5 replies to this topic

[S.R.Shah]

Hi All

 

Working on new project .

 

Requires Antoine constant and Equation for N-Propyl Bromide

 

Please help

 

SRSHAH

 

[Zauberberg]

Data from NIST Standard Reference Database: http://webbook.nist....Plot=on#ANTOINE

[breizh]

http://www.cheric.or...d=1592&prop=PVP

Another database in case .
Good luck
Breizh

[S.R.Shah]

Hello Zauberberg and Breizch

 

Thanks for Providing me Useful Links.

 

I have tried Link of NIST and checked  with vapour pressure available in MSDS.In One supplier's MSDS it does ot match and other supplier's MSDS .

 

What shall be criteria for Accuracy of Antoine constants to find vapour Pressure ?

 

SRShah

[Zauberberg]

I don't know the reasons for deviation. Can you elaborate?

 

If the difference is marginal, then it really does not matter in any case.

[MrShorty]

What shall be criteria for Accuracy of Antoine constants to find vapour Pressure ?

It seems to me that the main criteria for accuracy of any vapor pressure equation is how accurately it reproduces or fits good experimental data. In my experience, manufacturers and suppliers will use just about any number for MSDS with little regard to accuracy of that number, so I view any vapor pressure reported in MSDS's with a lot of skepticism.

 

At the same time, I find Stull's data (the data NIST used) can be hit and miss as far as quality. Sometimes his data is good, sometimes bad. Stull didn't actually measure any data. He took what he could find the literature and, with Cox charts and pins and string, he generated vapor pressure curves for a long list of organic chemicals. Of course, this approach is only as good as the literature data he had available to him, and some of that wasn't very good. I find that it is difficult to evaluate Stull's results without access to the original data that he used or additional experimental data.

 

I am not familiar with the Korean database that Briezh links to. As with any correlation, it is difficult to evaluate without access to the experimental data used to generate the correlation. Someone more familiar with the Korean database would have to dig in and see what data they used to obtain the correlation.

 

The two correlations agree pretty well with each other (within 1% at temperatures near room temperature), so that suggests that they are both based on the same or similar data. At this point, I would suggest that, if you need a measure of how reliable these correlations are, you need to delve deeper into the literature to find the experimental data these sources used to get to the reported correlations. Then you will be able to evaluate whether the experimental data are believable and determine how well the correlations reproduce the experimental data.

Edited by MrShorty, 14 April 2015 - 09:48 AM.