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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Ester-maniac on January 22, 2013, 11:07:50 AM

Title: Synthesis/purification of alkly esters?
Post by: Ester-maniac on January 22, 2013, 11:07:50 AM

I have been trying to do this synthesis for over a year and have quite a few questions.  I am willing to pay for any useful information.   I am using the liquid phase William Noyes formula, which calls for a molar excess of sodium nitrite relative to the base alcohol.  For instance, 1.1 to 1.  The concentrated sulfuric acid molar amount is equal to half the moles of the base alcohol.  For instance .5 to 1. 

Questions:  Noyes used a brine/baking soda wash to remove residual acid.  Why does he only use a 2% concentration of baking soda?  Will more degrade the nitrite?  Is nitric acid the primary acid being neutralized?
Is there any method that will raise the pH to 7.  So far, I can only get it to 5 with the baking soda wash.
What is the best/easiest way to remove unwanted nitrogen dioxides? 

Question:  Noyes maintains a reaction temperature near freezing temperature of water.  Can it be much colder or a bit warmer without affecting purity and yield?

Question:  I am using anhydrous potassium carbonate to preserve.  This acts as an acid sink.  Will this still work
if the crude yield after washing is still tainted with nitric acid?

I read that brine/baking soda technique cannot remove all the residual acid, evidenced by the fact that nitrites produced in this way corrode metal containers, which is not an inherent property of pure nitrite esters.  I believe
urea and nitric acid were used to neutralize the nitrite to the point where it would no longer corrode metals.

Thanks.  I think these questions are for chemistry wizards.

Title: Re: Synthesis/purification of alkly esters?
Post by: discodermolide on January 22, 2013, 11:21:04 AM

So if I have it correctly you are trying to make a nitrite ester of an alcohol?
Which alcohol?

Title: Re: Synthesis/purification of alkly esters?
Post by: Ester-maniac on January 22, 2013, 11:30:12 AM

Any of the base alcohols that produce nitrites which remain liquid at ordinary pressure and temps.

Title: Re: Synthesis/purification of alkly esters?
Post by: discodermolide on January 22, 2013, 11:33:24 AM

Well most alcohols can form nitrite esters. The conditions may vary according to the alcohol employed, which is why I asked which alcohol you had in mind or were using.

Title: Re: Synthesis/purification of alkly esters?
Post by: Dan on January 22, 2013, 12:49:56 PM

To me this looks like someone is trying to make poppers at home.

I have locked this thread, it may be reopened following discussion among the forum staff.