Environmental Engineering Reference
In-Depth Information
modified organisms can substitute petroleum-derived maleic acid/anhydride in the production
of bulk or specialty chemicals.
2,5-Furan dicarboxylic acid comes from the oxidative dehydration of C6 sugars or from
oxidation of 5-hydroxymethylfurfural. It can be the precursor of an array of compounds of the
furan family, including terephthalic acid, which is widely used in the production of the poly-
mer polyethylene terephthalate (PET).
3-Hydroxypropionic acid is produced by fermentation with limited yields so far and diffi-
culties in the purification process. 3-Hydroxypropionic acid can serve as a feedstock for the
production of an array of 3C compounds of the acrylic acid family, 1,3-propanediol, and
malonic acid.
L-aspartic acid may come from synthesis, extraction from protein, fermentation, and enzy-
matic conversion. Production of L-aspartic acid via fermentation from sugars is not cost-
effective yet. The most suitable method at the moment is by making ammonia react with
fumaric acid catalyzed by the presence of a lyase enzyme. L-aspartic acid is the precursor of
the sweetener aspartame as well as of many pharmaceutical compounds.
Glucaric acid is a derivative of the oxidation of glucose, or starch, with nitric acid, which
also yields an assortment of side products. Glucaric acid can be converted into lactones to
produce solvents or into polyglucaric esters and amides, which are precursors of nylons.
Glutamic acid, as a sodium salt, is produced via fermentation. The current challenge is the
development of a procedure to produce the free acid that would reduce downstream costs.
Glutamic acid is the precursor of a series of small molecule chemicals (e.g., glutaric acid,
1,5-pentandiol, 5-amino-1-butanol, and glutaminol) and has the potential of being polymer-
ized into polyglutamic acid.
Itaconic acid results from fungal fermentation, but the yields are still modest for mass pro-
duction of commodity chemicals from this precursor.
Levulinic acid is produced by acid catalyzed dehydration of 6C sugars, from starch or
cellulose, or from 5C sugars from hemicelluloses using many feedstocks, and can serve as the
precursor of important chemicals such as methyltetrahydrofuran, lactones, esters, acids, and
alcohols.
3-Hydroxybutyrolactone, a cyclic 4C compound, is generated by oxidative degradation of
starch. It can be the building block of solvents and pharmaceutical compounds.
Glycerol is a by-product of biodiesel production. Glycerol has applications in pharmaceu-
ticals, food and beverages, and personal care products, or it can be transformed into other
chemicals including the production of 1,3-propanediol—a precursor of polytrimethylene
terephthalate—propylene glycol, glyceric acid, and new polyesters.
Sorbitol is the product of hydrogenation of glucose under the presence of Raney nickel
catalyst. The main application of sorbitol is the food industry; however, it can be converted
into other compounds including lactic acid—the precursor of polylactate.
Xylitol and arabinitol are produced by hydrogenation of xylose and arabinose, respectively.
Both compounds, xylitol and arabinitol, can be converted into polyols and lactic acid and
possibly be building blocks of new polymers.
CHEMICALS FROM SYNGAS
Carbon monoxide and hydrogen contained in syngas have the potential of being the feedstock
of a number of chemicals via anaerobic fermentation or chemical route (Fig. 14.3). Several
species of genus Clostridium ( Clostridium ljungdahlii, Clostridium autoethanogenum,
Clostridium carboxidivorans ) and other anaerobic microorganisms, such as Peptostreptococcus
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