July 08, 2020, 09:29:59 AM
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Topic: synthesize acetic acid from alkyl halide  (Read 23554 times)

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polly

  • Guest
Re:synthesis
« Reply #15 on: April 02, 2004, 07:00:44 PM »
Hi GCT!  I appreciate your input.  However, I am not sure I understand fully what you mean.  Can you show me by writing out the reaction?? Also, will reacting acetylene with KMnO4 give you acetic acid??  If not what would you get?

Thanks

GCT

  • Guest
Re:synthesis
« Reply #16 on: April 03, 2004, 12:36:59 PM »
Quote
Hi GCT!  I appreciate your input.  However, I am not sure I understand fully what you mean.  Can you show me by writing out the reaction?? Also, will reacting acetylene with KMnO4 give you acetic acid??  If not what would you get?

Reacting acetylene with KmnO4...I doubt will give you acetic acid. Because it will cleave the triple bond to create two methyl acid, formic acid...or it might create different products.  Acetylene is very reactive.

What you need to do is to react acetylene with NaNH2, this will ionize in water to create the base NH2 anion which will react through a rather non-reversible acid base reaction.  This will create the acetylide anion.  Use a methyl halide...CH3I to react through SN2 reaction with the anion and thus the actylide anion will attack the halide, alkylateing it.  You are left with a three carbon species with triple bond at one end.  Using Kmno4 (you might need to use a stronger oxidant) will cleave the triple bond, substituting one hydroxyl group for each triple bond, which will then rearrange itself to form the carboxlic acid...acetic acid, and a formic acid I imagine.  You can separate these two through various methods.

As for the second equation, the simplest way (although other ways might be safer) is to react the aceytlene with two equivalents of the NaNH2, and two equivalents of the toulene halide (Ar-CH2I).  This will substitute at the ends of the aceytlene...reduce this...depending whether you want trans or cis product you will need to use the proper reagent (tell me if you do not know which agent to use).

Hope this helps.  Feel free to ask more questions.

polly

  • Guest
Re:synthesis
« Reply #17 on: April 03, 2004, 05:29:48 PM »
Thank you so much GCT!  That helped a great deal.  For the last one I am pretty sure you use lithium to get trans.  :)

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