Re: Anhydrification of Xylene

On Wed, 11 Oct 2006 17:31:01 GMT, <lucasea@xxxxxxxxxxxxx> wrote:


"mlundo" <mlundo@xxxxxxx> wrote in message
news:1160560677.104115.78520@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hallo everybody.
I have to remove water from about 1 liter of o-Xylenes. On the bottle
it's written that there is
0.04%w max of water , but perhaps water is more becouse product is old.
These are my questions:
can i use Na2SO4 or MgSO4 or CaCl2 for anhydrification?
Or is it better to make a distillation? Do Xylenes and water form
azeotropo?

The answer depends on how dry you need it, and thus on what you are going to
do with it. MgSO4 or CaCl2 will get it mostly dry. Better would be
activated 3A molecular seives, but watch out for seive dust. I have had
sieves, sieve
luck storing it over activated 3A molecular seives, then passing it through
sieves
activated alumina just prior to use, to get rid of residual water and the
seive dust. However, if you need it dry enough to do electropositive
sieve
organometallic chemistry, the easiest is to distill it from molten sodium.
Don't bother with ketyl, the low polarity and high distillation temperature
just destroys it. You could also make a ketyl pot (you'll need a *lot* of
tetraglyme to make it purple), and do vacuum transfer instead of
distillation. Polish it up after this (to get rid of benzophenone that
sublimes) by passing it through activated alumina.

Yes, I believe xylenes form azeotropes with water.

Eric Lucas


.

Relevant Pages

  • Re: Drying of Alcohols.
    ... Rest are some impurities with water. ... Running down a column of freshly activated 3A molecular sieves won't ... Distill under dry inert gas from Na butoxide or Mg butoxide ...
    (sci.chem)
  • Re: Molecular sieves
    ... I wish to distill and reuse this IPA but the water must be ... Molec sieves either 3A or 4A will work and I happen to ... 750F-850F and ran Carl Fischer Titration to make sure the cores were ...
    (sci.chem)
  • Re: Molecular sieves
    ... I wish to distill and reuse this IPA but the water must be ... Molec sieves either 3A or 4A will work and I happen to ... You must stir it. ... Vacuum lowers activation temp, ...
    (sci.chem)
  • Re: Molecular sieves
    ... I wish to distill and reuse this IPA but the water must be ... Molec sieves either 3A or 4A will work and I happen to ... 750F-850F and ran Carl Fischer Titration to make sure the cores were activated. ... I know some companies would lightly heat the cores under vacuum to reactivate them - we tested a few of the reactivated cores and guess what - they weren't ...
    (sci.chem)
  • Re: Molecular sieves
    ... I wish to distill and reuse this IPA but the water must be ... Molec sieves either 3A or 4A will work and I happen to ...
    (sci.chem)