Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Treated with tannins

Internal use is in the treatment of catarrh of the stomach and as an antidiarrheal. Not all tannins are suitable for all uses. In the treatment of large burns, tannins are absorbed in such large quantities that they can cause serious damage to the liver. That is the reason why large burns are not treated with tannin solution any more. [Pg.81]

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). [Pg.180]

A second Hud of tannin is produced whan indigo or similar compounds rich in carbon, are treated with nitric acid, as In (he foregoing method., A very bitter, orange-colored residue is obtained, which is soluble In water,... [Pg.498]

One hundred milliliters of a 0.001% solution of tetrachloroauric (III) acid (or silver nitrate) in distilled water ia treated with several drops of 1% sodium carbonate 10-hydrate and heated to boiling in a flask. Every 30 seconds one drop of a fresh 1% tannin solution (XJ.S.P.) is added with agitation. When a deep red gold color has formed (or yellow-brown to red-brown for the silver) the colloidal solution is cooled and stabilized by the addition of a few milliliters of chloroform or toluene. [Pg.272]

Clarke s Propellants. There were two varieties a)Smokeless cannon propint, patented in Apr 1868, which was prepd by treating woodpulp (previously impregnated with tannin or alum, and then dried) with mixed nitric-sulfuric acid. Then the resulting NC was separated from acid, washed with w (contg some Na carbonate or bicarbonate), impreg-... [Pg.109]

Volatile Acidity.—50 or 100 c.c. of the beer, freed from carbon dioxide and treated with a little tannin, are distilled in a current of steam until acid no longer passes over (usually 100—200 c.c. of distillate are collected), the distillate being then titrated with decinormal alkali hydroxide in presence of phenolphthalein. The result is expressed as grams of acetic acid per 100 c.c. of the beer (1 c.c. N/10-alkali —0006 gram ofjacetic acid). [Pg.168]

Stannous tannin solution is treated with 10 c.c, of a concentrated solution of stannous chloride in... [Pg.332]

Sugars may be tested for with Fehling s solution in the tannin solution treated with lead acetate and then with sodium sulphate and subsequently inverted. Since, however, tanning materials generally contain a certain quantity of reducing sugars, addition of glucose cannot always be proved by a mere qualitative test,... [Pg.336]

About 6o c.c. are then collected separately in a flask this should be colourless, or almost so, and a few drops of it, treated with a solution of gelatine and sodium chloride (or with some of the initial distillate, which contains a small quantity of gelatinous substances and is a good reagent for the detection of tannin), gives no turbidity. [Pg.342]

Further, an aqueous solution of the colouring matter may be treated with basic lead acetate (a basic colouring matter should first be precipitated with tannin), the excess of lead eliminated, the liquid filtered and the sugars tested for or determined saccharimetrically or with Fehling s solution. [Pg.439]

Basic mordant colouring matters (gallocyanin, etc.), if treated with salted caustic soda and then with formic acid, behave like basic colouring matters, except that they are extracted less completely. The acid extracts give with tannin a finer and less distinct precipitate. To distinguish them from ordinary basic colouring matters use is made of the fact that they are precipitated by chromium fluoride. [Pg.492]

The procedure for this test consists basically of three sequential treatments of the lignified tissue with 1% potassium permanganate, 3% hydrochloric acid (Note 1), and concentrated ammonium hydroxide. A small amount of wood meal or wood slices is placed on a watchglass or microscope slide and immersed in a 1% potassium permanganate solution for 5 min at room temperature. The solution is discarded and the sample is washed twice with water and then treated with a 3% hydrochloric acid solution until the color turns from black or dark brown to light brown. If necessary, additional hydrochloric acid may be added to facilitate discharge of the dark color. The hydrochloric acid solution is discarded, and the sample is washed twice with water. On subsequent treatment with concentrated ammonium hydroxide, a red-purple color develops for hardwoods and some tannins, and a brown color for softwoods. [Pg.29]

Applications for cold-setting, wood-laminating adhesives initially followed the same approach (47) used for laminating resins from western hemlock (38) (i.e., reaction of tannin with phenol-resorcinol-formaldehyde prepolymers). Improvements resulted through the application of Kreibich s Honeymoon technique (48) wherein one side of the material to be bonded is treated with resin and the other with catalyst. One of the preferred systems (49) was phenol-resorcinol-formaldehyde or tannin-resorcinol-formaldehyde at pH 8 with extra paraformaldehyde on the A-side and tannin at 53% solids or tannin-resorcinol-formaldehyde at pH 12 on the B-side. Such resin systems are currently used to laminate eucalyptus or pine in most South African timber-laminating plants. [Pg.167]

Tannin test When a neutral or acetic acid solution of a vanadate is treated with an excess of 5 per cent tannic acid, a deep blue (or blue-black) colouration is obtained. If ammonium acetate is present, a dark-blue (or blue-black) precipitate separates. The precipitate or colouration is destroyed by mineral acids. [Pg.529]

We will perform one of the two bioassays dealing with tannins in insect diet The compounds to be tested (tannic acid) are mixed into diet in varying concentrations. We measure how much chow the caterpillar has consumed and whether the effect is concentration dependent. (The second bioassay - in Chap. 19 - employs the Leaf disk lest. In this often used bioassay leaf sections of a standard size are treated with the compounds in question.)... [Pg.102]

We will perform the Leaf disk test, also known as leaf disk assay or leaf disk choice test, the second of two bioassays of tannins in the diet of insects in this book. In this often used bioassay, leaf sections of a standard size are treated with the compound(s) in question. Several circular leaf sections ( leaf disks ) (Ali et al. 1999, Filho and Mazzafera 2000, Shields et al. 2008, Wheeler and Isman 2000) or cellulose membrane filters (Hollister and Mullin 1999, Larocque et al. 1999) are presented to a caterpillar in a choice experiment. We measure how much chow the caterpillar has consumed and whether any feeding inhibition is concentration dependent. Regardless of what compounds are being tested, leaf disk tests serve as an important tool in bioassaying feeding inhibitors and stimulants in insects. The cited references are examples of such studies. (In the first tannic acid experiment - Chap. 18 - the tannic acid was mixed into diet in varying concentrations.)... [Pg.106]


See other pages where Treated with tannins is mentioned: [Pg.7]    [Pg.4]    [Pg.416]    [Pg.12]    [Pg.383]    [Pg.7]    [Pg.4]    [Pg.416]    [Pg.12]    [Pg.383]    [Pg.384]    [Pg.545]    [Pg.216]    [Pg.269]    [Pg.520]    [Pg.352]    [Pg.176]    [Pg.311]    [Pg.493]    [Pg.496]    [Pg.613]    [Pg.620]    [Pg.19]    [Pg.308]    [Pg.793]    [Pg.161]    [Pg.347]    [Pg.425]    [Pg.23]    [Pg.250]    [Pg.2014]    [Pg.106]    [Pg.114]    [Pg.192]    [Pg.151]    [Pg.167]   
See also in sourсe #XX -- [ Pg.246 , Pg.247 , Pg.248 , Pg.249 , Pg.250 ]




SEARCH



Tannins

© 2024 chempedia.info