March 28, 2024, 04:42:58 AM
Forum Rules: Read This Before Posting


Topic: From an aldehyde to a nitrile  (Read 3258 times)

0 Members and 1 Guest are viewing this topic.

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7981
  • Mole Snacks: +555/-93
  • Gender: Male
Re: From an aldehyde to a nitrile
« Reply #15 on: June 17, 2019, 02:08:16 PM »
HCOONa + HCl = HCOOH + NaCl

Sodium formate is very soluble in formic acid. Formic acid boils at about 101 ° C and forms azeotrope with water boiling at about 107 ° C. Addition of approximately 3 moles of sodium formate to 1 kilogram of formic acid, after deducting its consumption to neutralize hydroxylamine hydrochloride, increase the boiling point of the reaction mixture (see ebullioscopic constant of formic acid) above the boiling point of the azeotrope. In this way, we can remove water from the reaction environment by shifting the equilibrium towards ester formation - oxime formate, which at this temperature decomposes thermally to the nitrile.
AWK

Offline rolnor

  • Chemist
  • Sr. Member
  • *
  • Posts: 2203
  • Mole Snacks: +148/-10
Re: From an aldehyde to a nitrile
« Reply #16 on: June 17, 2019, 05:02:23 PM »
It could be that formic acid formylates the oxime before the elimination-step, if you use acetic anhydride you get acetylation. The acyl group is a better leaving group then the protonated oxim hydroxyl group

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 5594
  • Mole Snacks: +319/-22
Re: From an aldehyde to a nitrile
« Reply #17 on: June 28, 2019, 02:01:17 PM »
On page 467 of Catalysis in Chemistry and Enzymology (WP Jencks) there is a discussion of the pH dependence of the reaction of aldehydes and ketones with hydroxylamine.  The rate for acetone and hydroxyl amine is maximal between pH 4 and pH 5 (Figure 1 on page 469).  This issue may be tangential to the present discussion.

Offline Juaqui

  • Regular Member
  • ***
  • Posts: 22
  • Mole Snacks: +0/-0
Re: From an aldehyde to a nitrile
« Reply #18 on: June 30, 2019, 04:39:56 PM »
Thank you very much, guys!!!!

Sponsored Links