Preparation of ethanamide from ethanoic acid

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bbrain
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#1
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#1
How do you prepare ethanamide from ethanoic acid with a two-step reaction? Each step should involve a reagent so I can't dehydrate the ammonium salt for the second step.
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EierVonSatan
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#2
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I'd honestly just go through the dehydration step, it seems a bit silly to require another reagent

But if they're going to be awkward, convert the carboxylic acid into an acid chloride first :ninja:
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illusionz
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(Original post by jojo1995)
I'm not sure but wouldnt it be :

CH3COOH + NH3 - CH3CONH2 + H20

the oh would break off the ch3cooh making the c slightly positive which attracts the NH3 molecule, the a H form nh3 later breaks off joining with the previously broken off OH making H20 and CH3CONH2.

Is this edexcel unit 4 ? A2?
No.

OH is a bad leaving group (ie OH- almost never falls off a molecule. Also ammonia is a base. Acid + base --> salt
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jojo1995
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(Original post by illusionz)
No.

OH is a bad leaving group (ie OH- almost never falls off a molecule. Also ammonia is a base. Acid + base --> salt
thanks for the correction - I didn't know that :O I'll remember it now
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extons
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React the acid with PCl5 to get a mixture including the ethanoyl chloride. You can separate it with fractional distillation.

Now you can react this acid chloride with concentrated aqueous ammonia and there you go, ethanamide!
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F1's Finest
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Your first step is to form an acid chloride, via the addition of PCl5 to ethanoic acid. Then react the ethanoyl chloride with ammonia?
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extons
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(Original post by James A)
Your first step is to form an acid chloride, via the addition of PCl5 to ethanoic acid. Then react the ethanoyl chloride with ammonia?
Yes.
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EierVonSatan
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#8
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You could always convert the carboxylic acid to the acid chloride then react it with ammonia to give you the amide.
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Annachristinak
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#9
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This is too easy.. Do not think about it twice.. acid+ NH3 gives us an unstable molecule which leads to have a primary amide (Remember you have always acid + NH3 --> primary amide)
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Pigster
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#10
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(Original post by Annachristinak)
This is too easy.. Do not think about it twice.. acid+ NH3 gives us an unstable molecule which leads to have a primary amide (Remember you have always acid + NH3 --> primary amide)
You are replying to a thread which was last active in 2012.
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