[shubhamrawal]

Is it Propan - 1 - ol or Propan - 2 - ol ?

[kriggy]

What do you think? If the diazogroup is on carbon number one, could you get substitution on carbon number two?
Also, what are the conditions? Because you can get chloride too (if you use excess of HCl)

[pgk]

The major product of diazotisation of propan - 1 – amine, is propan - 2 – ol, accompanied by a small amount of propan - 1 – ol, together with propene.
The reaction mechanism starts by thermal liberation of gaseous nitrogen and formation of the corresponding carbocation:
CH3CH2CH2-N(+)ΞΝ, Cl(-)  →  CH3CH2CH2(+) + N2↑ + Cl(-)
Try to explain the formation of all above products from propane-1-carbocation and why propan - 2 – ol is the major product.
Reference: Peter Sykes, A Guidebook to Mechanism in Organic Chemistry, 2nd Edition, Longmans LTD, London, (1965), p. 85

[shubhamrawal]

Hi PGK ,
Thanks for replying to my question .
I also think that that propane-2-ol should be formed by hydrid shift in carbo cation rearrangement because carbo cation rearrangement is also observed in digitization of 1-cyclopentyl methan-1-amine .

But the answer suggested by this link is Propan-1-ol - http://chemwiki.ucdavis.edu/Organic_Chemistry/Amines/Reactions_of_Amines/The_Reaction_of_Amines_with_Nitrous_Acid

[sjb]

Hi PGK ,
Thanks for replying to my question .
I also think that that propane-2-ol should be formed by hydrid shift in carbo cation rearrangement because carbo cation rearrangement is also observed in digitization of 1-cyclopentyl methan-1-amine .

But the answer suggested by this link is Propan-1-ol - http://chemwiki.ucdavis.edu/Organic_Chemistry/Amines/Reactions_of_Amines/The_Reaction_of_Amines_with_Nitrous_Acid

Note the caveat below the equation on that page.

...The propan-1-ol will be only one product among many - including propan-2-ol, propene, 1-chloropropane, 2-chloropropane and others...

I think what the page is saying is that for each molecule of amine, you get a molecule of dinitrogen, and (presumably) depending on exact conditions you may get varying amounts of each of the potential organic products. I doubt whether this is of as preparative use as per ArNH₂ diazotation

[pgk]

Reference: Peter Sykes, A Guidebook to Mechanism in Organic Chemistry, 2nd Edition, Longmans LTD, London, (1965), p. 85

[shubhamrawal]

Thanks PGK