Re: ORGLIST:Bromination

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From: Jacob Zabicky (zabicky$##$bgumail.bgu.ac.il)
Date: Tue Aug 13 2002 - 08:47:57 EDT


Hello Darren,

What we have is batch. We use it for digestion of certain samples with
harsh reagents. The configuration is such that, IMO, it can be made
continuous tubular or backflow by drilling a couple of holes in strategic
places and buying the appropriate tubing and joints. Maybe Merck has better
ideas about that.

All the best,

Jacob

At 13:29 13/8/2, Darren Rhodes wrote:
>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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>> >>
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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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>> >> >
>> >> >
>> >> >_______________________________________________
>> >> >ORGLIST - Organic Chemistry Mailing List
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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
>> >>
>x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x
>> >>
>> >>
>> >>
>> >
>> >_______________________________________________
>> >ORGLIST - Organic Chemistry Mailing List
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>> >To post a message (TO EVERYBODY) send to everybody$##$orglist.net
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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
>> x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x
>>
>>
>>

x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x
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
x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x

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