Before You Begin
Question #44421
The Question
An organic chemist attempts to synthesize an ester by heating \ce{2,4,6-trimethylbenzoic acid} with excess \ce{2-methylpropan-2-ol} in the presence of catalytic \ce{H2SO4} at 350 K. According to Le Chatelier's principle, the excess alcohol is intended to drive the equilibrium forward. However, the esterification fails completely. Identify the major organic products formed in this reaction mixture.
Options
- A.
\ce{2-methylpropene} and \ce{2,4,6-trimethylbenzoic acid}
- B.
\ce{tert-butyl 2,4,6-trimethylbenzoate} and \ce{H2O}
- C.
\ce{2-methylpropene} and \ce{2,4,6-trimethylbenzene}
- D.
\ce{isobutyl 2,4,6-trimethylbenzoate} and \ce{H2O}
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Esterification Steric Hindrance|Esterification Reversibility|Reaction Progress Coordinate
Why This Question Is Tricky
Common Mistakes
The question tests the limits of Le Chatelier's principle when kinetic barriers (steric hindrance) prevent the desired thermodynamic equilibrium from being reached.
Students often assume that adding excess reactant will always yield the product.
However, the 'ortho effect' in 2,4,6-trimethylbenzoic acid prevents the formation of the tetrahedral intermediate required for Fischer esterification.
Additionally, the bulky tertiary alcohol has a lower activation energy for E1 dehydration than for nucleophilic attack.
The trap is assuming esterification occurs normally or that the acid undergoes decarboxylation.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Esterification Steric Hindrance |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |