From owner-chemistry@ccl.net Fri Feb 19 06:18:01 2010
From: "Alex Naden anaden**fsmail.net" <owner-chemistry#server.ccl.net>
To: CCL
Subject: CCL: Estimation of viscosity from molecular weight
Message-Id: <-41285-100219061638-30575-DlsZACLiLa/KfYh7zA3rNw#server.ccl.net>
X-Original-From: "Alex  Naden" <anaden%%fsmail.net>
Date: Fri, 19 Feb 2010 06:16:34 -0500


Sent to CCL by: "Alex  Naden" [anaden|*|fsmail.net]
Hi,

I am trying to find a way of estimating viscosity from molecular weight. I have found some information on Joback/Reid method but I am not sure if there is a software implementing this method or any alternative way to estimate the viscosity? I would be grateful if someone could help with this.

Thank you,

Alex


From owner-chemistry@ccl.net Fri Feb 19 11:28:01 2010
From: "Andreas Klamt klamt,cosmologic.de" <owner-chemistry()server.ccl.net>
To: CCL
Subject: CCL: Estimation of viscosity from molecular weight
Message-Id: <-41286-100219085627-9508-z+iFeiTVYejnAKsY47p+yA()server.ccl.net>
X-Original-From: Andreas Klamt <klamt#,#cosmologic.de>
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Date: Fri, 19 Feb 2010 14:56:09 +0100
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Sent to CCL by: Andreas Klamt [klamt[#]cosmologic.de]
Hi Alex,

an estimation of viscosity just from molecular weight is obviously
nonsense. No question, there is a considerable influence of the
molecular size (for which the weight may be a descriptor, but probably
volume or surface area are the better descriptors), but in addition
viscosity has a lot  to do with the interactions of the molecules.

Our COSMOtherm software includes a model for viscosity, based on the
molecular surface area and on the entropy of the liquid. The entropy is
calculated by COSMO-RS, and it is a measure of the degree of partner
changes. If each surface segment has a lot if different
thermodynamically available choices for the interaction partner, then
the entropy is high, and the liquid has a high viscosity, and vice
versa. Obviously this is not absolutely rigorous, but at least quite
plausible and it works quite well.

Best regards

Andreas

Alex Naden anaden**fsmail.net schrieb:
> Sent to CCL by: "Alex  Naden" [anaden|*|fsmail.net]
> Hi,
>
> I am trying to find a way of estimating viscosity from molecular weight. I have found some information on Joback/Reid method but I am not sure if there is a software implementing this method or any alternative way to estimate the viscosity? I would be grateful if someone could help with this.
>
> Thank you,
>
> Alex>
>
>
>   


-- 
PD. Dr. Andreas Klamt
CEO / Geschäftsführer
COSMOlogic GmbH & Co. KG
Burscheider Strasse 515
D-51381 Leverkusen, Germany

phone  	+49-2171-731681
fax    	+49-2171-731689
e-mail 	klamt-.-cosmologic.de
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Komplementaer: COSMOlogic Verwaltungs GmbH
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