Chemistry 211
Conjugate Acid
CH3
CH 2
CH 2
CH2
Conjugate Base
CH3
CH3
CH2
CH2
CH2
CH2
CH
CH
CH3
CH3
CH2
CH
CH
NH
CH3
CH2
CH
CH3
C
: :: :
CH3
CH2
CH :
19
O:
16
-
O:
O
NH2
CH3
-
C
H
H
NH
16
:-
16
H
-
: :
: :
O:
: O:
: O:
OH
O
O
C OH
O
CH3
N
C
-
O
O :-
: :
: :
CH 3
H
N
16
: :
:
C
~33
~ 27
-
OH
CH3
-
: :: :
C CH3
~ 37
~ 37
: :
:
:O :
-
CH2 :
NH-
:O :
~43
41
-
CH
CH
NH2
CH3 CH2 OH
NH
: :
:
CH
: O:
-
40
: :
:
CH2
NH 2
CH3
CH2 :
H
CH3
~50
~ 50
:-
CH3 CH2 NH2
CH
-
-
H
H
CH
-
CH 2 :
CH3
CH2
CH 2 :
CH2 :
CH3
CH3
pKa
: :
: :
: :
Table E
Equilibrium Controlled Reactions:
Class Group Activity #12:
Acid Base Reactions and Electron Energies - 6
: :
:
: :
A.
Fall 2007
10
9.6
4.8
2
Acid-Base & Electron Energy- 6
B. Based upon the data in Table E,
(i.e. Highest energy first and lowest energy last)
-
CH3 CH2 C
-
S:
CH3
CH
S:
-
: :
S:
:S :
:
CH2
CH
: :
CH
: :
CH2
: O:
CGA #12
CH3
Explain how you determined your order of energies citing as many supporting examples from
the data as possible.
The order of pKa’s follows a downward trend that lines up with the
ions in part B. Ion 50 has a very similar structure to `
C. Suggest theoretical explanations for the order of energies proposed in 1.
List the following ions in order of decreasing energy of their highest energy electrons:
CGA-12
Acid-Base & Electron Energy-6
3
D. Based upon your theory developed in C. above, predict which proton(s) in the molecule
below should be most acidic.
CH3
:
N
CH2
O
CH2
:
:
CH2
CH3
CH3
:O:
E. Note the differences in the pKa's of the following compounds from Table E.
4
Acid-Base & Electron Energy- 6
Conjugate Acid
CH3
CH3
CH2
CH2
CH2
CH
CH2
Conjugate Base
CH3
CH
CH3
CH3
CH3
CH2
CH 2
CH2
CH
CH
CH
CH
H
H
CH2
CH
pKa
CH2 :
-
~50
-
~43
CH2 :
:-
H
H
CH2
CGA #12
40
H
CH3
CH 2
CH
CH
CH
CH2 :
-
~33
:16
H
Are these differences consistent with the theory developed in C. above? Note specifically the
pKa of the last compound.
Why or Why not?
CGA-12
Acid-Base & Electron Energy-6
5
D. Out of Class Applications for Class Group Activity #12
1. For each of the following compounds, circle the most acidic proton(s) and explain your
choice using electron energy arguments.
O
O
:
:
2. Which of the following compounds are aromatic according to the Hückel theory?
H
H
H
N
N
CH3
+
H H
3. For each of the following acid-base reactions, predict whether the equilibrium constant
should be > or < 1. Explain your conclusion using electron energy arguments.
a.
O
OH
+
O
O
O-
b.
O
C
OH
+
O
O
C OH
NH
+
C OH
NH
C O-
+
4. Which of the following equilibrium controlled reactions should produce more product at
equilibrium. Explain your conclusion using electron energy arguments.
O
O
CH3
CH2
C
O
CH3
CH2
O-
+
C
O
CH2
C
CH3
O CH2
+
O-
CH2
+
CH3
O
CH3
CH3
CH2
C
O
O
C
O
O
CH3
CH3
CH2
C
O
+
CH2 O -
-
6
Acid-Base & Electron Energy- 6
CGA #12
C. Nomenclature of Amines
References:
1. CGWW: Ch. 2.0 p. 33
2. Tutorials:
a.
http://chemistry.boisestate.edu/people/richardbanks/organic/nomenclature/organicnomenclature1.htm
Developed by Richard C. Banks, Professor of Chemistry, Boise State University
Provides questions with answers
Sections Amines
b.
http://www.sci.ouc.bc.ca/chem/nomenclature/index-2.htm
Developed by Professor Dave Woodcock, Okanagan University College,
British Columbia, Canada
(Contains many examples.)
Sections:
5. Functional Groups with Suffix and Prefix
I. Introduction: Priority Rules
II. Alkanamines (Amines)
Note: Your browser must have the chemscape chime plug-in for these pages to
work. Select "1. Introduction to these pages", then click on "Nomenclature Index Chemscape Chime" and begin with the "How and Why". If you have problems, go
to the http://www.sci.ouc.bc.ca/chem/nomenclature/nom1.htm and click on
"chemscape chime" and follow directions to download the "chemscape chime plugin." If you have problems contact me.
c. http://www.acdlabs.com/iupac/nomenclature
Developed by Advanced Chemistry Development Laboratories
(Gives detailed rules for nomenclature.)
Recommendations 1993
R-5 Applications to Specific Classes of Compounds
R-5.4 Amines and Imines
R-5.4.1 Primary amines
R-5.4.2 Secondary and tertiary amines
3. Applications
a. Name the following:
N
NH2
N
Br
NH2
H
b. Draw structural formulas for the following compounds:
N-propyl-2,3-dimethylbutanamine
N-cyclopropyl-N-methyl-2-hexanamine
N,N-diethyl-4-methoxycyclohexanamine
3-octanamine