Assignment:
Q1. The Fischer esterification is really an example of
a. a nucleophilic acyl substitution reaction
b. an aldol condensation reaction
c. an elimination reaction (either E1 or E2)
d. an electrophilic addition reaction
e. a conjugated addition reaction
Q2. In Fischer Esterification (a) which group in the acyl compound is being substituted and (b) what is the substituting group?
a. (a) the carbonyl group of 2-phenylacetic acid
(b) the hydroxyl group of ethanol
b. (a) the hydroxyl group of ethanol
(b) the carbonyl group of 2-phenylacetic acid
c. (a) the hydroxyl group of 2-phenylacetic acid
(b) the oxygen of ethanol
d. (a) the hydroxyl group of ethanol
(b) the oxygen of the hydroxyl group of 2-phenylacetic acid
Q3. The ester oxygen (i.e. the -OEt) of the product of Fischer Esterification is the oxygen of the
a. hydroxyl group of the 2-phenylacetic acid
b. hydroxyl group of the ethanol
c. carbonyl group of 2-phenlyacetic acid
d. oxygen of sulfuric acid
Q4. An important characteristic in the mechanism of Fischer Esterification is the formation of a tetrahedral intermediate which is the result of
a. the alcohol attacking the 2-phenylacetic acid with the subsequent loss of a proton.
b. protonation of the ethanol by H2SO4.
c. protonation of the carbonyl oxygen of the 2-phenylacetic acid.
d. protonation of the hydroxyl group of the 2-phenylacetic acid.
Q5. The equilibrium of Fischer esterification reactions in general is slightly towards product formation. The equilibrium can be made more favorable for product formation by all of the following except:
a. Increasing the concentration of the 2-phenylacetic acid
b. Increasing the concentration of the ethanol
c. Removing water from the reaction mixture
d. Increasing the concentration of H2SO4
e. Removing ethyl -2-phenylacetate as it is formed
Q6. Esters can be hydrolyzed when heated with water and strong acids or bases- the reverse of Fischer esterification. However, whereas Fischer esterification is reversible, ester hydrolysis when carried out in aqueous base is not. This is because
a. base converts the resulting alcohol into an oxide ion
b. in base the resulting acid is converted to its carboxylate anion
c. base reacts with the resulting alcohol to form a participate
d. base reduces the resulting acid to an aldehyde
e. base oxidizes the resulting alcohol to an aldehyde
Q7. The complete conversion of 2-phenylacetic acid to ethyl-2-phenylacetate in Fischer Esterification is the result of
a. Ethanol being in excess relative to 2-phenylacetic acid
b. 2-phenylacetic acid being in excess relative to ethanol
c. Removing water from the reaction mixture
d. Increasing the concentration of H2SO4
e. Removing ethyl -2-phenylacetate as it is formed