April 27, 2024, 12:08:51 PM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: Drying of DMF  (Read 16355 times)

0 Members and 1 Guest are viewing this topic.

Offline poorstudent83

  • Regular Member
  • ***
  • Posts: 42
  • Mole Snacks: +0/-0
Drying of DMF
« on: May 16, 2011, 12:23:54 AM »
I need a large amount (approx.500 ml) of anhydrous DMF. Is it sufficient to reflux the solvent over 4A molecular sieves overnight then distill under reduced pressure?? I'm wary of the DMF decomposing if refluxed for that long...
Logged

Offline ATMyller

  • Chemist
  • Full Member
  • *
  • Posts: 223
  • Mole Snacks: +31/-6
Re: Drying of DMF
« Reply #1 on: May 16, 2011, 04:37:41 AM »
Allowing the liquid to stand over the sieves for overnight is usually enough, no refluxing needed. You might need to add some metallic sodium shavings before distillation to make sure all of the water is removed from liquid phase.
Logged
Chemists do it periodically on table.

Offline enahs

  • 16-92-15-68 32-7-53-92-16
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 2179
  • Mole Snacks: +206/-44
  • Gender: Male
Re: Drying of DMF
« Reply #2 on: May 16, 2011, 10:58:53 AM »
It decomposes slightly at its boiling point at atmospheric pressure to give a small amount of carbon monoxide and diethyl amine. If that is going to be a problem for your reactions, the distill at reduced pressure.
Logged

Offline Biginelli

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
  • Gender: Male
Re: Drying of DMF
« Reply #3 on: July 24, 2011, 05:42:16 AM »
I was drying DMF over calcium hydride for a few hours, then performed a distillation over it. Further reactions comprised sodium cyanide and proceeded well enough; thus, the drying was successful.
Logged
Pages: [1]   Go Up
« previous next »
Sponsored Links