Functional Groups Unit 3

Hydrocarbons There are four basic types of hydrocarbons: Alkanes Alkenes Alkynes Aromatic hydrocarbons

Functional Groups The term functional group is used to refer to parts of organic molecules: an atom or group of atoms within a molecule that shows a characteristic set of physical and chemical properties important for three reasons; they are 1. the units by which we divide organic compounds into classes 2. the sites of characteristic chemical reactions 3. the basis for naming organic compounds

Hydrocarbon Derivatives There are millions of organic compounds. We can categorize them into classes of compounds. Each of the classes has a specific functional group. A functional group is a set of atoms that gives a class of compounds its characteristics. There are 10 classes: five without a carbonyl group and five with a carbonyl group (C=O).

Non-Carbonyl Hydrocarbon Derivatives Here are the basic hydrocarbon classes. R is an alkyl group and Ar is an aryl group.

Carbonyl Hydrocarbon Derivatives

Organic Halides If a halogen atom (F, Cl, Br, I) replaces a hydrogen atom in a hydrocarbon, the new compound is an organic halide. Organic halides are used primarily as household and industrial solvents. They are found in many pesticides. They are essentially nonpolar molecules with low boiling points and properties similar to those of alkanes.

Alcohols & Phenols contain an -OH (hydroxyl) group Ethanol may also be written as a condensed structural formula When an –OH replaces a hydrogen atom on a arene, the resulting molecule is a phenol

Alcohols alcohols are classified as primary (1°), secondary (2°), or tertiary (3°) depending on the number of carbon atoms bonded to the carbon bearing the -OH group C H 3 - O A 1 ° a l c o h 2

Alcohols there are two alcohols with molecular formula C3H8O

Thiols A thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl (–C–SH or R–SH) group The functional group of a thiol is an SH (sulfhydryl) group The –SH functional group itself is referred to as either a thiol group or a sulfhydryl group

Ethers & Epoxides The functional group of an ether is an oxygen atom bonded to two carbon atoms Ethers tend to be quite unreactive. Therefore, they are good polar solvents. Epoxide: a cyclic ether in which oxygen is one atom of a three-membered ring

Amines contain an amino group; an sp3- hybridized nitrogen bonded to one, two, or three carbon atoms an amine may by 1°, 2°, or 3° C H 3 N Methylamine (a 1° amine) Dimethylamine (a 2° amine) Trimethylamine (a 3° amine) :

Carbonyl Compounds The carbonyl group is a carbon-oxygen double bond. Carbonyl compounds include many classes of compounds.

Aldehydes and Ketones contain a carbonyl (C=O) group

Carboxylic Acids contain a carboxyl (-COOH) group

Carboxylic Esters Ester: a derivative of a carboxylic acid in which the carboxyl hydrogen is replaced by a carbon group

Carboxylic Amide Carboxylic amide, commonly referred to as an amide: a derivative of a carboxylic acid in which the -OH of the -COOH group is replaced by an amine the six atoms of the amide functional group lie in a plane with bond angles of approximately 120°