There are more than a million organic compounds 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: Write the symbol for carbon as many times as necessary 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 2,2,4-trimethylpentane 2,3-dimethylhexane 4-ethyl-2,3,4-trimethyloctane 3,3-dimethyl-4-ethyloctane 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 Compounds Compounds that contain double or triple carbon- carbon bonds Alkenes: 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 Propyne Propane Propene

HALOCARBONS One of the branches is a halogen 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 Ketone -one

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 Ketone -one

CHALLENGE NAME THIS!

Organic Type Properties Uses Alkane Nonpolar Gases/Liquids Low boiling points Insoluble in water Gas/Oil/Fuels Methane: Natural Gas Propane: Homes/Grills Butane: Lighters Octane: Gasoline Alcohol Hydrogen Bonds Liquids Higher boiling points than the other groups Soluble in water (up to 4 carbons) Perfumes, Mouthwash, Hairspray, Antifreeze, Rubbing Alcohol, Antiseptic, Alcoholic Beverages Aldehyde (Ketones) Weak Hydrogen bonds Liquids or solids at room temperature Boiling points lower than alcohols higher than alkanes Soluble in water up to 5 carbons Flavoring agents Benzaldehyde: Almond oil Cinnamaldehyde: Cinnamon oil Vanilla flavoring Carboxylic Acid Hydrogen bonds Volatile liquids/Waxy solids Higher boiling points than other compounds Acetic acid: Vinegar Stearic acid: Wax candles Fatty acids Ester Polar but no hydrogen bonds (H not attached to O) Lower boiling points than other compounds 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

Esters may be prepared from a carboxylic acid and an alcohol SYNTHESIS OF ESTERS Esters may be prepared from a carboxylic acid and an alcohol

Esterification

NAMING ESTERS