Functional Groups 18.2

Functional Groups Any element/compound added to a parent chain that effect its chemical behavior Substituted hydrocarbon Functional groups you must learn: Double bonds (Alkenes) Triple bonds (Alkynes) Halogens Alcohols Carboxylic Acids Esters Ethers Ketones/Aldehydes 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,N-dimethyl methanamide N-methyl ethanamine

Creating Polymers Glucose Glucose Nucleotides Amino acids Polymers are long chains of repeating units (monomers) Names of polymers: Starch Cellulose DNA Protein Teflon Monomers are joined through various reactions based on their structure Glucose Glucose Nucleotides Amino acids Tetrafluoroethylene

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: Fractional Distillation: 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