Spinbars and beakers

Topic created by Charlie Chuckles
on Fri, 1 Oct 2021 at 05:06

Charlie Chuckles said on Fri, 1 Oct 2021 at 05:06...

Please some help with spinbars, because things I am reading are all over the board, and really don't apply much to the wet method for nitrites. Many reviews are mixing starters and yeast...

How do cross-shaped differ in performance vs pill shaped?
Are cross better at slow speed vs pill?
Do they create less vortex and do they scrape the bottom better?

For a half mol synthesis, should I be using a 250ml or 400ml beaker? And for a 1 mol?

And for a half mol should I be using the same size cross as a 1 mol?

Thank you for your help so I'm smart & responsible about buying equipment.

The Professor said on Fri, 1 Oct 2021 at 17:36...

I don't think it matters very much, if at all; more important is to use a very slow stir bar speed; enough to get circulation without creating a vortex.

Charlie said on Fri, 1 Oct 2021 at 19:27...

Thank you Professor. You're so kind to help me figure this out. I would be making so many wrong purchases if not for you. A million thanks, truly.

Charlie said on Sun, 3 Oct 2021 at 00:52...

Professor, if you had extra sealed ACS quality powdered reagents that are factory sealed that you don't intend to use for quite a while (maybe a year or 2), would you?
-leave them in their factory packaging and seal that container in a FoodSaver bag with some MSs or silica packets, or
-transfer the contents into mason jars with MSs and vacuum the lids on?

The Professor said on Sun, 3 Oct 2021 at 02:02...

The only powder I can think of for the liquid phase prep would be sodium nitrite? I think there are pics in the guide from popchef, showing how he stores his NaNO2 in mason jars and under vacuum, with alternating layers of NaNO2 and sieves. The NaNO2 isn't all THAT sensitive; it does oxidize of exposed to air, and NaNO3 is useless for this prep, but NaNO2 doesn't oxidize THAT quickly.

Just guessing, but maybe he used so much sieve because he had way too much of it, and wanted to use it up.

The Professor said on Sun, 3 Oct 2021 at 02:04...

I don't know if I answered your question, but I would use glad jar, probably a mason jar because I can pull a wrap vacuum at least worth the food saver lids, and is use perhaps 2/4 of the sieves as a start

Charlie said on Sun, 3 Oct 2021 at 02:18...

Thanks Prof. I don't think I was very clear, my apologies.

Just to confirm, you think that it's better to actually break the factory seal and rebottle in vacuumed mason jar?

Vs.

Keeping it factory sealed and adding an additional vacuumed bag with Silica/MSs around the product?

This is for extra product that I have and don't intend to use for a while. Just trying to figure out if the factory seal should be maintained... ty

Charlie said on Sun, 3 Oct 2021 at 02:24...

And yes, this is for NaNO2 that comes factory-sealed in some plastic bottles, which is also shrink wrapped.

The Professor said on Sun, 3 Oct 2021 at 16:01...

I'd rather store in glass under vacuum than plastic. The vacuum you can get from those fresh saver lids isn't very strong, compared to a lab grade vacuum pump. I'd probably check the seals periodically.

Charlie said on Sun, 3 Oct 2021 at 19:21...

Ok, thanks Prof.

I was thinking along the same lines since plastic is porous. I can't tell you how many times I have found the vacuum of FoodSaver bags broken under normal storage.