from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of various reddish-brown phenolic substances found in the bark of oak, etc.
from The Century Dictionary and Cyclopedia
- n. One of a class of amorphous red compounds, insoluble in water but soluble in alcohol and caustic alkalies, obtained by boiling tannins with dilute mineral acids or caustic alkalies. It occurs also to some extent in the tannin-bearing plants, owing to oxidation by the air. Also called cinchona-red, kino-red, etc.
The phlobaphene-solubilising property of Neradol D is closely connected with the influence of the latter on the colour of leathers tanned with natural tannins.
The varying phlobaphene contents of the tannins easily afford an explanation of the different properties above alluded to: the mangrove phlobaphenes are dark coloured bodies, those of mimosa, maletto, and chestnut are of lighter colour, and the last-named tanning materials enumerated above are either devoid of phlobaphenes or possess them only as very light coloured bodies.
Whereas the colour of leathers tanned with Neradol D only is nearly a pure white, those tanned with mixtures of Neradol D and vegetable tanning materials are more or less light coloured according to the quantity of Neradol D present, as has been explained when discussing the phlobaphene-solubilising action of Neradol D.
In order to determine its phlobaphene-solubilising effects, samplesof the product were mixed with concentrated quebracho extract in the proportions 5,10, 20, and 30 per cent. on the weight of extract, and the following observations made: -- 5 and 10 per cent. were without effect,
In some cases, however, synthetic tannins appear to solubilise natural tannins in concentrated solutions; when, however, the latter are diluted, the natural tannin is precipitated with varying completeness, the reason of which is often the presence of excessive acid or the presence of such salts as have no phlobaphene-solubilising properties.
It is hence clear that the [Greek: b] - sulphonic acid possesses phlobaphene-solubilising qualities greater than those of the [Greek: