Unsaturated Hydrocarbons CHAPTER 13 Unsaturated Hydrocarbons General, Organic, & Biological Chemistry Janice Gorzynski Smith

CHAPTER 13: Unsaturated Hydrocarbons Learning Objectives: Identify unsaturated hydrocarbons: alkenes, alkynes, aromatic compounds Alkene, Alkyne, Aromatic nomenclature Stereoisomers Addition Reactions Polymers Substitution Reactions Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Functional Groups Overview Alkane Alkene Alkyne Aromatic C − C C = C Hydrocarbon Functional Groups Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Hydrocarbon Chemical formulas CnH2n+2 if a chain CnH2n if a cycloalkane Alkane Alkene Alkyne Aromatic C − C C = C CnH2n if a chain with 1 dbl bond CnH2n-2 if a cycloalkene with 1 dbl bond CnH2n-2 if a chain with 1 triple bond Use modeling kit! C6H6 Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Molecule Shape Drawing Alkenes SIMPLIFY! H H H H .. H C C C C H H H H Use modeling kit! CH3CH2CH2=CH2 Smith. General Organic & Biolocial Chemistry 2nd Ed.

Straight Chain Alkane Name Nomenclature Alkanes # Greek Root Straight Chain Alkane Name 1 meth methane 2 eth ethane 3 prop propane 4 but butane 5 pent pentane 6 hex hexane 7 hept heptane 8 oct octane 9 non nonane 10 dec decane 4 6 2 1 3 5 prefix + parent + suffix What, where are the substituents? Example: 2,4- dimethyl prefix # Carbons Structure Alkyl Group Name 1 CH3- methyl 2 CH3CH2- ethyl 3 CH3CH2CH2- propyl 4 CH3CH2CH2CH2- butyl 5 CH3CH2CH2CH2CH2- pentyl 6 CH3CH2CH2CH2CH2CH2- hexyl parent How many carbons in longest chain? Example: hex suffix What is the functional group? Example: ane 2,4-dimethylhexane Smith. General Organic & Biolocial Chemistry 2nd Ed.

Straight Chain Alkane Name Nomenclature Alkenes & Alkynes # Greek Root Straight Chain Alkane Name 1 meth methane 2 eth ethane 3 prop propane 4 but butane 5 pent pentane 6 hex hexane 7 hept heptane 8 oct octane 9 non nonane 10 dec decane 4 6 2 1 3 5 prefix + parent + suffix First give location and type of substituents Second give location of double bond prefix # Carbons Structure Alkyl Group Name 1 CH3- methyl 2 CH3CH2- ethyl 3 CH3CH2CH2- propyl 4 CH3CH2CH2CH2- butyl 5 CH3CH2CH2CH2CH2- pentyl 6 CH3CH2CH2CH2CH2CH2- hexyl parent How many carbons in longest chain? suffix How many of the functional group and what is it? Alkene = ene; Alkyne = yne 2,4-dimethyl 1,5- hexa diene * Note: when we have more then 1 multiple bond the parent name has an “a” added on: hexa instead of hex Smith. General Organic & Biolocial Chemistry 2nd Ed.

Straight Chain Alkane Name Nomenclature Alkenes & Alkynes # Greek Root Straight Chain Alkane Name 1 meth methane 2 eth ethane 3 prop propane 4 but butane 5 pent pentane 6 hex hexane 7 hept heptane 8 oct octane 9 non nonane 10 dec decane 3 2 1 4 5 prefix + parent + suffix First give location and type of substituents Second give location of double bond prefix # Carbons Structure Alkyl Group Name 1 CH3- methyl 2 CH3CH2- ethyl 3 CH3CH2CH2- propyl 4 CH3CH2CH2CH2- butyl 5 CH3CH2CH2CH2CH2- pentyl 6 CH3CH2CH2CH2CH2CH2- hexyl parent How many carbons in longest chain? suffix How many of the functional group and what is it? Alkene = ene; Alkyne = yne 4-methyl 2- pent yne Smith. General Organic & Biolocial Chemistry 2nd Ed.

Straight Chain Alkane Name Nomenclature Alkenes & Alkynes # Greek Root Straight Chain Alkane Name 1 meth methane 2 eth ethane 3 prop propane 4 but butane 5 pent pentane 6 hex hexane 7 hept heptane 8 oct octane 9 non nonane 10 dec decane 4 5 3 2 1 prefix + parent + suffix First give location and type of substituents Second give location of double bond prefix # Carbons Structure Alkyl Group Name 1 CH3- methyl 2 CH3CH2- ethyl 3 CH3CH2CH2- propyl 4 CH3CH2CH2CH2- butyl 5 CH3CH2CH2CH2CH2- pentyl 6 CH3CH2CH2CH2CH2CH2- hexyl parent How many carbons in longest chain? suffix How many of the functional group and what is it? Alkene = ene; Alkyne = yne 3-methyl 1- cyclo pent ene Smith. General Organic & Biolocial Chemistry 2nd Ed.

o - m - p - Nomenclature Aromatics: Benzene 1,2-dimethyl benzene 5 6 o - m - p - 1 2 4 3 prefix + parent Give location, number, and type of substituent. You can also replace location & number with o, m, p prefix parent “Benzene” Polysubstituted Benzenes: Number to give lowest #s around ring Alphabetize substituents If part of common root name the molecule as a derivative of a monosubstituted benzene with common root at C1. 1,2-dimethyl benzene o-dimethyl benzene Smith. General Organic & Biolocial Chemistry 2nd Ed.

Practice naming Alkenes & Alkynes! Group Problem Practice naming Alkenes & Alkynes!

Bond Angles Alkenes & Alkynes ethylene 120° 180° acetylene Use modeling kit! 180° acetylene

Alkenes Stereoisomers R R R R Use modeling kit! CIS TRANS

Alkenes Stereoisomers Use modeling kit! Linoleic Acid

Alkenes Stereoisomers Stereoisomers Conformational Isomers Different 3-D shape Same bonds Conformational Isomers Different bonds between atoms Use modeling kit!

X Y X Y Alkene Reactions Addition Addition Rxns: when elements are added to a compound X Y Use modeling kit! X Y

Alkene Reactions Addition H H H2 Metal catalyst Hydrogenation X X X2 X = Cl or Br Halogenation H X HX X = Cl or Br Hydrohalogenation Use modeling kit! H2O H2SO4 Hydration H OH

Nucleophile vs Electrophile Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Polymerization: joining together of monomers Alkene Reactions Polymers Polymerization: joining together of monomers Use modeling kit!

H X X Y H Y Aromatic Reactions Substitution Substitution Rxns: when an atom is replaced by another atom or group of atoms H X X Y H Y Use modeling kit!

H Aromatic Reactions Substitution Cl2 Clorination HNO3 Nitration SO3 H2SO4 Nitration Use modeling kit! SO3H SO3 H2SO4 Sulfonation