October 31, 2024, 07:23:02 PM
Forum Rules: Read This Before Posting


Topic: Potassium Benzylamide  (Read 2219 times)

0 Members and 2 Guests are viewing this topic.

Offline Schrödinger

  • Chemist
  • Sr. Member
  • *
  • Posts: 1162
  • Mole Snacks: +138/-98
  • Gender: Male
Potassium Benzylamide
« on: June 01, 2016, 05:16:37 PM »
A simple salt metathesis reaction, I tried making the potassium salt of benzylamine (PhCH2NH2).

PhCH2K + PhCH2NH2  :rarrow: PhCH2NHK + toluene

I expected to see a white solid, PhCH2NHK. Instead I get a pink solid. Is this its real colour? Or am I doing something wrong?
"Destiny is not a matter of chance; but a matter of choice. It is not a thing to be waited for; it is a thing to be achieved."
- William Jennings Bryan

Offline discodermolide

  • Chemist
  • Sr. Member
  • *
  • Posts: 5038
  • Mole Snacks: +405/-70
  • Gender: Male
    • My research history
Re: Potassium Benzylamide
« Reply #1 on: June 02, 2016, 01:13:48 AM »
This may well be its actual colour.
Phenyl acetic acid is used to titrate n-Butyllithium, when the acid group has beed fully consumed the strong base starts to deprotonate the PhCH2- group to give a yellow colour, the end point of the titration. Point is that many of such anions are coloured.
Development Chemists do it on Scale, Research Chemists just do it!
My Research History

Offline Schrödinger

  • Chemist
  • Sr. Member
  • *
  • Posts: 1162
  • Mole Snacks: +138/-98
  • Gender: Male
Re: Potassium Benzylamide
« Reply #2 on: June 02, 2016, 12:20:57 PM »
I'm starting to believe it too. I did a lithium version of the reaction (in THF) and that turned out pink too. But then I pumped on it for a while to remove the solvent, and after 3 pentane washes, it now seems white. Perhaps it's a solvent thing... It might also be because of THF.
"Destiny is not a matter of chance; but a matter of choice. It is not a thing to be waited for; it is a thing to be achieved."
- William Jennings Bryan

Sponsored Links