I'm doing a project on permanent hair dye and there are a lot of reactions involved in actually forming the color while its in your hair. Dye intermediates and dye couplers are used to form the hair dye. They are colourless until oxidized by hydrogen peroxide, and once they are oxidized they can finally join together to created a coloured polymer that cannot be washed out of the hair.
In my presentation the picture example I have use the organic compounds p-phenelynediamine as the dye intermediate (primary intermediate), and m-phenylenediamine as the dye coupler (secondary intermediate). I understand that "p" means the substituent group is in a para position and the "m" is in a meta position but what effect does that have on a reaction mechanism that involves primary and secondary intermediates being oxidized in multiple reactions before joining together to form a polymer?
The reason I ask this is because i'm trying to show a step 1, step 2, etc of the reactions using their chemical formulas only so I can show why they are intermediates. Sure showing the organic structures shows the para and meta positions but when you're looking at it without the pictures (organic structures) and just the chemical formula... PPD and MPD are both C6H8N2. So showing
primary:
C6H8N2 (ppd) --> C6H6N2
secondary:
C6H6N2 + C6H8N2 (mpd) --> indo dye
final step:
(O)
indo dye --> final dye
IT LOOKS LIKE THERE ARE TWO OF THE SAME MOLECULE BUT IN REALITY THE PPD IS OXIDIZED TO A QUINONEDIIMINE AND THEN THAT QUINONEDIIMINE REACTS WITH THE COUPLER AND IS OXIDIZED TO FORM THE INDO DYE AND THEN THE INDO DYE IS OXIDIZED TO FORM THE FINAL COLOURED DYE
Two different molecules, same chemical formula, very different processes.
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Topic: what is the difference between PPD and MPD (Read 3396 times)