Re: Prussian Blue

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

First, thanks to all who responded so far. I read everything with great 

interest. The core of my question, however, relates to the dissociation 

properties of Pressian Blue in warm and acid media. Anyone who can point at 

a relevant graph - like degree of dissociation as a function of pH at 

different temperatures say in the interval 20 to 40 degrees C?



The comment by Ruth (below) is what I am most concerned about and want to 

understand better. The dissociation can be expected to be logarithmic - so 

what is meant by "safe"?.



One question is how much the pH variation may be in gastric juice - the pH 

can go down to _about_ 1.0 but because pH also is a logarthimic function a 

small numerical variation could potentially be important (or just whether 

the individual had something to eat over the previous hours - or even 

something acid to drink...). I am speculating - I don't know - but I also 

want to emphasize the point in my first qustion.



>I wouldn't take Prussian Blue on a bet! In solution there would probably be 

>at least some dissociation to cynanide ion. In acid solution, the Fe(II) 

>would likely oxidize to Fe(III).



My personal comments only,



Bjorn Cedervall    bcradsafers@hotmail.com

http://www.geocities.com/bjorn_cedervall/







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