Isopropyl and ethyl alcohol have similar physical properties. They both appear as colorless liquids with strong distinguishable odors. However, they differ in their chemical structure and properties. Ethyl alcohol's molecular formula is C2H5OH. According to Chem Spider, the compound has a molar mass of 46.07 g/mol, and a boiling point of 72.6 degrees C. Highly flammable, ethanol burns with a blue flame. The molecular formula of isopropyl is C3H7OH. It has a molar mass of 60.10 g/mol. Isopropyl burns at 73 degrees C, according to Chem Spider. In solution, isopropyl readily separates, whereas ethanol does not. Noticeably, the boiling points of ethyl and isopropyl are significantly lower than that of water (100.0 degrees C). The fewer number of hydrogen bonds between molecules allows these alcohols to evaporate faster than water.
The use of ethanol began centuries ago for various purposes. Consuming small amounts of the chemical can produce effects to the central nervous system that are relaxing or euphoric. The primary ingredient of alcoholic drinks is ethanol. Because ethanol burns to produce energy, it serves as a good, cost-effective source of fuel to power automobiles and other equipment. Using corn and sugar cane harvests to supply the ethanol is also a renewable resource, making it environmentally friendly. Conversely, isopropyl alcohol is not quite as versatile. It is primarily used as the active ingredient in rubbing alcohol and hand sanitizers. Both ethyl alcohol and isopropyl have antiseptic properties, but isopropyl is cheaper to produce, so it is used more commercially.
Ethanol is produced in different ways depending on its specific end use. For fuel, production by a chemical process known as ethylene hydration works effectively. Production for grain alcohol results from the fermentation of various live cultures of yeasts; ethanol is a byproduct of the yeasts' metabolism process. Production of isopropyl involves the chemical reaction between a mixture of water and propene.
Both ethyl and isopropyl are highly flammable and should be kept away from open flames. The vapor of these alcohols also combusts easily, so containers holding the liquids should be tightly closed and stored away. Ethanol does produce toxic effects to the body by slowing, or depressing, the central nervous system. Ingesting too much ethyl alcohol severely impairs the nervous system and can cause death. At approximately twice the toxicity of ethyl, isopropyl can be much more dangerous if ingested.
As antiseptics, both alcohols perform equally well. Alcohol has the ability to break down the outer membrane of many bacterias, killing them. For this reason, alcohol is the primary ingredient in hand sanitizers and other aseptic products used in hospitals and medical offices.