The role of Dimethyl Sulfoxide in Photographic Science ))

[bnxvs]

Hello everyone.
I'd like to discuss the use of DMSO as a solvent and preservative for developing substances (agents). And also as a liquid "sulfite".
DMSO is known to absorb SO2 very well. According to some reports, it is much better than DEA / TEA. In addition, gaseous oxygen is practically insoluble in it.
Unfortunately, there are not enough practical data on the use of DMSO in photochemistry. Therefore, I will be glad to any comments and opinions on this matter.

 

[Donald Qualls]

Better wear gloves -- I recall DMSO mainly for its property of absorbing quickly through skin and carrying whatever was dissolved in it into the body with it. Used to be (might still be) an "under the counter" material sold for joint pain, though I never understood the purported mechanism behind any effect it might have had. I do recall reports that merely touching the liquid with a finger would result in almost instantly tasting it, even if wearing a respirator with organic vapor cartridge.

Pretty sure I don't need metol, phenidone, hydroquinone, sulfites, sulfonates, etc. carried into my body by accidentally getting a drop of developer concentrate on my finger...

 

[bnxvs]

You overstate. Yes, DMSO penetrates well through the skin. But not so much that a drop of phenidone or metol solution will harm you. All the more so if you are careful and smart and use protective equipment.
However, you shouldn't take off your gloves now. Even in home)))

 

[Raghu Kuvempunagar]

I guess the relatively high freezing temperature of DMSO, 19C, has precluded its use in photochemistry. There is not mention of it in Haist.

 

[bnxvs]

Yes, this problem exists. But it is quite possible to store it at room temperature. In addition, a small amount of water (+ -95%) significantly lowers the freezing point. Just the pharmaceutical concentrate "Dimexide" meets these parameters. Other solvents (propylene glycol, acetone, ethyl alcohol) can be added too.
I used to use DMSO as a solvent for phenidon. But now I started thinking about the possibility of storing CD-4, PPD in it. And also to mix concentrated solutions "sulfite + developing agent(s) + organic base".

 

[AgX]

If one can store developer concentrates in glass bottles even topped with inert gas, I do not see the advantage of DMSO, more so with its shortcomings in mind.
These would also to be taken in if used just for its solvent function.

Though maybe I am slow on the uptake.

 

[Raghu Kuvempunagar]

Yes, this problem exists. But it is quite possible to store it at room temperature. In addition, a small amount of water (+ -95%) significantly lowers the freezing point. Just the pharmaceutical concentrate "Dimexide" meets these parameters. Other solvents (propylene glycol, acetone, ethyl alcohol) can be added too.

If by adding a bit of propylene glycol we can lower the freezing point of DMSO substantially, I would be interested in it as a solvent for storing p-aminophenol base. Any idea what's the solubility of PAP base in DMSO?

 

[bnxvs]

https://www.gaylordchemical.com/literature/dmso-solubility-data/

1,4-Benzenediamine:
https://echa.europa.eu/registration-dossier/-/registered-dossier/5680/4/10
"The solubility of MMB in DMSO was ≥ 20% w/w at ambient temperature."

If by adding a bit of propylene glycol we can lower the freezing point of DMSO substantially, I would be interested in it as a solvent for storing p-aminophenol base. Any idea what's the solubility of PAP base in DMSO?

4-Aminophenol:
"very soluble in dimethylsulfoxide."
Mitchel CS et al; Kirk-Othmer Encyclopedia of Chemical Technology. (2001). New York, NY: John Wiley & Sons; Aminophenols. Online Posting Date: Jun 20, 2003.

 

[fgorga]

A few words on DMSO from a retired chemistry professor...

In the chemical lab, DMSO is used as a solvent for stock solutions of many organic compounds that are destined to be diluted into a final aqueous (water) solution.

It is used this way because it is a relatively non-polar solvent (so organic compounds are soluble in it at relatively high concentrations) that is also miscible in all proportions with water. This latter property means that one does not have to worry about two phase systems when you add a DMSO-based stock solution to water.

Additionally, DMSO is a non-protic solvent which means, among other things, that it is relatively unreactive thus often making stock solutions that are relatively stable.

In addition to its ability (mention above) to carry other compounds across the skin one should be aware that DMSO is very hydroscopic... i.e.it will pick up water from the atmosphere. This is often not a problem unless you need an anhydrous stock solution.

 

[bnxvs]

A few words on DMSO from a retired chemistry professor...

In the chemical lab, DMSO is used as a solvent for stock solutions of many organic compounds that are destined to be diluted into a final aqueous (water) solution.

It is used this way because it is a relatively non-polar solvent (so organic compounds are soluble in it at relatively high concentrations) that is also miscible in all proportions with water. This latter property means that one does not have to worry about two phase systems when you add a DMSO-based stock solution to water.

Additionally, DMSO is a non-protic solvent which means, among other things, that it is relatively unreactive thus often making stock solutions that are relatively stable.

In addition to its ability (mention above) to carry other compounds across the skin one should be aware that DMSO is very hydroscopic... i.e.it will pick up water from the atmosphere. This is often not a problem unless you need an anhydrous stock solution.

Thank you!

p.s. The first experience in the preparation of PQ concentrate. I saturated a small amount of DMSO with sulfur dioxide (warmed up a little with potassium metabisulfite). Then, dissolved hydroquinone and phenidon (very easily, at room temperature, by hand). I added some TEA to the resulting solution.
The concentrate was diluted 1 + 25 with water. pH of solution turned out to be about 9.x The color is bright orange. A piece of Fuji's X-ray film HR-U turned black in 30 seconds...

 

[Raghu Kuvempunagar]

4-Aminophenol:
"very soluble in dimethylsulfoxide."

Ok, I will read this as > 100g of PAP per liter of DMSO.

To what temperature does DMSO need to be heated to dissolve Phenidone or PAP in it?

 

[bnxvs]

Phenidone dissolves well at room temperature. Up to about 0.5-0.6 g per ml. I usually make solutions of 0.1 and 0.3 g / ml. It doesn't take any effort at all.

 

[Alan Johnson]

DMSO doesn't seem to have a role in commercial photochemistry, is it suggested that it might have?
https://www.photrio.com/forum/threads/new-hc-110-formula.169322/page-3
From post 71, Tetenal know how to make DEA sulfur dioxide adduct and this is what was/is used.

 

[bnxvs]

There is no secret in the preparation of the ethanolamines sulfur dioxide adduct. There are many scientific papers on this topic. However, it should be borne in mind that in many countries now ethanolamines (MEA, DEA, TEA) are limited in retail sale, since they are precursors and components of chemical weapons. It has become more and more difficult to obtain them for the home darkroom. Moreover, ethanolamines are strong organic bases. This is not always a good thing, since the preservative should not introduce a serious imbalance in the final working solution and should not require big compensation for its effect on pH.
And, of course, DMSO is easier to work with, since many substances dissolve much more easily than in ethanolamines or glycols.
Of course, DMSO also has disadvantages: the danger of allergic reactions (if you don't use personal protective equipment) and a very unpleasant persistent smell of working solutions. By itself, DMSO is practically odorless, but in various solutions it begins to smell strongly. Quite a peculiar smell. Not everyone will like it)))

p.s. And please don't take the topic name seriously ))) This is just a reference to the famous article by Patrick Gainer (in memory of him) ...

 

[Alan Johnson]

Yes, on UK ebay there are 0 hits for DEA and 87 for DMSO.
It might be useful if [with suitable precautions] DMSO could be heated with some inorganic bisulfite to make some kind of sulfite solvent, after filtration of the residue.
Might this be possible?

 

[bnxvs]

In order for pyrosulfite (metabisulfite, bisulfite) to effectively release SO2, it must be heated to 150C. I don't think it will benefit the DMSO. So far, I see the only way - bubbling SO2 trough DMSO. In principle, nothing complicated. A pair of flasks, connecting hoses, tripods, etc. are available at any chemical store. At the same time, this will be useful in case of experiments with obtaining the adduct of SO2 in DEA, for example.

 

[Raghu Kuvempunagar]

Ok, I will read this as > 100g of PAP per liter of DMSO.

Here's more information on solubility of p-aminophenol:

(g/100 ml at 23°C after 24 hours)
Water*: S < 1
Ethanol: S < 1
DMSO: 1 ≤ S ≤ 10

So, solubility of PAP in DMSO is <= 100g per liter but >= 10g per liter according to this. Interestingly, Gainer's EZ Rodinal can take 80g of PAP in 1 liter of water thanks to the addition of NaOH.

 

[bnxvs]

It's a good news. Thank you.

 

[AgX]

In order for pyrosulfite (metabisulfite, bisulfite) to effectively release SO2, it must be heated to 150C. I don't think it will benefit the DMSO. So far, I see the only way - bubbling SO2 trough DMSO.

Seen the warnings on DMSO I would not try heating it up that much with an acid added (to release SO2). Maybe I am too timid in your eyes.
And I do not see even engaged Apuggers bringing a pressurized gas cylinder with SO2 into their home. Remains making a SO2 source oneself.

But I already inquired on the benefit of DSMO facing the hassle and dangers.

 

[bnxvs]

I already ordered a couple of Drexel bottles and a tripod. I have a lot of metabisulfite, so I can get a double benefit - a source of SO2 and pure potassium sulfite. It remains to assemble a heating installation with a temperature stabilization of 150-160C.
In principle, I'm thinking of adopting some old oven (grill) for this. They can be found inexpensively at thrift stores or garage sales.

 

[Raghu Kuvempunagar]

its ability (mention above) to carry other compounds across the skin one

Does DMSO do this at all concentrations? For instance, if a litre of working solution contains 10ml of DMSO along with Hydroquinone and Phenidone, will a spill on the skin immediately carry these into the system?

 

[fgorga]

Does DMSO do this at all concentrations? For instance, if a litre of working solution contains 10ml of DMSO along with Hydroquinone and Phenidone, will a spill on the skin immediately carry these into the system?

I was referring to solutions where DMSO is used as the primary solvent, as when one makes a stock solution.

I do not know DMSO acts similarly at low concentrations.

Bottom line... if you are worried about exposure to a compound you should use protective gear (gloves, etc) whether or not DMSO is present.

 

[bnxvs]

I found only the following information (I apologize for the Google translation):

"Suction activators (ethyl, cetyl alcohols, cetyl palmitate, cetylmeristat, dimethyl sulfoxide, dimethylformamide, turpentine oil, PEO, surfactant and others) can enhance the penetration of medicinal substances through the skin, by dissolving the lipid components of the skin or by acting as co-solvents, increasing thermodynamic activity medicinal substances in the stratum corneum. Dimethyl sulfoxide increases the absorption of sulfonamides, anabolic and androgenic hormones, glucocorticoids, mineralocorticoids, estrogens, progesterone, antineoplastic agents, antihistamines, anti-inflammatory, vasodilating and substances protecting against UV radiation, anticoagulants, salicylic acid, etc. However, there is information about a decrease in absorption from salicylate sodium ointments and prednisolone in the presence of DMSO. In dermatological ointments it is recommended to use up to 50% dimethyl sulfoxide, and in ointments for application to the mucous membrane - no more than 10%."
​

Probably we can conclude that less than 10% concentration of DMSO in solution isn't significant ?

 

[AgX]

Strangely this discussion is restricted to the in-crowd.

 

[bnxvs]

https://echa.europa.eu/registration-dossier/-/registered-dossier/15221/4/10 K2CO3 - in DMSO: 47 g/L
https://www.delasco.com/potassium-hydroxide-10-with-dmso/ (10% KOH in DMSO)