Thursday, November 14, 2013

Types Of Catalytic Reactions

  • Homogeneous catalysis.
  • Heterogeneous catalysis.
Homogeneous catalysis:
       In homogeneous catalysis the catalyst in the same phase as the reactants. Typically everything will be present as a gas or contained in a single liquid phase.
        ( i ) Homogeneous catalysis involves the influence of  H+ on the esterification of carboxylic acids, such as the formation of methyl acetate from acetic acid and methanol.

         ( ii ) Oxidation of  SO2  to SO3 with oxygen in the presence of nitric oxide as the catalyst in the lead chamber process.

Heterogeneous catalysis:
      The catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis. Typical examples involve a solid catalyst with the reactants as either liquids or gases.
       ( i ) The Haber process finely divided iron serves as a catalyst for the synthesis of ammonia from nitrogen and hydrogen. The reactants are in the gaseous phase while the catalyst is in solid phase.
                                       N2     +     3H2     →     2NH3
        ( ii ) Another example of heterogeneous catalyst is applied in the oxidation of sulfur dioxide on vanadium (V) oxide for the production of sulfuric acid.
                                       2SO2     +     O2     →     2SO3
Hydrogenation of ethene on a solid surface.


      Ethene  molecule is adsorbed by the surface of the platinum.

        Hydrogen molecule adsorbed and broken into atoms. 

        Hydrogen atom form a bond with one of the carbon atom of ethene.

        Another hydrogen atom form a bond with another carbon atom of ethene.
         Now the product molecule is free.

No comments:

Post a Comment