organic chemistry the study of carbon- containing compounds there are more than a million organic...
TRANSCRIPT
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