Environmental Engineering Reference
In-Depth Information
H
O
OH
O
O
O
O
O
Furfural
Furfuryl alcohol
Furfuryl acrylate
O
O
O
H
H
2,5-furancarboxydialdehyde (FCDA)
O
O
O
OH
HO
O
2,5-furandicarboxylic acid (FDCA)
O
H
HO
5-hydroxymethylfurfural (HMF)
O
Cl
Cl
2,5-furandicarboxylic acid dichloride (FDCC)
NCO
OCN
O
O
Isopropylidenebis-(2,5-furandiylmethylene)diisocyante
Figure 5.2
Furanic monomers; a sample of the variety afforded by furan based chemistry [67, 68].
condensate is then separated into various fractions, including furfural, by distilla-
tion; typical yields reach only about 15% of dry matter [67, 69]. Purified, furfural
is a clear liquid.
Unlike furfural, HMF is solid at room temperature. The production of HMF has
not yet moved beyond the pilot scale. A recent review details the chemistry of the
production of HMF from mechanism to process technology [64]. The three general
methods for pilot-scale production of HMF differ in reaction medium: an aqueous
process; a process with non-aqueous solvents; and a two-phase process with both
aqueous and non-aqueous solutions [64, 70-72]. The starting reagent for these pro-
cesses is typically fructose, and all three processes have drawbacks such as the use
of homogeneous acid catalysts and low yields; these challenges will need to be met
before HMF production can meet industrial-scale demand [64].
