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Posted

I need help identifying an unknown in my Organic Chemistry Lab class. I've literally spent 3 hours + on doing research and I'm really stuck...

A list of properties:

Physical State: liquid

Color: golden yellowish / amber

Odor: Pungent & Unpleasant; smells almost like ladybugs.

pH: 6 => too acidic to be an amine.. right?

Boiling Point: ~128 - 129 degrees C

Solubility in H20: Soluble

Aromatic Flame Test: Black Soot smoke => indicative of a unsaturated compound

Beilstein Test for Halides: Negative => no halogens present

Ferric Chloride Test for Phenols: Negative

Bromine-water test for Phenols: Negative => no phenols present

Also is a copy of the IR spectrum:

media%2Ffd5%2Ffd5d950e-3346-4748-9c92-e2

The peak at ~3400 cm-1 seems to hint at an alcohol but I don't know of any yellow, liquid alcohols. Also some aromatic peaks are present. I'm wondering if there isn't an amine present somewhere (hence the putrid smell) but the peak at ~3400 cm-1  seems to be too broad to not be an alcohol in my mind..

 

Any help/ guidance is greatly appreciated.

Posted (edited)
3 hours ago, 2-methyl-1,3,5-trinitroben said:

Boiling Point: ~128 - 129 degrees C

Isoamyl alcohol has b.p +131.1 C.. but it's colorless liquid.. and only slightly soluble in water (28 g/L). Smell disagreeable.

https://en.wikipedia.org/wiki/Isoamyl_alcohol

5be272a804bd0_isoamylalcohol.gif.894f2b93688c709831fbd3778fd52705.gif

 

 

 

2-Methyl-1-butanol has b.p. +127.5 °C .. but it's colorless liquid.. and only slightly soluble in water (31 g/L)

https://en.wikipedia.org/wiki/2-Methyl-1-butanol

 

You can confront your IR spectrum graph with correlation table on

https://en.wikipedia.org/wiki/Infrared_spectroscopy_correlation_table

 

Edited by Sensei
Posted (edited)
2 hours ago, BabcockHall said:

There is more going on in the IR besides the OH stretch.  Can you identify any other functional groups?

Well the peak at 3060 seems too high to be an alkane C-H so I'm thinking there's possibly an aromatic ring?

Also I am wondering if the peak at 1,295 could be a nitro group since they are usually anywhere from 1290 - 1360? That may also explain the positive flame test/ unsaturation. I am quite inexperienced with nitro groups in organic compounds so is it reasonable to think that it could also be responsible for the smell and yellow color of the solution as well? 

Am I misreading it entirely and the peak at 3400 is actually an amine? 

 

Also, the peak at 1592 is too low to be a carbonyl right?

 

Edited by 2-methyl-1,3,5-trinitroben
Posted

People more experienced in IR should probably guide you, but (going on memory here) the peaks in the range 1450-1600 are suggestive of an aromatic ring, and it might be possible to tease out some information regarding the substitution pattern.  I am not sure about the nitro group.

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