Safe cap for erlenmeyer

[Sicho Naut]

Hi all,

Aside from gathering materials, I am more or less ready to try a first extraction. I have settled on a STB, room temperature tek for a first try.

My question: I want to get a 1000ml erlenmeyer flask with PTFE lid, but I only worry about it not being a vented cap (which are unavailable to me). Is there a way of creating an airlock for an erlenmeyer flask that is safe to use with lye & naphta, i.e. to avoid pressure building up [edit: and for potential interactions with the solution]? Or some other safety measure?

The tek requires swirling every three hours or so for at least 8 times per pull, which, taking into account a period for sleeping, means that every pull will will require the solution to sit in the flask for approx. 36 hours (the point being that there must be some lid to prevent evaporation of the naphta).

Thanks ahead!

 

[Transform]

Just remember, naphtha is stored in similar bottles to this anyhow.

Considering you'll be doing the pulls at room temperature, there shouldn't be any pressure build-up once the temperature of the system has equilibrated. The principal source of heat comes from the dissolution of lye into water, so the flask will be cooling down for the first couple of hours or so. You can leave the cap slightly loose while the flask sits if you prefer, but it would be prudent to secure it during the periods of swirling. This swirling will possibly cause a small amount of pressure to build up but you can easily release it by cracking the lid open slightly every couple of minutes.The main thing then is to ensure there's no basic solution near the cap which might spray out, although you'll obviously be wearing sufficient PPE anyhow.

Airlocks are only relevant for continuous gas output, rather than evaporation of solvent.

Vapor pressure - Wikipedia

en.wikipedia.org

 

[Sicho Naut]

Thanks!