soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
identifying an unknown substance
I have a bottle that used to contain dipropylamine. It has decomposed and now the liquid distills at 95C (dpa bp is 109-111). I would like to find
out what the substance has turned into and am wondering what tests would be used to do that.
|
|
|
Sigmatropic
Hazard to Others
Posts: 307
Registered: 29-1-2017
Member Is Offline
Mood: No Mood
|
|
Diisopropyl amine boils at 84 C according to my sources. Perhaps it comes over as a high boiling azeotrope with water? Have you tried distilling over
KOH?
Edit: just read we weren't talking about isopropyl. Sorry. But then again have you dried it prior to distillation?
[Edited on 15-1-2019 by Sigmatropic]
|
|
|
Tsjerk
International Hazard
Posts: 3022
Registered: 20-4-2005
Location: Netherlands
Member Is Offline
Mood: Mood
|
|
Dipropylamine forms a azeotrope with water at 60 mol% DPA boiling at 86 C. Maybe you have water saturated DPA.
Triethylamine is known to boil at around 75 C when saturated with water, normal bp is 89 C.
|
|
|
soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
This should be real dry. There was no way for water to get in other than from the air exposure which was minimal. Also I was distilling it over KOH
and the pot temp was 95. (There was about 150 ml in a lL round bottom.)
|
|
|
AJKOER
Radically Dubious
Posts: 3026
Registered: 7-5-2011
Member Is Offline
Mood: No Mood
|
|
Photolysis (from a light source, especially UV) or the presence of transition metal impurites and any O2 may lead to a chemical breakdown of the
dipropylamine. Products could include a gas build up, which would be suggestive of this pathway, which leads to an assortment of products.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
