Amidol soluble in TEA or Glycol?

[sanking]

OK, I know this has been asked before, but I can not find/remember the answer. Is amidol soluble in either TEA or Propylene Glycol? If so, at what temperature?

Sandy

 

[gainer]

It's probably not going to be used alone. The pH requirements depend lso on whatever is used with the amidol. I have done both, and prefer to use glycol because it allows playing with the alkali. The following is a pretty good developer.

10 grams ascorbic or erythorbic acid.
0.1 gram amidol
Propylene glycol to 100 ml.

!0 ml of this in 250 ml water will require 2 ml of TEA to work in a reasonable time. With 10 ml TEA it will develop HP5+ or whatever the current Arista II in about 6 minutes. In this case, of course, you can figure that almost 2 ml went to neutralize the ascorbic acid.

 

[Tom Hoskinson]

Yep, I mixed a bunch of Amidol stock concentrate in Propylene Glycol over a year ago. I have about 1500ml of the concentrate left and it is still fully active. I use it to mix Michael Smith's Azo developer recipe.

 

[sanking]

Tom,

Was it very difficult to get the Amidol into solution with glycol? And what was the % solution you mixed. I tried to mix it with TEA but a lof of the Amidol settled out when the solution cooled.

Sandy

Yep, I mixed a bunch of Amidol stock concentrate in Propylene Glycol over a year ago. I have about 1500ml of the concentrate left and it is still fully active. I use it to mix Michael Smith's Azo developer recipe.

 

[Tom Hoskinson]

Tom,

Was it very difficult to get the Amidol into solution with glycol? And what was the % solution you mixed. I tried to mix it with TEA once but a lof of the Amidol settled out when the solution cooled.

Sandy

Not very difficult to get most of it into solution. As a test, I heated 200ml of glycol to 140 F then stirred in 8 grams of amidol (magnetic stirrer/hotplate). The color of the solution was a deep Indigo. There was a very small amount of debris (particulates) in the bottom of the beaker that would not dissolve in glycol. I heated the solution to 160F with continuous stirring and the debris still did not dissolve. I cooled and then decanted the solution from the beaker and used it to make a liter of the MAS Amidol paper developer - the developer worked fine.


I then put a few ml of deionized water into the beaker and the debris immediately dissolved - forming a blue liquid. I tested the blue liquid with a small piece of exposed film and the film quickly turned black. Thus, I believe that the debris was just more amidol.

I subsequently (July, 2004) mixed another batch of Amidol/Glycol. I took 400ml of Propylene Glycol, heated it to 140F and stirred in 24 grams of Amidol, again, most of the amidol dissolved, but a small amount of debris remained in the bottom of the beaker. Then I cooled the solution and decanted everything into a 500ml bottle. I use 133 ml of this amidol stock solution (including any debris) together with the other ingredients from the MAS recipe to mix 1 liter of amidol print developer.

I am inclined to try dissolving the remaining debris from this bottle of Amidol stock solution - (in a small amount of water), if the debris dissolve like before, I'll mix a few ml of glycol into it and see how long it lasts before it oxidizes and dies.

If Pat Gainer reads this, I'd like him to comment.

 

[gainer]

I'm off to the dungeon again to see if it would be profitable to separate amidol base from the HCl.

 

[Tom Hoskinson]

Thanks Pat, I eagerly await your report from "The Dungeon!"

 

[sanking]

I'm off to the dungeon again to see if it would be profitable to separate amidol base from the HCl.

I am just not able to get all of the amidol into solution with TEA. In fact, a whole lot of it goes out of solution when the TEA cools down. With the TEA mixed 1:1 with glycol it dissolved much faster, and I don't see any debris on the bottom, even when it cooled down.

Sandy

 

[Tom Hoskinson]

I am just not able to get all of the amidol into solution with TEA. In fact, a whole lot of it goes out of solution when the TEA cools down. With the TEA mixed 1:1 with glycol it dissolved much faster, and I don't see any debris on the bottom, even when it cooled down.

Sandy

Thanks Sandy, that's an interesting piece of information. How much Amidol did you get into the TEA/Glycol solution?

How does your TEA/Glycol/Amidol mixture behave? Have you tried mixing Michael Smith's Azo-Amidol Print Developer recipe with it?

 

[sanking]

Thanks Sandy, that's an interesting piece of information. How much Amidol did you get into the TEA/Glycol solution?

How does your TEA/Glycol/Amidol mixture behave? Have you tried mixing Michael Smith's Azo-Amidol Print Developer recipe with it?

Well, it was an idea, but it does not appear to have worked. The solution appeared fine at first, but then when I mixed it to make a developer I got heavy staining.

Visually the solution now looks thick, muddy, murky and very black.

I await Gainer's report from the dungeon.

Sandy

 

[gainer]

I'm not ready to condemn anyone else to what I did, at least not until I find out if it was worth it. I did some "let's see what happens" experiments with amidol and baking soda, amidol and carbonate and sure enough. these mixtures fizzed to beat the band. I never did see the precipitate I was expecting. Amidol sure makes a strong blue! Before I went to caustic soda I looked up some molecular weights. I figured 2 moles of NaOH to each mole of amidol and scaled it down to 10 grams of amidol and a little more than 8 grams of NaOH. I had a 50% NaOH solution, so I mixed 8 ml of that with the 10 grams of amidol. That was all the water I put in. I got a thick, very dark goo which could have been amidol base and sodium chloride. I'm not sure what else it could be. I added propylene glycol thinking maybe the salt would settle out. It was like trying to get something to settle out of cold Jello. Filter? Forget it. I started to heat it in the microwave to thin it out and immediately blew a fuse. I'm not even sure how to test it to see if it is the amidol base. If it develops film, it might be something else. Would the amidol base, dissolved in glycol, be blue? maybe its the stuff the Celts decorated themselves with before going into battle.

 

[Tom Hoskinson]

"Would the amidol base, dissolved in glycol, be blue?"

Well, the amidol (2,4-diaminophenol dihydrochloride) that I've dissolved in glycol is certainly a very deep dark blue.

Maybe you've done it, Pat.

Then again, maybe you HAVE re-created Woad!

 

[gainer]

After much immature consideration I finally found the light. I think.

Mixing amidol and NaOH in the right proportions gives NaCL, water and amidol base. The salt is of little concern because it will probably not dissolve in TEA or glycol, and if it did, the amount that would show up in the working solution is no greater than would show up in a water solution of amidol. The equation should look like this:

197.07 grams amidol + 80 grams NaOH => 124.14 grams amidol base + 115.9 grams NaCl + 36 grams(ml) water.

I took 10 grams of amidol and added 8.2 ml of my 50% NaOH (4.1 grams NaOH) and stirred the resulting sludge until the lumps were gone. I could see that extra water had appeared. Then I added TEA and 50 grams of pyrocat (i'm out of pyrogal) to make 500 ml. It dissolved with a little heating, enough to turn it from molasses in January to nice sugar syrup consistency.

This is twice the concentration of pyrocatechol in Sandy's Pyrocat developers, IIRC. The result seems to be quite a powerful developer at 1+50 with no sulfite or additional alkali.

There is some sediment at the bottom of the solution, which I would say is just NaCl. I don't think I would want to try to filter it out. I would decant what I want and make new when I get too close to the sediment. Perhaps with the proper filtering equipment it would be feasible.

 

[sanking]

What color was the mixture after you added the TEA and Pyrocat?

And how about fog? Did the negatives have more fog than normal?

Sandy

After much immature consideration I finally found the light. I think.

Mixing amidol and NaOH in the right proportions gives NaCL, water and amidol base. The salt is of little concern because it will probably not dissolve in TEA or glycol, and if it did, the amount that would show up in the working solution is no greater than would show up in a water solution of amidol. The equation should look like this:

197.07 grams amidol + 80 grams NaOH => 124.14 grams amidol base + 115.9 grams NaCl + 36 grams(ml) water.

I took 10 grams of amidol and added 8.2 ml of my 50% NaOH (4.1 grams NaOH) and stirred the resulting sludge until the lumps were gone. I could see that extra water had appeared. Then I added TEA and 50 grams of pyrocat (i'm out of pyrogal) to make 500 ml. It dissolved with a little heating, enough to turn it from molasses in January to nice sugar syrup consistency.

This is twice the concentration of pyrocatechol in Sandy's Pyrocat developers, IIRC. The result seems to be quite a powerful developer at 1+50 with no sulfite or additional alkali.

There is some sediment at the bottom of the solution, which I would say is just NaCl. I don't think I would want to try to filter it out. I would decant what I want and make new when I get too close to the sediment. Perhaps with the proper filtering equipment it would be feasible.

 

[Gerald Koch]

I question the convenience of making an amidol stock solution if its only intended use is to make print developer. A typical print developer contains sulfite, amidol and potassium bromide. Since the sulfite will either be weighed out or measured by volume, why not measure the amidol in the same manner? You've already got the scale out, right. It's practical to use potassium bromide as a percentage solution because we are dealing with a small quantity. Not so for the amidol.

The blue color may be due to a free radical. They typically display intense color. This would be even more likely if the color is discharged when the amidol solution is added to a sufite solution. BTW, the magenta coloration that simple Phenidone solutions take on is due to a free radical.

 

[Tom Hoskinson]

"I question the convenience of making an amidol stock solution if its only intended use is to make print developer."

Minimizing (or eliminating) the exposure to amidol dust and vapor is one reason.

 

[Gerald Koch]

"I question the convenience of making an amidol stock solution if its only intended use is to make print developer."

Minimizing (or eliminating) the exposure to amidol dust and vapor is one reason.

Amidol, being the dihydrochloride salt, does not have any significant vapor pressure. However, the dust could be a problem mainly from staining. The LD50 dose is rather high being 0.789 g/kg which means a 160 lb man would have to ingest 2 ounces. Amidol is therefore less toxic than Tylenol or asprin. Even if we consider long term exposure I would be more concerned with the two analgesics mentioned. Amidol is not currently considered to be carcinogenic and is used as an approved hair dye.

 

[Photo Engineer]

Aniline black is an approved hair dye, and I wouldn't consider ingesting any of it under any circumstances.

We used to use quinone as green ink as well. I shudder when I consider the number of times I have spilled that on my hands as a child or smelled the distinctive odor of green ink.

Gerald, can you cite a reference for that LD50? Thanks.

PE

 

[Tom Hoskinson]

Gerald, considerable vapor (which manifests both as a respiratory irritant and a disagreeable odor) is released when I remove the (screw-on) lid from my amidol storage jar.

This MSDS: http://physchem.ox.ac.uk/MSDS/DI/2,4-diaminophenol_dihydrochloride.html
lists the following amidol Risks:

R20 - Harmful by inhalation
R21 - Harmful in contact with skin
R22 - Harmful if swallowed
R36 - Irritating to eyes
R37 - Irritating to respiratory system
R38 - Irritating to skin

 

[avandesande]

Even if you forget about possible toxicity it is an annoying solid to handle. It is fluffy and sticks to things because of static charge.

 

[sanking]

Even if you forget about possible toxicity it is an annoying solid to handle. It is fluffy and sticks to things because of static charge.

I agree. Amidol is one of the chemials that I least enjoy working with in powder form. It would be a great advlantage IMO to be able to store it in liquid form that would not degrade.

Sandy

 

[gainer]

Things have taken a little turn here, as usual. Sandy wanted to make a solution containing significant amounts of amidol and pyrogallol in TEA. Storing amidol base in glycol or TEA solution seemed a way to do it, but if the main purpose is to have a final soultion like , say, PMK with all necessary ingredients in a concentrated stock including the alkaline activator, and you are hell bent on using amidol in place of metol, then it seemed that getting rid of the hydrochloride would be a good thing to do. That was put there to make amidol base soluble in water, but also made it not so soluble in glycol or similar organic solvents. Now you only have to handle the dreaded powder once or several hundred rolls or sheets of 8x10 film. Gordon Hutchings says to use a pinch of the powder. I presume he is still among the living and ripening normally.

The color of the pyrocat-amidol-TEA-bisulfite solution is very dark brown for all I can tell, but I can't see through more than half an inch of it. If I dilute it 1+1 with more TEA, I still can't see through it. It looks more like coal tar than a couple of coal tar derivatives. If I add 2 grams of sodium sulfite to a liter of 1+50 working solution, it turns to a very light amber color, not even dark enough to tempt anyone to drink it. Along with the color goes the coveted stain.

With only the 10 grams of bisulfite per liter of stock solution, which now is pretty much like Pyrocat M with amidol instead of M and dissolved in TEA, the working solution is somewhat darker when first mixed and rapidly darkens. I developed a test strip of Arista II 100 by the semi-stand method for 21 minutes at 70 F, agitating at 0, 7 and 14 minutes. The negative is very thin by most standards, but has all the detail. So far I have only scanned it, but the scanner loves it. It could have stood 30 minutes, I'm sure, but 35 mm users prefer, or should, low contrast negatives with minimum correct exposure.

I digress, as usual. Anyway, I think the original purpose has been met.

As regards saving amidol for use in paper developer, the same advantage applies of only having to encounter the powder once in a number of liters of developer rather than each time you mix it. I'm not trying to sell it or sell anybody on using it, just pointing out some facts along with a few suppositions.

 

[Gerald Koch]

It is fluffy and sticks to things because of static charge.

Interesting, the amidol that I used some years ago to develop nuclear emulsions was granular and easy to handle. Same for the pyrogallol. I have heard that there is a fluffy form of this too. BTW, by creating a large volume of solution you create the potential problem of spills and the difficulty of cleaning them up. Trading one problem for another. I would be inclined to look around for granular forms of these two chemicals.

LD50 values show a considerable variation, being partly dependent on the animal used (mouse, rat, rabbit, ...). Aldrich Chemical lists that for amidol (rat) as 240 mg/kg; JACTDZ 13,330,1994. Interestingly that for hydroquinone is equal to that for Tylenol, 300 mg/kg. Tylenol being toxic to the kidneys and liver. Doses facit venenum. It is the dose that makes the poison. While we should respect chemicals we should not fear them. I have worked with americium and plutonium, two of the most toxic substances known. I say this not to brag but to make the point that I would have been out of a job had I feared them.

 

[avandesande]

BTW, by creating a large volume of solution you create the potential problem of spills and the difficulty of cleaning them up. Trading one problem for another.

Handling liquids is preferable to handling solids 99% of the time. Any chemist will tell you this.

I would be inclined to look around for granular forms of these two chemicals.

Yeah right. Nobody seems to be able to find it at a reasonable price in any form.

 

[Gerald Koch]

It is fluffy and sticks to things because of static charge.

Interesting, the amidol that I used some years ago to develop nuclear emulsions was granular and easy to handle. Same for the pyrogallol. I have heard that there is a fluffy form of this too. BTW, by creating a large volume of solution you create the potential problem of spills and the difficulty of cleaning them up. Trading one problem for another. I would be inclined to look around for granular forms of these two chemicals.

LD50 values show a considerable variation, being partly dependent on the animal used (mouse, rat, rabbit, ...). Aldrich Chemical lists that for amidol (rat) as 240 mg/kg; JACTDZ 13,330,1994. Interestingly that for hydroquinone is equal to that for Tylenol, 300 mg/kg. Tylenol being toxic to the kidneys and liver. Doses facit venenum. It is the dose that makes the poison. While we should respect chemicals we should not fear them. I have worked with americium and plutonium, two of the most toxic substances known. I say this not to brag but to make the point that I would have been out of a job had I feared them.