heccubusiv

Does anyone know a way or a site to find the thermal conductivity of organic compounds. Organic compounds are ussually not the best crystals and most chemists don't look at pharmacuetical components as crystals due to there structure and shape. I need to find thermal conductivity values and cannot find them anywhere in any literature and wanted to know if anyone knew how to measure it for a moderatly enexpensive way. Its for some pretty cool dislocation research

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kutulu

You could try Perry's Chemical Engineer's Handbook

Amano

i'll second Perry's

You might also try the CRC handbook. There's an online version but you might need a subscription (through your university or company, perhaps) to access it.

Scorpion23

I'll put in a third for Perry's. Your University library should have a copy of it, and might have the CD version available for checkout.

heccubusiv

Perry's does not have the values for pharmacuetical compounds. Does anyone have techinques to measure them?

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kutulu

What physical for and geometies are you talking about? How big are the samples? Heat transfer experiments can be pretty simple if you are talking about measuring the thermal conductivity of a long bar or a brick but if it's some 5mg sample of a compound then you will have a great deal of difficulty taking accurate measurements due to equipment limitations and such.

If you have a sample large enough, then insert a thermocouple inside of it and immerse the room temperature object into a large (so you can model it as an 'infinite' heat sink) fluid (preferreably water) and measure the time it takes for the object to reach an equilibrium temperature with the surrounding environment. With proper use of the methods of time-dependant conduction in your heat transfer book, you should be able to measure the thermal conductivity.

heccubusiv

talking about powder samples around 2 grams in size. I need to measure the thermal conductivity before and after cryomilling. They sell a machine that can do it, but i was hoping for an easier way

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pig

Have you looked at Prausnitz "Properties of Liquids and Gases"? Doubt they have it, but it's possible. How exact of a number do you need? I would think you could do what kutulu suggests, or take the flux form of the heat transfer equation. I think most conductivity meters work with a known amount of flux and two thermal couples to measure the temp. gradient. With your sample size, you may be better off using kutulu's suggestion.

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kutulu

I think you'll need to buy the equipment. A 2g sample, even with a high heat capacity is going to heat up pretty fast and you'll have problems with the time delay of the thermocouples and in your ability to record temperatures. The equipment was made because people have a very difficult time measuring the thermal properties of small sample sizes. The fact that it is in a powder form only makes it worse since you'll probably have a 30% void fraction (meaning you'll be heating up air trapped in the sample at the same time and screwing up your measurements even more)

kutulu

I doubt that equipment is cheap