functional groups · physical properties the hydroxyl group is polar and allows for hydrogen...
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FUNCTIONAL GROUPSSCH4U7 - Organic Chemistry
Monday, January 30, 2012
FUNCTIONAL GROUPS
Functional groups are groups of atoms other than carbon and hydrogen linked to a hydrocarbon
They are where the real chemistry happens
They also give a compound distinct properties, like melting points, boiling points and reactivity
R is often used to represent a chain of hydrocarbons instead of writing them all out
Monday, January 30, 2012
A PREVIEW!
Monday, January 30, 2012
ALCOHOLS
Alcohols contain a hydroxyl (OH) group connected to carbon #1
General formula is R - OH where R is a hydrocarbon
Suffix is “ol”
Prefixes remain the same
Name these!
Methanol Pentan-1-olMonday, January 30, 2012
CLASSIFYING ALCOHOLSAlcohols are classified according to how many carbons the first carbon is attached to.
1) Primary alcohol-one in which the carbon to which the OH group is attached is attached to only ONE other C atom.
2) Secondary alcohol-one in which the carbon to which the OH group is attached is attached to only TWO other C atoms.
3) Tertiary alcohol-one in which the carbon to which the OH group is attached is attached to only THREE other C atoms.
Monday, January 30, 2012
SPECIAL ALCOHOLS
If there are 2 hydroxyl groups present then use the suffix “diol”
Draw out this compound: CH2OHCH2OH
Name it
If there are 3 hydroxyl groups present then use the suffix “triol”
Draw out this alcohol: CH2OHCHOHCH2OH
Ethanediol
propanetriol
Monday, January 30, 2012
PHYSICAL PROPERTIES
✴ The hydroxyl group is polar and allows for hydrogen bonding
✴Due to the increased intermolecular forces, the melting and boiling points of alcohols are higher than the corresponding hydrocarbon. MP & BP increases with chain length
✴ Since the hydroxyl group allows for hydrogen bonding, alcohols are quite soluble in water
✴ As the hydrocarbon chain increases in length, the solubility in water decreases. Why?
✴ C1-C5= highly soluble; C5-C7= moderately soluble; C8and above = slightly soluble/insoluble
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TRY IT !
Name these alcohols:
Draw these alcohols:
5-ethyl-3-methyl-2,3-nonanediol
3,4-dimethylhexan-2-ol
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TRY IT !
Monday, January 30, 2012
ALKYL HALIDES
R - X (where X is any halogen: F, I, Br, Cl)
Prefix used: fluoro, iodo, bromo, chloro
Use numbers to indicate where the halogen is
Same classification as with alcohols (primary, secondary, tertiary)
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PHYSICAL PROPERTIESAs we have seen before, the boiling point increases the longer the chain
Solubility DEcreases the longer the chain, since it is more hydrophobic
Name these haloalkanes:
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Monday, January 30, 2012
CARBONYL GROUPSCarbonyl group is C=O
There are 2 classes of organic compounds which contain this:
Aldehydes - contain C=O at the END of a chain
Ketones - contain C=O in the middle of a chain
Monday, January 30, 2012
ALDEHYDESSuffix: “al”
Carbon which is bonded to oxygen MUST be counted as number 1. Always. No exceptions. This means no number is needed to indicate where the oxygen is.
In the condensed form, abbreviated at CHO (avoiding confusion with alcohols)
ie) Ethanal
Draw & name: C2H5CHO
Draw: 4-methylpentanalMonday, January 30, 2012
KETONES
Suffix: “one”
Carbon which is bonded to oxygen MUST be indicated by a number
In the condensed form, abbreviated at CO.
ie) Propanone - why no number?
Draw & name: C3H7COCH3
Draw: Hexan-3-one
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PHYSICAL PROPERTIES
C=O is a polar group and creates a dipole
The intermolecular forces are stronger than in corresponding alkanes, but lower than in alcohols (since alcohols have hydrogen bonding)
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CARBOXYLIC ACIDA carboxylic acid is an organic acid which contains the functional group
Suffix used “oic acid”
Abbreviated COOH
Numbers are not required because the first carbon MUST be the one bonded to the oxygen and hydroxyl group
Monday, January 30, 2012
NEAT-O!
Draw & name: C2H5COOH
Draw: 3,4-dichloro-2,3-dihydroxyhexanoic acid!
Name:
Monday, January 30, 2012
PHYSICAL PROPERTIES
Since they contain both C=O and OH, they can form strong hydrogen bonds
Carboxylic acids will have the highest melting point of all comparable organic compounds
1) Order the following in ascending order of boiling point: Propanal, propanol, propanoic acid, propane
2) Does 3-pentanoic acid exist? If yes, draw it. If no, explain why.
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OTHER FUNCTIONAL GROUPS
At the SL level, you are only required to recognize the following groups:
Esters:
Amines:
Amides:
Ethers:
Benzene (phenyl)
Monday, January 30, 2012
TRY IT!
Monday, January 30, 2012
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Monday, January 30, 2012
Monday, January 30, 2012