Lecture_Packet_8_-_Oxygen_Compounds

Classes of Organic Compounds

• Key Structural Features are used to classify organic molecules.

Carbon-Hydrogen Compounds

• Types:

  • Alkane: Contains single bonds only (e.g., C-C)

  • Alkene: Contains at least one double bond (C=C)

  • Alkyne: Contains at least one triple bond (C≡C)

  • Arene: Contains aromatic rings

Oxygen-Containing Compounds

• Types:

  • Alcohol: Contains -OH (hydroxyl) group

  • Ether: Contains R-O-R' (alkoxy groups)

  • Phenol: Contains an -OH group attached to an aromatic ring

  • Aldehyde: Contains a carbonyl (-C=O) group with a hydrogen atom

  • Ketone: Contains a carbonyl group between two carbon atoms

  • Carboxylic Acid: Contains a carbonyl group and a hydroxyl group (-COOH)

  • Ester: Derived from carboxylic acids and alcohols

  • Thiol: Contains -SH (sulfhydryl) group

  • Amine: Contains -NH2 (amino) or similar structures

  • Amide: Contains a carbonyl group linked to a nitrogen atom

  • Phosphoanhydride: Contains P-O-P linkages in organic structures

Polyfunctional Compounds

• Fit into more than one class and display the properties common to each class.

  • Examples:

    • Galactose: Alcohol + Aldehyde

    • Oleic Acid: Alkene + Carboxylic Acid

    • Asparagine: Amine + Amide + Carboxylic Acid

Functional Groups

• Definitions:

  • Special names given to common pieces in organic molecules such as:

    • Hydroxyl Group (-OH)

    • Carbonyl Group (>C=O)

    • Carboxyl Group (-COOH)

• Determine physical properties (polarity, boiling points, solubility) and chemical reactivity locations.

Physical Properties of Oxygen-Containing Organic Molecules

1. Polarity

• Small Molecules: Generally polar due to oxygen's higher electronegativity.

  • Examples: Aldehydes, alcohols, carboxylic acids.

  • Determine bond polarity by calculating electronegativity differences.

2. Boiling Points

• Trends:

  • Boiling points increase with the number of carbons.

  • Compare boiling points within functional classes:

    • Lowest: Alkanes < Aldehydes/Ketones < Alcohols < Carboxylic Acids: Highest.

  • Intramolecular forces involved:

    • Dispersion Forces: Weakest, exist in all compounds.

    • Dipole-Dipole Attractions: Moderate for polar molecules.

    • Hydrogen Bonding: Strongest, occurs in alcohols and carboxylic acids.

3. Water Solubility

• General Rule: Like dissolves like.

• Types of Solutes:

  • Nonpolar molecules: Not soluble in water.

  • Polar molecules (no F, O, N): Soluble via dipole-dipole attractions.

  • Small molecules with F, O, N: Soluble via hydrogen bonding.

  • Larger molecules with nonpolar portions: Decreased solubility.

Naming Organic Compounds

Alcohols

• Named by changing the alkane ending from -e to -ol, specifying -OH position when more than 3 carbons.

Aldehydes and Carboxylic Acids

• Aldehydes: Change -e to -al.

• Carboxylic Acids: Change -e to -oic acid.

Ethers and Phenols

• Derived from water but with carbon substituents.

Chemical Properties of Alcohols

1. Dehydration

• Conversion to alkenes; requires heat & acid (e.g., H2SO4).

2. Oxidation

• Converts alcohols to aldehydes, ketones, or carboxylic acids based on the alcohol type (primary, secondary, tertiary).

Chemical Properties of Carbonyl Compounds

1. Aldehydes and Ketones

• Structure: Aldehydes have terminal carbonyl group; Ketones have it in the middle.

2. Carboxylic Acids

• Ionize in water to form carboxylate ions; neutralize with strong bases to form salts.

3. Esterification

• Reaction product of carboxylic acids with alcohols.