[gr1gn4rd]

I've been running an allylic oxidation using selenium(IV) oxide, SeO₂, and the by-products are quite smelly and insoluble. I believe the reaction generates selenic acid (H₂SeO₄) and colloidal Se(0), the latter of which coats the flask with an insoluble dark red residue.

I've tried several methods of cleaning my flasks, with some success. I usually do an initial acetone + DI water wash. Soaking in a base bath has little effect. Scrubbing with hot water and soap gets rid of most of the visible residue, and then a bleach/HCl stir seems to get the rest.

My question is: does anyone have a more efficient procedure for cleaning glassware after these procedures?

Thanks!

[discodermolide]

I've been running an allylic oxidation using selenium(IV) oxide, SeO₂, and the by-products are quite smelly and insoluble. I believe the reaction generates selenic acid (H₂SeO₄) and colloidal Se(0), the latter of which coats the flask with an insoluble dark red residue.

I've tried several methods of cleaning my flasks, with some success. I usually do an initial acetone + DI water wash. Soaking in a base bath has little effect. Scrubbing with hot water and soap gets rid of most of the visible residue, and then a bleach/HCl stir seems to get the rest.

My question is: does anyone have a more efficient procedure for cleaning glassware after these procedures?

Thanks!

Throw it away and get a new one!

[Honclbrif]

You can always try some Piranah Solution

http://en.wikipedia.org/wiki/Piranha_solution

I've also found that if aqua regia won't clean it off, its usually worth throwing away.

[gr1gn4rd]

Haha, discodermolide - you're not the first person to suggest that.

I'm familiar with piranha but I would like to avoid that at all costs. I haven't yet tried aqua regia because we're out of nitric acid and I haven't had a chance to pick up a new bottle. It will probably work, but I was curious if there were a less brutal method than concentrated acid to clean it up. I will post my aqua regia results some time soon for posterity's sake.

[gr1gn4rd]

Aqua regia works quite well! I'm glad because good glassware is scarce in our lab and I would have hated to have to throw these flasks away.

On a related note, stay away from these oxidations if you can help it. Apart from the glassware issues, the smell from the by-products is almost nauseating and will give you a headache if you hang out around it for too long.

[discodermolide]

Aqua regia works quite well! I'm glad because good glassware is scarce in our lab and I would have hated to have to throw these flasks away.

On a related note, stay away from these oxidations if you can help it. Apart from the glassware issues, the smell from the by-products is almost nauseating and will give you a headache if you hang out around it for too long.

Se and some of it's compounds smell wonderful! They get you a seat on a crowded bus, with plenty of space to spread out.

[Doc Oc]

Aqua regia works quite well! I'm glad because good glassware is scarce in our lab and I would have hated to have to throw these flasks away.

On a related note, stay away from these oxidations if you can help it. Apart from the glassware issues, the smell from the by-products is almost nauseating and will give you a headache if you hang out around it for too long.

It was my gut instinct to agree with discodermolide to throw it away, but I remembered how stingy some of the professors at my university were.  I hated washing test tubes from my flash columns, but that paled in comparison to the people who washed scintillation vials or even Pasteur pipets!

If I'm not mistaken, SeO₂ has a toxicity similar to arsenic and should be handled with the same care.  I, of course, did not bother looking this up until after I had started my reaction.  Suffice to say, now I make sure to look at the MSDS BEFORE opening the bottle.

[OC pro]

20-30% KOH in Isopropanol also works quite well. Let it stand for a couple of days. I cleaned up everything with this mixture.

Even better: diluted HF (~10% aq. solution). But I only recommend this for the highly experienced late graduate or even post-graduate chemists.
Cleaned Pd black residues in seconds...

[Honclbrif]

Se and some of it's compounds smell wonderful! They get you a seat on a crowded bus, with plenty of space to spread out.

Reminds me of Milkshake's tales of Adventures with Volatile Phosphines. Something about getting on a bus and everyone else getting off at the very next stop. Some via the windows.

Still better than Tellurium I suppose. Get dosed with that and you've got to withdraw from society until you work it out of your system.