Gearhead_Shem_Tov
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Kino and kinotannin
I collected about a kilo of the blood-red kino from a eucalyptus tree a few weeks ago here in South Australia, and for the past few days I've had
about a third of the mass sitting in a jar with enough methylated spirits to cover. I was hoping to dissolve the sticky mass thereby, but it seems to
be going very slowly, at least at ambient temperature. It's been unseasonably cool this summer, so ambient has been between 14 and 25C for that time.
I fancy I'm seeing a slight amber tinge to the methylated spirits, but it doesn't look as if any appreciable amount will dissolve any time soon. I
want to separate kinotannic acid from from kino, which supposed to be soluble in alcohol, but I guess the question to ask is which alcohol?
Should I try straight methanol instead? If it would appreciably dissolve in meths, I would prefer that rather than methanol (cheaper).
I'm trying to do this because I want to see if I can produce an iron-gall ink using the stuff (oak galls being fairly scarce down under). Would a
test with ferric chloride show the presence of kinotannic acid as (I read) it would for gallotannic? Would I be looking for a darkly coloured
precipitate if it does work?
-Bobby
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Boffis
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If Kino is a tannin then it will not be soluble in alcohol. You are better of extracting it with water to leave behind any resins and oils. It may
then be possible to precipitate the tannins by adding an equal volume of alcohol (ethanol but IPA might work too) this would leave the sugars in
solution. When you try to evaporate down aqueous solutions of tannins you always get a sticky mass, its very hard to dry without industrial vacuum
spray driers or similar.
Yes the ferric chloride test will work but may not give the expect blue black because difference source of tannin have different constitutents. Gall
nut tannin for instance is composed of sugar molecules attached to gallic acid (3,4,5 trihydroxybenzoic acid) while in the tannin called "cutch" the
main acid is 3,4 dihydroxybenzoic acid.
On the site library there is a book on the preparation of dye intermediated and it contains a detailed description of the preparation of gallic acid
and its amide from gallnut tannin. I have tried a modified version to extract 3,4 dihydroxybenzoic from cutch and gallic acid from winemakers tannin
with excellant results. The pure acids produce the same colours with ferric chloride asa the original tannin.
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Gearhead_Shem_Tov
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Quote: Originally posted by Boffis  | If Kino is a tannin then it will not be soluble in alcohol. You are better of extracting it with water to leave behind any resins and oils. ...
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Well, I am getting more amber colour in the meths, now, so maybe it is working. More reading has also told me that kinos are widely variable as to
their solubility in water; most seem to need at least hot water
| Quote: | | On the site library there is a book on the preparation of dye intermediated and it contains a detailed description of the preparation of gallic acid
and its amide from gallnut tannin. |
Great! I check that out. I've since learned that kinotannin might not make the best iron gall ink. It seems it makes an impermanent greenish ink
that fades to a rusty stain. But I still want to try it.
| Quote: | | I have tried a modified version to extract 3,4 dihydroxybenzoic from cutch and gallic acid from winemakers tannin with excellant results.
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I think I've read that cutch is similar to kino. Did you also try to make ink with it?
-Bobby
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Boffis
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No I haven't tried making ink but it gives a dark greenish black colour with ferric chloride which might indicate that kino tannins are catechuic acid
sacchrides like cutch.
I haven't tried the ammonia hydrolysis of cutch yet but it looks like an interssting route to 4 substituted catechol derivatives that are normally
difficult to produce due to the ease with which catachol (1,2 dihydroxybenzene) oxidizes.
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