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utsav55
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What will be the % of Enol form of this compound?
99% or 1%? Also give reason.
Thanks
99% or 1%? Also give reason.
Thanks
What will be the % of Enol form of this compound?
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In summary, the % of Enol form of this compound is 99%, despite the Keto form being more stable due to its aromaticity. This is a result of small energy differences having a significant impact on percent composition, with even a small difference of 4 kcal/mol resulting in over 99% of the more stable isomer. Additionally, the relationship between Gibbs free energy and chemical equilibrium is useful when calculating percent composition in reversible reactions.
- #2
Borek
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Try to draw enol form(s).
If it is a homework question (and it surely looks like one), you have asked in the wrong forum.
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methods
If it is a homework question (and it surely looks like one), you have asked in the wrong forum.
--
methods
- #3
utsav55
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It is not homework, its a doubt.
I think, it is 1% as Keto form is Aromatic and hence more stable, but the answer is 99%.
I think, it is 1% as Keto form is Aromatic and hence more stable, but the answer is 99%.
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sjb-2812
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What is the definition of aromatic, in this case?
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chemisttree
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I was going to say 99+% because in the enol form, you have the formation of the aromatic structure.
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Borek
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That's why I asked to draw enolic form, it should be obvious 
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methods
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methods
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chemisttree
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When calculating the percent of a certain species in solution obtained in a completely reversible reaction (like keto-enol tautomerism) it is useful to remember the relationship between the Gibbs free energy of the process and chemical equilibrium.
Namely
DeltaG = -RT ln(K)
This equation shows us that small differences in energy can have profound changes in percent composition. For stereoisomers (gauche- and anti-, for example) of substituted cyclohexanes, free energy differences of only 2kcal/mol results in >95% of the more stable isomer. A difference of only 4kcal/mol results in >99%.
Aromatic stabilization energies for benzene are on the order of 20 to 40 kcal/mol...
Namely
DeltaG = -RT ln(K)
This equation shows us that small differences in energy can have profound changes in percent composition. For stereoisomers (gauche- and anti-, for example) of substituted cyclohexanes, free energy differences of only 2kcal/mol results in >95% of the more stable isomer. A difference of only 4kcal/mol results in >99%.
Aromatic stabilization energies for benzene are on the order of 20 to 40 kcal/mol...
1. What is the % of Enol form of this compound?
The % of Enol form of a compound is the percentage of the total molecules present in the Enol form. It is calculated by dividing the number of Enol molecules by the total number of molecules and multiplying by 100.
2. How is the % of Enol form measured?
The % of Enol form is typically measured using spectroscopy techniques such as nuclear magnetic resonance (NMR) or infrared (IR) spectroscopy. These methods can differentiate between the Enol and the Keto forms of a compound and determine their relative amounts.
3. What factors can affect the % of Enol form?
The % of Enol form can be affected by several factors, including the solvent used, temperature, and the presence of other molecules or ions that can stabilize one form over the other. The electronic and steric properties of the compound can also influence the % of Enol form.
4. Why is it important to know the % of Enol form?
The % of Enol form is important because it can affect the reactivity and properties of a compound. For example, the Enol form is generally more reactive than the Keto form and can participate in different reactions. Knowing the % of Enol form can also help in understanding the stability and behavior of a compound in different conditions.
5. Can the % of Enol form change over time?
Yes, the % of Enol form can change over time due to various factors such as temperature, pH, and the presence of catalysts. For example, increasing the temperature can favor the formation of the more stable Keto form, which can lead to a decrease in the % of Enol form. Additionally, some compounds can undergo tautomerization, where the Keto and Enol forms can interconvert, further affecting the % of Enol form.
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