ALKOHOL (ALKANOL) : RUMUS UMUM, JENIS-JENIS ALKANOL, TATA NAMA IUPAC & TRIVIAL, ISOMER

Introduction

This tutorial provides a comprehensive overview of alkanols (alcohols), including their general formulas, classifications, naming conventions (IUPAC and trivial), and types of isomers. Understanding these concepts is essential for anyone studying organic chemistry, particularly in the context of alkane derivatives.

Step 1: Understanding the General Formula of Alkanols

• Alkanols, commonly known as alcohols, are organic compounds derived from alkanes.
• The general formula for alkanols is CₙH₂ₙ₊₁OH, where:
  • Cₙ represents the number of carbon atoms.
  • H₂ₙ₊₁ indicates the hydrogen atoms bonded to carbon.
  • OH is the hydroxyl functional group characteristic of alcohols.

Step 2: Classifying Alkanols

Alkanols can be classified into several types based on their structure:

1. Primary Alcohols:

   • The hydroxyl group is attached to a carbon atom that is bonded to only one other carbon atom.
   • Example: Ethanol (C₂H₅OH).

2. Secondary Alcohols:

   • The hydroxyl group is attached to a carbon atom bonded to two other carbon atoms.
   • Example: Isopropanol (C₃H₈O).

3. Tertiary Alcohols:

   • The hydroxyl group is attached to a carbon atom bonded to three other carbon atoms.
   • Example: Tert-butanol (C₄H₁₀O).

4. Monoalcohols:

   • Contain only one hydroxyl group.
   • Example: Methanol (CH₃OH).

5. Polyols:

   • Contain multiple hydroxyl groups.
   • Example: Glycerol (C₃H₈O₃).

Step 3: Naming Alkanols Using IUPAC and Trivial Names

• IUPAC Naming:

  1. Identify the longest carbon chain containing the hydroxyl group.
  2. Number the chain starting from the end nearest to the hydroxyl group.
  3. Use the suffix "-ol" to indicate the presence of an alcohol.
  • Example: For C₄H₉OH, the IUPAC name is Butanol.

• Trivial Naming:

  • Common names based on historical or traditional usage.
  • Example: Ethanol is commonly referred to as "ethyl alcohol".

Step 4: Exploring Isomers of Alkanols

Isomers are compounds with the same molecular formula but different structural arrangements:

1. Positional Isomers:

   • Differ in the position of the hydroxyl group on the carbon chain.
   • Example: 1-butanol vs. 2-butanol.

2. Functional Isomers:

   • Compounds with the same molecular formula but different functional groups.
   • Example: Alcohols vs. ethers.

3. Optical Isomers:

   • Compounds that are non-superimposable mirror images due to the presence of chiral centers.
   • Example: 2-butanol can exist as two enantiomers.

Conclusion

This guide has provided a structured overview of alkanols, covering their general formulas, classifications, naming conventions, and types of isomers. Understanding these fundamental concepts is crucial for further studies in organic chemistry and practical applications in various fields. For deeper insights, consider exploring the next part of the series, which covers the chemical and physical properties of alcohols and their synthesis.