnations with different cations] on the
catalyst’s ability to selectively dehydrate lactic to acrylic
acid in the gas phase. It is hoped that this investigation
will allow tailoring of catalyst properties, such as basic
and acidic characteristics, and will lead to a better
understanding of these characteristics on the selectivity
of the catalyst.
On a trip around Lake Geneva at the
picturesque town of Meersburg.
Application of Results
• Data collected from these experiments contribute to a
better understanding of the zeolite catalysts, their
acidic and basic properties, and how to manipulate
them
• Such understanding could lead to the synthesis of
catalysts which may be used in industry, allowing
lactic acid to serve as a feasible precursor for acrylic
acid on a large scale
References
[1] J. Zhang, Y. Zhao, M. Pan, X. Feng, W. Ji, C.-T. Au, ACS Catal. 1 (2011) 32-41. [2] C. T. Lira, P. J. McCrackin, Ind. Eng. Chem. Res. 32 (1993) 2608-2613. [3] G. C. Gunter, D. J. Miller, J. E. Jackson, J. Catal. 148 (1994) 252-260.