[Nomeru]

Hello. I'm an undergrad in Organic Q2. In lab recently we have been doing an azo dye synthesis. As the title says, I used sulfanilamide and 2-naphthol for my amine and aryl group. I believe a good amount of my end product is what it should be (I think the name is 4-[(2-hydroxynaphthalen-1-yl)diazenyl]benzenesulfonamide). However, I cannot be sure of that and I'm much less sure of what else I came up with. I seem to have come up with 2 products: a dark purple-black fine precipitant and a dark orange (or rather murky or dirty orange). I expected my product to be somewhere between orange and red.

Starting at the beginning: I used 4mL DI, 20 drops H3PO4 in a 25mL round bottom flask (cooled and stirring). Once cooled, I added 34mg (0.2mmol) sulfanilamide, and let it sit for 10 minutes stirring (still at 0C). Then added 20 drops NaNO2 soln (40mg NaNO2 in 2mL DI), let continue stirring cool 10 more minutes. At this point I added 29mg (2mmol) 2-naphthol. After 10 minutes, removed from ice bath and let sit.

Observations:
I saw an immediate change from clear to a light yellow after adding the 2-naphthol. Within a minute, it was turning light orange. That orange progressed to dark orange, then to red, then to a dark red-purple color. At this point (maybe 15 minutes since adding the 2-naphthol) I started seeing a purple precipitant on the side. This continued for 10 minutes more, with more and more precipitating out. My solution was still purple but had a much less concentrated look. I noticed at this time a single drop on the side of orange. Per my instructor's suggestion, I tried adding 15 drops more H3PO4. I saw no immediate change. The next 20 minutes though saw the solution turn more and more orange. The precipitant stayed, coating the bottom of the flask and the stir bar in a dark purple (looked almost black as a solid). I tried heating the dye solution as well during this time, but saw no change because of it that I could tell.

The dye solution was allowed to sit for 5 days. When I came back, it was about as I had left it. I had a murky/thick orange dye with a dark purple/black precipitant. I suspect the precipitant is what makes the orange so dirty/murky looking. I also suspect that the orange is most likely my desired product. However, why did that only form after the purple? I am not required to know what the purple is, but I really am curious. My instructor and lab tech seem to be puzzled by it themselves. Does anyone have any guesses as to what the purple product likely was?

Other data I have: 2 other people chose 2-naphthol and sulfanilamide. 1 had the same result as me, and another had a bright orange. I tested and found my solution to have a lambda max range of 380-440nm. Added .5ml dye soln to 2 test tubes: 1 w/ 2ml 1M NaOH - turned red (1mL did nothing, probably because of 15drops extra H3PO4). The other 1mL H2O - stayed orange.
Dyed cloth with red NaOH soln (in Fabric: Color - Wool: Dark Orange, Acrylic: White (no change), Polyester: pale yellow/white, Nylon: 'dilute' orange (not a light orange, but faint in color), Cotton: very light orange, Acetate: Strong orange color (not dark)).
I want to run a GC-MS tomorrow, but 1. I don't know if I'll be able to and 2. I don't know that I'll be able to do much with the results. I will likely run an IR spectrum as well (more likely).

Thank you.