November 24, 2024, 03:36:27 AM
Forum Rules: Read This Before Posting


Topic: R-CN -> acid conversion  (Read 4285 times)

0 Members and 1 Guest are viewing this topic.

Offline hobobot

  • Regular Member
  • ***
  • Posts: 79
  • Mole Snacks: +4/-0
R-CN -> acid conversion
« on: April 26, 2010, 11:38:47 AM »
I know you can convert an R-CN group to an acid using H+, H2O and heat. But, what happens when you try to do that reaction in a base?  I got as far as having a R-C(OH)NH group. Not sure if it can go farther than that.

Offline 408

  • Chemist
  • Full Member
  • *
  • Posts: 796
  • Mole Snacks: +103/-30
Re: R-CN -> acid conversion
« Reply #1 on: April 26, 2010, 12:20:11 PM »
You have an acidic proton in your basic reaction... It can go further...

Offline AC Prabakar

  • Full Member
  • ****
  • Posts: 109
  • Mole Snacks: +5/-1
  • Gender: Male
Re: R-CN -> acid conversion
« Reply #2 on: April 27, 2010, 07:21:55 AM »
Yes u r right.Hydrolysis"-CN" in basic medium proceeds via amide intermediate.You can find this in any basic organic chemistry book.
Hydrolysis sequence is as follows.
"-CN"----(fast)--->amide--(slow)----->acid.

In order to make "-NH2" of amide intermediate as leaving group,we should use strong base such as KOH/NaOH etc.
If u r continuing the reaction you can end up in acid.(After acidification only u will get acid!in basic medium it will be as carboxylate anion.)

Offline hobobot

  • Regular Member
  • ***
  • Posts: 79
  • Mole Snacks: +4/-0
Re: R-CN -> acid conversion
« Reply #3 on: April 28, 2010, 06:56:16 PM »
thanks! that does make sense. I didn't know that the amide->acid was the slow step. That's really helpful.

Sponsored Links