Question

3-nitrophthalic acid was reacted with propane diol and hydrazine to form 3-nitrophthalhydrazide.

Then 3-nitrophthalhydrazide is reacted with NaOH and Na2S2O4*H2O to make the final product luminol.

In luminol synthesis,

why is the reaction heated up so high in the first step?

Also what reaction would occur if conducted the first reaction at room temperature? (Provide a reaction scheme).

Lastly in the Mass Spectrometry, what are the possible ions that can be shown with luminol?

Answer 1

In the synthesis of luminol starting with 3-nitrophthalic acid, the first step involves condensation of carboxylic acid with amine. A water molecule is released in the process. The high temperature is needed so that the elimination of water molecule is facilitated in the dehydration cum condensation reaction and the formed water does not react back with the amide formed.

If the first step is carried out at room temperature we would simply get the ammine carboxylate salt of the 3-nitrophthalic acid substrate acordign to the scheme shown below.

In the mass the major peaks expected would be,

177 for M+

119 due to loss of NHNHCO part of the molecule