Besides its uses as transportation biofuel, ethanol also has interesting applications as bulk chemical from which C2 derivatives can be produced. In particular, ethanol can be converted via dehydration to ethene, one of the bulk petrochemicals, which has a world production of 107 million tons/year. Once produced from bioethanol, ethene can be then used for the pro­duction of other important chemicals like 1,2-dichloroethane (world production of 20 million tons/year), vinyl chloride, butadiene, and others.

6.2.1 C3 Bulk Chemicals

Acetone is an important chemical compound with a market volume of 3 million tons/year. As already mentioned, it is possible to produce acetone via the ABE fermentation process. This process is widely studied and is expected to be competitive in the market within the next 5-10 years (Bos et al., 2010). Acetone can be a valuable bulk chemical for the production of propene, whose production from fossil refinery is large (50 million tons/year) due to its wide applications (mainly as polypropylene).

Lactic acid is a promising bulk chemical which can lead to many derivatives (in particular polymers), thanks to two reactive sites, the carboxylic group and the hydroxyl group. The pro­duction of lactic acid from biomass (fermentation of sugars) is already established in the mar­ket, with an annual production around 0.26 million tons and a 10% annual growth (Jem et al.,

2010) . Major applications are in the food sector, industrial uses, and personal care. Important derivatives which can be produced from lactic acid are acrylic acid via dehydration (current global market of 2 million tons/year) and 1,2-propanediol by reduction (1.5 million tons/year).

3- HPA has the potential to be a key bulk chemical for deriving both commodity and specialty chemicals. The basic chemistry of 3-HPA is not represented by a current petrochemically derived technology (Werpy and Petersen, 2004). Its production from bio­mass depends on the development of low-cost fermentation routes, since this conversion pathway should in principle have the same yields of that leading to lactic acid. The potential derivatives are similar to those produced from lactic acid, since they have identical reactive sites. In both cases, the development of new catalysts able to directly reduce the carboxylic acid groups to alcohols is required. The esterification of the carboxylic group to an ester, and then reduce the ester, is technically easier, but the process is more expensive. The dehy­dration of 3-HPA to acrylic acid and acrylamide will require the development of new acid catalyst systems that afford high selectivity (Werpy and Petersen, 2004).