Ethanol fuel is ethyl alcohol, the same type of alcohol found in
alcoholic beverages, used as fuel.
It is most often used as a motor fuel, mainly as a biofuel
additive for gasoline.
It is commonly made from biomass such as corn or
sugarcane. Ethanol, also called drinking alcohol, is a chemical
compound, a simple alcohol with the chemical formula
C₂H₅OH. (CH₃−CH₂−OH or C₂H₅−OH), abbreviated as EtOH and
has a boiling point of 78.37 °C, molar mass of 46.07 g/mol and
a relative density 0.789 .
It is colorless volatile, flammable liquid which is produced by
the natural fermentation of sugars(carbohydrates).
It is product of anaerobic catabolism of carbohydrates.
Carbohydrate →n Glucose →2n Pyruvate →2n Ethanol+2n
History of Ethanol Production
The fermentation of sugar into ethanol is one of the earliest
organic reactions that man learned to carry out as dried
ethanol residue have been found on 9000 year old pottery in
China which indicates that Neolithic people in this part of the
world may have consumed alcoholic beverages.
Fermented solutions have been distilled since ancient times in
order to produce distilled beverages with a high ethanol
content, as distillation was well known by the early Greeks
and Arabs. Greek alchemists working in Alexandria during the
first century A.D. carried out distillation.
Methods for Ethanol Production
Consolidated bioprocessing (CBP), which integrates enzyme
production and fermentation into a one-step
process from starchy biomass.
To gain insights into starch-based ethanol production using CBP, an
extensive screening was undertaken to identify naturally occurring
yeasts that produce ethanol without the addition of any amylases.
Three yeast strains were capable of producing a significant amount
of ethanol. Quantitative assays revealed that Scheffersomyces
shehatae JCM 18690 was the strain showing the highest ethanol
production ability. This strain was able to utilize starch directly, and
the ethanol concentration reached 9.21 g/L. We attribute the
ethanol-producing ability of this strain to the high levels of
fermentation potential and ethanol stress tolerance.
It is interesting to note that fermentation process retains most
of the energy of the sugar in the form of ethanol.
The heat of combustion of solid sucrose is 5.647 MJ mol-1, the
heat of combustion of glucose is 2.816 MJ mol-1 but the heat
release is 1.371 MJ mol-1.
The equations are given below
Thus the above reactions show that 97% sugar transforms into
ethanol. But in practice, the fermentation yield of ethanol
from sugar is about 46% or one hundred grams of pure glucose
will yield 48.4 grams of ethanol, 46.6 g of CO2, 3.3 grams of
glycerol and 1.2 g of yeast.
Uses of Ethanol
Found as major component in alcoholic drinks such as beer, brandy,
Ethanol is a powerful psychoactive substance.
It is commonly used in the medical field as an antiseptic and as a
disinfectant as to sterilize the skin before injections, prevent the
spreading of bacteria in hospitals and related facilities.
It can be used as a solvent for different products such as culinary
extracts, essential oils, tinctures, concentrates,
Solvent:- Resins, pharmaceuticals , cosmetics ,household cleaning
products, industrial solvent
Fuel:- Used as a bio fuel , In internal combustion engines
Chemical intermediate -petroleum derived chemicals, Butadiene
In 1826, Samuel Morey invented the first internal combustion
engine that was built to run on alcohol — probably made from
In 1860, German inventor Nicholas Otto uses ethanol as fuel in
one of this engines. The first ethanol blended with gasoline for
use as an octane booster occurred in the 1920s and 1930s, and
was in high demand during World War II because of fuel shortages.
1975,Brazil launches its Programa Nacional do Álcool, a nation-wide
program intended to promote ethanol fuel on the domestic market.
E85 ethanol is a fuel made from a blend of 85% ethanol and 15%
unleaded gasoline. E85 was created for flexible fuel vehicles, or
vehicles that can run on any blend of ethanol up to 85%. In the
United States, the ethanol used in E85 is normally derived from
Ethanol‐blended fuel as E10 (10% ethanol and 90%
gasoline) reduces greenhouse gases by up to 3.9%.
Ethanol is considered a renewable energy resource
because it is primarily the result of conversion of the
sun's energy into usable energy.
It reduces greenhouse gases.
It reduces the amount of high‐octane additives.
The fuel spills are more easily biodegraded or diluted to
non toxic concentrations.
Exhaust gases of ethanol are much cleaner , it burns more
cleanly (more complete combustion)
The use of ethanol‐blended fuels such as E85 (85%
ethanol and 15% gasoline) can reduce the net emissions
of greenhouse gases by as much as 37.1%, which is a
You can use any plant for production of bioethanol, it only
has to contain sugar and starch. The best choice is sugar
cane, but you can also use potatoes, barley , wheat etc.
It is carbon neutral i.e. the carbon dioxide released in the
bioethanol production process is the same amount as the
one the crops previously absorbed during photosynthesis
The energy content of the petrol is much higher than the
one of bioethanol. Burning 1 litre of ethanol gives 34%
less energy than burning the same amount of petrol
phosphorous and nitrogen used in the production
have negative effect on the environment
During the production process of bioethanol a huge
amount of carbon dioxide is released.
The production of ethanol fills the air with greenhouse
gases (GHG) in the amounts comparable to the emissions
of internal‐combustion engines
Transportation – ethanol is hygroscopic, it means that it
absorbs water from the air and thus has high corrosion
Biodiversity – A large amount of arable land is required to
grow crops. This could see some natural habitats
destroyed including rainforests.
The food V fuel debate – There is concern that due to the
lucrative prices of bioethanol some farmers may sacrifice
food crops for biofuel production which will increase food
prices around the world.