Carbon Compounds-Hydrocarbons Organic Chemistry Carbon Compounds-Hydrocarbons Anura Hewagama, Ph.D.

Carbon Compounds - Introduction Carbon can more compounds than any other chemical element in the periodic table except for hydrogen. In general bonds of carbon with other elements are covalent bonds. The simplest organic compounds contain molecules composed of carbon and hydrogen. (Hydrocarbons).

Hydrocarbons Alkanes Alkenes Alkynes Contain only single bonds Contain at least one double bond Alkynes Contains at least one triple bond

Naming Hydrocarbons Steps Prefixes Identify the longest, continuous carbon chain (Parent Chain) Count the number of C atoms Name the hydrocarbon Alkanes ends with “..ane” Alkenes ends with “..ene” Alkyne ends with “.. yne” # of Carbon Prefix 1 Meth 2 Eth 3 Prop 4 But 5 Pent 6 Hex 7 Hept 8 Oct 9 Non 10 Dec

Homologous Series -Has a fixed numerical relationship between Among number of Atoms For Alkanes CnH2n+2

Isomers Hydrocarbons with same formula but different structures

Branched- Chain Alkanes So far we discussed: Single-Chain Alkanes ( Carbon atoms bonded to each other in a straight chain) Branched Chain: Example Alkyl Group CH3 = Methyl Fuel: Lighters Refrigerent, propellant (Shaving gel)

Naming Branched-Chain Alkanes Use IUPAC (International Union of Pure and Applied Chemistry) Rules Count the number of C atoms in the longest, continuous carbon chain (Parent Chain) Number each carbon in the parent chain, number 1 being the C closest to the substituent group (all substituent groups must receive lowest possible number) Name each alkyl group substituent For more than 1 alkyl groups use prefixes (di-, tri-, tetra,……); then use the number of the C atom to which each is attached to indicate the position When different alkyl groups are attached to same parent structure, place their names in alphabetical order, (do not consider prefixes in determining alphabetical order) Write the entire name, using hyphens to separate numbers from words and commas to separate the numbers.

4-ethyl- 3,5-dimethyl Octane Hyphen to separate numbers from words 4-ethyl- 3,5-dimethyl Octane Comas to separate numbers