Absolute ethanol, due to its high purity and miscibility with water, is a versatile solvent with numerous applications across various industries. It can dissolve a wide range of organic compounds, including both polar and non-polar substances such as hexane. Let’s delve into its uses and benefits.
How is Absolute Ethanol Used in Chemistry?
Absolute ethanol, with its purity level of 99-100%, is invaluable in both industrial and laboratory settings. Here are some key applications:
- Solvent: Its ability to dissolve non-polar organic compounds makes it ideal for use in perfumes, colognes, and other alcohol-based products like denatured alcohol, rubbing alcohol, hand sanitizers, and lotions.
- Reagent: In analytical experiments, absolute ethanol acts as a reagent, crucial in the synthesis of new substances or chemical derivatives.
- Laboratory Use: It’s used in labs to fuel alcohol lamps, preserve biological specimens, disinfect equipment, and dissolve organic compounds.
Antiseptic and Disinfectant Properties
Absolute ethanol is highly hygroscopic, meaning it readily absorbs water. This property enhances its effectiveness as an antiseptic and disinfectant, as it can dehydrate and inactivate many species of microbes. By forcing water out of cells, ethanol disrupts cell structure and biochemical activities, leading to cell death.
Differences Between Ethanol and Absolute Ethanol
Both ethanol and absolute ethanol share the chemical formula C2H5OH, but their purity levels set them apart. Ethanol is found in alcoholic beverages at lower concentrations, while absolute ethanol is nearly 100% pure, though it may contain trace impurities like benzene.
Production of Absolute Ethanol
Producing absolute ethanol involves multiple distillations and the use of separation agents due to ethanol’s hygroscopic nature. Here are common methods:
- Benzene Separation: Adding benzene to a 95.6% ethanol solution and performing fractional distillation at 78.2 °C produces absolute ethanol. However, this method leaves traces of poisonous benzene, making the ethanol unsafe for consumption.
- Desiccation: Using adsorbents like starch or zeolites, this method yields high-purity ethanol, commonly referred to as spectroscopic alcohol, used in spectroscopic analysis.
Concentration of Absolute Ethanol
Absolute ethanol contains less than 1% water. Achieving this level of purity through simple fractional distillation is impossible due to the azeotropic mixture of 95.6% alcohol and 4.4% water, which evaporates at the same rate and thus cannot be separated further.
Common Uses of Absolute Ethanol
Absolute ethanol’s high purity makes it suitable for a variety of applications, including:
- Reagent
- Solvent
- Disinfectant
- Antiseptic
- Feedstock
- Fuel
- Low-temperature Liquid
Summary
Absolute ethanol, with its nearly 100% purity, is an essential solvent and reagent in various industries and laboratory settings. Its ability to dissolve both polar and non-polar compounds, coupled with its hygroscopic properties, makes it a versatile and effective substance for numerous applications. Whether used in chemical synthesis, as a disinfectant, or in manufacturing, absolute ethanol’s high purity ensures optimal performance.