Re: ORGLIST:PTCDA purification, solving

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From: Vijay Sane (vsane$##$hotmail.com)
Date: Sat Oct 12 2002 - 12:16:16 EDT

Well, tough luck on the solubility part in acetic acid. But my guess is the dianhydride should be more soluble in organic polar solvents than the acid, so why not convert to dianhydride just by heating the acid under high vacuum, say 755 mm Hg, and distill out water. By weight reduction you should be able to judge the formation of dianhydride. This dianhydride then can crystallised from suitable solvent, say ethylene dichloride, methylene dichloride ( which are water immiscible, so no water comes in contact with dianhydride, otherwise you go back to tetra-carboxylic acid ).

Hope this may help, feel free to communicate in case of problems

regards

Vijay Sane

vsane@hotmail.com



 

>From: Georgi Ginev
>To: Vijay Sane , everybody@orglist.net
>CC: chemelf@gmx.net
>Subject: Re: ORGLIST:PTCDA purification, solving
>Date: Thu, 10 Oct 2002 23:30:51 -0700 (PDT)
>
>Thank you for the response, but PTCDA is not soluble
>in acetic acid and slightly soluble in DMSO.
>The purification with re-crystallization can not be
>done, since it is not sure which is the crystallized
>fraction - dianhydride or the dianhydride + H2O.
>Sensitivity to moisture is main problem for this
>material.
>Only one way is the sublimation, but I do not know how
>to check the quality of the new material.
>Many thanks
>Georgi
>
>--- Vijay Sane wrote:
>
>
>
>



>

Dear Georgi

>

Have you tried acetic acid as a solvent for

>purification? I have carried out purification on a
>similar type of tetra carboxylic acid and it works
>fine.

>
>
>
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