CARBOXYLIC ACIDS AND THEIR DERIVATIVES
A STUDENT SHOULD BE ABLE TO:
1.
Give the IUPAC name given the structure, and draw the structure given the name, of
carboxylic acids and their metal salts, acyl chlorides, esters, amides, and nitriles. Also,
draw the structure given any of the following common names: phthalic, oxalic, malonic,
succinic and gluctaric acids; formic and acetic acids and their salts, chlorides, esters, and
amides; acetic and phthalic anhydrides.
2.
Predict the solubility of carboxylic acids and their derivatives in water and in various
acidic and basic solutions. Compounds containing previously studied functional groups
may also be included.
3.
Predict the relative acidity and basicity of compounds and ions. Important criteria include:
The normal order of acidity of functional groups is: RSO3H > RCO2H > ArOH >
RSH > H2O > ROH > RC≡CH > RNH2 > RH.
Within a functional group family, conjugate acids are stronger acids than conjugate
bases. That is, H3X+ > H2X > HX–.
Within a functional group family, electron-donating (activating) groups give
stronger bases, and electron-withdrawing (deactivating) groups give stronger
acids. The effect of an electron-withdrawing group depends on its
proximity to the carboxylic acid moiety.
The stronger the acid, the weaker its conjugate base (and vice versa).
4.
Predict the product of reactions giving rise to carboxylic acids (many of these are review),
and the reactions of carboxylic acids and their derivatives, when given starting materials and
reaction conditions. Important reactions include:
Acid-base reactions. Stronger acid + stronger base  weaker acid + weaker base.
Oxidation of 1o alcohols, aldehydes, alkylbenzenes and alkynes.
Hydrolysis of nitriles.
Reductions with lithium aluminum hydride (LAH).
Carboxylation (carbonation) of Grignard reagents.
Nucleophilic acyl substitution (interconversion of carboxylic acids and their derivatives).
Reactions of acyl halides with R2CuLi and LiAl(OR)3H to make ketones and aldehydes
5.
Predict and explain experimental results from your knowledge and understanding of
nucleophilic acyl substitution mechanisms.
6.
Use the reactions of #4 above, plus others learned earlier, to propose syntheses of
carboxylic acids and related compounds.
7.
Predict and interpret spectra and solubility test results to identify unknown carboxylic
acids and their derivatives.
Solubility Tests for Monofunctional Compounds
This section tells you how to predict results for known compounds and use results to classify
unknowns. Some are useful as stand-alone tests, but compounds that dissolve in water are soluble
in all of the other reagents listed here; follow the whole scheme to get the best possible information.
For these tests, “soluble” means “one drop of unknown will dissolve in one mL of solvent”.
Compounds that are “insoluble” may still dissolve in a large volume of water.
Solubility in water
If a compound is soluble in water, it is a compound of about four carbons or less that
contains N or O (or it may contain more than one functional group). If the compound contains
five or six carbons it may be soluble. If it contains six carbons or more it will be insoluble if
there is only one functional group, but may be soluble with multiple groups. If the compound
is soluble, the solution is then tested with litmus paper.
If the solution turns blue litmus red, the unknown is a carboxylic acid (RCO2H).
If the solution turns red litmus blue, the unknown is an amine (RNH2, R2NH, or R3N).
If the solution is neutral to litmus, the unknown includes a neutral O- or N-containing
functional group such as alcohol, ether, aldehyde, ketone, ester, or amide.
If the compound is insoluble in water, go on to the next solubility test.
Solubility in 5% NaOH
If the compound is soluble in 5% NaOH but insoluble in water, it is acidic, either a phenol
(ArOH) or a carboxylic acid (RCO2H). This is reaction solubility, not like-dissolves-like
solubility; the alkaline test solution reacts with acidic compounds to give ionic, water-soluble
products. You must run the water solubility test first for this test to be useful; 5% NaOH is 95%
water, and compounds that dissolve in water also dissolve in 5% NaOH because of that.
To distinguish between phenols and carboxylic acids, you can use the NaHCO3 solubility
test (next). If the compound is insoluble in 5% NaOH, go to the 5% HCl solubility test.
Solubility in 5% NaHCO3
Sodium bicarbonate is weaker as a base than NaOH. This is another reaction-solubility
test; bicarbonate ion reacts with carboxylic acids but not with phenols to produce water-soluble
salts. The reaction also gives carbon dioxide, and these bubbles are visible, making this a useful
stand-alone test for carboxylic acids.
Solubility in 5% HCl
This is yet another reaction-solubility test. Basic organic compounds (amines) react with
the acid to give water-soluble products. As with the 5% NaOH test, it is necessary to test with
water first, for the same reason.
If the compound is insoluble in 5% HCl, go to the next (and last) solubility test.
Solubility in concentrated H2SO4
Alkenes, alkynes, and compounds that contain N and O are protonated by this extremely powerful
acid, and the products of these reactions dissolve. Concentrated sulfuric acid is approximately 94%
acid. Compounds that contain only alkyl groups, halogen atoms, and benzene rings (RH, RX, ArH,
ArX) will fail to dissolve.
To best prepare for this module, please work Chapter 21 Skill Builder problems in the textbook.
A STUDENT WHO HAS MASTERED THE OBJECTIVES FOR THIS UNIT SHOULD BE
ABLE TO SOLVE THE FOLLOWING PROBLEMS AND RELATED ONES:
1.1
1.2
Draw the structure of each of the following compounds.
a) malonic acid
b) acetic anhydride
c) sodium formate
d) acetonitrile
e) phthalic anhydride
f) dimethyl succinate
Name each of the following compounds.
O
b) ClCH2-C-OCH 2CH3
a) (CH3)3CCH2COOH
O
d) C-Cl
2.1
e)
O
CH3CH2CH2-C
O
C
OH
B. CH3COOCH2CH3
D. CH3(CH2)3CHO
Which of these compounds (a) does not dissolve in H2O but does dissolve in NaOH (aq)?
(b) does not dissolve in H2O but does dissolve in HCl (aq)?
A. CH3CH2CH3CO2CH2CH3
C. C6H5CH2CO2H
3.1
CH3
CH2CH3
f)
Which of the following compounds is most soluble in water?
A. CH3CH2COOCH3
C. CH3CH2COOH
2.2
N
O
c) CH3CHC-NH 2
B. CH3CH2CO2H
D. C6H5CH2NH2
Which of the following compounds is the strongest acid?
C. CH3CH2NHCH3
E. C6H5CH2OH
3.2
Which of the following compounds is the weakest acid?
CO 2H
A.
C.
B.
CH3
3.3
CO 2H
CO 2H
CO 2H
D.
NO 2
Cl
CN
Which of the following compounds is the weakest base?
CO 2
O
CO 2
A.
B.
O
D.
C.
CH3
CH3
Cl
Cl
3.4
Which of the following compounds is the strongest acid?
4.
Predict the product(s) of each of the following reactions.
a)
b)
O
C
Br
OH
+
+
Mg
CH3NH2
ether
room temp.
CO 2
H3O
4.
Reactions (Continued):
c)
d)
KMnO4
CH2CH3
H3C
CH3CH2CH2-Br +
OH , H2O, heat
CH3CH2CH2CH2-C
O
C
f)
SOCl2
(CH3)2CuLi
O
g)
CH3CH2CH2-C
h) H C
3
i)
O
C
NH2
O
C
CH3CH2C
OH
C-CH 3
+ H2O
H3O
heat
1. LAH
2. H3O
O3
C(CH
)
j) CH
CH
3CH
2CH
2CH
3CH
2CH
2CH=C(CH
3)2 2 2
5.
CH3CH2MgBr (excess)
then H2O
OH
+
Cl
H2O
H3O
NaCN
O
e)
H3O
H2O
O33
Zn/H2O
Zn/H
2O
Propose a mechanism for each of the following reactions.
O
O
a)
CH3C
Cl
+
2 OH
CH3C
O
+ Cl + H2O
O
O
b)
CH3C
Cl
+
CH3O
CH3C
OCH3
+
Cl
5.
Mechanisms (Continued):
O
c)
d)
6.
CH3C
+
OH
CH3OH
O
C OCH
3
+
CH3CH2-OH
O
H3O
CH3C
OCH3
+
H2O
O
C OCH CH
2
3
H3O
+
CH3-OH
Propose a synthesis of each of the indicated compounds from the given starting material
and any other needed reagents.
O
a)
C OCH3
from
O
b)
CNH2
c)
CH2CO 2H
CH3
O
from
from
C-OCH 2CH3
CH3
O
d)
CNH2
from
CH
CH2
6.
Synthesis (Continued):
e)
O
C
NHCH3
from
CH2OH
O
f)
C-OCH 2CH3
from
Br
g)
OH
C CH2CH3
from
C
N
CH2CH3
7.1
For these questions, choose the answer from the list of possible compounds at the end of
the section.
a)
Which of the following compounds has a broad peak in its IR spectrum in the
2500-3000 cm-1 region and gives an aqueous solution that turns blue litmus red?
b)
Which of them gives a broad, strong absorption peak in its IR spectrum near
3400 cm-1 is insoluble in water and 5% NaOH (aq), but is soluble in conc. H2SO4?
c)
Which of them is insoluble in water and soluble in both NaOH (aq) and NaHCO3
(aq)?
d)
Which of them has only one peak in its proton NMR spectrum?
The possible answers are:
A.
O
CH3C-OH
O
B. CH3C-CH 3 C.
COOH
D.
CH3
CH2OH
OH
E.
CH3
7.2.
Identify each of the following unknowns from the given spectroscopic information.
a)
C4H8O3
IR: broad peak in 2500-3000 cm-1 region and a peak at 1715cm-1
1
b)
H NMR:
triplet,
quartet
singlet,
singlet,
1.27
3.66
4.13
10.95
delta,
delta,
delta,
delta,
3H
2H
2H
1H
An unknown compound having the formula C11H14O2 gave the following proton
magnetic resonance spectrum:
doublet,
multiplet,
doublet,
multiplet,
 1.4,
 2.2,
 4.1,
 7.1,
6H
1H
2H
5H
A.
O
C O-CH 2CH(CH3)2
A.
C.
O
CH2C
CH(CH3)2
B.
B.
D.
CH3 O
CH2CHCH2COH
O
O
CH2CCH(CH3)2
SOLUTIONS TO SAMPLE PROBLEMS:
1.1
a) malonic acid
b) acetic anhydride
c) sodium formate
d) acetonitrile
e) phthalic anhydride
f) dimethyl succinate
O
CH3C
N
O
O
CH3O-C-CH 2CH2C-OCH 3
O
O
1.2
a)
b)
c)
d)
e)
f)
2.1
2.2
C
a) C b) D
3.1
3.2
3.3
3.4
B
A
B
C
4.
Predicting the products of reactions.
O
C
a)
b)
c)
d)
3,3-Dimethylbutanoic acid
Ethyl chloroethanoate (or ethyl chloroacetate)
2-Phenylpropanamide
Benzoyl chloride
N-Ethyl-N-methylbutanamide
Cyclobutane carboxylic acid
Br
H3C
OH
+
+ CH3NH2
ether
Mg
CH2CH3
CH3CH2CH2-Br +
O
C
room temp.
H3O
CO 2
H3O
KMnO4
+ CH3NH3
O
O
C
HOOC
OH
COOH
OH , H2O, heat
NaCN
H2O
H3O
CH3CH2CH2-COOH
4.
Predicting the products of reactions. (Continued):
O
e)
CH3CH2CH2CH2-C
SOCl2
CH3CH2MgBr (excess)
then H2O
OH
OH
CH3CH2CH2CH2C CH2CH3
CH2CH3
O
C
f)
+
Cl
O
g)
CH3CH2CH2-C
h) H C
3
i)
O
C
NH2
O
C
CH3CH2C
+ H2O
H3O
heat
1. LAH
2. H3O
OH
O3
C-CH 3
H2O
C(CH2)2 O3
j) CH3CH2CH2CH
j) CH3CH2CH2CH=C(CH3) 2
5.
O
C
(CH3)2CuLi
O3
CH3
CH3CH2CH2-COOH
CH3CH
OH
CH2-OH
CH3CH2-COOH +
CH3COOH
O O
Zn/H2O
Zn/H2O
CH3CH2CH2C-H
C
CH3CH2CH2
H
O
O
+ CH3-C-CH 3
+
CH3
C
CH3
Mechanisms:
O
O
a)
CH3C
Cl
+
2 OH
CH3C
+ Cl + H2O
O
O
CH3C
O
Cl
+
OH
CH3-C-Cl
OH
(Continued on the next page.)
5.
Mechanisms (Continued):
a) (continued)
O
O
CH3-C-Cl
CH3C
OH
O
CH3C
O
O
+
H
CH3C
OH
O
CH3C
+
Cl
CH3C
CH3O
CH3C
Cl
+
CH3-C
CH3O
Cl
O
OH
CH3OH
H
O
CH3C
+
OH
Cl
Cl
O
+
Cl
CH3C
OCH3
CH3C
+
OCH3
O
CH3-C
OCH3
O
O
c)
H2O
+
O
O
b)
Cl
+
OH
+ H-O-H
OCH3
O
H3O
CH3C
O
CH3C
OCH3
H2O
O H
H
OH
+
CH3C
(Continued on the next page.)
water
+ H2O from
OH
catalyst
5.
Mechanisms (Continued):
c)
(Continued)
O H
O H
CH3C
CH3-C
+ CH3-OH
OH
weak
nucleophile
OH
CH3-O-H
good leaving group
O H
CH3-C
OH + H2O
CH3-O
H
O H
CH3-C
H O H
OH + H-O-H
CH3-O
H
CH3-C
OH + H2O
CH3-O
water
from
catalyst
H O H
CH3-C
CH3-C
OH
CH3-O
d)
O
OH
OH + H2O
H
O
CH3C
same as CH3-C-OCH 3 + H2O
water from
catalyst
O
C OCH
3
+
O
C OCH
3
CH3CH2-OH
H
+
H-O-H
water, a
product
CH3-O
CH3-O
CH3-O
CH3-C
CH3-C
OH
H3O
OCH3
+ H3O
catalyst
regenerated
O
C OCH CH
2
3
+
O H
C OCH
3
(Continued on the next page.)
+ H-O-H
CH3-OH
5.
Mechanisms (Continued):
d) Continued
O H
C
OCH3 + CH3CH2-OH
OH
C
CH 3O
H
OH
OH
C
CH 3O
OCH 2CH 3
OCH 2CH 3
+
H 2O
CH 3O
C
OCH 2CH 3 + H3O
H
H
H OH
OH
+ CH 3O
H-O-H
C
OCH 2CH 3
H2O + CH 3O
H OH
CH 3O
C
OCH 2CH 3
O H
C OCH CH
2
3
CH 3OH
C
OCH 2CH 3
O H
C OCH CH
2
3
+
O
C OCH CH
2
3
+ H 2O
+ H 3O
6.
a)
Propose a synthesis.
CH3
KMnO4
OH , H2O
heat
O
b)
C-OCH 2CH3
H3O
H2O
H3O
O
C OH
O
C OH
O
CH3OH
C OCH3
acid
heat
SOCl2
NH3
O
CNH2
6.
Synthesis (Continued):
c)
CH3
d)
CH
Br2
CH2Br
light
CH2
KMnO4
OH , H2O
heat
CO 2
Mg
ether
H3O
O
H3O
C OH
CH2CO 2H
xs, NH3
SOCl2
O
CNH2
e)
CH2OH
O
Na2Cr2O7
H2SO 4
H2O
C
O
C
f)
Mg
ether
Br
SOCl2
OH
O
C
xs, CH3NH2
Cl
O
CO 2
MgBr
then H3O
C-OH
NHCH3
CH3CH2OH
H3O
O
C-OCH 2CH3
g)
C
O
H2O
N
H3O, heat
O
C-Cl
SOCl2
C-OH
2 CH3CH2MgBr
then H3O
7.1
a) A
b) E
c) C
CH2CH3
d) B
7.2
O
a)
CH3CH2-O-CH 2-C
OH
OH
C CH2CH3
b) A
Name ____________________________________
Organic Chemistry 2220D
1)
Which of the following compounds is the strongest acid?
CO 2H
CO 2H
CO 2H
C.
B.
A.
NH2
2)
Seventh Drill Test (Sample A)
Answer All Questions
CO 2H
D.
CH3
O C-CH 3
Draw: Benzyl benzoate
3)
CCl3
Name:
O
(CH 3)3CCH 2CH 2-C-NH 2
4)
Predict the major product(s) (if any) of each of the following reactions.
O
C NH 2
a)
O3
b)
c)
5)
CH 3CO 2
H 2O
H 3O
Zn/H2O
CH 2OH
+
Propose a mechanism for the following reaction.
O
O
O
CH 3-C-O-C-CH 3
6)
+
O
+
CH 3CO 2
+ CH 3-C-O-
Propose syntheses, from the given starting material and any other needed reagents.
O
a)
C NH 2
from
CH 2OH
O
O
b)
b)
c)
CHBrCO 2H
CH3CH2CH2
C
CH 2CO 2H
from
f rom
H
from
CH 2CN
CH3CH2CH2
CH 3
C
Cl
Name __________________________________________
Organic Chemistry 2220D
1.
Seventh Drill Test (Sample B)
Answer All Questions
Nomenclature: Give the name when given the structure or the structure when given the name.
(a) Draw: N,N-diethylbenzamide
(b) Draw: benzyl propanoate
(c) (CH3)2CCH2CH2COOH
(d) HOOC-COOH
2. Write an acceptable mechanism for the following reaction.
O
CH3
3.
O
C OH +
CH3CH2OH
H3O
CH3
C OCH CH + H O
2
3
2
Propose a synthesis of the compound indicated, from the given starting material and any other
needed reagents.
(a)
(b)
(b)
CH2COOCH2CH3
C
CH3
CH3
CH3
O
CH3CHCH-COOH
Br 2
(CH3) 2CHCH
from
from
CH3
f rom
O
CH3CHCH2CH2-OH
(CH3) 2CHCH2
C
OH
4.
Which of the following is the weakest base?
(a)
COO
(b)
CCl3
5.
O
(c)
CH3
Identify the following compound from the given spectroscopic information.
IR Spectrum: broad peak in 2500-3000 cm-1 region and a peak at 1715 cm-1
1
H NMR spectrum:
Triplet
Multiplet
Triplet
Singlet
δ 1.08
δ 2.07
δ 4.23
δ 10.97
(3H)
(2H)
(1H)
(1H)
Predict the product(s) (if any) of each of the following reactions.
(a)
N
C
H3O
H2O, heat
CH2CH2CH2-OH + KMnO4
(b)
OH
H2O
H3O
O
(c)
CH2-C
O
C
(d)
7.
O
(d)
CCl3
CH3
C4H7BrO2
6.
COO
OCH2CH3
+
xs, LAH
(CH3)2CHCH2-OH
H2SO4
H2O
Cl
For questions (a) and (b), choose the answers from the list of possible compounds shown below.
OH
(a)
CH3CHCH 3
OH
(a)
(b)
(b) (CH3)2CH(CH 2)3CH
(c)
(d) (CH3)3CCH 2COOH
(e) CH3CH2CO2H
OH
Which compound is insoluble in water and 5% NaOH(aq), but is soluble in conc. sulfuric
acid?
Which compound is insoluble in water, and soluble in both NaHCO3 (aq) and NaOH?.