Chemistry - Functional Groups

Hydrocarbons: Types

• molecules composed of carbon and hydrogen only

ex: alkanes, alkenes, alkynes

Alkanes

saturated hydrocarbon: single covalent bond between carbon atoms, straight chain

Alkenes

unsaturated hydrocarbon: double bonds between carbon atoms

Alkynes

unsaturated hydrocarbon: triple bonds between carbon atoms

Alcohols

• hydroxy functional group: oxygen atom bonded to a hydrogen atom

• a single covalent bond

Bond: OH

Aldehydes

• carbonyl functional group: carbon atom bonded to an oxygen atom

• double bond

• carbonyl group in terminal position

Bond: C=O at terminal

Ketones

• carbonyl functional group: carbon atom bonded to an oxygen atom

• double bond

Bond: C=O within carbon chain

(also called alkanones)

Carboxylic acids

• carboxyl functional group (carbonyl group + hydroxyl group)

• carboxyl (C=O) + hydroxyl (OH) → COOH or CO₂H

Bond: COOH or CO₂H

Esters

• ester functional group

• carbonyl group bonded to oxygen atom

• single bond, asymmetric

• pleasant tastes and smells

Bond: RCOOR'

Ethers

• alkoxy functional group

• oxygen atom bonded to 2 alkyl groups

Bond: R–O–R’

Amines

• amino functional group

• nitrogen atom bonded to hydrogen atoms or alkyl groups

• derivatives of ammonia; can be either primary, secondary, or tertiary

• nitrogen atom has a lone pair of electrons

Bond: R–NH2

Amides

• amido functional group

• carbonyl group bonded to amino group

• derivatives of ammonia; can be either primary, secondary, or tertiary

Bond: R–CONH2

Halogenoalkanes

• halogeno functional group

• alkanes in which one or more hydrogen atoms are replaced with a halogen atom

  • fluorine, chlorine, bromine or iodine

Bond: R–X

Arene

• phenyl functional group

• cyclical structure

  • 6 carbon atoms + 5 hydrogen atoms

  • benzene ring minus hydrogen atom

• aromatic hydrocarbons

Primary Alcohol Oxidation

• 2-step oxidation

  1. aldehyde (carbonyl group): lose 2 hydrogen, C=O double bond

  2. carboxylic acid (carboxyl group)

Secondary Alcohol Oxidation

• 1-step oxidation

  1. keytone (carbonyl group), C=O bond not in terminal position

Nucleophile

electron-rich species attracted to regions of positive charge (nucleus)

Electrophile

proton-rich species attracted to regions of negative charge (electrons)

Nucleophile Reducing Agents

Hydride ion H^- reducing agents:

• Sodium Borohydride NaBH₄^- for aldehyde and ketones

• Lithium Aluminium Hydride LiAlH₄^- for carboxylic acid

  • explodes in water, reactive, use in low temperature and dry conditions, high yield

2-steps:

1. Reducing agent or nucleophile, above “→”

2. H⁺ (aq) acidified solution, exothermic, below “→”

Oxidizing Agents

Potassium Dichromate(VI) K₂Cr₂O₇^2-

permanganate ion, MnO₄-

Hydrogenation

Chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum

• Halogenation with halogens

• Bromination with bromine

Organic Reaction Pathways