2-methyl-1,3,5-trinitroben Posted November 7, 2018 Posted November 7, 2018 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: 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.
Sensei Posted November 7, 2018 Posted November 7, 2018 (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 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 November 7, 2018 by Sensei
BabcockHall Posted November 7, 2018 Posted November 7, 2018 There is more going on in the IR besides the OH stretch. Can you identify any other functional groups?
2-methyl-1,3,5-trinitroben Posted November 8, 2018 Author Posted November 8, 2018 (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 November 8, 2018 by 2-methyl-1,3,5-trinitroben
BabcockHall Posted November 9, 2018 Posted November 9, 2018 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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