Distinguishing Amines
Three isomeric
(C7H15N) liquid amines are found in separate bottles
with no labels. We shall refer to these unknowns as A, B & C. These amines
are known to be aminocycloheptane, 4,4-dimethylpiperidine &
dimethylaminocyclopentane (structures shown to the right). Each of these
compounds is slightly soluble in water (ca. 4%), and each dissolves
completely in 10% aqueous HCl.
To discover which is which, two chemical tests may be applied to these
unknowns:
1. Treatment with cold nitrous acid (HONO).
2. (i) Treatment with benzenesulfonyl chloride
(C6H5SO2Cl) in KOH solution.
(ii) Acidification of the mixture obtained from (i).
| Isomer | Treatment with HONO |
C6H5SO2Cl in KOH |
Acidification of resulting mixture |
| A | |||
|---|---|---|---|
| B | |||
| C |
Once you have conducted your tests, make structural assignments to A, B & C in the boxes following the compound names.
| Aminocycloheptane ............. 4,4-Dimethylpiperidine ............ Dimethylaminocyclopentane .. |