Do the subsituents on an azo dye affect its color?
while dyes have a wide variety of structures- the all have one thing in common: dye molecules called chromophores. A chromophore is a compound that is highly conjugate and usually has a characteristic group such as azo, carbonyl, or nitro. The extended conjugation enbles the dye to interact with various wavelengths of light.
What makes a dye good?
it should be colorfast; shoul have enough intermolecular interactions to fix to the fabric
what about the azo dye makes it interact well with the fiber?
it has polar sulfonate groups that can interact well with other polar sites in the fiber
Which form of indigo was the reduced form?
White indigo; water soluble
What is the purpose of the sodium carbonate?
deprotonates H+ from HSO3- this makes sulfonic acid solublel this also makes it highly activated (electron rich)
Why do we add glacial acetic acid?
used as a catalyst that doesn’t entirely protonate aniline; some of the catalyst will react with aniline to initate reaction with diazonium salt