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Author: Subject: Ispropyl Nitrite synth now requires heating?
Antiswat
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[*] posted on 13-1-2020 at 08:43
Ispropyl Nitrite synth now requires heating?


So, im gonna start off with saying the NaNO2 im using i made myself by thermal decomposition of NaNO3, i have done this with quite an amount of NaNO3 so far and got the whole deal under control, i have tested the finished NaNO2 with conc H2SO4 and copper wires and it yields a very boring and mundane reaction, a slight bit of NO3 is no issue and is natural to occur as NO2 absorbs oxygen from air over time.

Anyhow- to the point of this thread, long ago when i was much less experienced i prepared a nice heap of IPN, the reaction was quite swift and i used 50% H2SO4 with bought NaNO2 and same grade of isopropyl alcohol as i do today
back then when i added the reagents it heated up well and produced visible NOx fumes
this is no longer the case, and i have done this reaction a bunch of times with more and more resistance, as i from vasodilating properties of the mixture in the flask noticed there surely was some IPNitrite i decided to pull 50mL into my new 100mL flask and see if i could lure any of it out, and as its heating up to around 60-70*C its now turning into the characteristic HNO2 color, despite the NaNO2 had been predissolved and whats worse, i had zero heat being produced when i cautiously poured the IPA + H2SO4 with NaNO2 solution

but its quite evidently now generating HNO2
is my memory really that bad, did this always require heating and are all the preparations online bogus? is it possible that all the synths have been edited, and that lining up with my memory being entirely wrong
i have had many reactions working against me and even some being entirely impossible no matter how far i stretched it, but this reaction is known to require cooling as the heat produced is quite frightening and the thing might turn into a runoff reaction if it gets just a bit too warm

im just wanting to hear if other people are experiencing preparations changing personality overnight or if anyone has been around IPN synth lately




~25 drops = 1mL @dH2O viscocity - STP
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DavidJR
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[*] posted on 13-1-2020 at 11:33


No, you need to keep it ice cold because HNO2 is very unstable at room temperature
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[*] posted on 13-1-2020 at 13:17


I remember adding the alcohol/96% sulfuric mixture ice cold to ice cold nitrite in water. Remember it is a esterfication. You want as little water as possible, you do need some however as you need to keep the nitrite dissolved while having a homogeneous mixture. Also you don't want your HNO2 too concentrated and dissolved in as much water as possible.

On Prepchem there are a couple of different preps with alcohols, sulfuric (or HCl) and nitrite, none of them uses diluted acid, and the one using HCl is low yielding.
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[*] posted on 13-1-2020 at 14:57


Can you outline the thermal decomposition to nitrite? I've seen several threads on here with conflicting info about this procedure and Wikipedia/refs don't seem to corroborate either.
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[*] posted on 21-1-2020 at 09:57


using HCl it now appears to be working out, im not chilling it but im adding HCl to NaNO2 / IPA one "whoops" at a time, i have seen the HNO2 persist even with pretty high temperature, which shouldnt be possible, the HNO2 having a lightblue color, distillation removed this from both solutions

as for the decomp of NaNO3 into NaNO2, its quite simple, it yields oxygen

NaNO3 --> NaNO2 + ┬ŻO2
some sodium oxide may be formed too, but also some small amounts of NOx appears to form as the stainless steel container turned into a very neat superblack, oxygen at high temperature doesnt do this afaik

maybe i used too much water, but it just doesnt add up still, the HNO2 should react somewhat fast with the IPA, and i followed recipe for it, i also had a batch where even heating the NaNO2 slurry with acid in it and IPA didnt create anything at all
also NaNO2 solution turns into some type of a thin gel as IPA makes NaNO2 insoluble in water

one time i managed to offend it enough to runoff it didnt cause any NOx fumes, but rather the IPN just boiled out? maybe the way to go is to just throw this into a 500mL flask, attach distillation bridge and pour it all together and hope for the best, let it distill itself
of what ive understood nitritification is less problematic than nitration




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
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[*] posted on 22-1-2020 at 00:38


|I did the nitrite ester formation reaction with several different alcohols (methanol, iso-propanol, n-propanol, n-butanol). In all cases, the reaction proceeds fast and without any hassle. I use cold (not ice cold, just cold) solutions. I mix the alcohol with some dilute acid and to this I slowly add a cold solution of NaNO2. With CH3OH this leads to vigorous bubbling (escape of the gaseous CH3ONO, which easily burns with a grey flame), with the other alcohols I get a yellow layer on top of the aqueous layer. It easily can be pipetted from the aqueous layer and neutralized with NaHCO3. Never had any issues with this reaction. I use commercial grade NaNO2.



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