Organic Chemistry - Alcohols: Ethanol

Objective

State the uses of ethanol as:

1. (a) a solvent
2. (b) a fuel

(a) Ethanol as a Solvent

Ethanol is a versatile solvent due to its ability to dissolve a wide range of substances. This is because ethanol is a polar molecule, capable of forming hydrogen bonds with polar and ionic compounds, as well as dissolving some non-polar substances.

Specific Uses as a Solvent:

• Pharmaceuticals: Ethanol is widely used in the production of medicines and syrups. It helps to dissolve active ingredients and create a homogenous solution.
• Cosmetics and Perfumes: It acts as a solvent for fragrances, oils, and other ingredients in perfumes, lotions, and other cosmetic products.
• Chemical Reactions: Ethanol can be used as a solvent in various chemical reactions, particularly those involving polar reactants.
• Cleaning Agent: Ethanol is a common ingredient in cleaning solutions, especially for removing grease and grime.

(b) Ethanol as a Fuel

Ethanol can be used as a fuel in internal combustion engines. It is often used as a biofuel, either on its own or mixed with gasoline (e.g., E10, E20).

Advantages of Ethanol as a Fuel:

• Renewable Source: Ethanol can be produced from renewable sources like corn, sugarcane, and other biomass.
• Lower Emissions: Burning ethanol generally produces lower greenhouse gas emissions compared to gasoline.
• Higher Octane Rating: Ethanol has a higher octane rating than gasoline, which can improve engine performance.

Considerations:

• Lower Energy Density: Ethanol has a lower energy density than gasoline, meaning that vehicles using ethanol may have a slightly reduced range.
• Compatibility Issues: Ethanol can be corrosive to some materials used in older vehicles, requiring modifications to fuel systems.

Use	Description
Ethanol as a Solvent	Dissolves a wide range of substances due to its polarity. Used in pharmaceuticals, cosmetics, chemical reactions, and cleaning agents.
Ethanol as a Fuel	Can be used in internal combustion engines as a biofuel. Offers renewable source, lower emissions, and higher octane rating.