Phenolic acids INDEX

Dr. Joe Vinson of the University of Scranton believes that there is something to the chocolate effect, and he came to Belmont to tell us about his intriguing research. Vinson has determined the total polyphenol content of various chocolates and has also found a way of measuring how effective these mixtures are in preventing the oxidation of human ldl in a test tube. In other words, he has calculated a phenol antioxidant index, which takes into account both the quantity and the quality of these desirable substances. At the symposium Vinson reported that cocoa powder and dark chocolate are the best, followed by milk chocolate. Instant cocoa mixes trail the field. Then Vinson delivered the kicker chocolate has more, and better, polyphenols than fruits or vegetables and more than red wine. A forty-gram bar of dark chocolate has as many polyphenols as a cup of that widely promoted antioxidant cocktail we call tea. But there is still the matter of chocolate s fat content. Researchers tell us, though, that at least half of it is stearic acid, which does not raise blood cholesterol. 

The total polyphenol index is obtained by diluting the wine and measuring its absorbance at 280 nm. The index is given as the absorbance multiplied by the dilution factor (100 in the case of red wines). This test does not take into account the colorless chalcone forms of anthocyanins (Figure 3) nor the phenolic acids that absorb at 230 nm, though these compounds are present in such small quantities that they contribute little to the overall polyphenol content. 

The Colour Index (up to June 1991) Hsts 21 direct violets with disclosed chemical constitutions. Commercially important are Cl Direct Violet 9 [6227-14-1] (79) (Cl 27885) (sulfanihc acid coupled to cresidiue followed by alkaline coupling to V-phenyl J-acid) and Cl Direct Violet 66 [6798-03-4] (80) (Cl 29120) (a copper complex of 2-arniao-l-phenol-4-sulfonarnide (2 mol) coupled to 6,6 -imiQobis-l-naphthol-3-sulfonic acid). 

The reaction mixture is heated and allowed to reflux, under atmospheric pressure at about 100°C. At this stage valve A is open and valve B is closed. Because the reaction is strongly exothermic initially it may be necessary to use cooling water in the jacket at this stage. The condensation reaction will take a number of hours, e.g. 2-4 hours, since under the acidic conditions the formation of phenol-alcohols is rather slow. When the resin separates from the aqueous phase and the resin reaches the requisite degree of condensation, as indicated by refractive index measurements, the valves are changed over (i.e. valve A is closed and valve B opened) and water present is distilled off. 

Examples of the protection of alkynes, carboxylic acids, alcohols, phenols, aldehydes, amides, amines, esters, ketones, and alkenes are also indexed on p. xvii. Section (designated with an A 15A, 30A, etc.) with protecting group reactions are located at the end of pertinent chapters. 

This group has examples of many types of acids derived from aliphatic, aromatic and heterocyclic radicals, with carboxylic, phenolic or sulfonic or related functional substituents. Individually indexed acids are ... 

Table I. Index of ozone injury to foliage of 12 peanut cultivars and total plant phenol expresses "a % caffeic acid equivalents in assay...

A widespread method for determining the induction period for autoxidation of oils and fats consists of passing a continuous stream of air through the heated sample and collecting the volatile acids evolved in a water trap, where they are determined on a real time basis. The time plot usually presents a flat appearance for a certain period and then takes off in an accelerated manner. This test is the basis of several national and international standards (e.g. AOCS Cd 12b-92—oil stability index" ISO 6886—accelerated oxidation test for oxidative stability of fats and oils ) and the design of the Rancimat equipment, where the end determination is based on conductivity measurements . In addition to oxidation stability as determined by the Rancimat method and POV, which negatively affects virgin olive oil stability, other nonstandard properties were proposed for better assessment of the quality of this oil, namely LC determination of Vitamin E (21), colorimetric determination of total polar phenols and UVD of total chlorophyll. ... 

The Surlyn A ionomers (E. I. du Pont de Nemours Co.) are believed to be derived from copolymers of ethylene with minor amounts of methacrylic acid which are treated subsequently, so that substantial amounts of the carboxylic acid are converted to the sodium or other metal carboxylate. Resins similar to the one studied in this work contain about 10 weight % methacrylic acid. The ash (sodium carbonate) indicates about 40% neutralization. This resin, which contains 0.05% Santo-white Powder (Monsanto Chemical Co.), a phenolic antioxidant, is of medium molecular weight—i.e., probably corresponding to an ethylene homopolymer with a melt flow index around 20 (17). The molecular weight distribution is broad (17). 

To improve the solubility of polyimides, Korshak and co-workers used l,l-dichloro-2,2-bis(4-aminophenyl)-ethylene as the starting nucleophile [17] (Scheme 3.2). The resulting polymers turned out to be of relatively high molecular weight (r = 1.2-1.4 dl/g), heat resistant > 270 °C) and fire resistant (oxygen index (OI) = 36-39) (Table 3.2). Polypyromellitimide was soluble in H2SO4 only, but polyimides based on the dianhydrides of benzophenone-3,3, 4,4 -tetracarboxylic acid and diphenyloxide-3,3, 4,4 -tetracarboxylic acid were also soluble in w-cresol and a trichloroethane (TCE)/phenol (3 1) mixture. Diphenyloxide-3,3, 4,4 -tetracarboxylic acid was soluble even in N-methyl-2-pyrrolidone (NMP) (Scheme 3.2). 

The distillate may contain volatile neutral compounds as well as volatile acids and phenols. Add a slight excess of 10-20 per cent sodium hydroxide solution to this distillate and distil until it is judged that all volatile organic compounds have passed over into the distillate. If necessary, the determination of the refractive index of the distillate or the application of specific chemical tests (e.g. for carbonyl compounds use the 2,4-dinitrophenylhydrazine reagent) should be used to confirm completion of distillation. Keep this distillate (S,) for Step 4. 

Mononitradlazochlorobenzoquinone, CgH2ClN303 mw 203.5 6,N 20.64%. Only one isomer is known 4-/Vitro-2-diazo-6 cbloro-o-benzoquinone [ called Chloronitrodiazophenol inCA35, 7716(194 1) not found in CA Formula Index( 1920-5 6)] [called 6-Chlor-4-nitro-o-chinon-diazid-(2) or 6-Chlor-4 -nitro 2 di azo-phenol in Ger], brn-red scales (from ale), mp explodes vigorously above 100° sol in coned H2S04 from which soln it is pptd by addn of w diffc sol in ale, eth or hot w was first prepd by Griess(Refs 1 2) by passing nitrous acid fumes thru a warm ale soln of 4-nitro, -6-chloro-2-aminophenol. This compd when mixed... 

Examples of alkylation, dealkylation, homologation, isomerization, and transposition are found in Sections 1, 17, 33, and so on, lying close to a diagonal of the index. These sections correspond to such topics as the preparation of acetylenes from acetylenes carboxylic acids from carboxylic acids and alcohols, thiols, and phenols from alcohols, thiols, and phenols. Alkylations that involve conjugate additions across a double bond are found in Section 74 (alkyls, methylenes, and aryls from olefins). 

Fumed silica A-200 (Pilot plant at the Institute of Surface Chemistry, Kalush, Ukraine specific surface area Ascorbic acid (vitamin C) and all-rac-a-Tocopheryl acetate (vitamin E acetate) were used as adsorbates. Folin-Ciocalteu s phenol reagent (Merck) was used to measure the total polyphenolic index. Silica samples with different degree of surface silylation were obtained using gas-phase chemical modification of highly disperse silica (A-200) surface by trimethylchlorosilane.6... 

Antioxidant activity of silica nanocomposites with immobilized vitamin C was tested using the polyphenolic activity index.8 After adsorption of ascorbic acid on the silica surface and centrifugation, the excess solution was removed to obtain the suspension of a fixed volume (2 ml). Distilled water, sodium carbonate solution, and Folin-Ciocalteu s phenol reagent were subsequently added to suspensions and to the reference Vitamin C solution. The suspensions were then stored for 30 min, and the optical density of supernatant was measured at X = 750 nm. The reference solution of ascorbic acid was used to compare antioxidant activity of vitamin-containing nanocomposites with the activity of dissolved vitamin C. 

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