Jor
National Hazard
Posts: 950
Registered: 21-11-2007
Member Is Offline
Mood: No Mood
|
|
ethylenediamine HCl
I wanted to prepare some ethylenediamine hydrochloride.
First attempt was to add a mL of ethylenediamine to about 3mL 37% HCl. All I can say, that is what I call the definition of a vigorous reaction  . Droplets were sprayed around, aloud sissing noise, and my entire fume hood was
filled with thick smoke!!! However, I obtained a small amount (maybe 50% yield, rest sublimed as smoke) of pure white crystals.
My next attempt was to add 2mL ethylenediamine to 15mL of 2,5M HCl. No vigorous reaction, just heating up. Next I boiled to about 4ml total volume. At
the start of boiling away, the liquid went yellow, and after boiling down, i have brownish liquid, wich crystallises to give a light brown solid on
cooling.
My question was, what reaction does take place? Since when does ethyelediamine dihydrochloride reacts with itself? Or is it something else, possibly
oxidation by air?
I think my next attempt will be bubbling HCl through ethylenediamine-solution in DCM or similar.
I need it for a metal-complex synthesis, where you need the solid salt, and neutralise after with NaOH. A combination of NaCl and ethylenediamine, I
think that won't work, but I can try it.
|
|
|
chemoleo
Biochemicus Energeticus
Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline
Mood: crystalline
|
|
Did you calculate the stoichiometry for the dihydrochloride?
It's best to precipitate the ED2HCl with something like EtOH/acetone etc in large excess (put in freezer to crystallise efficiently).
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
Try isothermal distillation.
Dissolve the ethylenediamine in roughly 10 X EtOH or other alcohol in a wide mouthed beaker or jar, or evaporating dish. Place it into a polyolefin
container ("Tupperware") or similar. Then place a beaker containing a severalfold excess of the hydrochloric acid into the larger container, seal it
up with the lid, and let it sit. The HCl distills from the concentrated acid to the ethylenediamine solution, forming the salt free of any metal
salts in the acid.
You could first chill the amine solution, even place it on a freezer coldpack in the larger container to keep its volatility down.
Give it a day or two, then open, take the amine.HCl solution, chill, add cold toluene or DMC to precipitate the salt.
|
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
