Biofine Hydrolysis Process and Derivative Product Upgrading Technologies 195
gas turbines for electrical generation [47]. The production of LA esters from LA
produced by the Biofine process has an added advantage that this method does not
produce glycerol as coproduct that needs to be disposed.
LA can be converted to GVL by dehydration to angelica lactone and subsequent
reduction or by reduction to 4-hydroxy-pentanoic acid and subsequent dehydration.
These reductions are carried out at relatively low temperatures (373–543 K) and high
pressures (50–150 bar), and both homogeneous and heterogeneous catalysts can be
employed [48]. The highest yield of GVL (97%) was obtained at 423 K and 34.5 bar
using Ru/C catalyst and dioxane as solvent [49]. The external hydrogen is often replaced
by formic acid that acts as a hydrogen donor solvent. More recently, GVL has also
been produced by integrating hydrolysis/dehydration/hydrogenation of carbohydrates in
a single vessel [48,50]. LA can also be catalytically hydrogenated to GVL, which upon
further hydrogenation yields 1,4-pentanediol and finally MTHF [10,32]. The reaction is
carried out at an elevated temperature of 240°C and a pressure of 100 atm. This method
uses trifluroacetic acid as a hydrolysis medium due to the poisoning of Ru/C catalyst by
sulfuric acid. Fructose and sucrose gave better yields of GVL than glucose and cellulose
when formic acid as a hydrogen donor solvent and external hydrogen are used [8].
MTHF insertion in a blend (gasoline and ethanol) has led to the creation of
P-series fuels. These types of fuels can be either used alone or mixed with any proportions with gasoline [8]. These types of fuels reduce ozone-forming potential and
reduce emission of non-methane hydrocarbons and total hydrocarbons. MTHF is
also an excellent solvent (better than THF) and can also be produced from furfuryl
alcohol [8]. Dimethyl THF can also be produced from HMF.
7.3.2 gAmmA-vAleroleCTone
GVL is a versatile platform chemical, which can be used as a fuel additive, a solvent,
or a reactant for diverse upgrading strategies for the production of fuels and chemicals [51]. GVL’s low-energy density, blending limits, and high solubility in water
limit its use as a direct fuel. GVL needs to be separated from water, or an aqueous
solution of GVL should be processed to produce hydrophobic liquid alkanes with an
appropriate molecular weight to be used as liquid fuels.
Dumesic et al. [29–42] have outlined some of the alternatives for converting GVL
to liquid hydrocarbons. Serrano-Ruiz et al. [52] have shown that the aqueous solution
of GVL (50 wt%) can be upgraded to C 9 hydrocarbons by ring opening to produce
pentenoic acids and subsequent hydrogenation to produce pentanoic acids [53]; both
of these reactions can be catalyzed by water-soluble Pb/Nb 2 O 5 catalysts. The yield of
pentanoic acid is controlled by the metal content in the catalyst and the partial pressure of hydrogen. The best yields of pentanoic acid (92%) were obtained with 0.1%
Pd at 598 K and 35 bar (50% H 2 and 50% He) [32,54].
The pentanoic acid can be upgraded to 5-nonanone by ketonization over CeZrO x
at 698  K and pressures from 1 to 20  bar [55]. The hydrogenation/dehydration of
5-nonanone over Pt/Nb 2 O 5 at 528–568 K and 60 bar produces nonane [56]. In the
overall process, lower ketones are converted to C 6 –C 7 alkanes that can be removed
in the gas phase, and nonane remains in the liquid phase to be used as a blender in
diesel fuels [29–42].