Organic Chemistry

The study of carbon-containing compounds

There are more than a million organic

compounds

HYDROCARBONS

• The simplest organic compounds containing only carbon and hydrogens– Carbon has 4 valence electrons and therefore

always forms 4 covalent bonds

HYDROCARBON PREFIXES

Prefix # of Carbons

Meth- 1

Eth- 2

Prop- 3

But- 4

Pent- 5

Hex- 6

Hept- 7

Oct- 8

Non- 9

Dec- 10

Methods of Illustrating Hydrocarbons

Formula Description

C4H10 Molecular Formula

Complete Structural Formula (Lewis Structure)

CH3-CH2-CH2-CH3 Condensed Structural Formula: C-H bonds understood

CH3CH2CH2CH3 Condensed Structural Formula: C-C and C-H bonds understood

CH3(CH2)2CH3 Condensed Structural Formula: All bonds understood, parentheses indicate CH2 are linked

in a continuous chain

C-C-C-C Carbon skeleton: all hydrogens and C-H bonds understood

Line-angle formula: All carbons and hydrogens understood; carbon atoms are located at each intersection and at the ends of lines.

ALKANES

• A hydrocarbon in which there are only single covalent bonds– In an alkane, all the carbon-carbon bonds are

single covalent bonds• All other bonds are carbon-hydrogen bonds

– The carbon atoms in an alkane can be arranged in a straight chain or in a chain that branches

• Alkanes are called saturated compounds because they contain only single bonds

Straight Chain Alkanes

• Carbon atoms are one after another in a chain– Homologous Series: There is a constant

increment of change from one compound in the series to the next

• In an alkane a CH2 is the increment of change

Naming Alkanes

• For all alkanes the name ends in –ane

• Count the carbon atoms and add the appropriate prefix

Example: C6H14

To draw the structural formula:

1) Write the symbol for carbon as many times as necessary

2) Complete each carbon’s 4 bonds with hydrogen atoms

Example: Octane

Branched Chain Alkanes

• An alkane with one or more alkyl groups– Substituent: An atom or group of atoms that

takes the place of a hydrogen atom on a parent alkane

– Parent Alkane: The longest continuous chain of a hydrocarbon

– Alkyl Group: A hydrocarbon substituent

Naming the alkyl groups

• Name end in –yl

• Add the appropriate prefix based on # of carbons in the alkyl group

Practice Problems

Drawing Structural Formulas for Alkanes

1) 2,2,4-trimethylpentane

2) 2,3-dimethylhexane

3) 4-ethyl-2,3,4-trimethyloctane

4) 3,3-dimethyl-4-ethyloctane

5) hexane

6) 2-methylbutane

ISOMERS• Compounds that have the same molecular

formula but different molecular structures– Structural Isomers: compounds that have the

same molecular formula, but the atoms are joined together in a different order

Differ in physical properties like boiling and melting points

Also have different chemical reactivities

The more highly branched the hydrocarbon structure, the lower the boiling point

Unsaturated CompoundsCompounds that contain double or triple carbon-

carbon bondsAlkenes: hydrocarbons containing one or more carbon-carbon double covalent bonds

Plastics (more reactive than alkane)

Alkynes: hydrocarbons containing one or more carbon-carbon triple covalent bonds

Preparing organic solvents, starting material for polymers, oxy-acetylene flame for welding

NAMING ALKENES/ALKYNES

• The parent chain must contain the double/triple bond. Number from the side closest to that bond.

• If it contains a double bond, it ends in –ene

• If it contains a triple bond, it ends in –yne

– # the double-triple bond

– Name substituents as with alkanes

Naming Examples

Structural Formula Examples

1) Propyne

2) Propane

3) Propene

HALOCARBONS

• Alkane + Halogen Halocarbon + Hydrogen Halide

CH4 + Cl2 CH3Cl + HCl

• One of the branches is a halogen– Named chloro, fluoro, bromo, iodo

• Building blocks for

things like Teflon & PVC

• Organic compounds can be classified according to their functional group– Functional Group: A specific arrangement

of atoms in an organic compound that is capable of characteristic chemical reactions

Functional Groups (R = any carbon chain)

Compound Type

Compound Structure

Name ends in

Functional Group

Alcohol —OH -ol Hydroxyl

Aldehyde -al Carbonyl

Carboxylic Acid

-oic acid Carboxyl

Ester -oate Ester

Ketone -one Ketone

Naming:•drop the –e ending of the parent alkane name and add the ending to the proper functional group ending•Parent alkane is the longest continuous chain that includes the carbon attached to the functional group•If the functional group can occur at more than one position, its position is designated with the lowest possible number.•Alcohols containing 2, 3, or 4 –OH substituents are named diols, triols, and tetrols

Compound Type

Compound Structure

Name ends in

Functional Group

Alcohol —OH -ol Hydroxyl

Aldehyde -al Carbonyl

Carboxylic Acid

-oic acid Carboxyl

Ester -oate Ester

Ketone -one Ketone

CHALLENGENAME THIS!

Organic Type

Properties Uses

Alkane NonpolarGases/LiquidsLow boiling pointsInsoluble in water

Gas/Oil/FuelsMethane: Natural GasPropane: Homes/GrillsButane: LightersOctane: Gasoline

Alcohol Hydrogen BondsLiquidsHigher boiling points than the other groupsSoluble in water (up to 4 carbons)

Perfumes, Mouthwash, Hairspray, Antifreeze, Rubbing Alcohol, Antiseptic, Alcoholic Beverages

Aldehyde(Ketones)

Weak Hydrogen bondsLiquids or solids at room temperatureBoiling points lower than alcohols higher than alkanesSoluble in water up to 5 carbons

Flavoring agentsBenzaldehyde: Almond oilCinnamaldehyde: Cinnamon oilVanilla flavoring

Carboxylic Acid

Hydrogen bondsVolatile liquids/Waxy solidsHigher boiling points than other compoundsSoluble in water up to 5 carbons

Acetic acid: VinegarStearic acid: Wax candlesFatty acids

Ester Polar but no hydrogen bonds (H not attached to O)LiquidsLower boiling points than other compoundsSoluble in water up to 5 carbons

Pleasant, fruity odors (blueberries, pineapples, pears, apples, bananas); perfumes & fragrances

Boiling Points: Carboxylic Acid > Alcohol > Aldehyde > Alkane

Solubility in Water Alkanes: Insoluble

Alcohol/Aldehyde/Ester/Carboxylic Acid: Soluble up to 4-6 carbons

SYNTHESIS OF ESTERS

Esters may be prepared from a carboxylic acid and an alcohol

NAMING ESTERS