From: A De (ocad$##$mahendra.iacs.res.in)
Date: Thu Apr 20 2006 - 01:41:55 EDT
Dear Zia,
Be very careful about dimethyl sulfate that contains acid which forms upon
standing. You should wash the reagent WITH EXTREME CAUTION with sodium
bicarbonate before use. Dimethyl sulfate is toxic. I know a pparticular
case when a research supervisor while showing his student how to use
separating funnel in washing reagents had a shower of it all over himself
and had to be hospitalised for several months. Check with pH paper.
Methylation must be carried out in alkaline medium (NaOH) and the pH has
to be monitored with pH paper all throughout the reaction. Whenever the pH
falls below 7, alkali has to be added.
Best wishes
ASish
On Wed, 19 Apr 2006, muhammad ziaurrehman wrote:
>
> Dear All!
>
> I have to do N-methylation with dimethyl sulphate. Dimethyl sulphate that
> I have, is quite acidic and looking impure. Can anyone tell me the method
> to purify it. By simple distillation, a large %age of it comes out at
> lower temperature than its boiling point perhaps due to its degradation
> with high temperature.
>
> Zia
>
>
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-- Professor Asish De Department of Organic Chemistry Indian association for the Cultivaion of Science Jadavpur; Kolkata - 700 032 India Honorary Secretary, Royal Society of Chemistry(Eastern India Section) Tel : +91-33-2473-4971 (Ext : 403/421) Fax : +91-33-2473-2805 http://www.iacs.res.in/ocad.html_______________________________________________ ORGLIST - Organic Chemistry Mailing List Website / Archive / FAQ: http://www.orglist.net To post a message (TO EVERYBODY) send to everybody$##$orglist.net To unsubscribe, send to everybody-request$##$orglist.net the message: unsubscribe your_orglist_password your_address
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