dave321
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iron gall ink b.s.3484 1962
ok , although the above british standard may have been withdrawn / replaced, my question is in the quoted formula below, what would be the equivalent
to 0.3g of sulphuric acid (s.g. 1.84) if replaced by Hydrochloric acid ~36% ?
grams per 100 ml
gallic acid 0.64
tannic acid 1.95
sulphuric acid (s.g.1.84) 0.3
ferrous sulphate heptahydrate 2.5
phenol 0.1
blue dye,aniline blue 0.3
distilled water to 100ml
hydrochloric acid is preferable because of the gaseous nature of the hcl when drying which is lost from the paper.
residual sulphuric acid can cause paper degredation.
the above is equivalent to 5g of iron per litre.
[Edited on 6-1-2018 by dave321]
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OldNubbins
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FeSO4 + 2HCl -> ?? + ??
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dave321
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yes, iron chloride formation also works in this ink complexing to form the gallotannate complex
but how much hcl to use, forgive me, I am no chemist, not in this area anyway
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SWIM
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There's always that old folk rhyme:
If muriate in thine ink instead of vitriol must be
Then multiply ye volumme bye three.
I am sometimes amazed at all the things they used to have rhymes about.
Seriously, 3 times the volume will give you about the same number of acidic hydrogens, but the extra water and the fact it's a different acid might
make some difference as far as I know.
Is this something you read somewhere, or something you're just trying out as a test?
Edit: I see the solution is diluted to a known volume at the end, so at least the extra water doesn't matter.
[Edited on 6-1-2018 by SWIM]
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dave321
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I would like to make a test batch up using hydrochloric acid.
its supposed to be more friendly on the paper, if there is excess acid present, since the hcl is essentially volatile as it were.
any excess sulphuric acid tends to hang around on the paper, eventually leading to problems, so I think hydrochloric is preffered from what ive read
on the subject.
using the quoted composition, it certainly gives a great colour change on paper right before your eyes, from blue to very dark blue- black just as in
the old style writing inks, and of course its is very permanent, no washing out or anything
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OldNubbins
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FeSO4 + 2HCl -> FeCl2 + H2SO4
As long as you have FeSO4 in solution, you will generate H2SO4 by adding HCl
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dave321
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oh, so that idea may not work then
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OldNubbins
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https://books.google.com/books?id=UM1BAQAAMAAJ&pg=PA975#...
Alkaline gall ink from the 1930's used to address concerns over acidic inks.
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unionised
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One reason that the reaction goes the other way (compared to how you have written it) is that HCl is volatile.
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OldNubbins
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Would that bring me back to SWIM's comment (multiply ye volumme bye three) and require additional HCl to drive the reaction forward as it evaporates
leaving a mix of FeSO4 and FeCl2?
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