CHAPTER 11: ALKYNES ALKYNE INTRODUCTORY … 1 CHAPTER 11: ALKYNES ALKYNE INTRODUCTORY TOPICS...
7
Page 1 C HAPTER 11: A LKYNES ALKYNE INTRODUCTORY TOPICS EXAMPLES H˚ per mol reactant (kcal/mol) Adj. H˚ per mol product (kcal/mol) -373 / 5 mol product -75 -337 / 4 mol product -84 -317 / 3 mol product -106 H 3 C CH 3 + 7/2 O 2 2 CO 2 3 H 2 O + H 2 C CH 2 + 3 O 2 2 CO 2 2 H 2 O + HC CH + 5/2 O 2 2 CO 2 1 H 2 O + C C H H Acetylene Hot burning fuel Welding
Transcript of CHAPTER 11: ALKYNES ALKYNE INTRODUCTORY … 1 CHAPTER 11: ALKYNES ALKYNE INTRODUCTORY TOPICS...
Page 1
CHAPTER 11: ALKYNES
ALKYNE INTRODUCTORY TOPICS
EXAMPLES
DH˚ per mol
reactant (kcal/mol)
Adj. DH˚ per mol
product (kcal/mol)
-373 / 5 mol product
-75
-337 / 4 mol product
-84
-317 / 3 mol product
-106
H3C CH3 + 7/2 O2
2 CO2 3 H2O+
H2C CH2 + 3 O2
2 CO2 2 H2O+
HC CH + 5/2 O22 CO2 1 H2O+
C CH H
AcetyleneHot burning fuel
Welding
Page 2
ALYKNE NAMING
1. Number so first carbon of the triple bond is the lowest # possible.
2. When alkyne + alcohol are in the same molecule, the name is “#-alkyn-#-ol.” The alcohol is given the lower number.
“Synthesis of Anthropomorphic Molecules: The NanoPutians” Tour, J., J. Org. Chem, 2003, 68, 8750-8766
Page 3
1H NMR SPECTRA OF ALKYNES
CHEMICAL SHIFT
Alkene H: Alkyne H:
TERMINAL ALKYNE SPLITTING
Zoom in of peak at 2.1 ppm
Page 4
ALKYNE REACTIONS
BOND ENERGIES
Bond Type(s) kcal/mol
C-C s 88
C=C 152
200
GENERAL REACTION PATTERN
ADDITION OF X2
GENERAL PATTERN
MECHANISM
C C CH3H3CBr2
CH2Cl2
X= Cl, Br
Page 5
ADDITION OF HX
GENERAL PATTERN
MECHANISM
ADDITION TO ASYMMETRIC ALKYNES
C C CH3H3CHBr
Page 6
TERMINAL ALKYNE ACIDITY
Compound
pKa
ACETYLIDE REACTIONS
ACID-BASE REACTION
SUBSEQUENT REACTIONS
Page 7
SUMMARY PROBLEMS Synthesizing alkynes from acetylene:
Synthesize this alkyne from a terminal alkyne:
Give the major organic product.
