Quiz 9: Fischer Esterification Flashcards
The following product is isolated from the Fischer esterification reaction. What splitting pattern is expected for protons on carbon A, carbon B, and carbon D?
*See Question 1 on Quiz 9
A. A = singlet C = singlet D = singlet B. A = triplet C = singlet D = quartet C. A = quartet C = doublet D = doublet D. A = triplet C = doublet D = quartet
C
The Fischer reaction shown below is an equilibrium reaction with a relatively unfavorable Keq. How could the reaction be made to produce more product?
*See Question 2 on Quiz 9
A. use an excess of alcohol B. use an excess of carboxylic acid C. remove water as it’s formed D. both a & b E. all will work (a, b & c)
E
What is the role of the carboxylic acid in the Fischer esterification reaction?
A. electrophile
B. leaving group
C. catalyst
D. nucleophile
A
The following product is isolated from the Fischer Esterification reaction. How many signals are expected in 1H NMR?
*See Question 4 on Quiz 9
A. 4
B. 5
C. 6
D. 7
B
Fischer Esterification reactions typically have an unfavorable equilibrium that leads to a low percent yield. Why might that be?
A. The starting material & product both possess poor LGs of similar basicity.
B. The sulfuric acid readily reacts with the alcohol to form an unwanted side product.
C. The newly added R’ group causes unfavorable steric strain in the product molecule.
D. The alcohol used is a weak nucleophile that cannot readily attack the carbonyl carbon of the carboxylic acid.
A
The Fischer Esterification reaction shown below is performed. During the extraction work up, the organic layer is washed with 0.5 M sodium bicarbonate and bubbling is noticed. What is the identity of the gas?
*See Question 6 on Quiz 9
A. H2
B. CO2
C. HCl
D. N2
B
What is the role of the sulfuric acid in the Fischer Esterification reaction?
A. It protonates the alcohol to make it a stronger nucleophile.
B. It protonates the OH of the carboxylic acid to form a good LG.
C. It protonates the carbonyl oxygen of the carboxylic acid to form a better electrophile.
D. It auto-ionizes the produce H3O+ and HSO4-.
C
Which of the following statement(s) is/are TRUE?
I. Many esters are fragrant compounds that are used in the food and perfume industries.
II. Formation of an ester from a carboxylic acid & alcohol in the presence of acid favors formation of the products because the ester is more stable that either of the reactants.
III. After the Fischer esterification rxn is complete, excess acid is removed in the workup by washing with 1M HCl.
A. only I
B. only I & II
C. only I & III
D. all of the above
A
What functional group transformation is noticed in the Fischer Esterification reaction?
A. forming an ester from a carboxylic acid and alcohol
B. forming an alcohol from carboxylic acid and ester
A
In the synthesis of isoamyl acetate, a student began with 3.072 g of acetic acid (MW = 60.05 g/mol) and 2.234 mL of isoamyl alcohol (MW = 88.15 g/mol D = 0.804 g/mL). If the mass of isoamyl acetate (MW = 130.18 g/mol) collected was 2.493 g, what is the % yield?
A. 40%
B. 75%
C. 83%
D. 93%
D
What is the number of signals in 1H NMR for the compound shown below?
*See Question 11 on Quiz 9
6
Why is sodium bicarbonate (NaHCO3) added?
to remove excess acid present
