Phenols vegetables

The formation of humic acid in soil may involve oxidation of phenolic vegetable substances such as tannins while adsorbed on silica. A solution of pyrogallol passed rapidly over silica gel produces brown oxidation products. The silica surface plays a role since it is inactivated by being heated to high temperature or by absorption of Al, Ca, or Mg ions (167). The mechanism of the reaction was examined by Zeichmann (168). 

Inhibition of nitrosation is generally accompHshed by substances that compete effectively for the active nitrosating iatermediate. /V-Nitrosamine formation in vitro can be inhibited by ascorbic acid [50-81-7] (vitamin C) and a-tocopherol [59-02-9] (vitamin E) (61,62), as well as by several other classes of compounds including pyrroles, phenols, and a2iridines (63—65). Inhibition of iatragastric nitrosation ia humans by ascorbic acid and by foods such as fmit and vegetable juices or food extracts has been reported ia several instances (26,66,67). 

Lysol consists of a mixture of the three cresol isomers solubilized using a soap prepared from linseed oil and potassium hydroxide, to form a clear solution on dilution. Most vegetative pathogens, including mycobacteria, are killed in 15 minutes by 0.3—0.6% lysol. Lysol has a phenol coefficient of 2. Bacterial spores are very resistant. Lysol is also the name of a proprietary product, the formula of which has changed over the years other phenols have been substituted for the cresols. 

There are many types, and only the most important can be mentioned here. [See also Hunter, in Dunstan (ed.). Science of Petroleum, vol. 3, Oxford, New York, 1938, pp. 1779-1797.] They are used fairly extensively in treating petroleum distillates, in vegetable-oil, refining, in extraction of phenol-bearing coke-oven liquors, in some met extractions, and the like. Kalichevsky and Kobe (Petroleum Refining... 

More recently, a modification of the system described by Kreibich has been used extensively in industry with good success. Part A of the adhesive is again a standard phenol-resorcinol-formaldehyde (PRF) cold-setting adhesive, with powder hardener added at its standard pH. Part B can be either the same PRF adhesive with no hardener and the pH adjusted to 12, or a 50 to 55% tannin extract solution at a pH of 12-13, provided that the tannin is of the condensed or flavonoid type, such as mimosa, quebracho, or pine bark extract, with no hardener [118,135-137], The results obtained with these two systems are good and the resin not only has all the advantages desired but also the use of vegetable tannins and the halving of the resorcinol content makes the system considerably cheaper [118,135-137]. 

The first plastic was celluloid, made of nitrocellulose softened by vegetable oils and camphor. It was used for car windshields and for movie film. The first completely synthetic plastic was bakelite (1910) produced from phenol and formaldehyde for use in the electrical industry. 

Sulphates, silicates, carbonates, colloids and certain organic compounds act as inhibitors if evenly distributed, and sodium silicate has been used as such in certain media. Nitrates tend to promote corrosion, especially in acid soil waters, due to cathodic de-polarisation and to the formation of soluble nitrates. Alkaline soils can cause serious corrosion with the formation of alkali plumbites which decompose to give (red) lead monoxide. Organic acids and carbon dioxide from rotting vegetable matter or manure also have a strong corrosive action. This is probably the explanation of phenol corrosion , which is not caused by phenol, but thought to be caused by decomposition of jute or hessian in applied protective layers. ... 

The reduction of the stable 1,1 -diphenyl-2-picrylhydrazyl radical (DPPH) has been used to assess the efficiency of antioxidants in beverages (Larrauri et al, 1999 Porto et al, 2000), vegetable oils (Espin et al, 2000) and of pure phenolic compounds (Madsen et al, 2000), reaction [16.17] ... 

Paganga, G. et al.. The polyphenolic content of fruit and vegetables and their antioxidant activities what does a serving constitute Free Radical Res., 30, 153, 1999. Maatta, K.R. et al.. High-performance liquid chromatography (HPLC) analysis of phenolic compounds in berries with diode array and electrospray ionization mass spectrometric (MS) detection Rihes species, J. Agric. Food Chem., 51, 6736, 2003. 

Organophilic polyphenolic materials for oil-based drilling fluids have been described [407], The additives are prepared from a polyphenolic material and one or more phosphatides. The phosphatides are phosphoglycerides obtained from vegetable oils, preferably commercial lecithin. Humic acids, ligno-sulfonic acid, lignins, phenolic condensates, tannins the oxidized, sulfonated, or sulfomethylated derivatives of these polyphenolic materials may serve as polyphenolic materials. 

Herrmann, K. (1979). The possibUity of evidence of adulteration of fruit and vegetable products by means of the phenolic components. Lebensm. Gerichtl. Chem. 33,119-121. 

Tocopherol can be produced as the pure 2R,4 R,8 R stereoisomer from natural vegetable oils. This is the most biologically active of the stereoisomers. The correct side-chain stereochemistry can be obtained using a process that involves two successive enantioselective hydrogenations.28 The optimum catalyst contains a 6, 6 -dimethoxybiphenyl phosphine ligand. This reaction has not yet been applied to the enantioselective synthesis of a-tocopherol because the cyclization step with the phenol is not enantiospecific. 

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