Download Synthesis of Platform Chemicals from Renewable Resources by

Synthesis of Platform Chemicals from Renewable Resources by
Applying Micro Reaction Technology
Tobias Türcke, Dr. Stefan Löbbecke,
Fraunhofer Institute for Chemical Technology ICT,
76327 Pfinztal, Germany
Despite the fact that today’s chemical production is still dominated by petroleumderived chemical components, the interest in renewable resources as chemical
feedstock’s has been growing fast in recent years. Diminishing petrochemical
resources, increasing oil costs as well as growing concerns about global warming
and rising CO 2 emissions are major drivers to increasingly seek for sustainable
resources. Therefore, biomass is currently considered as a promising and renewable
substitute for fossil-based resources.
Not only the exploitation of new resources but also the efficient use of biomass by
effluent treatment and the recovery of chemicals from biomass waste streams have
become industrial issues of major economic and environmental importance. The
ability to convert industrial waste streams into valuable products can make the
difference between realizing and abandoning a chemical process.
Here, we report on our recent studies on the continuous conversion of fructose from
biomass into 5-hydroxymethylfurfural (5-HMF) and xylose from pulp waste into
furfural by applying micro reaction technology. Both 5-HMF and furfural are promising
building blocks for chemical industry to form polymers, fine chemicals and solvents.
Different continuous microreaction processes for rapid screening of different process
condition were set up to analyze and improve the acid-catalyzed dehydration of
fructose to 5-HMF and the conversion of xylose to furfural. To allow processing of
viscous media under harsh process conditions special designed micro reactors were
developed. The microreactors were made of glass and could be operated at
pressures up to 25 bar and temperatures up to 300°C. The reactions were carried out
either in pure aqueous solutions or by using appropriate organic co-solvents for
product extraction. Variations in temperature (150-200°C), residence time (30-60 s)
and acid concentration were done by processing both freshly prepared solutions and
diluted aqueous waste streams coming from the pulp process. The reactions were
terminated by rapid quenching of the reaction mixture. The latter was analyzed by
HPLC.
5-HMF was obtained with 75% selectivity and 54% yield at 71% fructose conversion
in a pure aqueous solution. In comparison to published data, a 24% increase in
selectivity and a 21% increase in conversion were achieved. For the xylose
containing waste media conversions of more than 50% and furfural yields higher than
20% could be reached.
Moreover, by adding organic co-solvents and extraction agents to the reaction
system the conversion and yield were dramatically increased. For the fructose
conversion both 5-HMF selectivity and yield could be further enhanced to 85% and
82%, respectively. For the pulp waste streams a xylose conversion of more than 80%
and yields higher than 50% were achieved.