Dissolving phenidone in glycol

[ntenny]

Based on a suggestion I found in this forum from way back in the dim past, I've just tried to mix up a stock solution of phenidone in propylene glycol for general darkroom uses.

I heated the glycol to a totally imprecise temperature---bottle hot to the touch but not painful---and dumped in the phenidone powder, at a ratio of 10 g phenidone/100 ml glycol. My understanding from this forum is that this ratio is Known To Work, but it seems like the phenidone isn't dissolving completely---after several hours on the shelf with intermittent agitation, I have a significant amount of visible phenidone powder.

Obviously I could add more glycol, but 1 g/10 ml is such a nice ratio that I hate to mess with it when others have used it successfully. Do I just need to leave it overnight, or should I reheat the solution, or what?

Thanks

-NT

 

[Tom Hoskinson]

Based on a suggestion I found in this forum from way back in the dim past, I've just tried to mix up a stock solution of phenidone in propylene glycol for general darkroom uses.

I heated the glycol to a totally imprecise temperature---bottle hot to the touch but not painful---and dumped in the phenidone powder, at a ratio of 10 g phenidone/100 ml glycol. My understanding from this forum is that this ratio is Known To Work, but it seems like the phenidone isn't dissolving completely---after several hours on the shelf with intermittent agitation, I have a significant amount of visible phenidone powder.

Obviously I could add more glycol, but 1 g/10 ml is such a nice ratio that I hate to mess with it when others have used it successfully. Do I just need to leave it overnight, or should I reheat the solution, or what?

Thanks

-NT

In my direct experience, Phenidone is quite soluble in Propylene Glycol at a temperature of about 80F. If you try to dissolve too much Phenidone in Glycol, the solution will saturate and will look "milky." Just add some warm Glycol and stir - it will all go into solution.

 

[ntenny]

In my direct experience, Phenidone is quite soluble in Propylene Glycol at a temperature of about 80F. If you try to dissolve too much Phenidone in Glycol, the solution will saturate and will look "milky." Just add some warm Glycol and stir - it will all go into solution.

Well, it's definitely milky, so I guess I've got a saturated solution and need to dilute it down a little. But I'm almost sure it was you who reported easy success with the same amounts I'm using---why is my solution saturated and yours not? Any ideas?

Thanks

-NT

 

[patrickjames]

I assume that you are mixing a concentrated stock solution with which you will do further mixing. I have always mixed phenidone into PG in a 2% solution which works well for me. I put 10g in 500ml PG. You can extrapolate this into any developer you want.


Patrick

 

[ntenny]

Well, I found a really perverse solution to my problem: I dropped the phenidone/glycol solution, with the bottle open, into the hot-water bath I was using to warm it! It turns out that it dissolves really nicely under those conditions... :-(

More phenidone is on the way, and I'll use more glycol (and more caution about screwing the lid on) when it arrives.

-NT