Quebracho extract

Quebracho extract Quenching Quenching oils Quercetin... 

Tannins occur in many plants and are separated by extraction. At present, only quebracho extract is used as a mud thinner in significant quantity in the United States. Quebracho is an acidic material and performs best at high pH. It is an excellent thinner for lime-treated and cement-contaminated muds. However, it is not effective at high salt concentrations. Sulfomethylated tannin products are functional over a wide range of pH and salinity and have either been treated with chromium for good thermal stabiUty (58) or are chrome free. Concentrations of tannin additives are ca 1.5—18 kg/m (0.5—6 lb/bbl). 

Pit charcoal Pitch, wood Pyroligneous acid Quebracho extract Quercitron extract Rosin, produced by distillation of pine gum or pine wood... 

Styphnic Acid. 2,4,6-Trinilro-l,3-benzenediol 2,4,6-trinitroresorcinol 2,4 -dihydrixy -1,3,5 -trinitrobenzene, C(H,N,Ot mo] wt 245.11. C 29.40fv, H 1.23%, N 17.14%, O 52.22%. May be prepd from natural sources, such as Pernambuco wood extract or quebracho extract by the action of nitric acid Einbeck, Jablonski, Ber. 54, 1086 (1921). Prepd industrially by first sulfonating, then nitrating resorcinol Merz, Zetter, Ber. 12, 681, 2037 (1879) Datta, Varma, J. Am. Chem. Soe. 41, 2043 (1919). Prepd by nitrating 2,4-di. nitroresorcinol Kametani, Ogasawara, Chem. Pharm. Bull IS, 893 (1967). 

Inhibitors. Sodium nitrate has already been mentioned as a practical inhibitor for steel exposed to boiler waters. Crude quebracho extract and waste sulfite liquor are also used. Buffer ions, such as PO, are useful because they avoid high concentrations of OH in concentrated boiler water. In accelerated tests, the addition of 3% NaCl or 2% sodium acetate to boiling 60% Ca(N03)2 + 3% NH4NO3, at 108°C was found to inhibit cracking (>200 h) [21] of mild steel. 

Quebracho Extract. An extract of tannin from the S. American tree Quebracho Colorado. It has found some use, particularly as sodium tannate, as a deflocculant for pottery slips. 

Angelinetti A R, Cantera C S, Sofia A, Martinez J 1978 Rapid tanning of shoe leather using a quebracho extract. Rev Tech Ind Cuir 70(8) 237-240... 

QUEBRACHO EXTRACT. Contains quebracho alkaloids and tannen. In limited laboratory tests, quebracho extract caused mild attack (- 4 mpy) of 3003 alloy at 204°C (400°F). 

Another approach to the prevention of caustic cracking involves maintenance above a certain value of the ratio of sodium sulfate to alkalinity in the boiler water. If chemically treated water is used along with condensate as the feed water, then the ratio of d plus 804 " to NaOH should be no less than five. Excessive alkalinity may be reduced by neutralizing with H2SO4 and then using an ion-exchange resin to free the water of excess alkalinity by replacing Na" " ions with H ions. The most widely accepted chemicals for the prevention of caustic embrittlement are the nitrate ion and quebracho extract. The amount of nitrate used is critical and must be 35 to 40% of the total alkalinity, calculated as NaOH. 

It i employed as a pretanning agent for heaw leathers that are to be subjected to vegetable tarmii, because it accelerates penetration of the vegetable tannins . Teiy rapid tannage is reported w hen skins pretanned with formaldehyde are treated with quebracho extract and borax. After... 

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