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zeshkani:
 hi there, well ill be running an experiment next week and its a maybe a soild or liquid and iam supposed to figure out the structure of the compound, and this will be my procedure, maybe if you guys have some thoughts or ideas if i should do something different or, and i only have 6 hours in the lab to figure out the structure

1. Get IR spectra, see if there are any carbonyl groups, alcohols, and aromatic rings
2. If unknown is liquid, get NMR for hydrogen and also Carbon, this can give me the number of Carbons ?
3. i dont know, should i run Mass spec.
4. if solid get melting point, if liquid get micro-melting point.
5. if liquid run a GS, i dont know what this will help me at ?
6.  if carbonyl group present, test with NaCo3 for carboxylic acid, and to other test if not carboxylic acid
7. are there any suggestions on what else i can do, to figure out the stracture ?

any help is welcome thanks

Ψ×Ψ:
If solid, you can dissolve in CDCl3 (or another handy deuterated solvent) and get NMR.  Even if it's a neat liquid, it's probably a good idea to throw a little chloroform-d in there.  Else, you can get crazy splittings in the peaks because of coupling between adjacent molecules.  (That might not be quite the right explanation, but I think it's the one I was given.  Happened to me in an "ID-the-unknown" class once upon a time.)

Sam (NG):
I'm not sure that you can get the number of Carbons from the nmr.  Mass Spec is always useful, but do you have the time to do all these things....?

Dan:

--- Quote from: Sam (UoN) on March 30, 2007, 07:40:49 AM ---I'm not sure that you can get the number of Carbons from the nmr.  Mass Spec is always useful, but do you have the time to do all these things....?

--- End quote ---

13C nmr will give you the number of carbon environments, which may or may not be the total number of carbons - MS will help clear that up.

I would certainly get 1H and 13C (solution) nmr, MS, IR and melting/boiling point.
If possible/necessary, get DEPT, HMQC and COSY nmr spectra too. Maybe an HMBC if you're still stuck. A UV spectrum may also help.
Getting the data in under 6hrs will depend on the resources available and the competition for them. For example, if you have one nmr spectrometer between 30 people you will probably have to settle for just 1H and 13C nmr.

zeshkani:
these are the things that iam allowed to do, get NMR anykind, IR and Mass spec, and also any kind of experimentation, like for testing for aromatic rings, and alcohols, and all those other things

but thanks for all the replys

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