After reading about the destructive effects strong bases have on glass, I had some questions. The Vovin tek advises to use a glass separatory funnel. If one were to follow this tek, would they have to worry about the separatory funnel eventually shattering from being weakened by NaOH? That sounds very dangerous to me. If so, then how long would it take for these effects to compromise the strength of the glass? Im sure the answer to that question varies a lot depending on the frequency of use, so I guess I am asking how many extractions can be done until the glass weakens. Most of the warnings I have seen were on STB forums. Is an A/B extraction any less dangerous in this regard? The only difference I see is that the Vovin tek says to basify the extract to a ph of 12-13, where most STB teks recommend 14. Does one more point on the ph scale really make much of a difference regarding the threat it poses to glass? Lastly, would KOH be any safer to use with glass?

???

swim has had the same sep funnel from early '04, has done about 7 extractions of various plants. he's taken the pH to 13 and 14 about 5 times. there's no sign of any "chipping", "etching", or anything else you've read.

borosilicate glass is very inert, it's supposed to resist caustic/corrosive liquids.
some reagents you won't use, like hydrofluoric acid, will dissolve glass.

Sodium hydroxide reacts with glass to form sodium silicate. The reaction is very slow. So it does degrade your glassware after many years of use if it’s concentrated enough. You can speed up the reaction with heat.

Yeah, there's essentially nothing to worry about with a sep funnel made of good borosilicate glass. The dangers of strong NaOH solutions in glass containers are more relevant when talking about glass canning jars, where a little etching at a weak point can be potentially disasterous.

Yeah really. Unless you're extracting with CsOH I don't think you have much to worry about

Thanks for the info. I guess I was just being a little paranoid about it. Better safe than sorry when dealing with dangerous chemicals.

after accidentally breaking a sep funnel filled with loaded NP, swim has become a HUGE fan of empty milk containers (with screw on lids) and an ice pick.

Aproximtly the same amount of mechanical loss- maybe just a tad bit more (when dealing with large volumes).

Milk jugs... water bottles etc- they dont break, and they dont arouse suspicion!

Swim would fill container with liquid, cap, agitate, turn container on its side to maximise surface area between layers and then gently rotate the container so a corner was face up, then puncture a hole with the ice pick.

He'd then cover the hole with a finger, gently rotate the container so it was in a normal up position, then half unscrew the lid and then separate the bottom layer. A little bit of rotation of the container was done to make sure the layers fully and wholey separated towards the end- just a tiny bit of extra work- fraction of the cost. Swim is now sold!

That'll work.

Also, there are chemical resistant plastic separatory funnels that won't break. They have them made of PTFE and also PP. The PTFE ones are extremely chemical resistant.