[Pasta_Fazul]

What's up guys, new guy here. I had a question on rxn mechanisms for the synthesis of acetaminophen. Im not in organic chemistry 1 yet, I'm in chemistry 2 at the moment. I'm currently doing an experiment on the synthesis of acetaminophen as well as a 15 minute presentation on the synthesis in front of a small science committee. I already conducted the synthesis and yielded a very white slightly tan powder. I have plans to recrystallize soon. I start organic chemistry soon but not soon enough to be able to understand reaction mechanisms. I would really love for someone to break down how electron flow takes part in this reaction with the addition of each reactant. I'll move onto the reaction now.

-2.1g p-aminophenol and 35ml H2O are added to a 125mL erlenmeyer flask. Are the hydrogens on the water nucleophilic? Is the nitrogen electrophilic? Does it prefer to deprotonate on the -NH2? What exactly happens here and why? Are there now OH- ions within the solution of p-aminophenol?

-To this, HCl is added drop wise until all the p-aminophenol dissolves. So I know from chemistry HCl is a strong acid and dissociates 100%. This tells me that HCl can't precipitate and possibly the H+ from Hal deprotonates and forms H2O from the aqueous OH- ions and Chlorine is now an electrophilic ion. Idk if any of this is right, at this point a hydrochloride salt of p-aminophenol is formed.

-A buffer is prepared using 2.5g NaOAc in 7.5mL of H2O. I know buffers are used so that the pH will stay relatively the same when added to the p-aminophenol HCl. When NaOAc dissociates does it only form acetic acid since sodium hydroxide is a strong acid and won't precipitate? NaOAc(aq)+H2O(l)--->OH-(aq)+HCH2CO3-(aq)+Na-(aq)?

-Heat the p-aminophenol solution. To this, add the NaOAc buffer solution. Immediately add 2mL of acetic anhydride. A stir bar is timed for 10 minutes. Im lost here. I've read that the p-aminophenol changes due to acetylation but whats the chemistry behind whats happening?

-The rxn cools in an ice bath and this is when i filtered it and arrived at a white/tan powder.

I really like chemistry but I haven't been taught this in class yet. It's really exciting to learn and there's just so much information in organic chemistry, I'm lost at where to even start. I've watched some videos on electron flow, pushing arrows, some rxn mechanism too but none are applying to my synthesis project for me to understand. I would really appreciate anyone who can kindly explain to me whats happening here. Thanks for any guidance!

[Pasta_Fazul]

Whoops! Sorry i meant to say NaOH is a strong base and will remain dissociated.

[pgk]

Please, not so puzzle thoughts!
More simply:
1). p-Aminophenol is insoluble in water but as having an amine group, p-aminophenol can form a p-hydroxylphenylammonium chloride salt, which is soluble in water; therefore, HCl is dropwise added, up to complete solvation.
2). p-Hydroxylphenylammonium chloride is a salt of a weak base (p-aminophenol) with a strong acid (HCl) and thus, it is acidic and not fully ionized but it exists in equilibrium of the ionized with the unionized form (p-aminophenol + HCl).
3). The reactivity order of acetic anhydride is: amine > phenol > water, respectively.
4). Thus, the unionized form of p-aminophenol,HCl selectively reacts with acetic anhydride anhydride and forms acetaminophen (= Paracetamol) + HCl + acetic acid.
5). Once acetaminophen is formed and according with the Le Chatelier principle, the equilibrium is driven to further deionization and so, the reaction goes on.
6). But the so formed HCl can simultaneously catalyze the esterification of p-aminophenol, as well as the hydrolysis of acetic anhydride.
7). AcONa is a salt of a strong base (NaOH) with a weak acid (AcOH) and apart existing in equilibium, it is quite alkaline and thus, it can neutralize the liberated HCl, avoiding the simultaneous formation of side products.
. By writing all involved reactions and their products on a piece of paper, you will immediately clarify the issue by yourself.