Alkanes and Cycloalkanes By Prof. Dr. Adel M. Awadallah Organic chemistry for medicine and biology students Chem 2311 Chapter 2 Alkanes and Cycloalkanes By Prof. Dr. Adel M. Awadallah Islamic University of Gaza

Alkanes and Cycloalkanes Hydrocarbons (contain only carbon and hydrogen) Saturated: (Contain only single bonds) Alkanes (CnH2N + 2 ) Cycloalkanes (CnH2N ) b) Unsaturated: contain Alkenes: double bonds (,,,CnH2N) Alkynes: triple bonds ((CnH2N - 2) Aromatic: benzene like compounds

The structure of alkanes

Alkyl groups

Nomenclature of substituted alkanes Choose the largest continuous chain Start numbering (lowest possible numbering) List substituents alphabitically. Use di, tri, tetra, penta, hexa, hepta, octa, nona, deca for identical groups Examples

If there are two equally long continuous chains, choose the one with most branches

Physical properties of alkanes 1) Water insoluble 2) low boiling point, which increases upon increasing the number of carbons in the alkane 3) branched alkanes have lower boiling points than the corresponding long chain alkanes

Conformations of Alkanes: Conformers: Stereoisomers that are interconvertible by bond rotation

Cycloalkanes:

Conformations of Cyclohexane

Reactions of Alkanes:

Draw the monochloro and dichloro products expected from chlorination of propane