January 15, 2025, 11:41:45 PM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: alkenes and aldehydes  (Read 7226 times)

0 Members and 1 Guest are viewing this topic.

Offline fran008

  • Regular Member
  • ***
  • Posts: 27
  • Mole Snacks: +0/-7
  • I'm a mole!
alkenes and aldehydes
« on: February 27, 2006, 05:10:22 AM »
Can alkenes react with HCN and can aldehydes react with HBr. Why or why not?
Logged

Offline Albert

  • Lonely Wanderer
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1050
  • Mole Snacks: +112/-22
  • Gender: Male
  • Half Decent Pharmaceutical Chemist
Re:alkenes and aldehydes
« Reply #1 on: February 27, 2006, 08:19:22 AM »
Generally speaking, alkenes cannot react with HCN, because they are less electrophilic than alkynes, unless we consider alkenes whose double bond is activated by electronegative groups.
Logged

Offline victor

  • Regular Member
  • ***
  • Posts: 84
  • Mole Snacks: +2/-0
  • Gender: Male
  • I'm a cat!
Re:alkenes and aldehydes
« Reply #2 on: March 03, 2006, 06:46:36 AM »
I think alkene can react with HCN if acidic catalyst is present.
Logged

Offline Alberto_Kravina

  • Assault Chemist
  • Retired Staff
  • Full Member
  • *
  • Posts: 608
  • Mole Snacks: +70/-15
Re:alkenes and aldehydes
« Reply #3 on: March 03, 2006, 07:59:17 AM »
Quote from: victor on March 03, 2006, 06:46:36 AM
I think alkene can react with HCN if acidic catalyst is present.
Yup! That's possible!
Logged

Offline HP

  • Chemist
  • Full Member
  • *
  • Posts: 350
  • Mole Snacks: +33/-5
  • Gender: Male
Re:alkenes and aldehydes
« Reply #4 on: March 03, 2006, 08:54:06 AM »
What about if HCN + H2O-->prussic acid :)
Logged
xpp

Offline Alberto_Kravina

  • Assault Chemist
  • Retired Staff
  • Full Member
  • *
  • Posts: 608
  • Mole Snacks: +70/-15
Re:alkenes and aldehydes
« Reply #5 on: March 03, 2006, 08:58:23 AM »
Quote
What about if HCN + H2O-->prussic acid
Is this reaction possible: HCN + 2 H2O ----> HCOOH + NH3 ?
HCN is a nitrile, so it could hydrolyze to form formic acid....I don't know if this is possible, but I know that Cyanogen (CN)2 hydrolyses to Oxalic acid.
Logged

Offline HP

  • Chemist
  • Full Member
  • *
  • Posts: 350
  • Mole Snacks: +33/-5
  • Gender: Male
Re:alkenes and aldehydes
« Reply #6 on: March 03, 2006, 09:27:11 AM »
Yes so,  the HCN solution is unstable and decomposes on standing, giving amorphous insoluble substances, and ammonium formate, oxalic acid, &c.
I think that HCN addition to alkene(for example ethylene) could be possible in present of catalitic amount conc. H2SO4 or H3PO4(may be on solid support) because the acid sulfate or phosphate addition intermediates are very good leaving groups. Then the product HCN addition to ethylene should be acetonitrile CH3CH2CN...But i dont know such industrial process present :)
Logged
xpp
Pages: [1]   Go Up
« previous next »
Sponsored Links