AP Notes Chapter 10 Organic Chemistry

Alkanes and Cycloalkanes Hydrocarbons Alkanes and Cycloalkanes

Alkanes: hydrocarbons containing only carbon-carbon single bonds the first two alkanes are methane and ethane

Hydrocarbon: a compound composed of only carbon and hydrogen

Alkanes the first 10 alkanes with unbranched chains Generic Alkane Formula: CnH2n+2

Constitutional Isomerism Constitutional isomers: compounds that have the same molecular formula but different structural formulas (connected differently)

Constitutional Isomerism

Map of Organic Isomerization

Nomenclature

IUPAC Names The IUPAC name of an alkane with an unbranched chain of carbon atoms consists of two parts: (1) a prefix: the number of carbon atoms in the chain (2) the suffix -ane: shows that the compound is a saturated hydrocarbon

IUPAC Names Alkyl group: a substituent group derived from an alkane by removal of a hydrogen atom commonly represented by the symbol R- named by dropping the -ane from the name of the parent alkane and adding the suffix -yl

IUPAC Names 1. The name for an alkane with an unbranched chain of carbon atoms consists of a prefix showing the number of carbon atoms and the ending -ane

IUPAC Names 2. For branched-chain alkanes, longest chain of carbon atoms is the parent chain and its name is the root name

IUPAC Names 3. Name and number each substituent on the parent chain; use a hyphen to connect the number to the name

Nomenclature Example

IUPAC Names 4. If there is one substituent, number the parent chain from the end that gives the substituent the lower number

IUPAC Names 5. If the same substituent occurs more than once, number the parent chain from the end that gives the lower number to the substituent encountered first

IUPAC Names 5. If the same substituent occurs more than once, indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so on

use a comma to separate position numbers IUPAC Names 5. If the same substituent occurs more than once, use a comma to separate position numbers

list them in alphabetical order IUPAC Names 6. If there are two or more different substituents list them in alphabetical order

IUPAC Names 6. If there are two or more different substituents number the chain from the end that gives the lower number to the substituent encountered first

IUPAC Names 6. If there are two or more different substituents if there are different substituents in equivalent positions on opposite ends of the parent chain, give the substituent of lower alphabetical order the lower number

IUPAC Names 7. Do not include the prefixes di-, tri-, tetra-, and so on, or the hyphenated prefixes sec- and tert- in alphabetizing; alphabetize the names of substituents first, and then insert these prefixes

Nomenclature Example

Cycloalkanes Cyclic hydrocarbon: a hydrocarbon that contains carbon atoms joined to form a ring

Cycloalkanes

Cycloalkanes Nomenclature to name a cycloalkane, prefix the name of the corresponding open-chain alkane with cyclo-, and name each substituent on the ring if there is only one substituent on the ring, there is no need to give it a location number

Alkenes and Alkynes Alkene: a hydrocarbon that contains one or more carbon-carbon double bonds ethylene is the simplest alkene

Alkenes and Alkynes Alkyne: a hydrocarbon that contains one or more carbon-carbon triple bonds acetylene is the simplest alkyne

Alkenes Cis-trans isomerism because of restricted rotation about a carbon-carbon double bond, an alkene with two different groups on each carbon of the double bond shows cis-trans isomerism

Alkenes - IUPAC Names To name an alkene use the ending -ene to show the presence of the C=C branched-chain alkenes are named in a manner similar to alkanes; substituted groups are located and named

Alkenes - IUPAC Names Examples

Alkenes - IUPAC Names Examples

Alkenes - IUPAC Names Examples

Benzene and its Derivatives

Aromatic Compounds Aromatic compound: a hydrocarbon that contains one or more benzene-like rings arene: a term used to describe aromatic compounds Ar-: a symbol for an aromatic group derived by removing an -H from an arene

Kekulé structure for benzene (1872)

The electrons of Benzene are Delocalized sp2 hybridized

Nomenclature Example

Functional Groups and Reactions of Organic Compounds

Alkanes They burn! Hydrocarbon and Oxygen yields Carbon Dioxide and Water

Reactions of Alkenes: ADDITION REACTIONS Alkenes are unsaturated — more bonds can form to the C atoms Molecules such as Br2, H2, HCl, HBr, and H2O add to the double bond

An Addition Reaction Fat placed in Br2 vapor

An Addition Reaction The fat in bacon is partially unsaturated. The fat adds Br2 to the C=C bonds.

An Addition Reaction Saturated Fats Fats can be “hydrogenated” with H2. Saturated Fats Peanut butter has partially hydrogenated vegetable oil.

Reactions of Aromatics Substitutions — not additions — are typical. + C H 3 l A AlCl3 is a catalyst. Catalysts typically used in aromatic substitutions.

Functional Groups See CD-ROM Screens 10.5 & 10.6

Alcohols Butanol Methanol Characterized by –OH group [R-OH Name: add – ol to name of hydrocarbon Methanol Butanol

Structures of Alcohols C3H5OH: how many structural isomers? Add -ol to name of 3-C hydrocarbon. Indicate position of OH with number.

Alcohol Properties Alcohols are a derivative of water Many alcohols dissolve in water Methanol dissolves in water. Butanol is NOT soluble in water.

“Sterno” Alcohols burn in air A mixture of ethanol + calcium acetate = STERNO

GLYCOLS Alcohols with Two OH Groups Ethylene glycol Propylene glycol

Alcohol Reactions Screen 11.6 Substitution Elimination

Sugars: Related to Alcohols Sugars are carbohydrates, compounds with the formula Cx(H2O)y. O H C 2 1 3 4 5 a - D g l u c o s e b p n h i f r m

Amines Alcohols are derivatives of H2O (R–OH) and amines are derivatives of NH3. Trimethylamine Dimethylamine Methylamine

Amines generally have terrible odors! Pyridine Cadaverine

Amines, like NH3, are bases 2 C 6 H 5 N ( a q ) + S O 4 3 - A n i l e u m o

Amines Many natural products and drugs (such as nicotine and cocaine) are bases. Nicotine

Structures of Aldehydes Odors from aldehydes and ketones Cinnamaldehyde

carbonyl group

H H methanal FORMALDEHYDE

CH3CH2 H propanal

R H an ALDEHYDE

CH3 CH3 dimethylketone propanone ACETONE

CH3 CH2CH2CH3 2-pentanone

CH3CH2 CH2CH3 3-pentanone

R R’ a KETONE

Carboxylic acid group with acidic H+ Carboxylic Acids Acetic acid Benzoic acid Carboxylic acid group with acidic H+ All are WEAK acids Acids are found in many natural substances: bread, fruits, milk, wine

Formic acid, HCO2H, gives the sting to ants. Carboxylic Acids

OH H methanoic acid FORMIC ACID

OH CH3 ethanoic acid ACETIC ACID

OH CH2CH2CH3 butanoic acid BUTYRIC ACID

OH R a CARBOXYLIC ACID

an AMINO ACID

Acids + Alcohols --> ESTERS Esters have generally pleasant odors

Acids + Alcohols --> ESTERS 3 2 A c e t i a d E h n o l y

Acids + Alcohols --> ESTERS — H + ' 2 a r b o x y l i c d A h E s t e

Aspirin, acetylsalicylic acid, Acid and Ester

Fats with C=C bonds are usually LIQUDS Fats and Oils Fats with C=C bonds are usually LIQUDS Oleic acid: a monounsaturated fatty acid C=C Bond

Fats and Oils Saturated fats are more common in animals. Fats with saturated acids (no C=C bonds) are SOLIDS. Saturated fats are more common in animals.

Trans Fatty Acids Acid and Alkene C=C Bond

Trans Fatty Acids Oleic acid is a mono–unsaturated cis-fatty acid Trans fatty acids have deleterious health effects. Trans fatty acids raise plasma LDL cholesterol and lower HDL levels.

Acids + Amines --> AMIDES N-methylacetamide

Acids + Amines --> AMIDES Acetoaminophen Tylenol, Datril, Momentum, ...

Polymers Giant molecules made by joining many small molecules called monomers Average production is 150 kg per person annually in the U.S.

Polymer Classifications Thermoplastics (polyethylene) soften and flow when heated Thermosetting plastics — soft initially but set to solid when heated. Cannot be resoftened.

Polymer Classifications Other classification: plastics, fibers, elastomers, coatings, adhesives

Polymer Preparation Addition polymers — directly adding monomer units together Condensation polymers — combining monomer units and splitting out a small water (water)

Polyethylene: Addition Polymer A polymer with a molar mass of a million has about 36,000 units.

Mechanism of Addition Polymerization Initiation Addition Propagation Termination Addition Polymerization

Types of Polyethylene Cross-linked PE, CLPE Linear, high density PE (HDPE) Cross-linked PE, CLPE Branched, low density PE, LDPE

Types of Polyethylene Table 11.12: others are PVC, acrylonitrile, polypropylene, polymethyl methacrylate

Polystyrene Polystyrene is nonpolar material and dissolves in organic solvents. PS foam is mostly air, and when it dissolves it collapses to a much smaller volume.

Condensation Polymers H O C 2 + n t e r p h a l i c d y g o P ( E T ) , s

Polyesters, PET Jackets made from recycled PET soda bottles Soda bottles, mylar film.

Polyesters: Mechanism Reaction of Diacid and Diol

Polyamides: Nylon Nylon Rope Trick

Polyamides: Nylon Each monomer has 6 C atoms in its chain. A polyamide link forms on elmination of HCl Result = nylon 66 Proteins are polyamides

Polymer Recycling Symbols LDPE = Low density PE = 0.910-0.925 g/cm3 HDPE = High density PE = 0.941-0.965 PP = Polypropylene = 0.90 V = PVC (Vinyl chloride) = 1.30-1.58