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Offline Supercryptid

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Chemical Information
« on: 08/12/2003 04:17:26 »
Hello, I am new here and I would like for anyone to tell some of the following information. If you can tell me the answer to ANY of these questions, please do:

1) The density of solid azulene in grams per cubic centimeter.
2) The density of liquid prismane in grams per cubic centimeter.
3) The heat of formation of liquid prismane in joules per mole.
4) The density of liquid fulvene in grams per cubic centimeter.
5) The heat of formation of liquid fulvene in joules per mole.

I would also appreciate it if you could give me the source of information in which you obtained it so that I can see if it is reliable.


 

Offline Ylide

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Re: Chemical Information
« Reply #1 on: 08/12/2003 05:53:19 »
Have you tried going to the library and looking in the CRC handbook?  My usual sources (chemfinder.cambridgesoft.com and webbook.nist.gov) don't have those particular pieces of information for those compunds.  I don't think those compounds are stable isomers, at least not in the phases you want them in.  I have no idea wtf prismane is but azulene and fulvene are likely to isomerize to benzene and naphthalene.  (less strain, armomatic systems, much more stable)

This is probably why you're having problems finding that information.



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Offline Supercryptid

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Re: Chemical Information
« Reply #2 on: 09/12/2003 04:56:04 »
Yes, but azulene (C10H8) is stable. It is a blue crystal at standard pressure and temperature. If it exists as this, then it has a density. I have searched the NIST webbook and countless msds and even my college library. None of them state azulene's density.

Prismane (C6H6) is a highly strained hydrocarbon that resembles a prism in structure. It has been formed as a liquid, so it should also have a density and heat of formation.

I have seen the heat of formation of fulvene (C6H6) gas, which infers that it has some stability about it. I would expect it to be more stable than prismane, because it has less angle strain and it also has double bond conjugation. If they can make fulvene gas, then fulvene liquig should also be obtainable, considering that liquids contain less kinetic energy that might destroy molecules than gases do.
 

Offline Ylide

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Re: Chemical Information
« Reply #3 on: 09/12/2003 08:42:31 »
Have you tried using Hess's law to calculate the heats of formation?  Or perhaps a bomb calorimetry experiment is in order.  

As far as the densities go, if they're not in the CRC handbook, you're probably not going to find them without experimenting yourself.  Unfortunately, if they're not cataloged by the major sources, there is probably a good reason for it.  



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Offline Supercryptid

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Re: Chemical Information
« Reply #4 on: 10/12/2003 05:16:18 »
I could use Hess's law, but I don't know of any references to prismane combustion enthalpies or anything like that. I don't have any of these materials on hand either, so I can't experiment.
 

Offline Supercryptid

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Re: Chemical Information
« Reply #5 on: 10/12/2003 05:17:09 »
I could use Hess's law, but I don't know of any references to prismane combustion enthalpies or anything like that. I don't have any of these materials on hand either, so I can't experiment.

I would assume that azulene should have a density similar to naphthalene, somewhere around 1.00 g/cc.
 

Offline Ylide

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Re: Chemical Information
« Reply #6 on: 10/12/2003 05:49:01 »
I don't know if I'd make that assumption...density is a function of intermolecular attractive forces, size, and shape.  Azulene is different enough from naphthalene in structure that it very well may have a significantly different density.  (Azulene's electron density is "clumped" on the 5 membered ring whereas in napthalene it is evenly distributed.)


If I may ask, what do you need these quantities for?







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Offline Supercryptid

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Re: Chemical Information
« Reply #7 on: 10/12/2003 18:51:39 »
I want these values so that I can calculate the energy released by the following reactions:

1) Prismane(l) > Benzene(l)
2) Azulene(s) > Naphthalene(s)
3) Fulvene(l) > Benzene(l)

But I would prefer to calculate how much energy is released when 1 cc of prismane/azulene/fulvene is transformed. I feel that calculating energy released by volume is a more effective measure of energy density than by weight or molarity.
 

Offline Ylide

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Re: Chemical Information
« Reply #8 on: 10/12/2003 19:23:10 »
So you're going to use the work/energy theorem from the changes in volume?  

If you can't work it out that way, maybe you want to look into bond energies, figure out what bonds are broken and reformed during the transformation and calculate the net energy change per mole by subtracting energy from broken bonds and adding energy from reformed bonds.  (angle, strain, conjugation, etc all play into it so be careful)





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Offline Ylide

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Re: Chemical Information
« Reply #9 on: 14/12/2003 09:38:21 »
Oh, I was looking at a 2003 CRC Handbook the other day finishing a lab report and thought of your problem...and guess what?  That information isn't there.  No density for azulene or fulvene is given, even though it lists melting point, boiling point, and refractive index.  Oddly enough, a couple different methyl substituted azulenes had densities listed.  I have no idea why this is.  I'd ask one of the chem department faculty, but we're on semester break right now.



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Re: Chemical Information
« Reply #9 on: 14/12/2003 09:38:21 »

 

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