Sciencemadness Discussion Board

3Å molecular sieve suggestions ?

CycloRook - 16-3-2022 at 00:48

I want to buy some 3Å molecular sieves to dry solvents etc.

I don't have much experience so I want to choose correctly.

This is mostly a branding thing.

I would buy from sigma but they don't sell to individuals.

I'm just afraid of buying sieves that break apart or react with my experiments.

Does anyone have a good brand they recommend.

Thanks

Sulaiman - 16-3-2022 at 00:58

I can not help with suggestions for good quality
but if your application allows 4A sieves then I recommend
cheap (eBay, Amazon etc.) 3A sieves.
Give them a wash and dehydration cycle before use to remove dust,
and they will be usable.

CycloRook - 16-3-2022 at 05:56

Wouldn't 3Å give the best results?

CycloRook - 16-3-2022 at 16:37

Hello.

Sulaiman - 16-3-2022 at 17:46

both 3A and 4A sieves absorb water,
4A sieves will also absorb small molecules such as ethanol
so 3A sieves are more selective of water

I think tht the cheap '3A' sieves are meant for dessiction of the air in double-glazed windows etc. where 3A and/or 4A sieves are useful.

So using the cheap (Chinese) 3A sieves will absorb water
and possibly some of your solvent also.
For cheap solvents this is ok

CycloRook - 17-3-2022 at 01:01

Quote: Originally posted by Sulaiman  
both 3A and 4A sieves absorb water,
4A sieves will also absorb small molecules such as ethanol
so 3A sieves are more selective of water

I think tht the cheap '3A' sieves are meant for dessiction of the air in double-glazed windows etc. where 3A and/or 4A sieves are useful.

So using the cheap (Chinese) 3A sieves will absorb water
and possibly some of your solvent also.
For cheap solvents this is ok
I want to be selective of water.

macckone - 19-3-2022 at 14:48

Selectivity is relative. Cheaper sieves are generally less selective. But no seive is going to be 100% uniform.