Fueling of Our First Engines
Ethanol is involved in a wide variety of applications, stretching from the production of alcoholic beverages, the synthesis of drugs and complex chemicals, and the provision of energy by fueling our everyday household items such as heaters, lamps and vehicles. Some of the oldest combustion engines ran on ethanol, resulting in a closely tied relationship between the history of cars and ethanol fuel. Discovery of ethanol as liquor dates back to the fifteen-century while the discovery of ethanol fuel officially dates back to 1826 when Samuel Morey discovered the first American internal combustion engine that ran on ethanol, derived from corn.
Some alternative names of ethanol include ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol. Ethanol is characterized as flammable, evaporative, and colorless. It bears the structural formula of CH
3
CH
2
OH. The presence of hydroxyl group in a short carbon chain largely affects the physical properties of ethanol. The hydroxyl group may participate in hydrogen bonding, leading to its relatively higher viscosity and lower volatility, when compared to organic compounds of similar molecular weight; a comparative example includes propane. Ethanol is a versatile solvent, miscible with water and with many organic solvents, including acetic acid, acetone, benzene, carbon tetrachloride, chloroform, diethyl ether, ethylene glycol, glycerol, nitromethane, pyridine, and toluene. It is miscible with light aliphatic hydrocarbons, such as pentane and hexane, and also with aliphatic chlorides such as trichloroethane and tetrachloroethylene
(Wikipedia).
Ethanol is produced through two methods:
1) Fermentation of sugars
2) Hydration of ethylene
Either method is preferred based on the prevailing prices of petroleum and grain feedstocks. Ethanol fermentation occurs when yeasts anaerobically convert sugars including glucose, fructose, and sucrose into metabolic energy, yielding ethanol and carbon dioxide as side product. It is the oldest method in which human uses to produce ethanol. It is also the process used to produce the vast majority of ethanol fuels on the market. The chemical formula for the conversion of sugar into ethanol and carbon dioxide is shown below:
C
6
H
12
O
6
→ 2 CH
3
CH
2
OH + 2 CO
2
One molecule of sugar is converted into two molecules of ethanol and two molecules of carbon dioxide. Another method of synthesizing ethanol involves ethylene hydration.
Ethanol produced through ethylene hydration is commonly referred to as synthetic ethanol, since it is not a product of a biological process. Synthetic ethanol is primarily used as a solvent and as an industrial feedstock. An acid catalyst is commonly used in this method. The chemical formula for the hydration of ethylene is shown below:
C
2
H
4
+ H
2
O → CH
3
CH
2
OH
Ethanol can be produced from starch-based, sugar-based, or cellulosic feedstocks.
In the United States, ethanol is primarily produced from corn grain; while in Brazil, ethanol is primarily produced from sugar cane. The first step in the extraction process

involves grounding of wheat and corn kernels in a hammer-mill. The grounded grain is then mixed with water and this mixture is briefly heated. Next, enzymes are added to convert the starch to sugar using a chemical reaction called hydrolysis. Yeast is added to ferment the sugars to ethanol. Lastly, ethanol is separated from the mixture by distillation. The fermentation process is rather simple; a glucose molecule is broken down into ethanol molecules and one carbon dioxide molecule, the carbon dioxide is released into the air and you are left with a colorless, clean burning liquid with a strong odor
(Ethanol History).
Ethanol is classified as a primary alcohol, meaning that the carbon its hydroxyl group attaches to has at least two hydrogen atoms attached to it. Many ethanol reactions occur at its hydroxyl group. In the presence of acid catalysts, ethanol reacts with carboxylic acids to produce ethyl esters and water:
RCOOH + HOCH
2
CH
3
→ RCOOCH
2
CH
3
+ H
2
O
Strong acid desiccants cause the dehydration of ethanol to form diethyl ether and other byproducts. If the dehydration temperature exceeds around 160 °C (320 °F), ethylene will be the main product. Millions of kilograms of diethyl ether are produced annually using sulfuric acid catalyst:
2 CH
3
CH
2
OH → CH
3
CH
2
OCH
2
CH
3
+ H
2
O (on 120 °C)
Ethanol is a neutral molecule and the pH of ethanol solution in water is nearly 7.00.
Ethanol can be quantitatively converted to its conjugate base, the ethoxide ion
(CH
3
CH
2
O
−
), through a reaction with an alkali metal such as sodium:[27]
2 CH
3
CH
2
OH + 2 Na → 2 CH
3
CH
2
ONa + H
2
Ethanol is not used industrially as a precursor to ethyl halides, but the reactions are illustrative. Ethanol reacts with hydrogen halides to produce ethyl halides such as ethyl chloride and ethyl bromide via an S
N
2 reaction:
CH
3
CH
2
OH + HCl → CH
3
CH
2
Cl + H
2
O
There is a lot of room for progression in the technology that works around ethanol. It may one day be a very reliable resource that we can count on to make a bigger impact in the world. As Henry Ford sees it in 1925, ethanol is the fuel of the future.