catalysis by organometallic compound

1)  what is alkene hydrogenation  ?

An alkene  addition reaction is a process  called  hydrogenation . In a hydrogenation reaction  two hydrogen atom  are added  across   the double bond  of an alkene  resulting  in a saturated  alkene . The heat released is called  heat of hydrogenation .

 2) what is  wilkinson's catalyst ?

  First effect homogenious  catalyst   is a  square  planner  16 electron  d8 complex  chlorotris (triphenyl phosphine ) rhodium(1) called wilkinson's catalyst . 

3) what do you understand by Tolman catalytic loops ? 

 A  reaction  involving  a true catalyst  can always be represented  by   a closed loop is called  Tolman catalytic loops.

 4)Explain the term hydroformylation  ?

Hydroformylation   also called a oxoprocess  or oxo synthesis 

It is an industrial process  to prepare  aldehyde from alkanes . 

In this process  there is a net addition  of formyl group(-CHO) and  a hydrogen atom to a   C = C  double bond .

This process is considered as very important  because aldehydes are easily  converted into a large no  of secondary product .

5) Describe the steric effect in  hydroformylation process ?

   In this effect  where hydrogen  is transferred to the C  atom  which has  most hydrogen atom  . The resulting alkyl group  has a larger  steric bulk close to  the ligand  on the cobalt . The bulky ligand in the cobalt . The bulky ligand on  the cobalt   have  greater steric effect . Thus the mixed  carbonyl  phosphine complexes offer a great  selectivity towards  those products which have a straight chain .

 6) What is asymmetric   hydrodformylation ?

prochiral alkanes   form new stereocenters by  their hydroformylation  can be tailored to favour  one  enantiomer .