Jacques,
Practice trumps theory. I have also read in several authoritative
sources that bromide does not restrain phenidione. I can only
conclude that the studies that came to this conclusion were based on
formulas in which phenidone was compared on its own or in
superadditive formulas involving a reducer other than pyrocatechin.
Regardless of theory the addition of a small amount of phenidone in
the Pyrocat-HD formula has a significant restraining impact on
phenidoine.
However,there is more. I have also experimented with using restrainer
in asuperadditive combination of ascorbic acid + phenidone, and
bromide restrains the phenidione in this formula as well. So much for
the books.
However, benzotriazole will also work. In fact, it is an even more
effective restrainer than bromide in the Pyrocat-HD formula. You will
need to use quite a bit less of it than bromide to get the same
effect, perhaps as little as 1/10 the amount, but in the end both
will work just as well.
Sandy King
>First I would like to thanks Sandy King for his fine work on the Pyrocat-HD
>Formula. We are always looking for the Holy Grail of developers, I think
>Sandy is one step from reaching it. I have some questions, but for the sake
>of simplicity I will ask them one at a time.
>
>The restrainer is potassium bromide, but as experience says and textbooks
>also, that with phenidone it should be benzotriazole. Not that the formula
>doesn' t work, on the contrary, my question is what would happen if we used
>benzotrialoze instead of potassium bromide? Of course some one will say why
>don't you try? Pertinent and logical question, but if some one has already
>invented the wheel why have all the trouble.
>Thanks,
>Jacques
Received on Tue Jul 20 07:58:31 2004
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