Alcohols

Alcohol

An organic compound containing the functional group -OH, known as the alcohol group.

Homologous series

1. General molecular formula: R-OH, where R represents the alkyl group.
2. For example: Methanol ($CH_3OH$), Ethanol ($C_2H_5OH$).
3. Successive members differ by one -CH₂- group.

Nomenclature of alcohols

1. Similar to naming alkanes, but the suffix -ane is replaced by -anol.
   • Example 1: Ethane → Ethanol ($C_2H_5OH$)
   • Example 2: Heptane → Heptanol ($C_7H_{15}OH$)

Commercial production of alcohol

1. Fermentation process

1. Yeast breaks down sugar into alcohol and carbon dioxide.
2. Word equation: Glucose + Yeast → Alcohol + Carbon Dioxide
3. Types of fermentation: a) Alcoholic Fermentation: Produces alcohol. b) Lactic Acid Fermentation: Produces lactic acid.

Example of fermentation

1. In beer, barley, hops, water, and yeast are fermented to produce alcohol.
2. Distillation is used for stronger alcohol like vodka or rum.

2. Local preparation of alcohol

1. Raw materials: Sugar beet, cereals (cassava, millet, maize).

3. Industrial preparation

1. Raw materials: Maltose sugar ($C_{12}H_{22}O_{11}$).
2. Starch is converted into maltose using the enzyme diastase.
3. Fermentation using yeast produces alcohol.

Properties of alcohol

1. Colorless with a characteristic odor and taste.
2. Soluble in water, forming a homogeneous mixture.
3. Boiling point: 78°C.
4. Pure ethanol is a non-electrolyte.

Reactions of alcohol

1. With Carboxylic Acid
   • Forms ester and water (esterification reaction).
   • Example: Ethanol + Ethanoic Acid → Ethyl Ethanoate + Water
2. With Electropositive Metals
   • Produces metal alkoxides and hydrogen gas.
   • Example: $C_2H_5OH + Na \rightarrow C_2H_5ONa + H_2$
3. With Oxidizing Agents
   • Produces carboxylic acids.
   • Example: $C_2H_5OH \rightarrow CH_3COOH$ (Ethanol oxidized to Ethanoic acid).
4. With Concentrated Sulfuric Acid
   • Acts as a dehydrating agent.
   • Example: $C_2H_5OH \rightarrow CH_2=CH_2 + H_2O$
5. With PCl₅, PCl₃, SOCl₂
   • Produces alkyl halides.
   • Example: $C_2H_5OH + PCl_5 \rightarrow C_2H_5Cl + POCl_3 + HCl$

Uses of ethanol

1. Manufacture of spirits: Used in hospitals and salons as a sterilizing agent.
2. Preservation: For specimens and food.
3. Fuel and light: Alternative energy source.
4. Solvent: In varnishes, paints, soaps, and medicines.
5. Raw material: For producing chemicals like trichloromethane.
6. Alcoholic drinks:
   • Beer: Contains 2-6% ethanol.
   • Wine: Contains about 10% ethanol, made from fermented grapes.

Harmful effects of alcohol

1. Brain damage: Causes shrinkage of brain cells and impairs reasoning.
2. Liver damage: Can lead to liver cancer and other health issues.
3. Digestive issues: Causes anemia and disrupts digestion.
4. Accidents: Alcohol impairs judgment, leading to accidents.
5. Family issues: Misuse can result in conflicts and financial problems.
6. Toxicity: Methanol ingestion (as little as 30 mL) can cause blindness or death.