Tannins quebracho

Antifoams to reduce the risk of carryover employed emulsions of castor oil and similar substances. Caustic embrittlement was avoided by the use of quebracho tannins, chile niter (sodium nitrate), and salt cake (sodium sulfate), which was later discredited as an inhibitor. 

Carbon dioxide is absorbed first using a potassium hydroxide solution. Oxygen is the next gas absorbed, using pyrogallol (the same oxygen scavenger produced from quebracho tannins). The glass absorption chamber also contains steel wool as a catalyst. 

Yeasts. An interesting paper published in 1984 (59) claimed that rat-caecal microflora degraded catechin. To our knowledge no paper has dealt with yeasts, other than that some yeasts degrading wattle of quebracho tannins were able to grow weakly with catechin as a sole carbon source (32). 

Salawu, M.B., Acamovic, T., Stewart, C.S., Hovell, F.D.DeB. and McKay, I. (1997) Assessment of the nutritive value of Calliandra calothyrsus in sacco degradation and in vitro gas production in the presence of Quebracho tannins with or without Browse Plus. Animal Feed Science Technology 69, 219-232. 

The profisetinidins are the most important proanthocyanidins of commerce, making up the major constituents of wattle and quebracho tannins. New entries are collated in Table 11.8. 

Figure 4. Binding of a protein (hemoglobin) to several tannin extracts (tannic acid, sugar maple tannins, yellow birch tannins, quebracho tannins see 29) at various pH values. Ranges of microbial chitinase activity, NPV activity, and Bt toxicity are given. See text for discussion and references.

Table 10. Contents of low molecular weight (LMP) and high molecular weight (HMP) phenolic derivatives in aerial parts of typical plant species from an exposed grassland slope of the northern Andes to 2100 m asl. LMP amounts are in mg equiv of salycilic acid g w/w and HMP are in mg equiv of quebracho tannin g w/w. Unusually large amounts may be due to differences in oxidation potential relative to the standard. Errors are one SD. Data from Alonso-Amelot et al. 2005.

Vivas, N., Nonier, M.F., and Vivas De Gaulejac, N. (2004). Structural characterization and analytical differentiation of grape seeds, skins, steams and Quebracho tannins, Bull. O.I.V., 883-884,643-659. 

In the case of some tannins, namely quebracho tannin, a third reaction of importance is present,... 

Comparative gel times (s) of Acacia mangium tannin, commercial mimosa tannin and quebracho tannin at different pH levels... 

As regards the tannin origin by location, the areas of strong industrial production today are Brazil, South A ica, India, Zimbabwe, Tanzania for mimosa tannin Argentina for quebracho tannin Indonesia for mangrove and for cube Gambier tannins and Italy and Slovenia for chestnut tannin. Tha-e are many other small to very small producers a bit everywhere, for example, small pine tannin factories in Turkey and Chile, an oak tannin factory in Poland and a grape pip tannin factory in France. 

In the case of some tannins (e.g. quebracho tannin) a third important reaction occurs, namely the simultaneous hydrolysis of some interflavonoid bonds, hence a depolymerization reaction, partly counteracting and thus slowing down the hardening process [12, 42, 43]. 

In general, tannins are used to depress dolomite, calcite, and quartz. The depressing performance of quercus tannin in the flotation of bornite and quartz using, respectively, xanthate and oleic acid as collector is shown in Fig. 4.1. The depressing performances of quebracho tannin and willow tannin in the flotation of cassiterite and quartz are shown in Fig. 4.2. 

Fig. 4.2 Depressing performance of willow and quebracho tannins in the flotation of quartz and cassiterite...

The profisetinidins have been studied intensively by Roux s school at The University of the Orange Free State, Bloemfontein, South Africa. The heartwoods of Acacia mearnsii and Colophospermum mopane contain a series of 2R isomers and these compounds have all been synthesized (Tables 7.6.9 and 7.6.10). The commercially important quebracho tannins from Schinopsis and Rhus contain a series of 2S isomers and these compounds have also been synthesized recently. Fifteen dimers, nine trimers, and nine tetramers have now been thoroughly de-... 

These results also imply that the Acacia baileyana polymer is of relatively low molecular weight, as significant proportions of Type 2 polymer is retained on Sephadex LH-20 after elution with methanol-water, when wattle or quebracho tannin is subjected to similar separations (L. J. Porter, unpublished observations). 

The leather-tanning industry of India used about 120000 tons of assorted vegetable tannins in 1970 (203). India imported about 25000 tons of wattle extracts to supplement domestically available tannins such as myrobalan nut tannins (3500 tons/year) and wattle tannins (2000 tons per year). Vegetable tannins (primarily mixtures of chestnut, wattle, and quebracho tannins) are also used widely in Italy (173). In the Peoples Republic of China, much of the leather manufactured is made using vegetable tannins. Research efforts are being accelerated on the use of tannins from indigenous plants such as Larix and Firms spp. (Sun and Foo, personal communication 1986). 

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