Hello,
I did some reading on degradation pathways for alkyl nitrites (otherwise discussed as leather cleaner, room odorizer, solvent cleaner, etc)
What is usually the reason for poppers “going bad”?
Alkyl nitrites react with water in the presence of acids or bases and decompose back into its parent alcohol and nitrous acid.
Any time the chemical is exposed to the air, it’s also exposed to the water within that air. If there’s any additional acid in the solution (there usually is), that acid is going to cause a reaction that decomposes the alkyl nitrite.
There are quite a few strategies to combat this and help preserve the product. Keep in mind that “no water” is difficult if you don’t have a glove box or some method of controlling the composition of the environment the product is exposed to when opened, so it’s not likely that a product would ever be stable indefinitely. While not a comprehensive list, common practices include…
- Store with Potassium carbonate or other acid absorbent.
There’s a paper from the University of Wisconsin from 1958 where researchers analyzed variance in gas formation in amyl nitrite ampuls when exposed to a number of alkaline substances intended to preserve the nitrite.
Over a 12 week time period, they studied a strong base (triethylamine), solid acid absorbents (potassium carbonate, sodium phosphate, magnesium oxide, and sodium bicarbonate), a weak base (pyridine), and amines that may react with nitric acid. All preservatives were added in a 2% concentration with 0.5mL isoamyl nitrite in an ampul. While other options performed alright, potassium carbonate completely stopped gas formation over a 12 week study.
This works because alkaline salts such as potassium carbonate are capable of reacting with the acidic chemicals formed during the degradation (ie Nitrous acid). The neutralization of these acids stabilizes the chemical and prevents hydrolysis.
- Molecular sieve.
Specific to this product, a research group from South Africa published a paper suggested storing over 3-A molecular sieve at 0C. Beyond this specific product, molecular sieves are noted drying agents for organic solvents in many applications.
This works as a means to capture water that absorbs into the solvent due to exposure. Once the water enters the solvent, the water molecules get trapped in the pores of the molecular sieve, but the larger nitrite molecules don’t. 3A sieves should perform the best in this case because the pore size is ideal for trapping water.
- Glycerol (humectants)
There’s a paper from 1960 by researchers from Jawant college that talks about storing their experimental solutions of alkyl nitrites in glycerol at 0C. However, this is not a technique that is specific to alkyl nitrites – glycerol is a highly hygroscopic humectant, meaning it has a strong affinity for water molecules. It forms hydrogen bonds with water, preventing water from interacting with the solvent. By sequestering water, glycerol helps inhibit chemical reactions that might be catalyzed or accelerated by the presence of water.
- Storage in amber glass
Hydrolysis is not the only way that alkyl nitrites degrade. Alkyl nitrites are also susceptible to photolysis, which basically means that absorption of photons drives reactions into other things. The photo-degredation of alkyl nitrites was studied all the way back in 1937 by the faraday society and the mechanism and degradants is documented.
There’s a book called “Advances in Photochemistry Volume 14” that captured the absorption spectra for the alkyl nitrites. They were all found to be below 400 nm, which consequently also happens to be where the UV spectrum ends and the visible light spectrum begins.
Amber glass blocks wavelengths from 10 nm to 400 nm, so storage in amber glass should prevent alkyl nitrite photolysis.
- Storage under Nitrogen gas:
The atmosphere usually has 4% water content, based on NOAA metrics. If a bottle containing alkyl nitrites is sealed with good old fashioned atmospheric air, the degradation process starts immediately based on the presence of water.
Preserving items under nitrogen (or argon) gas is common practice – it’s what they use to puff up bags of chips. In chemistry labs, the nitrogen gas is bubbled into liquids that react with atmospheric air to flush away any chemicals that are not inert, therefore preventing any unwanted reactivity.
This post is brought to you by Unspillables Solvent Cleaners. The brand, while obviously unaffiliated with poppers products and this blog, has a side interest in social studies on the LGBTQ community.
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