From: Jacob Zabicky (zabicky$##$bgumail.bgu.ac.il)
Date: Tue Oct 03 2000 - 05:06:31 EDT
Hello Yoann,
the reply is through the list, as there may be other persons interested or
willing to contribute in this thread.
Pyrolysis of even the simplest compounds is a complex process and with rare
exceptions it's also messy. I did not claim that "there is no preferential
release of CO and CO2," in fact, I wouldn't even dare to make a suggestion
on a prefferential product without knowing the system in hand. As for coal
pyrolysis the literature is vast and you probably have some good sources to
start with. A difficult problem with the pyrolysis of natural materials is
that besides the organic matter, some minerals may have catalytic action
that accelerates certain processes, changing the product composition in
nonequilibrium situations.
It is possible to characterize some of the substitutents of the aromatic
framework of coal. In fact, the "structural formulas of coal" that have
been occasionally publised are based on information gatthered about such
groups, which are mainly oxygen-containing functions.
You may find valuable information, though a little bit old, about these
matter in the second supplementary volume of The Chemistry of Coal
Utilization (Wiley).
All the best,
Jacob
>Hello Dr Zabicky,
>Thank you for your quick answer.
>The pyrolyze conditions, are Rock Eval 6 (RE6) pyrolyze ones, developped
>by IFP (Institut français du pétrole). CO take into account in the
>calculation of Oxygen Index (OI), an organic parameter, between 300-550°C.
>The temperature is limited at 550°C to avoid the possible interference
>with the occurence of Boudouard's reaction : CO2 + C ----> 2CO.
>More precisely, I don't know if it's possible to characterize the nature
>of aryl or alkyl oxygen groups (COOH, C=O, OH, ether, ..) by the RE6
>pyrolyze products (for example by the temperature top pics of CO and CO2).
>is there any preference for these oxygen groups to product CO or CO2
>during pyrolyze (between 300-550°C) ?
>But according to your reply, there is no preferential release of CO and CO2....
>All the best,
>Yoann
>
>
>>Hello Yoann,
>>
>>All oxygen-containing groups in an organic compound are potential sources
>>for CO on pyrolysis. It al depends on the conditions you are running.
>>
>>Say, you got some water or carbon dioxide after elimination, then, at high
>>temperatures:
>>
>>H2O + C <----> CO + H2
>>CO2 + C <----> 2CO
>>
>>These are well known equilibria. See for example, the chemistry of coal
>>gasification. As for >SO, >SO2, -SO3H, -NO, -NO2, -PO3H, etc., all can
>>be reduced by H or C atoms in the system and the products ultimately react
>>with water and/or carbon to give CO.
>>
>>All the best,
>>
>>Jacob
>>
>
>
>------------------------------------------------------
>Yoann Copard
>Phd-Student
>Institut des Sciences de la Terre d'Orléans (ISTO)
>Laboratoire de Géologie de la Matière Organique
>Bât. Géosciences
>BP 6759, 45067 ORLEANS cedex 2
>téléphone : (33) 02-38-41-71-71, poste 7905
> ou 06 60 75 19 73
>fax : (33) 02-38-41-73-08
>e-mail : Yoann.Copard$##$univ-orleans.fr
>
>-----------------------------------------------------
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