Phenidone + paRodinal - a bit of an obscure chemistry question.

pdeeh · Aug 8, 2014

I just saw a photograph of a graduate filled with a mixture of Phenidone, paRodinal and water - the resultant mixture being a rather interesting shade of green.

I didn't quite believe it, and as I have all three to hand I tried it myself - yep, green.

Now I have no particular interest in trying this out as a developer or whether there is any rationale for mixing these two agents, but I am interested to know what's happened that the combination is green.

if we can keep the explanation at "Chemistry for Little Folk" level that would be nice as I stopped studying it as a school subject in 1974

(my paRodinal contains paracetamol, Potassium hydroxide, Sodium sulfite and Sodium metabisulfite, by the way)

pdeeh · Aug 8, 2014

Whenever I've mixed Phenidone and water, I've immediately got a slightly pink solution using my tap water, but then what you see as orange I may see as pink.
The paRodinal is a deep amber undiluted and a pinkish-orange )) in solution.

I realise I've asked a trivial question bordering on the absurd, but the colour change was so marked it has tickled my "why bone" ...

Xmas · Aug 8, 2014

Hi

If you take a pinch of Phenodine powder and drop it on a damp surface like hand wash basin surface do you get orange or pink?

Noel

pdeeh · Aug 8, 2014

Hang on, I'm just reading Mason ...

pdeeh · Aug 8, 2014

Mason 2nd Edition 1975, p84:

LFA Mason said:
If attempts are made to oxidise past the pyrazolone stage, in alkaline solution, a series of highly coloured products are obtained, the colour of the product being very dependent upon the pH. These colours are obtained very easily by subjecting solutions of Phenidone in various alkaline buffers to prolonged aerial oxidation. It has been shown in the author's laboratory that these solutions of coloured oxidation products can be separated into several coloured components by various applications of the technique of chromatography. The predominant species are deep red and bright blue, but a yellow compound is also present in large amounts at high pH values.138g These coloured compounds have also been observed by Keiler23 and by Willems and Van Veelen114 all of whom suggest that they are further inter-mediate oxidation products.

Of course this is preceded by several pages of stuff I haven't a clue of understanding, and if the pyrazolone stage came and bit me on the ankle I wouldn't know what it was, but as Michael suggested it looks like it's oxidation and pH related

pdeeh · Aug 8, 2014

I expect it'll be over 11

Photo Engineer · Aug 8, 2014

A number of developing agents turn green upon oxidation. HQ itself oxidizes into Quinone which is very intense green. It is so intense, it was used as green ink at one time. Anyhow, I have seen a number of different solutions turn green and if I chased down the chemistry of each one, I would never get anything done!

PE

pdeeh · Aug 8, 2014

But PE, I thought your sole function now in life was to write up detailed responses to ludicrous questions posed at APUG ?

Better still, I could send you samples of my tap water, Phenidone and paRodinal and you can do a full analysis for me

Photo Engineer · Aug 8, 2014

Please ask easier questions!

MattKing · Aug 8, 2014

Photo Engineer said:
Please ask easier questions!

Isn't that just like Umut's new APUG signature?

Photo Engineer · Aug 8, 2014

Oh, yeah.

But, I have been thinking about this question and realize that staining developers give yellow green stains for the same reason. Quinones form and they are green. Many developers turn yellow green on keeping and the list goes on and on due to the nature of many of the organic chemical bonds involved.

Eventually, carried to completion, you get a black tar!

PE

Alan Johnson · Aug 9, 2014

In my experiment with phenidone +sodium hydroxide the green color only appears if sodium sulfite is also added, see the result after ~18hrs in an open container.
Without sulfite it goes yellow.

Phenidone + paRodinal - a bit of an obscure chemistry question.

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