From: Lalor, Fergus (f.lalor$##$ucc.ie)
Date: Tue Dec 02 2003 - 16:18:48 EST
> ----------
> From: Lalor, Fergus
> Sent: Tuesday, December 2, 2003 14:01 PM
> To: 'Dmitry Kuklev'
> Subject: RE: ORGLIST:drying of THF
>
> This advice seems to me to be far too imprecise. Giiven the 200 litre
> scale involved it would seem to me to be
> foolhardy in the extreme - not to say downright crazy - to attempt to dry
> the thf by any method without having
> reliable information on the extent to which it is contaminated with
> peroxide. Violent explosions have been reported
> on the addition of KOH (and even more so with LiAlH4 or alkali metals) to
> thf containing significant quantities of
> peroxide. Peroxide in thf can be detected qualitatively by a variety of
> standard tests and - much better - can be
> detected quantitatively using test papers available from (I think) Merck.
> Following detection of peroxide - if any -
> it can be safely removed as described, for instance, in Perrin &
> Armarego's 'Purification of Laboratory Chemicals'.
> The thf can then be safely pre-dried by standing over and distilling from
> KOH and then rendered anhydrous by
> refluxing with Na wire and benzophenone under nitrogen until the intense
> blue colour of benzophenone ketyl appears.
>
> Fergus Lalor
>
>
> ----------
> From: Dmitry Kuklev
> Sent: Monday, December 1, 2003 21:11 PM
> To: hviana$##$fsa.br; everybody$##$orglist.net
> Subject: RE: ORGLIST:drying of THF
>
> Dear friends,
>
> The best idea would be take a sample of the THF (about a half of litre)
> add some KOH (about one gram) into the sample and watch the result. If you
> will see red colored deposite over the KOH particles or disolving of KOH
> added the addition of met. Na will result in magnificent explosion.
>
> If you will see green color over the KOH particles (granules, briketts)
> and nothing more for 24 hours you can add Na without any problem, but the
> it would be better to add into your 200 L container about 2-5 kg of NaOH
> (technical grade will work perfectly) and keep it there for about one week
> and only then separate THF from the deposite and add Na. To obtain THF of
> good quality it would be very helpful to boil it under reflux over
> Na/benzophenone to get deep blue color of the corresponding sodium
> benzophenolate and distill the resulting dry and peroxyde-less THF.
>
> Good luck!:)
>
> Dmitry
>
>
>
> >From: "Prof. Dr. Hamilton M. Viana"
> >To: "Orglist"
> >Subject: ORGLIST:drying of THF
> >Date: Sat, 29 Nov 2003 09:00:54 -0300
> >
> >
> >Hello,
> >
> >I have tried some ways to dry THF, and maybe the best option would be use
>
> >metalic sodium.
> >
> >Does somebody know if could happen some explosion using metalic sodium
> for
> >drying THF with 2000 ppm of water?
> >
> >The NaOH formed can be separated later, but I´m worry about the risk of
> >explosion, because I intend to put metalic sodium into a 200L container.
> >
> >Thanks.
> >
> >Prof. Dr. Hamilton M. Viana
> >Material Science Engineering
> >Engineering College "Engº Celso Daniel"
> >Centro Universitário Fundação Santo André
> >Fone 55-11-4979-3451
> >
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