what happens when (+) 2-iodobutane is treated with NaI in acetone?

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After treating the compound with NaI, we should follow Sn2 mechanism and the product will follow optical inversion giving us (-)2-iodobutane but the answer is (±)2-iodobutane.



After going through various articles, I am getting reason such as there will be an equilibrium created between the reactants and the products, hence we will get both the products (±)2-iodobutane.



And there is a same question where we are treating (R)2-bromobutane with NaI in acetone, but the answer is (S)2-iodobutane.



What could be the reason?
I believe we should simply get one product in the question, and there will be no equilibrium be created, as there shouldn't be enough NaI left to form another compound.










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  • 1




    Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
    – orthocresol♦
    4 hours ago






  • 1




    If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
    – user55119
    1 hour ago














up vote
2
down vote

favorite












After treating the compound with NaI, we should follow Sn2 mechanism and the product will follow optical inversion giving us (-)2-iodobutane but the answer is (±)2-iodobutane.



After going through various articles, I am getting reason such as there will be an equilibrium created between the reactants and the products, hence we will get both the products (±)2-iodobutane.



And there is a same question where we are treating (R)2-bromobutane with NaI in acetone, but the answer is (S)2-iodobutane.



What could be the reason?
I believe we should simply get one product in the question, and there will be no equilibrium be created, as there shouldn't be enough NaI left to form another compound.










share|improve this question







New contributor




kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.















  • 1




    Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
    – orthocresol♦
    4 hours ago






  • 1




    If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
    – user55119
    1 hour ago












up vote
2
down vote

favorite









up vote
2
down vote

favorite











After treating the compound with NaI, we should follow Sn2 mechanism and the product will follow optical inversion giving us (-)2-iodobutane but the answer is (±)2-iodobutane.



After going through various articles, I am getting reason such as there will be an equilibrium created between the reactants and the products, hence we will get both the products (±)2-iodobutane.



And there is a same question where we are treating (R)2-bromobutane with NaI in acetone, but the answer is (S)2-iodobutane.



What could be the reason?
I believe we should simply get one product in the question, and there will be no equilibrium be created, as there shouldn't be enough NaI left to form another compound.










share|improve this question







New contributor




kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











After treating the compound with NaI, we should follow Sn2 mechanism and the product will follow optical inversion giving us (-)2-iodobutane but the answer is (±)2-iodobutane.



After going through various articles, I am getting reason such as there will be an equilibrium created between the reactants and the products, hence we will get both the products (±)2-iodobutane.



And there is a same question where we are treating (R)2-bromobutane with NaI in acetone, but the answer is (S)2-iodobutane.



What could be the reason?
I believe we should simply get one product in the question, and there will be no equilibrium be created, as there shouldn't be enough NaI left to form another compound.







organic-chemistry halides optical-properties






share|improve this question







New contributor




kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









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share|improve this question






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asked 5 hours ago









kiv

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112




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New contributor





kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






kiv is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 1




    Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
    – orthocresol♦
    4 hours ago






  • 1




    If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
    – user55119
    1 hour ago












  • 1




    Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
    – orthocresol♦
    4 hours ago






  • 1




    If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
    – user55119
    1 hour ago







1




1




Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
– orthocresol♦
4 hours ago




Iodide is attacking and kicking out another iodide, so you cannot ever run out of it.
– orthocresol♦
4 hours ago




1




1




If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
– user55119
1 hour ago




If iodide can react with the (R)-enantiomer, why not the (S)-enantiomer? As orthocresol states, it goes on and on until racemization occurs. This is classic experiment that shows that racemization is twice the rate of SN2 displacement. Imagine you have two (R)-molecules. You only have to invert one to (S) to achieve racemization. At that point, only one of the two (R)'s has reacted. Think about how radioactive iodide would be useful in this regard.
– user55119
1 hour ago










1 Answer
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There is no equilibrium in the second reaction because the sodium bromide formed by the iodide displacement is not soluble in acetone so there is no Br- to displace iodide. In contrast with the first reaction, NaI is soluble in acetone so there is always excess I- around to continue the reaction. This is called the Finkelstein reaction, further information here finkelstein reaction






share|improve this answer






















  • But in the first reaction, could the final major product be only (-)2-iodobutane?
    – kiv
    5 hours ago











  • No, because the iodides keep exchanging so you get the mixtures.
    – Waylander
    4 hours ago










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1 Answer
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up vote
4
down vote













There is no equilibrium in the second reaction because the sodium bromide formed by the iodide displacement is not soluble in acetone so there is no Br- to displace iodide. In contrast with the first reaction, NaI is soluble in acetone so there is always excess I- around to continue the reaction. This is called the Finkelstein reaction, further information here finkelstein reaction






share|improve this answer






















  • But in the first reaction, could the final major product be only (-)2-iodobutane?
    – kiv
    5 hours ago











  • No, because the iodides keep exchanging so you get the mixtures.
    – Waylander
    4 hours ago














up vote
4
down vote













There is no equilibrium in the second reaction because the sodium bromide formed by the iodide displacement is not soluble in acetone so there is no Br- to displace iodide. In contrast with the first reaction, NaI is soluble in acetone so there is always excess I- around to continue the reaction. This is called the Finkelstein reaction, further information here finkelstein reaction






share|improve this answer






















  • But in the first reaction, could the final major product be only (-)2-iodobutane?
    – kiv
    5 hours ago











  • No, because the iodides keep exchanging so you get the mixtures.
    – Waylander
    4 hours ago












up vote
4
down vote










up vote
4
down vote









There is no equilibrium in the second reaction because the sodium bromide formed by the iodide displacement is not soluble in acetone so there is no Br- to displace iodide. In contrast with the first reaction, NaI is soluble in acetone so there is always excess I- around to continue the reaction. This is called the Finkelstein reaction, further information here finkelstein reaction






share|improve this answer














There is no equilibrium in the second reaction because the sodium bromide formed by the iodide displacement is not soluble in acetone so there is no Br- to displace iodide. In contrast with the first reaction, NaI is soluble in acetone so there is always excess I- around to continue the reaction. This is called the Finkelstein reaction, further information here finkelstein reaction







share|improve this answer














share|improve this answer



share|improve this answer








edited 4 hours ago

























answered 5 hours ago









Waylander

4,5841619




4,5841619











  • But in the first reaction, could the final major product be only (-)2-iodobutane?
    – kiv
    5 hours ago











  • No, because the iodides keep exchanging so you get the mixtures.
    – Waylander
    4 hours ago
















  • But in the first reaction, could the final major product be only (-)2-iodobutane?
    – kiv
    5 hours ago











  • No, because the iodides keep exchanging so you get the mixtures.
    – Waylander
    4 hours ago















But in the first reaction, could the final major product be only (-)2-iodobutane?
– kiv
5 hours ago





But in the first reaction, could the final major product be only (-)2-iodobutane?
– kiv
5 hours ago













No, because the iodides keep exchanging so you get the mixtures.
– Waylander
4 hours ago




No, because the iodides keep exchanging so you get the mixtures.
– Waylander
4 hours ago










kiv is a new contributor. Be nice, and check out our Code of Conduct.









 

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