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Author Topic: Melting point determination  (Read 5375 times)

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glaizy

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Melting point determination
« on: July 04, 2011, 06:52:35 AM »

Why should you always use a new capillary tube with a sample of your compound
when doing a second melting point determination? 

i have searched a lot about this in the internet but i ended up nothing...

 ???
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discodermolide

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Re: Melting point determination
« Reply #1 on: July 04, 2011, 07:02:29 AM »

Why should you always use a new capillary tube with a sample of your compound
when doing a second melting point determination? 

i have searched a lot about this in the internet but i ended up nothing...

 ???

Because you may have generated a new crystal modification, which has a different MPt.
Or the compound may have decomposed.
Capillary tubes are not expensive
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glaizy

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Re: Melting point determination
« Reply #2 on: July 04, 2011, 07:08:59 AM »

Why should you always use a new capillary tube with a sample of your compound
when doing a second melting point determination?  

i have searched a lot about this in the internet but i ended up nothing...

 ???

Because you may have generated a new crystal modification, which has a different MPt.
Or the compound may have decomposed.
Capillary tubes are not expensive



THANK YOU SO MUCH!i have some other question regarding melting points..

which has a wider melting range , a mixture or a pure substance?
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discodermolide

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Re: Melting point determination
« Reply #3 on: July 04, 2011, 07:21:53 AM »

Why should you always use a new capillary tube with a sample of your compound
when doing a second melting point determination?  

i have searched a lot about this in the internet but i ended up nothing...

 ???

Because you may have generated a new crystal modification, which has a different MPt.
Or the compound may have decomposed.
Capillary tubes are not expensive



THANK YOU SO MUCH!i have some other question regarding melting points..

which has a wider melting range , a mixture or a pure substance?

A mixture
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Development Chemists do it on Scale, Research Chemists just do it!
My Research History

glaizy

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Re: Melting point determination
« Reply #4 on: July 04, 2011, 07:49:32 AM »

Why should you always use a new capillary tube with a sample of your compound
when doing a second melting point determination?  

i have searched a lot about this in the internet but i ended up nothing...

 ???

what is the effect of the impurity of the boiling point of a substance?

some of my sources said that i will increase and some told me that it will decrease...

 ???

Because you may have generated a new crystal modification, which has a different MPt.
Or the compound may have decomposed.
Capillary tubes are not expensive



THANK YOU SO MUCH!i have some other question regarding melting points..

which has a wider melting range , a mixture or a pure substance?

A mixture
Logged
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