Notices
Results 1 to 5 of 5

Thread: 1,3,5 cyclohexatriene?

  1. #1 1,3,5 cyclohexatriene? 
    Moderator Moderator AlexP's Avatar
    Join Date
    Jul 2006
    Location
    NY
    Posts
    1,838
    Is there such a thing as 1,3,5 cyclohexatriene (hope I named it correctly), or does a six-membered ring structure with alternating single and double bonds automatically take on the resonance structure of benzene (thus losing the distinction between its single and double bonds)?


    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
    Reply With Quote  
     

  2.  

    Related Discussions:

       

    • #2  
      Forum Bachelors Degree
      Join Date
      May 2007
      Location
      NC USA
      Posts
      488
      A six-membered ring structure with alternating single and double bonds is benzene. And yes, it always loses its distinction between its single and double bonds. I suppose you can also call it 1,3,5-cyclohexatriene if it amuses you, in the same way that we can refer to water as dihydrogen monoxide.


      Reply With Quote  
       

    • #3  
      Moderator Moderator AlexP's Avatar
      Join Date
      Jul 2006
      Location
      NY
      Posts
      1,838
      Quote Originally Posted by SteveF
      A six-membered ring structure with alternating single and double bonds is benzene. And yes, it always loses its distinction between its single and double bonds. I suppose you can also call it 1,3,5-cyclohexatriene if it amuses you, in the same way that we can refer to water as dihydrogen monoxide.
      Except to me calling it 1,3,5-cyclohexatriene (and not benzene) seems to imply that the bonds are fixed, which they are not. My point was kind of just to see if the resonance is really caused by that particular configuration of bonding, or if you could have that configuration with fixed bonds, with something else causing the resonance, if you see what I mean.
      "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
      Reply With Quote  
       

    • #4  
      Forum Bachelors Degree
      Join Date
      May 2007
      Location
      NC USA
      Posts
      488
      Your idea goes back to 1865, when Kekule first propsed the resonant structure of benzene that we accpet today. At the time he met strong objections from his colleagues opposed to the idea of resonance. They insisted on the 1,3,5-cyclohexatriene as you proposed, and claimed the single and double bonds were fixed.

      To test the idea they chlorinated benzene to 1,2-dichlorobenzene. If the 1,3,5-cyclohexatriene model were correct they would be able to find two isomers, one in which the chlorine atoms were attached to a pair of single-bonded carbon atoms, and another in which they were attached to two double-bonded atoms. Naturally, they found only one isomer.

      These experiments confirmed Kekule's model and established the resonance theory. As a side benefit, the intense interest in the project helped launch the great German chemical industry in the 19th century.
      *
      Reply With Quote  
       

    • #5  
      Moderator Moderator AlexP's Avatar
      Join Date
      Jul 2006
      Location
      NY
      Posts
      1,838
      Quote Originally Posted by SteveF
      Your idea goes back to 1865, when Kekule first propsed the resonant structure of benzene that we accpet today. At the time he met strong objections from his colleagues opposed to the idea of resonance. They insisted on the 1,3,5-cyclohexatriene as you proposed, and claimed the single and double bonds were fixed.

      To test the idea they chlorinated benzene to 1,2-dichlorobenzene. If the 1,3,5-cyclohexatriene model were correct they would be able to find two isomers, one in which the chlorine atoms were attached to a pair of single-bonded carbon atoms, and another in which they were attached to two double-bonded atoms. Naturally, they found only one isomer.

      These experiments confirmed Kekule's model and established the resonance theory. As a side benefit, the intense interest in the project helped launch the great German chemical industry in the 19th century.
      *
      Good background info. Thanks, much appreciated.
      "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
      Reply With Quote  
       

    Bookmarks
    Bookmarks
    Posting Permissions
    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •