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Hydrolysis of hydroxynitriles and reduction

I have a question about the hydrolysis of hydroxynitriles.

I know that when you hydrolyse a nitrile, you get a carboxylic acid like this:

CH3CN + H2O + H+ = CH3COOH + NH4 (unbalanced)

But how does it work with a hydroxynitrile such as 2-hydroxypropanenitrile? Would you still get propanoic acid? What would be the equation?


Also, how would you obtain CH3CH(OH)COOH from CH3COCOOH? I was thinking of using NaBH4 simply because it can't be LiALH4 and its the only other reducing agent I can thinking of. But if I did use NaBH4, how would you do it? Is it right to use that? :confused:


Edit: Additional question:
I've always been confused with structural formula and displayed formula. I've always thought structural formula is like CH3CH2CHO, for example, then displayed is when you draw it out. Is this right, and if it is, when you have something with a double bond, do you have to include it eg. CH3C=OCH3

Thank you :smile:
(edited 13 years ago)
Original post by LadyLoveDisdain
Edit: Additional question:
I've always been confused with structural formula and displayed formula. I've always thought structural formula is like CH3CH2CHO, for example, then displayed is when you draw it out. Is this right, and if it is, when you have something with a double bond, do you have to include it eg. CH3C=OCH3

Thank you :smile:


These are not structural they are condensed formulae. For structural you must show all bonds.
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Avatar for Kyri
Kyri
15
In a similar fashion to what you've seen already, hydrolysis of 2-hydroxypropanenitrile should lead to 2-hydroxypropanoic acid, otherwise known as lactic acid. The OH behaves the same as in a normal alcohol so shouldn't react under those conditions. Yes, with HCl in there you could get some dehydration of the alcohol to CH2=CH-COOH but you won't really get any of this with only dilute HCl as you require harsher conditions for that.

CH3-CH(OH)-CN + 2 H2O + HCl ---> CH3-CH(OH)-COOH + NH4Cl

For the reduction, NaBH4 should be ok. This generally reduces aldehydes and ketones, but not carboxylic acids or esters so you won't need to do anything special.
Not true. CH3CH2CHO is indeed a structural formula. You only include bonds where they are necessary to explain the structure, such as C=O, as correctly said above. I've never heard of a condensed formula.
Original post by LadyLoveDisdain
I have a question about the hydrolysis of hydroxynitriles.

I know that when you hydrolyse a nitrile, you get a carboxylic acid like this:

CH3CN + H2O + H+ = CH3COOH + NH4 (unbalanced)

But how does it work with a hydroxynitrile such as 2-hydroxypropanenitrile? Would you still get propanoic acid? What would be the equation?


Also, how would you obtain CH3CH(OH)COOH from CH3COCOOH? I was thinking of using NaBH4 simply because it can't be LiALH4 and its the only other reducing agent I can thinking of. But if I did use NaBH4, how would you do it? Is it right to use that? :confused:


Edit: Additional question:
I've always been confused with structural formula and displayed formula. I've always thought structural formula is like CH3CH2CHO, for example, then displayed is when you draw it out. Is this right, and if it is, when you have something with a double bond, do you have to include it eg. CH3C=OCH3

Thank you :smile:


Just to slide in here, when you hydrolyse a nitrile with one equivalent of water you get an amide, then on hydrolysis of the amide (with a second equivalent of water) you get the carboxylic acid. NaBH4 would reduce the nitrile to the amine, as would LiAlH4.

Structural formula is either drawn out with groups abbreviated, or linear with showing the connectivity. Displayed is drawn out, all bonds shown.


Edit: Just saw that the thread is 5 years old

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