conversion;but-1-ene to but-2-ene

I am giving 2 methods involving catalytic isomerization of 1-Butene. In first method Ni catalyst used to give 2-Butene and in the second method alumina is used as catalyst to give a mixture of cis- and trans-2-butenes.

(i) 1-butene is converted to 2-butene by catalytic isomerization. 1-Butene undergoes isomerization to 2-Butene on a nickel catalyst in the presence of hydrogen at around 65 degree C. In this reaction, double-bond migration undergoes simultaneously with the hydrogenation reaction.

  Ni catalyst/65o 

CH3CH2CH=CH2 --------------------> CH3CH=CHCH3

1-Butene  Hydrogenation  2-Butene

 

(ii) The reaction is the isomerization of the olefin 1-butene to a mixture of cis- and trans-2-butenes in the presence of freshly dried, activated alumina which is used as the catalyst.

  • 3

When an alkene of 4 or more carbon atoms is treated with H+, isomerization may occur by migration of the C=C bond along the carbon chain. A strong base such as potassium amide, KNH2, can also promote double bond isomerization. The acid or base acts as a catalyst, i.e. the reactions are acid-catalysed or base-catalysed isomerizations. The C=C bond moves to a more substituted position within the carbon chain, for example but-1-ene isomerizes to but-2-ene in the presence of H+CH3CH2CH=CH2 (H+catalyst)= CH3CH=CHCH3

  • -2
What are you looking for?