Re: ORGLIST:Bromination

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From: Darren Rhodes (drhodes$##$globalnet.co.uk)
Date: Tue Aug 13 2002 - 08:29:21 EDT


Is this a batch reactor or a continuous flow reactor ??? Darren.

----- Original Message -----
From: "Jacob Zabicky" <zabicky$##$bgumail.bgu.ac.il>
To: "Darren Rhodes" <drhodes$##$globalnet.co.uk>;
<suzukicar$##$belais.freesurf.fr>; <everybody$##$orglist.net>; "Jacob Zabicky"
<zabicky$##$bgumail.bgu.ac.il>
Sent: Tuesday, August 13, 2002 1:26 PM
Subject: Re: ORGLIST:Bromination

> Hello,
>
> We have a microwave reaction system, with vessels of PTFE that withstand
40
> bar. The equipment, including the oven, was supplied by
>
> E. Merck
> 64271 Darmstadt
> Germany
>
> All the best,
>
> Jacob
>
> At 15:07 11/8/2, Darren Rhodes wrote:
> >A couple of UK companies (Production Techniques Ltd, 13 Kings Road,
Fleet,
> >Hampshire, Enlgand GU13 9AU tel 01252 616757 facs 01252 615818 and Cowie
> >Technology tel 01642 599190 facs 01642 596810) should be able to supply
you
> >with suitable PTFE vessels.
> >
> >Does anyone know the name and contact number of the people in Jenna
> >(Germany) who are currently using lab scale microwave reactors????
> >
> >Darren.
> >
> >
> >----- Original Message -----
> >From: "Jacob Zabicky" <zabicky$##$bgumail.bgu.ac.il>
> >To: "Darren Rhodes" <drhodes$##$globalnet.co.uk>;
> ><suzukicar$##$belais.freesurf.fr>; <everybody$##$orglist.net>; "Jacob Zabicky"
> ><zabicky$##$bgumail.bgu.ac.il>
> >Sent: Sunday, August 11, 2002 6:51 AM
> >Subject: Re: ORGLIST:Bromination
> >
> >
> >> Hello again,
> >>
> >> If we come to microwave reactors, as Darren suggested, ultrasound is
also
> >> a possibility. IMO in both cases you will need a specially designed
> >vessel,
> >> both to allow inflow of energy to the reaction mixture and to avoid
> >outflow
> >> if the deletereous bromine vapors.
> >>
> >> All the best,
> >>
> >> Jacob
> >>
> >> At 13:15 8/8/2, Darren Rhodes wrote:
> >> >It would be interesting to this sort of thing under microwave
conditions
> >...
> >> >This should bring down your reaction time and if you wanted to do the
> >work
> >> >on a larger scale you could use a continuous flow microwave reactor
...
> >For
> >> >the batch microwave work talk to http://www.personalchemistry.com/
(the
> >web
> >> >page seems a bit bloated but it should give you contact details). For
> >the
> >> >continuous flow ... maybe the personalchemistry people again ???
Perhaps
> >> >someone else on the list could give appropriate details and refs and
> >perhaps
> >> >their own experiences of these techniques .....
> >> >
> >> >Darren.
> >> >
> >> >----- Original Message -----
> >> >From: "Jacob Zabicky" <zabicky$##$bgumail.bgu.ac.il>
> >> >To: <suzukicar$##$belais.freesurf.fr>; <everybody$##$orglist.net>
> >> >Sent: Thursday, August 08, 2002 12:32 PM
> >> >Subject: Re: ORGLIST:Bromination
> >> >
> >> >
> >> >Hello Bel,
> >> >
> >> >The pressure in the vessel will be somewhat lower than 4 bar. If your
> >> >reaction mixture is over a couple of mL, you should carry out the
process
> >> >in a Teflon-lined pressure vessel. If you can do it in small batches,
> >> >then you can prepare thick-walled test tubes, of outer diameter not
> >bigger
> >> >than say 10 mm, place your mixture, freeze it with ice-salt or other
> >> >cooling medium (below -10C), and seal the tubes while slightly
evacuating
> >> >at the end.
> >> >
> >> >You can place the tubes in boiling water or in a
temperature-controlled
> >> >heating block, all this, of course in a well protected hood.
Thick-walled
> >> >tubes of small diameter withold some pressure quite well.
> >> >
> >> >Good luck,
> >> >
> >> >Jacob
> >> >
> >> >
> >> >At 16:23 7/8/2, Bel wrote:
> >> >>Dear all,
> >> >>
> >> >>I would like to know If any has experience with bromination in harsh
> >> >>conditions, using sealed tube at high temperature. I found one
procedure
> >> >>concerning the bromination of an electronically poor aromatic
> >(pyridinium
> >> >>derivative) which must be done by heating during 3 days at 180C. The
> >> >>bromine's boiling point is 58.7C, which means a very high pressure in
> >the
> >> >>tube at 180C. So does anyone know how to make such reaction in a safe
> >way,
> >> >>and which kind of tube may resist to such pressure?
> >> >>
> >> >>Regards
> >> >>
> >> >>Bel
> >> >>
> >> >>
> >> >>
> >> >>_______________________________________________
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> >> >Prof. Jacob Zabicky
> >> >Institutes for Applied Research
> >> >Ben-Gurion University of the Negev Private: POB 12366,
Beer-Sheva
> >> >84863
> >> >POB 653, Beer-Sheva 84105, ISRAEL Tel. +972-8-6496792
> >> >http://profiler.bgu.ac.il/site/main.cfm
> >> >Tel. +972-8-6461271/6461062/6472754
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> >>
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> >> >
> >> >
> >> >_______________________________________________
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> >> >
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> >> Prof. Jacob Zabicky
> >> Institutes for Applied Research
> >> Ben-Gurion University of the Negev Private: POB 12366, Beer-Sheva
> >84863
> >> POB 653, Beer-Sheva 84105, ISRAEL Tel. +972-8-6496792
> >> http://profiler.bgu.ac.il/site/main.cfm
> >> Tel. +972-8-6461271/6461062/6472754
> >> Fax. +972-8-6472969
> >>
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> >>
> >>
> >>
> >
> >_______________________________________________
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> Prof. Jacob Zabicky
> Institutes for Applied Research
> Ben-Gurion University of the Negev Private: POB 12366, Beer-Sheva
84863
> POB 653, Beer-Sheva 84105, ISRAEL Tel. +972-8-6496792
> http://profiler.bgu.ac.il/site/main.cfm
> Tel. +972-8-6461271/6461062/6472754
> Fax. +972-8-6472969
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>
>
>

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