P glycol and BZT

[Wayne]

I'm looking to eliminate the alcohol smell from my phenidone and benzotriazole % solutions. I know phenidone disollves in PG, does the BZT?

 

[Gerald Koch]

Yes, its very soluble in ethylene glycol, propylene glycol, and polyethylene glycol.

 

[Wayne]

Is there any reason to choose poly over propy? I can order propylene glycol at the pharmacy for about $10/pint. Does it have a strong smell or other potentially unpleasant qualities I should know about before I order it?

 

[gainer]

Is there any reason to choose poly over propy? I can order propylene glycol at the pharmacy for about $10/pint. Does it have a strong smell or other potentially unpleasant qualities I should know about before I order it?

It's practically odorless, but then my smeller is 78 years old. You can get it from www.chemistrystore.com for about $16 a gallon plus shipping. You might get some triethanolamine (TEA) while you're at it. This is a nice company to deal with. They cater mostly to makers of soaps and cosmetics, but have many of the chemicals photographers use.

 

[Wayne]

what would I use the TEA for?

 

[avandesande]

polyethylene glycol is an ether, and as such will form peroxides and undergo decomposition. I would recommend proplyene glycol over PEG.

 

[Mark Layne]

polyethylene glycol is an ether, and as such will form peroxides and undergo decomposition. I would recommend proplyene glycol over PEG.

Is that PEG the same stuff sold for filling cells in green wood to stop it splitting.If so there's a lot of it in basements around here.

 

[Tom Hoskinson]

what would I use the TEA for?

Triethanolamine (TEA) is also an excellent solvent for several developing reagents including Glycin, Metol, Amidol, Hyroquinone, Ascorbic Acid, Pyrogallol and Pyrocatechcol. TEA is also an organic source of alkali when water is added to it. Try an Apug search on TEA.

 

[srs5694]

what would I use the TEA for?

PC-TEA and Ryuji Suzuki's developers (DS-10, DS-12, DS-14, DS-15) use TEA. These are all ascorbic acid developers; PC-TEA, DS-10, and DS-12 are for film, while DS-14 and DS-15 are for paper. In PC-TEA, the TEA is the solvent; water is only used for diluting just prior to use. I believe Suzuki uses TEA as one of several preservatives, but water remains the principal solvent.

 

[Tom Hoskinson]

PC-TEA and Ryuji Suzuki's developers (DS-10, DS-12, DS-14, DS-15) use TEA. These are all ascorbic acid developers; PC-TEA, DS-10, and DS-12 are for film, while DS-14 and DS-15 are for paper. In PC-TEA, the TEA is the solvent; water is only used for diluting just prior to use. I believe Suzuki uses TEA as one of several preservatives, but water remains the principal solvent.

True for the Suzuki Developers,

But in Pat Gainer's PC-TEA and in jdef's 510 Pyro, the TEA plays two roles:
1. TEA is the developing reagent solvent and
2. TEA becomes the alkali source when water is added.

 

[Ryuji]

True for the Suzuki Developers,

But in Pat Gainer's PC-TEA and in jdef's 510 Pyro, the TEA plays two roles:
1. TEA is the developing reagent solvent and
2. TEA becomes the alkali source when water is added.

I've run tests with all sorts of combinations of different amines, not just triethanolamine, in various formulations.

Amines are ok solvents for some compounds, but they are not a good solvent for MANY compounds. So, in order to make a good developer with this solvent system, there is a great limitation in the formulation, yet you'll still have to make compromises. A good example is Kodak HC-110. On the other hand, developers like Ilfotec DD-X and T-MAX developer use water as the primary solvent for a good reason.

What I see as a strength of certain organic amines is their ability to buffer the developer pH (in a limited range particular to each amine compound) and also stabilize water-based ascorbate developers. The best results are usually obtained with a blend of two or more amines of different properties, preferrably combined with a good amount of radical scavengers. The details are perhaps too complicated for casual audience but I've been able to make interesting developers this way, some of which are found to be very practical. One is an improved version of DS-10, which keeps better than DS-10. Another is a Dimezone-ascorbate developer concentrate that combines the fine grain of D-76 1+1, speed of DD-X and give good accutance. I took a lot of nighttime landscape pictures on Fuji Acros in 120 size, and developed in this developer (1+29), printed on 11x14 size for scanning (and 20x24 for framing). Surprisingly, I didn't want to use sharpening function on my photoshop (I usually use smart sharpen on photoshop cs2, btw) because the scanned image was already VERY sharp even after reducing the size. The concentrate is primarily water-based.

Anyway, we are getting better idea of what is going on in the ascorbate developers during storage, and how to deal with this problem safely, cheaply and very effectively.

 

[Kirk Keyes]

polyethylene glycol is an ether, and as such will form peroxides and undergo decomposition. I would recommend proplyene glycol over PEG.

Is peroxide formation really a consideration here? And by decomposition, to you mean explosion? PEG and Carbowaxes seem fairly stable to me.

I'd go with whichever is less expensive.

 

[avandesande]

No it is not going to turn into a bomb on you, but it will yellow over time. I am not sure if it has an effect on photochemistry.
Also keep in mind that PEG is not a single molecule but a mixture of polyethlene glycols of different length and has any number of impurities. It is a pot product and not distilled, whatever catalyst junk they put in there to polymerize the ethylene oxide stays. Because of this it is hard to assay.

Propylene glycol is a distinct compound, easy to purify and easy to assay. If you want to use peg go ahead but I don't know of any chemist that would recommend it as a solvent, unless it has some property you can't get elsewhere.

Is peroxide formation really a consideration here? And by decomposition, to you mean explosion? PEG and Carbowaxes seem fairly stable to me.

I'd go with whichever is less expensive.

 

[avandesande]

I also forgot to mention that polyethlene glycols are a suspected tetrogen.
Proplyene glycol is so safe it is allowed as a sweetner in animal feeds.

 

[Jordan]

I can't understand why anyone would want to use polyethylene glycol as a solvent for a developer. Polyethylene glycol refers to a family of polymers: the low-molecular-weight ones are thick oils, while the higher-molecular-weight ones are waxes and solids. I'm surprised at these toxicity concerns, too -- PEG is used in a LOT of cosmetics (and maybe food or medical products?)

Propylene glycol works perfectly well as a solvent for Pat Gainer's developers. I mixed a stock solution of ascorbic acid (100g/L) and phenidone (2g/L) in propylene glycol in October 2003 (this is the "PC-Glycol" stock solution) and have been using it since then with great results. I use either sodium carbonate (5 g/L) or triethanolamine (20 ml/L) as activators.

I would imagine that ethylene glycol would do just as well, but it is much more toxic by ingestion.

 

[gainer]

Lately I have been adding just enough TEA to a propylene glycol solution of phenidone or p-aminophenol base and ascorbic acid to make a water solution just about inactive. That means it will take til Christmas after next to make an image, or maybe not. If I use p-aminophenol, I need a lot more of it than of phenidone, but it is soluble in the glycol. Making the weight of TEA equal to the weight of ascorbic acid * 149/176 is close enough for government work. This ploy allows a greater choice of alkalis for the working solution. It is better to weigh the TEA because it freezes at about 70 F and the volume changes with temperature, so if you want to pour it, it's best to warm it up and weigh it. I am thinking that the metol base might be even better for some purposes than phenidone, and it should be soluble in the glycol but not much in water. Neutralizing the hydrosulfate ought to precipitate the base which can then be filtered from the other stuff.
If any of my grand plan works out, I will, of course, do some carefully planned experiments (I know many of you think I don't know what that means. I did however write a branch memo for my branch of NASA on the use of "Magic Squares" in planning experiments.) to find a good ratio. If anyone wants to join in the phun, the more the merrier.

 

[Gerald Koch]

I can't understand why anyone would want to use polyethylene glycol as a solvent for a developer.

Where in this thread is someone advocating using PEG to make a developer?
The original question was about the solubility of benzotriazole in glycol. I listed all the glycols mentioned on a website about BZT. The complete list of solvents given is

Solvent Wt%
-----------------------------------
Water ~2.5
Ethylene glycol 40.0
Isopropanol 45.0
Polyethylene glycol 47.7
Ethanol 50.0
1-Methoxy-2-propanol 55.0
Methanol 71.6

 

[Wayne]

I ordered some propylene glycol and it should suit my present purposes.

 

[Wayne]

Ok, my propylene glycol is here. Now, should I make 10% solutions of BZT and phenidone rather than 1 or 2 % (I have syringes to measure small amounts), since I only have a pint of PG for now? Will I need to heat it? I seem to recall some things need heat to dissolve in it but I dont recall which things.

 

[Jordan]

Gerald, on the first page of this thread several posters seemed to be discussing the merits of using PEG as a solvent for photographic chemistry. Perhaps I mis-interpreted.

 

[Gerald Koch]

On further thought I believe that Polaroid used PEG in developers for their develop in camera films.

 

[Jordan]

To keep the developer "gooey" and gel-like, right? Actually, I seem to remember Ryuji Suzuki mentioning something like this (a gel-based developer) either here or on pure-silver some time ago.

 

[gainer]

Ok, my propylene glycol is here. Now, should I make 10% solutions of BZT and phenidone rather than 1 or 2 % (I have syringes to measure small amounts), since I only have a pint of PG for now? Will I need to heat it? I seem to recall some things need heat to dissolve in it but I dont recall which things.

Propylenr glycol is rather viscous. Heating it thins it and makes things dissolve faster. I doubt you would need any more than the temperature of hot tap water. I haven't used BZT yet, but phenidone dissolves easily. I wouldn't make a 10% solution for my use. In fact, when I make as much as half a liter of something like PC-Glycol or PC-TEA I use the phenidone powder because 1 or 2 grams are not difficult to measure with sufficient accuracy. When I am making small quantities of something I'm playing with, a 1% solution is better.

 

[Wayne]

Too late! But thanks. I mixed up 2% solutions of BZT and phenidone. I realized 2% was perfect for how much of each that I had, and thats what I usually use when I mix in alcohol. The PG wasnt very cooperative, but it did finally dissolve them both at room temp. Next time I may try a little heat, but I'm good for several months now.

 

[gainer]

Hey! Whatever pleases you tickles the heck out of me, as a buddy of mine used to say to me. I'm just usually at one extreme or the other. I have my teaspoons pretty well calibrated for the powder, and my eyedropper pretty well calibrated for the 1%.