CITRAL


CITRAL, 3,7-Dimethyl-2,6-octadien-1-al, (C10H16O):
     Citral is the most important member of the acyclic monoterpenoids.
        It is found in oil of orange ( 6 to 7 %) and in citronella oil.
        It is pale yellow liquid having boiling point 238⁰C.
   The structure of Citral is elucidated from the following:
     i.            Molecular formula of Citral is C10H16O.
  ii.            Citral reacts with bromine to form a tetrabromide derivative. This indicates the presence of two C-C double bonds in the citral  molecule.
iii.            Citral reacts with hydroxylamine to form an oxime. It also adds sodium bisulfite.  These reactions indicate the presence of an aldehyde (-CHO) or a ketone (-CO-) group.


iv.            Citral  undergoes reduction with sodium amalgam and water to give a primary alcohol geraniol,   C10H18O. It undergoes oxidation with the silver oxide to yield geranic acid, C10H16O2 , containing the same number of carbons.  These reaction indicates the presence of an aldehyde group.



V.  When Citral is heated with potassium bisulfate, it is  converted to p-cymene . This indicates the relative positions of methyl and isopropy groups in the citral molecule.



VI. Citral undergoes hydrolysis with potassium carbonate to give 2-methyl-2-hepten-6-one (methylheptenone) and acetaldehyde. 


VII.Citral undergoes ozonolysis to give acetone, glyoxal, and  levulinic aldehyde. This reaction clearly establishes the position of the two C-C double bonds in the citral molecule.