Kunamalla, Alekhya
(2016)
Dehydration of Biomass-derived Carbohydrates in a Biphasic Reactor using Cation Exchange Resin Catalyst for the Production of Hydroxymethylfurfural and Furfural.
Masters thesis, Indian Institute of Technology Hyderabad.
Abstract
Biomass is a source of carbohydrates, which is composed of two different types of sugars hexose
(glucose, galactose and mannose) and pentose (xylose and arabinose). These sugars can be
dehydrated to produce platform chemicals like 5
-
HMF (5
-
hydroxymethylfur
fural) and furfural.
These are most promising chemicals because they are used in the production of fine chemicals,
polymers and also starting materials for new products as well as for replacement of oil
-
derived
chemicals. This work focuses on the productio
n of 5
-
HMF and Furfural by dehydration of
fructose and xylose respectively. Dehydration of carbohydrates in aqueous phase can produce
unwanted products because of side reactions such as rehydration, hydrolysis and condensation.
To eliminate unwanted side r
eactions an organic phase and inorganic salt were added to the
system. Organic phase consisting of solvents which can extract the product from aqueous phase
as it formed to eliminate the degradation of product and addition of salt to the reaction system
wi
ll increase the partition coefficient. Dehydration reaction was performed in a batch reactor
over a cation exchange resin catalyst. Effect of reaction parameters such as temperature, time,
and feed compositions were optimized to increase the yield. Effect
of salt was studied and
concluded that product concentration depends on salt concentration because of salting
-
out effect.
Difference between using glucose and fructose to produce 5
-
HMF was also studied and
concluded that using fructose product concentrati
on increased compared to the glucose. The
reason behind this is dehydration of glucose can produce ene
-
diol intermediate which consists of
unstable ring structure that can produce unwanted by products. So, glucose was initially
isomerized to fructose and t
hen dehydrated to produce 5
-
HMF.
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