[chanman1]

So I'm trying to determine what an unknown compound is. I know what it is because I looked up and compared IR's of the possible compounds, but I need to prove it some other way. What's known is that the compound is that it's a liquid amine and it's MP is 198C give or take 5 degrees. I performed a neutralization equivalent on it and found that it's MW is roughly 121. From these facts I've narrowed my possibility down to the following:

1-Amino-1-Phenylethane
N,N-Dimethylaniline
2-Amino-1-Phenylethane

All of these have MW of 121. I used the Nitrous Acid test and the IR to determine that my compound is an amine. The following tests probably don't matter, but I'll list them anyway. Negative Belstein Test; Negative 2,4-DNP Test; Negative Chromic Acid test; and Positive Ignition Test.

I've tried to make a benzamide derivative but did not have any luck, 4 times. I also could not make the Acetamide derivative either. I need some help with any possible way to distinguish the above 3 compounds from each other. Are there any other tests I could perform? Is there anyway to distinguish the 3 aside from making derivatives? Thanks in advance.

[AWK]

MP is 198C

It is boiling point not melting point

How you distinguish teriary amine from primary ones?

[chanman1]

A tertiary amine would not react, or if it did would react as an secondary amine, in the nitrous acid test. From my nitrous acid test I found that it could be a primary aromatic amine, which points more toward the other two.

How can I distinguish the other two apart?

[AWK]

But primary amines form acetamides and benzamides.
N,N-dimethyl aniline also reacts with HNO2 to form 4-nitroso derivative

[Garneck]

You should do a Hinsberg test. Tertiary amines don't give a positive result.

And a 1H NMR spectrum would be useful if you would have to determine if it's one of those phenylenate amines.

[Dude]

I would take a good look at the IR again.  You should immediately be able to rule out N,N-dimethylaniline based upon wheter NH2 absorptions are present in the IR (dimethylaniline as no NH bonds)- unless you are confusing it with 3,5-dimethyl aniline, in which case you can use aromatic absorptions to distinguish.  The fine structure of the IR (i.e. methyl group stretching etc at 1377 cm-1) might allow you to distinguish the remaining two since one has a methyl group and a methine group and the other has two methylene groups.  See "Spectroscopic Identification of Organic Compounds" - Silverstein etc. and focus in on the C-H absorptions which are generally overlooked.

[dexangeles]

hmmmm funny, that's the same final lab I did in the last weeks