CHEMISTRY OF BIOFUELS AND BIOFUEL ADDITIVES FROM BIOMASS - Biomass as a Sustainable Energy Source for the Future - page 557

OH Ethanol HO OH Glycerol and derivative

OH

OH

Lactic acid

O Furanics

HOCH 2 /H O

COOH

O

Levulinic acid

COOH

HOOC

Succinic acid

HOOC

OH OH

Sorbitol

OH

3-Hydroxypropionic
acid

COOH

HO

HO

OH OH

OH OH

Isoprene and other
biohydrocarbons

Xylitol

HO OH

OH

FIGURE 18.4 New top chemical opportunities from a biorefinery. The chemicals on the left
are produced through fermentation of sugars, and the chemicals on the right are produced
through chemical conversion (mainly dehydration and hydrogenation) of sugars. Based on
information from Bozell and Petersen (2010).

alterations to the traditional bulk-scale crude oil and coal-oriented chains. The tran-
sition to a biobased economy also requires the development of integrated processes
where (ligno)cellulosic streams can be used directly as feed. Current developments
aim at the direct fermentation of cellulosic streams to ethanol, thereby circumventing
the need to produce glucose as intermediate; there are many reviews available (see
for a representative overview, e.g., Blanch, 2012). In addition, chemical catalytic
processes are under development, which focus on the processing of cellulosic streams,
such as the one-pot bifunctional catalytic conversion of cellulose into sorbitol using a
combination of acid hydrolysis and metal-catalyzed hydrogenolysis (Van de Vyver
et al., 2011). Another example is the hydrogenolysis of starch and cellulosic
feedstocks to LA (Ruppert et al., 2012). Hydrogenolysis has as major disadvantage,
being the extra and costly production of hydrogen. Integrated biorefinery examples
where, e.g., formic acid as side product is used for the hydrogenolysis are expected
to lay out the basis for future developments (Wright and Palkovits, 2012).

18.4 GREENNESS OF THE CONVERSION OF PLATFORM
MOLECULES INTO BIOBASED FUEL ADDITIVES

18.4.1 Hydroxymethylfurfural

The most well-studied transformation occurs upon elimination of three water
molecules from fructose and/or glucose, leading to the formation of HMF. The con-
version of glucose is shown in Figure 18.5.