- #1
ephemeral1
- 28
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If you dehyrate 1-butanol, wouldn't you get 2-butene due to rearrangement? This is not a homework question. This is an mcat review question. The question asks: when 1-butanol is dehydrated, the new compound's heat of hydrogenation is most likely? The answer is between 30 and 33 kcal/mol
It gives you a table of heats of hydrogenation
1-butene 30.3
1-pentene 30.1
cis-2-butene 28.6
trans-2-butene 27.6
I'd assume that the new compound would have a heat of hydrogenation similar to trans-2-butene since the carbocation would undergo rearrangement. It is more thermodynamically favored. However, the answer that the review book gives favors a product that is more kinetically favored. I guess 1-butene would produce faster but if time allows, wouldn't it convert to a more thermodynamically favored product? Could anyone explain? Thank you
It gives you a table of heats of hydrogenation
1-butene 30.3
1-pentene 30.1
cis-2-butene 28.6
trans-2-butene 27.6
I'd assume that the new compound would have a heat of hydrogenation similar to trans-2-butene since the carbocation would undergo rearrangement. It is more thermodynamically favored. However, the answer that the review book gives favors a product that is more kinetically favored. I guess 1-butene would produce faster but if time allows, wouldn't it convert to a more thermodynamically favored product? Could anyone explain? Thank you