Hello,
So I am a grade 12 chemistry student and I have not learned any organic chemistry. For my culminating assignment we have to do a presentation on a topic we are interested in and explain the chemistry behind it and relate it back to the curriculum. I am doing my presentation on the chemical reactions involved in dying your hair with permanent box hair dye. I'm focusing my presentation on redox rxns and pH and I wasn't going to include any organic chemistry because we just haven't learned it yet. However... the only way to understand how colour is formed (precursors and primary intermediates) is to look at it organically.
Primary intermediates: ortho or para diaminobenzenes, aminohydorxybenzenes, and dihydorxybenzenes.
Couplers: phenols, meta distributed phenylenediamines, phenyleneaminophenols, ad resorcinols (1, 3-dihydroxybenzene) derivatives.
I understand that amino and hydroxyl groups are rich in electrons which when present alongside a series of double bonds allows the molecules to become coloured.
aka- the para and ortho benzenes and the meta phenols (you get the gist) are monomers that can create a polymer through oxidation.
Oxidation in terms of organic chemistry is a rxn in which a carbon atom forms more bonds to oxygen atoms or fewer bonds to hydrogen atoms.
I also know that ortho, para, and meta have to do with positions of atoms.
THAT IS ALL I KNOW ABOUT ORGANIC CHEMISTRY NOTHING MORE NOTHING LESS
I guess what I would like to know is if I am right with what I have said and also to explain oxidation a little more in depth in comparison to oxidation in electrochemistry involving oxidizing and reducing agents.
My next and definitely more in depth question is... What is electrophilic aromatic substitution?
There are 3 steps in the process of dying hair (not bleaching which happens before hand just dying)
-The primary intermediate is oxidized by the H202
-The oxidized intermediate joins the coupler in "electrophilic aromatic substitution"
-The product of this (oxidized intermediate-coupler polymer) is oxidized to create the final hair dye
I have no idea what EAS is and in terms of explaining it to my class that also has no knowledge on it, could someone please explain this to me in the simplest way not going to much into detail but enough to understand it in relation to oxidation in hair dye.
PS- The only reason that I want to learn about organic chemistry and include it in my presentation even though I do not have to is because it really is the only way to understand the reactions happening in the colouring process. The bleaching process is very straight forward and no mention of organic chem is needed. But in simplest terms, the formation of dye in the rxn is from monomers joining together to form a polymer that is too big to escape the cuticle thus why the dye is permanent. The coupler does not oxidize readily so the only way it can join with the primary intermediate to form color is for the primary intermediate to be oxidized so they can join. But the two join through "electrophilic aromatic substitution" which I have no understanding of, and when discussing monomers and polymers I don't think it would be correct to just call that a synthesis reaction and not mention any organic chemistry. Monomers and polymers, and talking about phenols and diamines and ortho and meta positions is organic chemistry so I feel the need to understand EAS as i'm already mentioning organic chemistry
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Topic: Electrophilic Aromatic Substitution (Read 2348 times)