Producing my own Rodinal Developing Agent

[Kresado]

Apologies is this is a dumb question. I've been mixing
ECN-2 and D76 for a while now and want to extend that to Rodinal. I can source all of the ingredients except P-Aminophenol Hydrochloride
I don't want to make it out of Paracetamol or Tylenol too avoid impurities and the high cost. However I can buy P-Aminophenol quite cheap in its Powdered white form. To my understanding adding HCl would form the P-Aminophenol Hydrochloride so evaporating what's left would leave me with what I need. If I'm totally wrong any help would be appreciated and I'd love to know the correct process to get P-Aminophenol Hydrochloride from P-Aminophenol.

 

[Donald Qualls]

I believe you would need to treat the acetaminophen (n-acetyl p-aminophenol) with potassium hydroxide or sodium hydroxide to cleave off the acetyl group before reacting with HCl -- and in the process you'd have to prevent oxidation by adding something like sodium sulfite. Perhaps someone who's a better chemist than I am (not a high bar) could suggest whether HCl of sufficient concentration could simply replace the acetyl group.

 

[Raghu Kuvempunagar]

Why are you thinking of converting PAP base to PAP HCl? If you are going to brew Rodinal substitute like Gainer's EZ Rodinal, you can use PAP base itself. Search for EZ Rodinal formula on this website.

 

[Raghu Kuvempunagar]

OP: here's Gainer's EZ Rodinal formula for your perusal.

https://www.photrio.com/forum/threads/rodinal-ez-gainer-formula-troubleshooting.39438/

 

[john_s]

My understanding is that the HCl version keeps well a a pure powder, but p-Aminophenol deteriorates (as a powder).

 

[Kresado]

Thanks for the recipe
I was initially looking at a recipe from //www.digitaltruth.com/forum/viewtopic.php?t=1068
and was under the impression that straight up PAP would not work unless in its Hydrochloride form. I'll definitely try his recipe out!

 

[Raghu Kuvempunagar]

Thanks for the recipe
I was initially looking at a recipe from //www.digitaltruth.com/forum/viewtopic.php?t=1068
and was under the impression that straight up PAP would not work unless in its Hydrochloride form. I'll definitely try his recipe out!

You're welcome.

 

[Lachlan Young]

I can source all of the ingredients except P-Aminophenol Hydrochloride

Read the last line of Ian Grant's Rodinal resource here. It also summarises most of the recipes.