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Topic: Unstable ester issue  (Read 3657 times)

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Offline Ingeniosuccinimide

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Unstable ester issue
« on: October 05, 2013, 02:32:51 PM »
Hello,

I have to perform one reaction for which i-PrNO2 is used (I guess as a solvent). As I need only about 10 mL, and we are able to buy only a bulk quantity (not less than 500 mL), I decided to prepare it according to the following procedure:

http://pubs.acs.org/doi/abs/10.1021/jo00277a030?prevSearch=cephems&searchHistoryKey=

described on the page 3911. Now, I did everything in the procedure as described, except that the quantities were reduced by factor 10 and I used a simple baloon-syringe equipment to introduce nitrogen as atmosphere instead of using classic gas bubbler.

I obtained around 60 mL of straw-colored oily liquid, however I have two issues:

the liquid is greatly unstable when exposed to atmospheric conditions and it emits NO2 when exposed to air. Shouldn't i-PrNO2 be a stable ester which does not break so easily? I also noticed just while googleing that it is used as a drug "poppers" by some people, together with other alkyl nitrites, and now I'm even more skeptical if I obtained the right compound (the NMR is unavailable to me for a next couple of days).

second question regards to the vacuum distillation. I was told that I should purify the compound, but I never performed this distillation, and I'm not sure if it's recommended to do it, given the evolution of NO2 and low flash point. Any suggestions.

I would also like to ask when (or why) is i-PrNO2 used as a solvent? Why specifically it? Is there something better that could substitute it?

Offline Archer

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Re: Unstable ester issue
« Reply #1 on: October 05, 2013, 03:10:05 PM »
Could you be mixing up your nitroalkanes and your alkyl nitrites?

Alkyl nitrites are never used as solvents as they are too reactive. They also degrade over time so if they are being used as a reagent they generally need to be freshly distilled (under reduced pressure).

Can't discuss the synthesis of i-PrONO as it violates forum rules.
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Offline Borek

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Re: Unstable ester issue
« Reply #2 on: October 05, 2013, 04:01:25 PM »
We will keep the thread open for now. Please remember it can get closed any time we decide it goes into too much details.
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Offline Archer

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Re: Unstable ester issue
« Reply #3 on: October 05, 2013, 11:13:39 PM »

I have to perform one reaction for which i-PrNO2 is used


Could you provide details of the reaction you are planning which requires this substance?

Alkyl nitrites are generally employed as a reagent where aqueous HONO cannot be used. I don't see why any higher homologues would not suffice in most applications.
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Offline Ingeniosuccinimide

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Re: Unstable ester issue
« Reply #4 on: October 06, 2013, 07:52:03 PM »
Honestly, I think I made a mistake. What does actually i-PrNO2 stand for? Is that isopropyl nitrite or 2-nitropropane? Is the latter commonly used as a solvent in some reactions?

Offline Archer

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Re: Unstable ester issue
« Reply #5 on: October 06, 2013, 08:06:37 PM »
Honestly, I think I made a mistake. What does actually i-PrNO2 stand for? Is that isopropyl nitrite or 2-nitropropane? Is the latter commonly used as a solvent in some reactions?

R-NO2 usually denotes a nitro group. So you probably want 2-nitropropane.


Nitroalkanes are used as solvents, I have never used iPr but frequently use nitromethane. Nitrites are usually (not always) given the notation R-ONO to avoid confusion.
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