carbon from the corn — a portion
of which is released as carbon
dioxide. the bottom line is that
only two-thirds of the plant can
be fermented to produce ethanol.
to make matters worse, even if
ethanol could be produced more
efficiently, its low density makes
it unsuitable as a gas substitute in
most engines. that’s why gas sold
at gas stations has no more than
10 percent ethanol. “car engines
do not behave well with ethanol,”
Mccann observes. “there are
problems with corrosion.”
courtesy of texarkana college
Students from Texarkana College (TX) tour Red River Biodiesel, a developer
of biofuel technology in New Boston, TX. The biodiesel is synthesized from
any single seed oil, animal fat, or a combination of these ingredients.
What about flex vehicles,
which are designed to use up
to 85 percent ethanol (e85)?
unfortunately, at present only
a few gas stations offer e85, so most owners are forced to use
low-ethanol gasoline. and motorists aren’t buying enough flex
cars to prompt gas companies to add more e85 pumps.
Catalysts are key
environmentalists realize the only way to produce truly green
fuel is to go beyond the energy-intensive and wasteful fermenta-
tion process and use the entire plant. unlike ethanol, cellulosic
fuels need not be made from corn or soybeans. rather, they
can be made from non-food crops, including fast-growing grasses
and trees. even better, the variety of low-maintenance plants
that can be used for cellulosic biofuels enables them to be
grown nationwide, not just in the corn Belt. this reduces the
energy spent transporting fuel.
Promise in a pond
at the enterprise rent-a-car
institute for renewable fuels in st.
louis, richard sayre is also working
toward turning biomass into fuel. But
he eschews terrestrial plants in favor of
“algae have the potential to produce
2 to 10 times more biomass per land
than any terrestrial crop,” he said. “up
to 65 percent of the mass is neutral
lipids that can be converted to the full
spectrum of fuels — gas, diesel, and
www.acs.org/undergrad • APRIL/MAY 2011 • inChemistry