In recent years, the strong restrictions applied to emissions
from road transport together with the scarce availability of conventional
fuels responsible for a constant increasing of fuel prices
have encouraged the research activity towards alternative fuels.
An increasing use of bio-fuels for transport is emerging as an
important policy strategy to replace petroleum fuels. The European
Union (EU) was aimed at achieving a 5.75% target of biofuels by
2010 (calculated on the basis of energy content), set by the EU
Directive 2009/28/EC on the promotion of the use of energy from
renewable sources and adopted by most Member States in their
national biofuel objectives. Bio-ethanol is a renewable energetic
source, and therefore it can contribute to reduce green house gas
emissions. The benefits are as much high as greater is the efficiency
of ethanol global productive process, taking into account also land
use competition with other human needs. Bioethanol can be produced
from various kinds of biomass such as corn, sugarcane, sugar
beet, cassava, and red seaweed. It is one of alternative fuels most
employed because of its oxygen content which favors the further
combustion of gasoline. Besides, gasoline blends well with ethanol,
compared to diesel, resulting in lower sulfur and aromatics content,
higher octane number, and higher vapor pressure compared
to the base fuel. Recently, the attention towards n-butanol as alternative
fuel is increasing due to its high affinity with gasoline.
Moreover, n-butanol when blended with gasoline is characterized
by a high stability: in presence of water, in fact, n-butanol/gasoline
blends do not separate. The most negative aspect is toxicity to humans
from excessive exposition to n-butanol.