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Topic: What is my unknown compound?  (Read 25028 times)

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Offline mjoa123

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Re: What is my unknown compound?
« Reply #30 on: December 07, 2012, 12:37:16 AM »
No it's not them. I can see you reasoning.
Go back to
http://en.wikipedia.org/wiki/Proton_NMR
and look at the table.
Think about the triplet at 4.1 ppm. What does that mean?

NO2?

Offline discodermolide

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Re: What is my unknown compound?
« Reply #31 on: December 07, 2012, 12:41:04 AM »
Where did NO2 come from? The table gives the shifts of protons attached to such groups.
PROTONS.
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Offline mjoa123

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Re: What is my unknown compound?
« Reply #32 on: December 07, 2012, 12:45:27 AM »
Where did NO2 come from? The table gives the shifts of protons attached to such groups.
PROTONS.

Eh.. I have no clue if I'm even looking at the same table. At 4.1 on CH3 it says NO2 to the right of it.

Offline discodermolide

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Re: What is my unknown compound?
« Reply #33 on: December 07, 2012, 12:50:37 AM »
Look at OCOR also says 4.1. also look at COR shifts in the table.
I can't remember the shifts exactly in your NMR, again what does the IR tell you?
remember we have
CH3-CH2-Unknown-Unknown-Unknown-CH3
Just 3 unknown groups/atoms to go
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Offline mjoa123

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Re: What is my unknown compound?
« Reply #34 on: December 07, 2012, 12:52:59 AM »
Look at OCOR also says 4.1. also look at COR shifts in the table.
I can't remember the shifts exactly in your NMR, again what does the IR tell you?
remember we have
CH3-CH2-Unknown-Unknown-Unknown-CH3
Just 3 unknown groups/atoms to go

Is it a methyl or ethyl?

Offline discodermolide

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Re: What is my unknown compound?
« Reply #35 on: December 07, 2012, 12:54:35 AM »
Is what a methyl or ethyl?
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Offline mjoa123

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Re: What is my unknown compound?
« Reply #36 on: December 07, 2012, 12:55:51 AM »
Is what a methyl or ethyl?

My compound. Sorry I'm really dumb when it comes to this stuff, I can't believe you've stuck around.

I mean does the name start with methyl or ethyl or propyl? I'm thinking it's ethyl ethanoate?

Offline discodermolide

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Re: What is my unknown compound?
« Reply #37 on: December 07, 2012, 12:59:53 AM »
Neither.
Consider the signal at 2.05, the singlet. Look at the table, what does it correspond to? It looks like COCH3 to me.
So we have CH3-CH2-Unknown-Unknown-C=O-CH3, that is an acetate at one end.
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Offline mjoa123

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Re: What is my unknown compound?
« Reply #38 on: December 07, 2012, 01:05:55 AM »
Neither.
Consider the signal at 2.05, the singlet. Look at the table, what does it correspond to? It looks like COCH3 to me.
So we have CH3-CH2-Unknown-Unknown-C=O-CH3, that is an acetate at one end.

Are you sure the oxygen is attached to both C and CH3?

Offline discodermolide

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Re: What is my unknown compound?
« Reply #39 on: December 07, 2012, 01:10:21 AM »
Sorry my fault, Look at the picture, THe X represent those groups you have not found yet.


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Offline mjoa123

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Re: What is my unknown compound?
« Reply #40 on: December 07, 2012, 01:12:59 AM »
Well I'm assuming the two that are left are both CH2. Still have no idea what it's called though :/

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Re: What is my unknown compound?
« Reply #41 on: December 07, 2012, 01:17:33 AM »
No they are not both CH2, only one is. Back to the NMR, the signal at 4.1 is a triplet, meaning it is attached to a carbon bearing 2 hydrogens. The 4.1 signal for this group also means something else according to the table it could be attached to oxygen. What do you think?
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Offline mjoa123

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Re: What is my unknown compound?
« Reply #42 on: December 07, 2012, 01:22:29 AM »
No they are not both CH2, only one is. Back to the NMR, the signal at 4.1 is a triplet, meaning it is attached to a carbon bearing 2 hydrogens. The 4.1 signal for this group also means something else according to the table it could be attached to oxygen. What do you think?

So one of them is CH2 and the other is CO?

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Re: What is my unknown compound?
« Reply #43 on: December 07, 2012, 01:22:39 AM »
YES, so what we have is propyl acetate.
Attached is a calculated NMR of the compound. Compare it to yours.

One thing, please explain the 5 lines at around 1.75 to me.

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Offline mjoa123

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Re: What is my unknown compound?
« Reply #44 on: December 07, 2012, 01:24:54 AM »
Come on we are nearly there.

Is the other one CO or something else?

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