Methylphenidone instead Phenidone (A)

lamerko

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Hello,

I have been looking at the forum for a long time, and I just registered.
I've been meaning to get back into film photography for a while now, and I've finally decided. I am currently in the process of collecting the missing chemicals, some of which are really hard to get.
I will probably have a lot of questions that I can't find an answer, but I am currently facing a dilemma - I have the opportunity to acquire the following two chemicals:

1. Phenidone - CAS 92-43-3
2. Methylphenidone - CAS 2654-57-1

As far as I understand, the second one is a little more stable, and it will be a little cheaper. However, this form of phenidone is practically not mentioned anywhere - is there any problem with it, and if not - can I make a complete substitution in the formulas and in what ratio?

Pavel
 

Andrew O'Neill

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ArgentixCa said:
As far as I know, methylphenidone is considered a controlled substance (apparented to Ritalin) in several countries.
I would rather go with the regular phenidone.
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Bonjour Jacques! Great seeing you here!
 

john_s

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I had never heard of methyl-phenidone. A search gave a synonym as Phenidone-B (based on the CAS).

Is that an improvement over the original Phenidone?

There are other improvements apparently, Dimezone and Dimezone-S seems to be the latest one.
 

Andrew O'Neill

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cullah said:
methylphenidate is generic ritalin, methylphenedone is not
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I think you are telling the wrong person... I was just saying hi to Jacques
 

john_s

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My understanding is that there are four phenidones, each with a different CAS number:
Phenidone-A (is that the same as the original, common phenidone?)
Phenidone-B
Dimezone
Dimezone-S

This excerpt is from a Ryuji Suzuki article on his last publicly available developers:

"In DS-14, Dimezone S may be substituted with Dimezone, Phenidone B, or Phenidone in decreasing order of desirability. However, preparation of concentrate may face solubility challange with Dimezone or Phenidone B. Phenidone or Phenidone A provides equal image quality, but with inferior solution keeping property. One work-around is to prepare the concentrate with any of these Phenidone derivatives, and add Phenidone or Dimezone immediately before use."

The last sentence is not clearly expressed. He means obviously to add the chosen phenidone just before use, after dilution. I'm not sure if he implies that Phenidone is not the same as Phenidone-A. His articles sometimes had typos.
 

removedacct3

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I'll add some first hand user experience. Yesterday I've mixed another batch of DS-14 using a magnetic stirrer. It took about an hour to dissolve 0.5 gram Dimezone-S in 800 ml of distilled water at room temperature and that was after I crunched it as best as I could using a Patersson cruncher / mixer spoon. Perhaps I could have speed it up a bit by turning on the heating plate. I have opted not to do so as I had all the time in the world and secondly, and more importantly, Ascorbic Acid, also needed for DS-14, already starts to deteriorate at 40 deg Celcius or so. Better safe than sorry ...
 

Anon Ymous

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I have Phenidone (presumably A, unspecified) and Dimezone-S. My Phenidone takes ages to dissolve in water, but dissolves quickly in warm propylene glycol. I mix a 1% solution this way and it keeps very well, in excess of a year. It could be 2 years or more, but I just don't remember... My Phenidone isn't a fine powder, flakes more like. My Dimezone-S, is a very fine powder and dissolves very quickly in water.
 
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john_s

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My Dimezone-S dissolves fairly quickly. It's not a particularly fine powder.
 

removedacct3

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Anon Ymous said:
My Dimezone-S, is a very fine powder and dissolves very quickly in water.
Click to expand...

john_s said:
My Dimezone-S dissolves fairly quickly. It's not a particularly fine powder.
Click to expand...

Thank you for chiming in! I guess the take away is .... sometimes it dissolves quickly and sometimes it does not. Our observations seem to be inline with Ryuji's as he writes "may face solubility challenge".
 

john_s

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One possible variable: I have never dissolved Dimezone-S (or phenidone for that matter) in pure water, it has always usually been in an alkaline developer which has at least sulphite in it and usually carbonate or borax. Some powders dissolve much better in alkaline or acid solutions.

Actually, in the case of Pyrocat_HD Part_A it's acidic (metabisulphite).
 

Anon Ymous

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Good catch, I also dissolved Dimezone-S in alkaline solutions, but it's also likely that I did so with Phenidone too (E6 FD). Phenidone took ages to dissolve.
 
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lamerko

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From my research, I have come to the conclusion that:
1. Phenidone A = the original Phenidone (CAS: 92-43-3) C9H10N2O;
2. Phenidone B = Methylphenidone (CAS: 2654-57-1) C10H12N2O, referred to in the subject;
3. Dimezone C11H14N2O and Dimezone-S C11H14N2O2 are derivatives of Phenidone / Methylphenidone;

Since it is too difficult for me to get Dimezone / Dimezone-S, I settled on the first two. I'll get both though - that way I'll have a comparison
 

pentaxuser

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40C destroys the vitamin C but in terms of why Ascorbic Acid is needed does 40C have any adverse effect on the DS-14?

The reason I ask this is that Andrew O'Neill in his "My 510 Adventures Have Begun" video uses Ascorbic Acid in liquid that must have been way above 40C

pentaxuser
 

albada

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When designing a new developer years ago, I dissolved ascorbic acid into propylene glycol many times at 75C or a little higher, with no apparent adverse effects. Perhaps ascorbic acid slowly deteriorates at high temperatures such that 10-20 minutes of heat does negligible harm.
 

Rudeofus

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@albada Ascorbic Acid is extremely unstable not on its own, but together with an oxidizer like Oxygen. Aparently Oxygen does not dissolve in PG, so you won't have issues at higher temperatures.

@lamerko You can order Dimezone-S from Fototechnik Suvatlar in Germany. The biggest advantage of Dimezone-S is that it is less prone to hydrolyzation in alkaline solution, because the two substituents at the 4 position somehow block access to whatever it is that cracks the open. If you want to keep developer or developer concentrate for months, then Dimezone-S is better than the other phenidones. If you only mix fresh, then plain Phenidone is most likely the cheapest option.
 
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lamerko

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@Rudeofus I looked there recently, but in my haste I didn't notice that they list it as "Hydroxylmethyl-methyl-phenidon". However, the price remains a factor - 20 grams for 21 euros is not profitable if compared to the price of Phenidone. I have already ordered the others, waiting for delivery

About the concentrate - I understand that when dissolved in alcohol (propylene glycol) it is quite stable.
 

Rudeofus

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I have seen the solution in PG go pale yellow to dark yellow over time, so some oxidation does seem to occur. I am too careless in my processing to tell, whether this discoloration affects image results. Yes, Dimezone-S is quite expensive, but since very little is used in developers, effective cost is manageable. If you have very high throughput, then Keten from Poland may be a good source. Their Metol and HQ were dark gray/brown, but I have used them for years to mix my D-72 and it just works. Even if it's not on their current list, they most likely still have Metol/HQ/Phenidone at very good prices.
 
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lamerko

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Finally, today the ordered chemicals arrived. I haven't opened the package yet, but I'll try to do a comparison test between the two tonight
 
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