Organic Chemistry

Classification of Organic Compounds

Organic compounds are classified by their carbon backbone (skeletal) and by the functional groups they contain.

Alkanes

Alkanes are saturated hydrocarbons with the general formula CnH2n+2, characterized by single bonds and non-polarity.

Drawing Alkanes

To name and draw alkanes, identify the longest carbon chain, number from the end closest to a substituent, and name branches.

Structural Isomerism

Structural isomers have the same molecular formula but different bonding arrangements, distinguished by chain branching and functional group position.

Structural Diagrams

Complete diagrams show all atoms and bonds, while line diagrams assume carbon at ends/bends and hydrogens fill remaining bonds.

Sigma Bonds

Sigma bonds are single covalent bonds that allow rotation and lead to staggered conformations minimizing electron cloud repulsion.

Cyclic Hydrocarbons

Cyclic hydrocarbons use the prefix 'cyclo-' and follow the formula CnH2n; count ring carbons and use the lowest numbers for substituents.

Pi Bonds

Pi bonds occur in double/triple bonds, limiting rotation and creating fixed atom orientations like cis/trans or E/Z isomers.

Reactions of Alkenes and Alkynes

Alkenes/alkynes can undergo addition reactions to produce alkanes, alcohols, or halogenoalkanes with various reagents.

Degrees of Unsaturation

Calculated using the formula: (2C + 2 - H + N - X)/2; each degree indicates a ring or double bond.

Reactions of Alkanes

Alkanes can undergo combustion and substitution reactions with halogens to form halogenoalkanes.

Alcohols

Alcohols contain an -OH group and can be classified as primary, secondary, or tertiary based on their carbon connections.

Nomenclature of Alcohols

To name alcohols, identify the longest chain with -OH, number it from the -OH end, and draw structural or line diagrams.

Oxidation of Alcohols

Alcohol oxidation converts primary alcohols to aldehydes and then carboxylic acids; secondary alcohols yield ketones.

Substitution Reactions of Alcohols

Alcohol + HCl forms halogenoalkanes without needing a catalyst, transforming -OH groups into better leaving groups.

Ethers

Ethers are R–O–R' compounds named by identifying both sides as substituents; they are non-polar and unreactive.

Formation of Ethers

Ethers form through condensation of alcohols with an acid catalyst, resulting in an ether and water.

Carbonyl Group

The carbonyl group (C=O) is polar and reactive, found in aldehydes and ketones, often involved in reduction reactions.

Naming Aldehydes and Ketones

Aldehydes end with -al while ketones end with -one; numbering should give the carbonyl the lowest number.

Reduction of Carbonyl Compounds

Reduction of carboxylic acids yields aldehydes and primary alcohols; ketones yield secondary alcohols using reducing agents.

Comparing Physical Properties

Physical properties depend on functional groups, molecular size, and packing; H-bonding affects solubility and boiling point.

Carboxylic Acids

Carboxylic acids contain the -COOH group, are acidic and polar, named with the suffix -oic acid.

Ester Formation

Esterification occurs when a carboxylic acid reacts with an alcohol in the presence of an acid catalyst to form an ester.

Amines

Amines are derivatives of NH₃, act as bases, and are named with the suffix -amine based on carbon attachments.

Amides

Amides, containing -CONH₂, are polar compounds formed from carboxylic acids and amines, present in proteins.

Addition Polymerization

Addition polymerization involves joining alkenes without losing atoms, producing polymers like polyethylene from ethene.

Condensation Polymerization

Condensation polymerization links monomers with two functional groups and releases water, forming materials like nylon.

Properties of Polymers

Properties of polymers depend on their structure, affecting applications in plastics, textiles, electronics, and medicine.