Oak-bark

Compound CAS Registry Number Piae bark Oak bark Spmce bark... 

Leayes.—Of the foliage of trees containing tannin, very few, if any, are now employed in the manufacture of leather. The leaves of the heath were once extensively used in tins country but this material has long been abandoned, preference being given to oak barks and other substances of native and foreign growth,... 

Compound CAS Registry Number Pine bark Oak bark Spruce bark... 

The gallic acid used in the preparation of 1,2,3-benzenetriol can be obtained by microbial degradation of tannins, which are complex combinations of glucose and gallic acid obtained from oak bark and gallnuts. A few other representatives of the many types of naturally occurring derivatives of polyhydric arenols are... 

Fig. 27.15. AOA of water (A) and alcohol (B) herb extracts obtained by photometric and potentiometric methods. Herb extracts samples (1) Haw (2) Juniper fetus (3) Acorus calamus rhizome (4) Dandelion roots (5) Oak bark.

Suberins. The cork cells in the outer bark contain polyestolides or su-berins. The suberin content in the outer layer of the cork oak bark (cork) is especially high and amounts to 20-40% in the periderm of birch bark. Polyestolides are complicated polymers composed of co-hydroxy monobasic acids which are linked together by ester bonds. In addition, they contain a,/3-dibasic acids esterified with bifunctional alcohols (diols) as well as ferulic and sinapic acid moieties. The chain lengths vary but suberins are enriched with molecules having 16 and 18 carbon atoms. There are also double bonds and hydroxyl groups through which ester and ether cross-links are possible. The outer layer of the epidermis contains so-called cutin, which is heavily branched and has a structure similar to suberin. 

For many years, most of the leather in the United States was tanned with domestic tannins from hemlock and oak bark and from chestnut wood. Today only a small amount of tannin comes from these and other domestic sources. The most important source of vegetable tannin today is the wood of the quebracho tree, which grows mainly in Paraguay and Argentina. The tannin content of this tree and a few other sources of vegetable tannin are shown in Table 28.10. 

A mixture of nitroglycerine, oak bark, and sodium or potassium nitrate. Was used in Germany and England as a permissible explosive. 

Others, however, clearly did use botanical subsitutes. Through interviews with aged Confederate surgeons, Joseph Jacobs was able to present a valuable picture of dmg conditions in the South during the war and how they coped with shortages.39 One surgeon used red oak bark added to water as a disinfectant, slippery elm as an emollient, may apple and strong teas of peach tree leaves as laxatives, and for... 

Querci-tannic Acid.— Another tannic acid, probably also a catechu-tannic acid, as it yields the same products as above, is known as querci-tannic acid. It derives this name from Quercus, the generic name for the oak tree, as it is found in oak bark, but not, however, in oak galls. 

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