Introduction to Organic Chemistry - Alkanes

1. Introduction to Organic Chemistry - Alkanes Chemistry 11 – Organic Chemistry 1

2. Organic Chemistry: • Organic Chemistry is all about the study of organic compounds – compounds that contain carbon. Exceptions to this classification include diamond, graphite (pure carbon) and oxides of carbon (CO and CO2). Organic compounds are important because there are a huge variety of compounds that include carbon. • In higher level organic chemistry, scientists are concerned with how to synthesize various organic compounds, typically for medicinal use.

3. Naming Alkanes: • Alkanes are the simplest organic compounds. They include chain(s) of carbon and hydrogen that have only single bonds with each other, without any cycles or loops. To name alkanes, we need to use prefixes to indicate the number of carbons in the chain:

4. Prefixes: • 1 – meth • 2 – eth • 3 – prop • 4 – but • 5 – pent • 6 – hex • 7 – hept • 8 – oct • 9 – non • 10 – dec

5. Examples: • Name the following compounds: • CH3CH2CH3 Propane • C3H8 Propane • Ethane

6. Structure of Carbon Compounds: • Carbon is a versatile element because it is able to have four bonds. Since bonds are made up of electrons which have negative charges, any bonds that are created (as well as lone electron pairs) will tend to stay away from each other as far as possible. Therefore, a fully-bonded carbon will take a tetrahedron shape:

7. Examples: Draw the molecules below in 3D. • CH3CH3 • Propane • Butane

8. Naming Alkanes with Halogens: • An alkane may have halogens attached to it. To name these compounds use the following guidelines: • Figure out what type of alkane you are working with (methane, butane, etc.) • Number each carbon. Figure out which carbon number the halogen is attached to. Use the lowest number possible for the halogen. • If there is more than one halogen in the carbon chain with the same number priority, prioritize them alphabetically.

9. To name the alkane, use the number followed by a hyphen followed by the name of the halogen. If there is more than one of the same halogen, use Greek prefixes (di, tri, etc). • The halogens should be listed alphabetically in the naming. (i.e. 2-bromo-1-chlorooctane)

10. Examples: • Name the following alkanes: • bromoethane • 1-bromo-3-fluoropropane • 1-bromo-5-fluoro-3,3-diiodopentane

11. 1,3-dibromopropane • 2-bromo-1-fluoro-4-iodobutane • 5-bromo-1,1-difluoro-6-iodohexane

12. Assignment Worksheet