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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: rhyeal on May 27, 2004, 11:53:50 AM

Title: methanol and isopropanol
Post by: rhyeal on May 27, 2004, 11:53:50 AM

is there any case where methanol and isopropanol would bond to raise/lower the boiling point of each other?  we are doing a sludge project and the data we have is close to either, save the boiling point which is 79C.  this is closer to isopropanol, but the time/temp data we have suggests that there is a plateau at 75C and again at 79C.  the way we see it is either of these could be isopropanol or methanol.  any help would be great as this project is due tomorrow and we only discovered the apparent Liquid C plateau today.

Thanks,
Rhyeal

Title: Re:methanol and isopropanol
Post by: Donaldson Tan on May 27, 2004, 01:09:42 PM

I don't have any data for you, but I do have some theory.

Check out Raoult's Law.

Note both methanol and isopropanol contributes to the vapour pressure (being volatile), their residual proportion to each other will decide the boiling point for the mixture.

Title: Re:methanol and isopropanol
Post by: Mitch on May 27, 2004, 02:13:24 PM

Can you take any spectral data? Like an NMR or maybe look at the firgerprint in IR?

Title: Re:methanol and isopropanol
Post by: hmx9123 on May 27, 2004, 09:56:10 PM

Another good way to test is just to smell the sample.  If it smells like rubbing alcohol, it's i-PrOH.  If it's got more of a sweetish odor, it's MeOH.

Title: Re:methanol and isopropanol
Post by: jdurg on May 27, 2004, 10:01:39 PM

Is it possible for the methanol and isopropanol to maybe form an azeotrope?  (I don't recall ever hearing of an MeOH and Isopropanol azeotrope, but organic was never my strong field).  :P

Title: Re:methanol and isopropanol
Post by: hmx9123 on May 27, 2004, 10:06:17 PM

Might be.  I'm sure they're miscible in one another, so it may well be a mixture.