Phenolic components

Approximately 4-6 wt % phenol can typically be recovered following novolac reactions. Free phenol can be removed by washing with water repeatedly. The recovered phenolic components may contain 1,3-benzodioxane, probably derived from benzyl hemiformals (Fig. 1.1) ... 

Most frequently, SEC with dextran-, pullulan-, or polystyrene calibration standards has been used to characterize the molecular properties of xylans. However, as for viscometric studies [108], a sufficient solvent ionic strength is a prerequisite for useful SEC measurements of charged polysaccharides, including glucuronoxylans [111-113]. An advantage of the SEC technique is that the presence of protein and phenolic components or oxidative changes can be detected by simultaneous ultraviolet (UV) detection. 

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. 

Weston, R. J., Mitchell, K. R., and Allen, K. L. (1998). Antibacterial phenolic components of New Zealand manuka honey. Food Chem. 64, 295-301. 

The Concentration of Some Phenolic Components in Roasted Coffee39... 

Rahn, W., Meyer, H. W., Koenig, W.A., Effect of steam treatment on the composition of phenolic components of green and roasted coffee, Z. Lebensm.-Unters. Forsch. 169, 346, 1979. (CA92 40077m)... 

Depolymerization techniques that cleave ester bonds release the indicated aliphatic monomers and phenolic components from suberin. 

This principle of formation proved to be general for quinocyclopropenes of type 61a ( phenylogous cyclopropenones )- The required p-hydroxy-phenyl cyclopropenium cations were available by electrophilic substitution of phenolic components (preferentially 2,6-disubstituted) and heterosubstituted cyclopropenium cations (75 and 109), as the representative examples 11099 11176 112and 113 show ... 

Somers TC and Ziemelis G. 1985. Spectral evaluation of total phenolic components in Vitis vinifera grapes and wines. J Sci Food Agric 36 1275—1284. 

Gollucke APB, Catharino RR, de Souza JC, Eberlin MN and de Queiroz Tavares D. 2008. Evolution of major phenolic components and radical scavenging activity of grape juices through concentration process and storage. Food Chem 112(4) 868—873. 

PHENOLIC COMPONENT SILOXANE BLOCK 1 tTcq2 POLYMER wt % Si3 tTcC)2 ... 

Wood contains a small proportion (usually less than 5%) of components which are extractable by organic solvents such as ethanol or dichloromethane. The proportion of these extractives varies in hardwoods and softwoods and also between species. Although many of these substances are removed during the chemical pulping process, some may still be retained in the final sheet of paper. Their chemical composition is very varied, and they include alkanes, fatty alcohols and acids (both saturated and unsaturated), glycerol esters, waxes, resin acids, terpene and phenolic components. The proportion which remains in pulp and paper depends upon the pulping process used. In general, acidic components such as the resin and fatty acids are relatively easily removed by alkali by conversion to their soluble... 

Finally gallein may be mentioned in it pyrogallol is the phenolic component. 

V. Rastija, A. Mornar, I. Jasprica, G. Strecnik and M. Medic-Saric, Analysis of phenolic components in Croatian red wines by thin-layer chromatography. J. Plan. Chromatogr.—Mod. TLC 17 (2004) 26-31. 

A hydrolysis step is involved in the pulp industry in order to concentrate the cellulose from wood. This uses large-scale processes whereby a liquid fraction, the lignocellulose, is formed as a by-product in the process, and contains high levels of phenolic components and their derivatives. These compounds also constitute an environmental problem due to their possible introduction into rivers, lakes, and/or seas. Chlorophenols from the cellulose bleaching process have traditionally attracted most of the interest in the analysis of industrial waste because of their high toxicity. 

MnP catalyzes hydrogen-peroxide-dependent oxidation of Mn to Mn, which in turn oxidizes phenolic components of lignin [102]. Oxidative demethylation, dechlorination, and decolorization of bleach plant effluent by the MnP of Phanerochaete chrysosporium has been demonstrated [103,104]. 

Dicoumarol Dicoumarol, 3,3 -methylene-bis(4-hydroxycoumarin) (24.1.8), is synthesized from 4-hydroxycoumarine (24.1.7), which is in turn synthesized from salicylic acid methyl ester by cyclization to a chromone derivative using sodium or sodium methoxide or from o-oxyacetophenone by reacting it with diethylcarbonate in the presence of sodium ethoxide. Condensation of the resulting 4-hydroxycoumarin with formaldehyde as a phenol component gives dicoumarol [6-9],... 

The opposite can be observed with acidic analytes as shown in Figure 2.18. Here, with classical RP and methanol at pH 3 the best selectivity and peak shapes were observed. On the other hand, with the shielded phases, acetonitrile gives the best separation. As already discussed, with shield phases the retention of nonpolar components (here peak 6 dimethyl phthalate) is reduced, whereas that of phenolic components (e.g., peak 5 p-hydroxy benzoic acid methyl ester) is increased. 

Krasnov, F.A. et al., Phenolic components of Empetrum nigrum extract and the crystal structure of one of them, Chem. Nat. Compd., 36, 493, 2000. 

The isolation procedure that we have developed involves extracting the leaf tissue with boiling, deionized water, precipitation of phenolic components with lead acetate (Pb0Ac2 3H20) and... 

At higher concentrations, the antioxidant activities of thymol and carvacrol were close to that of a-tocopherol and were in fact responsible for the antioxidant activity of many EOs which contain them [12, 17, 139, 153, 163, 164, 168, 170-174]. The high potential of phenolic components to scavenge radicals might be explained by their ability to donate a hydrogen atom from their phenolic hydroxyl groups [175]. 

Application of Laccase as a Radical Donor in Adhesives for Particle Boards. The properties of laccase with regard to lignin render it a candidate for application in technical processes. A two-component adhesive was formulated with lignin as the phenolic component and laccase as radical donor. The process is described in more detail elsewhere (1). 

In general, a high-molecular-weight phenolic resin is less alkaline-soluble than a low-molecular-weight one. Therefore, these high molecular weight poly(p-vinyl phenol) components may contribute to the decrease in solubility. Furthermore, we assume that the etching type dissolution of these resists is non-fractional, as was previously shown in the case of poly (methyl methacrylate-co-acrylonitrile) (15). 

On the other hand, in Japan, Sang-Bai-Pi (the root bark of Chinese mulberry tree) imported from China has been used as an herbal medicine, hence a study of the components of this crude drug purchased in the Japanese market was undertaken. Its phenolic components are different from those of Japanese mulberry tree. For example, morusin (3) and kuwanon G (1) are the main phenolic components of Japanese mulberry tree, in the case of Sang-Bai-Pi , these components are minor ones, while sanggenons A (4) [16], C (5) [17], and D (33) [61] are the main components [24]. Sanggenons C (5) and D (33) showed the hypotensive effects as follows Sanggenon C (5) caused transient decrease in arterial blood pressure at the doses of 1 mg/kg in pentobarbital-anesthetized rabbit by 15 mm Hg, while at the doses of 5 mg/kg the compound (5) caused a transient decrease by 100 mm Hg, which continued for more... 

Table IV gives the Rf values determined under these conditions. Figure 3 shows the chromatograms of the reaction products of the re-esterification of a number of plasticizers. It is obvious that the method is suitable for identifying the alcohol components of all frequently used ester types. Difficulties have been met with phenolic components although they are present primarily in phosphoric acid esters. To identify these, evaporate to dryness a few drops of the reaction mixture of an alkaline saponification and mix this with a bit of the precipitated alkali salt. Add this residue to 10 to 20 drops of chloroform and gradually evaporate it repeat...

There is evidence684,685,685 for the attachment of phenolic components (ferulic and coumaric acids) both to / -(l— 4)-linked D-galactose and a-(l— 3)-linked L-arabinose in the primary cell-wall, suggesting feruloylation-coumaroylation of pectic neutral side-chains. Earlier papers686-688 had also suggested the attachment of these phenolic compounds to primary-wall polysaccharides which remained uncharacterized. 

Recently, an extensive review of fruit phenolics was given by Van Buren (128). The available literature indicates that a tremendous amount of research effort has been applied to phenolic components of fruits, particularly grapes and their important role in winemaking and quality. 

There is an intriguing and unanswered question what contribution did this phenolic component make to the nature of the observed effects of TMA Assays on the isolated contaminant could answer that, but they have not yet been made. 

Fry SC. 1982. Phenolic components of the primary cell wall. Feruloylated disaccharides of D-galactose and L-arabinose from spinach polysaccharide. Biochem J 203 493-504. 

Solinas, M. (1987). HRGC analysis of phenolic components in virgin olive oil in relation to the ripening and the variety of olives. Magn. Resort. Chem. 64, 255-262. 

The addition of smoke to meat also imparts antioxidant properties (42). This has also been shown on application of smoke to fatty fishes (43). Porter ( 6) has reviewed the antioxidant properties of smoke and concluded that a number of phenolic compounds are responsible. Several of these phenolic components, including phenol, guaiacol and catechol, are not only potent antioxidants but also have antibiotic activity. 

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