Sciencemadness Discussion Board - Does DMSO dissolve..... glass, to any extent?

Does DMSO dissolve..... glass, to any extent?

FireLion3 - 4-2-2016 at 20:08

I feel like this is a dumb question but I have to ask.

For the first time ever I was using DMSO as a solvent in a reaction. The reaction temperature didn't go over 70c. Yet, over the course of the night, I noticed that the sanded/opaque glass coating on the outside of my 24/40 stoppers was becoming totally clear! I've used these many times before in all kinds of solvent systems but never has this happened. The DMSO isn't even refluxing or stirring too violently, but it's clear that some of it has made it's way between the stoppers and the flask-necks.

It would almost seem as if I can push one of the stoppers further into the flask neck than it is supposed to go... as if the outside of the stopper has been corroded (and yes they are definitely glass not plastic)

I did find a post on researchgate of someone saying that microporous silica is slightly soluble in DMSO, but I know nothing of this.

Is there any reason for me to be concerned here. What is going on?

[Edited on 5-2-2016 by FireLion3]

Detonationology - 4-2-2016 at 20:19

Have you actually inspected the glass joints separately? It sounds like you have only observed the joint while inside another, correct? I have noticed that during a reflux or distillation, if I neglect to use joint grease, distillate will become between the joint giving the appearance of unfrosted glass. I've gotten pretty scared, but it was only an optical illusion. After washing the glass, no damage was observed.

FireLion3 - 4-2-2016 at 20:23

Hm. I did remove one of the stoppers briefly and it still appears to be unfrosted, but then again I didn't wipe it off. Perhaps the liquid layer is effecting the light that hits it? I just know this is the first time I've ever seen something like this happen. Then again DMSO is a pretty unique liquid.

Detonationology - 4-2-2016 at 20:42

Here is a flask of isopropyl formate. The contents are irrelevant.

The joint is wet when the septum is on, and appears to not be a frosted joint. Then after removing and allowing the liquid on the joint to evaporate, it can be seen the joint is indeed frosted.

[Edited on 2-5-2016 by Detonationology]

Texium - 4-2-2016 at 21:59

Quote: Originally posted by FireLion3

Hm. I did remove one of the stoppers briefly and it still appears to be unfrosted, but then again I didn't wipe it off. Perhaps the liquid layer is effecting the light that hits it? I just know this is the first time I've ever seen something like this happen. Then again DMSO is a pretty unique liquid.

Yep, as Detanationology shows with the pictures, that is just a commonly oberved phenomenon that you can see with any wetted glass joint. It seems to me that the effect is particularly intense when the liquid has a similar index of refraction to the glass.