The weakest link:
Posted on Poppers Guide's Forum
Topic created by The Professor
on Fri, 13 Aug 2021 at 18:53
The Professor said on Fri, 13 Aug 2021 at 18:53...
here's a pic describing the overall composition of an Alkyl nitrite.
The R section is a number of methyl groups (the body), determined by the type of alcohol used. The first red ball from the left is Oxygen (the neck), and the double bonded red and blue balls are nitric oxide (the head)
The active ingredient in any Alkyl nitrite is Nitric Oxide (NO). In use, the inhaled vapor is metabolised; first the head falls off of the neck, leaving an Alkoxy radical (RO) and nitric oxide (NO). Nitric oxide does its job, and the alkyl radical is pissed away.
The strength of that neck bond (which is the same regardless of nitrite type) is verty weak; with a BDE of about 40kcal/mol.
The nitrite's greatest strength (the ability to provide NO) is also its greatest weakness (the bond strength to release NO into the bloodstream).
In the bottle, that O-NO bond is the weakest, and first to break, starting the entire degradation cascade.
the remaining degradation interactions involve decomposition of the alkoxy radical, and subsequent reshuffling of ions to produce various degradation products.
No amount of stabilizer is going to 'fortify' the weakest link; it's a function of the van der walls forces between nitrogen and oxygen.
A question might be "why then does N-Amyl nitrite (for example) degrade slower than X nitrite (where X is a more reactive nitrite.
This question has two answers, depending on perspective.
In a sealed bottle, degradation STARTS with that ONO bond liberating NO gas and the alkoxy radical, and that decomposition has a very low barrier of activation (about 40kcal/mol). Once it starts, it proceeds at the rates I've posted earlier
So if the barrier to decomposition is the same, why the APPARENT differences in degradation speed? simply because of reactivity differences between the nitrites (essentially their vapor pressure).
With something weak, like n-Amyl (72% reactive) only so much of the nitrite 's molecules may be above that hurdle (energy wise).
Now step up to n-butyl nitrite (81% reactive) and that extra 9% of energy ensures that more of the nitrite molecules will be at an energy level ABOVE that hurdle.
A bit of a catch 22 situation; the vapor is what does the job, and it releases NO, yet the NO bond is responsible for degradation and the nitrites that produce more vapor appear to decompose more quickly.
As with most things, it all comes down to the user.
Open the bottle repeatedly, store in sunlight on the kitchen table, and things will deteriorate within hrs/days.
Open the bottle sparingly (just to fill a dosing device) and store in a cool dry place with stabilizer (and maybe even squirting some argon in before re-capping ) and you'll get weeks/months out of the same bottle.
Canuck SB said on Sat, 14 Aug 2021 at 04:01...
Id really enjoy becoming a maker but having difficulty acquiring the elements needed here in canada wheres the best place to find a hobbyist chemist?
Your name or nickname goes in this blank bar said on Thu, 26 Aug 2021 at 02:01...
@Canuck SB I've seen your question a few times on here but nobody ever answers. Probably Reddit has the answers. There are some videos on youtube but the people are making isopropyl which causes eye problems so not good.
Jacko said on Sun, 29 Aug 2021 at 03:03...
Canuck SB, I can't speak for Canada specifically, but have found here in NZ that I can get the required muriatic or sulfuric acid from hardware and pool supply stores.
Sodium nitrite is available from either food ingredient or chemical distributors. Look for smaller local players, rather than big multinationals, and ask about their minimum order sizes first. I got 5L of n-butanol and 1kg of sodium nitrite from two small chemicals distributors and 500ml of pentyl alcohol from a school laboratory chemicals supplier. Just emailed and placed website orders, no questions asked. Some home brewers will say food grade nitrite is not pure enough, but my experience has been it works just fine. Keep sealed and dry though.
The worst that can happen is they say no. As far as I know, asking to purchase any of these things is not going to get you into trouble.