Chemical solvability

[swmcl]

Morning !

I wonder if this thread might be a place to pass on findings relating to the solubility of various photochems - a more concentrated location where our collective learnings are shared.

I'd like to see various chemical solubilities in propelene glycol (glycol) and triethanolamine (TEA) in particular.

One should of course state the conditions in which the solubility occurs (temp. and agitation method in particular).

Any reasonable assumptions should also be eliminated if possible. For example, TEA means what it says ... 99% TEA. Not an admixture of DEA and certainly not the watered down variety !

Other issues should also be observed, like something precipitating out of solution again at 20 C ...

So to start out, what how much pyrogallol can I dissolve into TEA at 70 degrees C with constant agitation ?

Then there's the Pyrocatechol in glycol ...

I believe the solubility will change when more chemicals are added to the brew so the estimates we see here may not be absolutely correct but we should be able to come to a fair estimate nonetheless.

I trust I've made a reasonable request !

Cheers,

[NPR]

FWIW, in propylene glycol all of the following at room temp (20-22C and about 5-6 days, turning bottle slowly upside down to mix)

catechol at 400g/L,
HQ and Pyrogallol at least 200g/L,
Ascorbic Acid 160g/L,
P-aminophenol (base) 50g/L (I don't recommend keeping a glycol stock solution, since it keeps better by itself in a glass jar),
Dimezone-S and Phenidone at least 20g/L. (this is very handy to measure small amounts)

None of these need heat to dissolve. Glycin will go into 99% TEA at 100g/L, and you will need some heat to do that. Glycin in TEA keeps well if you have no air in the glass bottle. Glycin and Metol will dissolve in glycol if you mix them first with a very small amount of TEA (10-20ml) and then add glycol, but they oxidize practically overnight. Metol at least keeps well in a mason glass jar. Overall, my experience has been that TEA doesn't work as well as glycol, if you are using these as stock solutions and glycol gives you more flexibility in the developer part 'B'.

[swmcl]

Many thanks NPR. This is an excellent summary.

Do you have any experience with sodium sulfite in either glycol or TEA ?

I wouldn't mind betting NPR that you know a few tricks.

[NPR]

Many thanks NPR. This is an excellent summary.

Do you have any experience with sodium sulfite in either glycol or TEA ?

I wouldn't mind betting NPR that you know a few tricks.

Almost all of what I have learned came from a few very helpful individuals over at APUG (and the search engine). I have never tried sulfite in PG, according to the phrase like dissolves like, I don't think that sulfite (inorganic) will dissolve in glycol (organic). You can use ascorbic acid in the place of sulfite if you are mixing the Pyrocat series (all the details are on the website under mixing). When I want to use sulfite, I will mix with water in small batches, or mix up an A part in glycol and a B part in water with the accelerator plus the sulfite. At this point I only use a couple developers: DS-10/12, the Pyrocats, and Ansco 130 for paper. I can say that the best and cheapest place to get PG in my neck of the woods (eastern USA) is at the Tractor Supply company, they have a gallon/3.8L jug for about 22 dollars and it is 99% purity grade. I think it is used on cows' utters.