Functional Groups18.2

Functional Groups• Any element/compound added to a parent chain that

effect its chemical behavior– Substituted hydrocarbon

• Functional groups you must learn:1) Double bonds (Alkenes)2) Triple bonds (Alkynes)3) Halogens4) Alcohols5) Carboxylic Acids6) Esters7) Ethers8) Ketones/Aldehydes9) Amines/Amides

Writing Functional Groups• R symbol of any hydrocarbon• R’ symbol for a second

hydrocarbon; maybe the same as R or may be different

• X symbol of any element within a certain group

• When oxygen is connected to carbon with a single bound -O-

• When oxygen is connected to carbon with a double bound -CO- -C=O-

Halogenated Compounds• Hydrocarbon + a Halogen• R-X; X= F (floro), Cl (cloro),

Br (bromo), or I (iodo)• High density; often used in

solvents and refrigerants• Chlorofluorocarbons

(CFCs) used in aerosol cans and air conditioners (Freon) but have been shown to remove Ozone (O3) from the atmosphere

2-bromopentane

1-chloromethylcyclohexane

Alcohols• Hydrocarbon + Hydroxyl

Group• R-O-H• Polar molecules, high

boiling points, water-soluble

• Solvents, disinfectants, antifreeze, etc…

• Ethanol used in many products that kill bacteria; produced by adding water to Ethene gas

• Drop last “e” of any hydrocarbon and add “-ol”

2-butanol

trans-2-pentanol

2-methyl-2-butanol

Carboxylic Acids• Hydrocarbon + Carboxyl Group• R-COOH; First O is double

bonded to Carbon which also has a Hydroxyl group

• Acidic, strong odors, water-soluble

• Vinegar, toxins, spoiled dairy• Drop last “e” and add “-oic acid”• Pheromones carboxylic acids

used by living things to communicate to each other; strong smells can travel distances and express emotions/states of being

Methanoic acid

Ethanoic acid

Esters• Hydrocarbon + Carboxylic

group + a second Hydrocarbon

• R-COO-R’• Strong aromas, volatile• Scents in perfumes, back-

bone of DNA, fat storage in cells

• Carboxylic group is parent chain; drop “e” + “oate”

• R’ is treated like a side group

methyl methanoate

ethyl ethanoate

phenyl ethanoate

Ethers• Hydrocarbon + Hydroxyl Group

+ a second Hydrocarbon• R-O-R’• Unreactive, insoluble in water,

volatile• Anesthetics (pain killer),

Dissolving fats• Name both hydrocarbons as

side groups and then add “ether”

• Diethyl ether effective anesthetic because is dissolves through plasma membrane

1,1-dimethylethyl methyl ether

1,2-dimethylbutyl ethyl ether

methylcyclohexyl methyl ether

Ketones and Aldehydes• Aldehyde Hydrocarbon +

Carbonyl Group– R-CO-H

• Ketone Carbonyl Group + 2 hydrocarbons– R-CO-R’

• Very reactive, specific odors• Solvents, plastics and adhesives

(glue)• Aldehyde drop last “e” + add

“-al”• Ketone drop “-ane”, add

position number, add “-one”

ethanal phenylethone

cyclohexanal 2-methyl-3-pentone

Amines and Amides• Amines Hydrocarbon +

Amino group – R-NH2

– Basic, ammonia odor• Amide Hydrocarbon +

Carbonyl and Amino Groups– R-CO-NH2

– Neutral• Solvents; Amino acids;

Proteins; hormones• Amines drop “e”, add

position number, add “-amine”• Amide drop “e” + “-amide”

N-methylethanamine

N,N-dimethylmethanamide

Creating Polymers• Polymers are long chains

of repeating units (monomers)

• Names of polymers:StarchCelluloseDNAProteinTeflon• Monomers are joined

through various reactions based on their structure

NucleotidesGlucose

Glucose

TetrafluoroethyleneAmino acids

Polymerization Reactions• Addition Reaction:– Monomers are added to

growing polymers– Often a double bond is

broken as Carbon connect

• Condensation Reaction:– Monomers units with H

atoms and hydroxyl groups (-OH) build polymers

– H atom and –OH break away to make H2O

Rubber and Oils• Cross-linking:– Various polymers are heated

together which allows many connecting points

– The more connection points the stronger the rubber

• Fractional Distillation:– Longer polymers have higher

boiling points– Oils can be separated by

boiling them together; high density oils will remain on the bottom while low density oils move towards the top

Breaking Down Polymers• Cracking:– Break large polymers into

monomers or smaller polymers using a catalyst

– Can convert alkane polymers into alkene monomers

• Recycling plastics:– Thermoplastics can be

melted down to form new plastics from a liquid polymer

– Thermosetting plastics cannot be melted down easily because of crosslinking

– Causing landfill problems