Chapter 11: Alkenes, Alkynes, and Aromatic Compounds ...adhunter.people.ysu.edu/Teaching/Chem506/notes11.pdf · Chapter 11: Alkenes, Alkynes, and Aromatic Compounds Hydrocarbons with

Chemistry 506 Dr. Hunter’s Class Chapter 11.1

2000, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University

Chemistry 506: Allied Health Chemistry 2

Chapter 11: Alkenes, Alkynes, and Aromatic Compounds

Hydrocarbons with Multiple Bonds

Introduction to General, Organic & Biochemistry, 5th Edition byBettelheim and March: Chapter 11, Pages 353-390

Outline Notes by Dr. Allen D. Hunter, YSU Department ofChemistry, 2000.

Outline

11A SECTION(S) 11.1/2/4 INTRODUCTION AND NOMENCLATURE OF ALKENES ...................................................... 2

11B SECTION(S) 11.3 ππ -BONDS ................................................................................................................................................... 4

11C SECTION(S) 11.5 PHYSICAL PROPERTIES ..................................................................................................................... 5

11D SECTION(S) 11.6 CHEMICAL PROPERTIES: ADDITION REACTIONS................................................................... 6

11E SECTION(S) 11.7 ADDITION POLYMERS ........................................................................................................................ 8

11F SECTION(S) 11.8 ALKYNES ............................................................................................................................................... 13

11G SECTION(S)11.9/10 AROMATIC HYDROCARBONS ................................................................................................... 17

11H SECTION(S)18.2 AMINO ACIDS HAVING SIMPLE AROMATIC SIDE CHAINS .................................................. 22

11I SECTION(S) 11.11 AROMATIC REACTIONS ................................................................................................................. 23

11J SECTION(S) 11.12 FUSED RING AROMATICS .............................................................................................................. 25

11K SECTION(S)11.13 HETEROCYCLICS (NOT COVERED IN DETAIL)....................................................................... 26



11A Section(s) 11.1/2/4 Introduction and Nomenclature of Alkenes

Ø Ethene = (Ethylene), CH2=CH2

Ø IUPAC Rules

Ø Start numbering from the end that gives the double bond the

lowest number.

Ø Indicate position of double bond(s) by numbers.

Ø Use the ene ending

Ø Indicated number of double bonds by prefixes (ene, diene,

triene, tetraene, etc.)

Ø Examples



Ø Geometric Isomers

Ø No free rotation (π-bonds)

Ø Experimental observations

Ø cis isomers vs. trans isomers

Ø Examples



11B Section(s) 11.3 π-Bonds

Ø Bonding: sp2 hybridization for 3 σ-bonds to the three atoms

bonded to each carbon

Ø pz orbital for π-bond

Ø Typical C=C bond distance (i.e., 1.34

Å) shorter than C-C bond distance (i.e., 1.54 Å)

Ø slightly shorter C-H distance than alkanes



11C Section(s) 11.5 Physical Properties

Ø Almost identical to Alkanes of same MW

Ø Van der Waals forces

Ø Slightly higher Mp and Bp

Ø Smell (turpentine like)

Ø Density

Ø Solubility



11D Section(s) 11.6 Chemical Properties: Addition Reactions

Ø Addition reaction (generic)

Ø π-bonds weaker than σ-bonds

Ø Hydrogenation: Addition of H2 or D2 (Pt catalyst)

Ø Addition of Cl2 or Br2 (X2)



Ø Addition of HX ((HF) HCl, HBr (HI))

Ø Halide Influences

Ø Markovnikov Addition

Ø Addition of Water (Hydration)

Ø H+ Catalyst

Ø Markovnikov



11E Section(s) 11.7 Addition Polymers

Ø Definition of Addition Polymers

Ø No loss of mass

Ø Rapid chain growth

Ø π-bond opening

Ø “Generic” Synthesis Reaction

Ø typical monomers are CH2=CH-R

Ø Role of Catalysts

Ø Speed reaction but aren’t themselves consumed

Ø Highly reactive species



Ø Reversibility of Reactions

Ø Polymerization under low temperatures/high pressures

Ø i.e., monomer (liquids or gasses) -> polymer (solids)

Ø Depolymerizations (unraveling) at high temperatures

Ø i.e., polymer -> monomer

Ø Molecular Weights and Molecular Weight Distributions

Ø High average Molecular Weights

Ø Distributions rather than discrete weights

Ø Linear Chains vs. Branched Chains



Ø Examples

Ø Polyethylene, PE, Synthesis

Ø CH2=CH2, R = H

Ø Poly(vinyl chloride), PVC, Synthesis

Ø CH2=CH-Cl, R = Cl



Ø Polypropylene, PP, Synthesis

Ø CH2=CH-CH3, R = CH3

Ø Polystyrene, PS, Synthesis

Ø CH2=CH-C6H5, R = C6H5

Ø Poly(methyl methacrylate), PMMA, Synthesis

Ø CH2=C(CH3)(CO2CH3)



Ø Teflon Synthesis

Ø CF2=CF2

Ø Rubber (Polyisoprene) Synthesis

Ø CH2=CH-CH=CH2



11F Section(s) 11.8 Alkynes

Ø Carbon-Carbon Triple Bonds

Ø sp hybridized

Ø Very Short C≡C Bond distance (i.e., 1.20 Å ), much shorter

than the C=C distance (i.e., 1.34 Å) and the C-C distance

(i.e., 1.20 Å)

Ø Bonding: 1 σ-bond and 2 π-bonds (px and py)

Ø slightly shorter C-H distance than alkanes or even alkanes

Ø Ethyne = Acetylene, H-C≡C-H

Ø Physical Properties

Ø Almost identical to Alkanes/Alkenes of same MW

Ø Van der Waals forces

Ø Slightly higher Mp and Bp

Ø Density

Ø Solubility



Ø Nomenclature

Ø yne ending

Ø yne > ene in priority of naming

Ø Examples



Ø Alkyne Reactions

Ø Generic Reaction

Ø Very like Alkenes

Ø Normally Double Addition

Ø Hydrogenation: Addition of H2 or D2 (Pt catalyst)

Ø Addition of X2 (Cl2 or Br2)



Ø Addition of HX (most commonly HCl and HBr)


Ø Addition of H2O (H+ catalyst)


Ø Secondary elimination of water from diol

Ø gives carbonyl group (aldehyde or ketone)



11G Section(s) 11.9/10 Aromatic Hydrocarbons

Ø Sources

Ø Coal Tar

Ø Coke production

Ø Direct separation

Ø Start of industrial chemistry

Ø Petroleum

Ø multiple processing steps

Ø Uses

Ø Octane enhancers in gasoline

Ø Plastics

Ø Pigments/Dyes

Ø Pharmaceuticals

Ø Aromatic: Properties, Reactivity, C/H Ratios (cf.

Alkane/Alkenes/Alkynes)



Ø Substitution Reactions not Addition Reactions (i.e., not like

alkenes)

Ø Bonding / Resonance Stabilization



Ø Nomenclature

Ø IUPAC Names

Ø Halobenzenes (X = F, Cl, Br, I)

Ø Nitrobenzene (Z = NO2)

Ø Alkylbenzenes (phenylalkanes)



Ø Common Names (IUPAC)

Ø Phenol (Z = OH)

Ø Aniline (Z = NH2)

Ø Toluene (Z = CH3, methylbenzene)

Ø Benzoic Acid (Z = CO2H)



Ø Multiply Substituted Arenes

Ø Numbering Ring Positions

Ø Ortho, Meta, Para, Ipso

Ø As Side Chains (phenyl groups)



11H Section(s) 18.2 Amino Acids having Simple Aromatic Side

Chains

Ø Generic AA = H2N-CHR-CO2H

Ø Phenyl Alanine (non-polar)

Ø R = CH2C6H5

Ø PKU



11I Section(s) 11.11 Aromatic Reactions

Ø Substitution Reactions

Ø Require catalyst

Ø "Generic"

Ø Z+ Electrophiles

Ø Nitration (Z = NO2, HNO3/H2SO4, TNT)



Ø Sulfonation (Z = SO3H, H2SO4/SO3)

Ø Halogenation (X = Cl or Br, Cl2/Fe or Br2/Fe)



11J Section(s) 11.12 Fused Ring Aromatics

Ø Polycyclic Aromatic Hydrocarbons, PAHs

Ø Toxicity

Ø Naphthalene (C10H8)

Ø Anthracene (C14H10)

Ø Phenanthrene (C14H10)



11K Section(s) 11.13 Heterocyclics (Not covered in detail)

Ø Replace C-H by Heteroatom Groups such as: N, O, S, etc.

Ø Important in Biomolecules

Ø Pyridine (C5H5N)

Problems: All up to 11.50



Index of Topics and Vocabulary

1

1.20 Å................................................................................ 13

1.34 Å............................................................................ 4, 13

1.54 Å 4

A

Acetylene .......................................................................... 13Addition ............................................................................ 15Addition of HX................................................................... 7Addition of Water ............................................................... 7Addition Polymers.............................................................. 8Addition reaction................................................................. 6Addition Reactions............................................................ 18aldehyde ............................................................................ 16alkanes ................................................................................. 4alkenes ............................................................................... 18Alkenes.............................................................................. 15Alkylbenzenes................................................................... 19Alkyne Reactions.............................................................. 15Alkynes ............................................................................. 13Amino Acids having Simple Aromatic Side Chains......... 22Aniline............................................................................... 20Anthracene ........................................................................ 25Arenes ............................................................................... 21Aromatic............................................................................ 17Aromatic Hydrocarbons.................................................... 17Aromatic Reactions........................................................... 23

B

Benzoic Acid..................................................................... 20Biomolecules ..................................................................... 26Bonding................................................................... 4, 13, 18Bp ................................................................................. 5, 13Br2 ................................................................................. 6, 15Br2/Fe................................................................................ 24Branched Chains ................................................................. 9

C

C≡C Bond distance ........................................................... 13C/H Ratios......................................................................... 17C=C bond distance.............................................................. 4C=C distance..................................................................... 13C10H8 ................................................................................. 25C14H10................................................................................ 25C5H5N ............................................................................... 26Carbon-Carbon Triple Bonds............................................ 13carbonyl group .................................................................. 16catalyst .............................................................................. 23Catalysts.............................................................................. 8C-C distance...................................................................... 13CF2=CF2............................................................................ 12C-H distance.................................................................. 4, 13CH2=C(CH3)(CO2CH3)..................................................... 11CH2=CH2 ...................................................................... 2, 10

CH2=CH-C6H5 .................................................................. 11CH2=CH-CH=CH2............................................................ 12CH2=CH-CH3 ................................................................... 11CH2=CH-Cl....................................................................... 10CH2=CH-R.......................................................................... 8chain growth........................................................................ 8Chemical Properties: Addition Reactions.......................... 6cis isomers........................................................................... 3Cl2 ................................................................................. 6, 15Cl2/Fe................................................................................. 24Coal Tar............................................................................. 17Coke .................................................................................. 17Common Names ................................................................ 20

D

D2 ................................................................................. 6, 15Density .......................................................................... 5, 13Depolymerizations.............................................................. 9diene .................................................................................... 2diol..................................................................................... 16Double Addition................................................................ 15Dyes .................................................................................. 17

E

Electrophiles...................................................................... 23ene ................................................................................. 2, 14ene ending............................................................................ 2Ethene.................................................................................. 2Ethylene .............................................................................. 2Ethyne............................................................................... 13

F

free rotation......................................................................... 3Fused Ring Aromatics ....................................................... 25

G

gasoline.............................................................................. 17Geometric Isomers .............................................................. 3

H

H+ catalyst......................................................................... 16H+ Catalyst.......................................................................... 7H2 ................................................................................. 6, 15H2O ................................................................................... 16H2SO4/SO3......................................................................... 24Halide Influences................................................................. 7Halobenzenes .................................................................... 19Halogenation ..................................................................... 24HBr................................................................................ 7, 16H-C≡C-H .......................................................................... 13HCl................................................................................ 7, 16Heteroatom Groups........................................................... 26Heterocyclics..................................................................... 26HF ....................................................................................... 7HI ....................................................................................... 7HNO3/H2SO4..................................................................... 23HX................................................................................. 7, 16



Hydration ............................................................................ 7Hydrogenation............................................................... 6, 15

I

industrial chemistry .......................................................... 17Ipso ................................................................................... 21IUPAC Names .................................................................. 19IUPAC Rules ...................................................................... 2

K

ketone................................................................................ 16

L

Linear Chains ...................................................................... 9

M

Markovnikov....................................................................... 7Markovnikov Addition ................................................. 7, 16Meta .................................................................................. 21methylbenzene .................................................................. 20Molecular Weight Distributions ......................................... 9Molecular Weights.............................................................. 9monomer.............................................................................. 9monomers............................................................................ 8Mp................................................................................. 5, 13

N

Naphthalene....................................................................... 25Nitration............................................................................ 23Nitrobenzene..................................................................... 19Nomenclature .............................................................. 14, 19

O

Octane ............................................................................... 17Ortho................................................................................. 21

P

PAH .................................................................................. 25Para.................................................................................... 21PE ..................................................................................... 10Petroleum .......................................................................... 17Pharmaceuticals................................................................. 17Phenanthrene..................................................................... 25Phenol................................................................................ 20Phenyl Alanine.................................................................. 22phenyl groups.................................................................... 21phenylalkanes .................................................................... 19Physical Properties........................................................ 5, 13Pigments............................................................................ 17PKU .................................................................................. 22Plastics .............................................................................. 17PMMA.............................................................................. 11Poly(methyl methacrylate)................................................ 11Poly(vinyl chloride)........................................................... 10Polycyclic Aromatic Hydrocarbons.................................. 25Polyethylene...................................................................... 10Polyisoprene...................................................................... 12Polymerization.................................................................... 9Polymers ............................................................................. 8Polypropylene ................................................................... 10Polystyrene........................................................................ 11PP ..................................................................................... 10

Problems............................................................................ 26Properties .......................................................................... 17PS ..................................................................................... 11Pt catalyst...................................................................... 6, 15PVC ................................................................................... 10px ..................................................................................... 13py ..................................................................................... 13Pyridine............................................................................. 26pz ....................................................................................... 4

R

Resonance Stabilization .................................................... 18Reversibility of Reactions................................................... 9Ring Positions ................................................................... 21Rubber............................................................................... 12

S

Secondary elimination of water ........................................ 16Smell.................................................................................... 5Solubility....................................................................... 5, 13sp hybridized..................................................................... 13sp2 hybridization ................................................................. 4Substitution Reactions ................................................ 18, 23Sulfonation ........................................................................ 24

T

Teflon................................................................................ 12tetraene................................................................................ 2TNT................................................................................... 23Toluene.............................................................................. 20trans isomers ....................................................................... 3triene.................................................................................... 2

V

Van der Waals forces .................................................... 5, 13

X

X2 ................................................................................. 6, 15

Y

yne ending......................................................................... 14

Z

Z+ ..................................................................................... 23

C-CC-C

C-C bond distance ............................................................... 4

ππ

π-bond ................................................................................. 4π-bond opening.................................................................... 8π-bonds.......................................................................... 3, 13π-Bonds............................................................................... 4π-bonds weaker than σ-bonds............................................. 6

σσ

σ-bond ............................................................................... 13σ-bonds................................................................................ 4



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Chapter 11: Alkenes, Alkynes, and Aromatic Compounds ...adhunter.people.ysu.edu/Teaching/Chem506/notes11.pdf · Chapter 11: Alkenes, Alkynes, and Aromatic Compounds Hydrocarbons with