Phenolic fraction

In the case of low temperature tar, the aqueous Hquor that accompanies the cmde tar contains between 1 and 1.5% by weight of soluble tar acids, eg, phenol, cresols, and dihydroxybenzenes. Both for the sake of economics and effluent purification, it is necessary to recover these, usually by the Lurgi Phenosolvan process based on the selective extraction of the tar acids with butyl or isobutyl acetate. The recovered phenols are separated by fractional distillation into monohydroxybenzenes, mainly phenol and cresols, and dihydroxybenzenes, mainly (9-dihydroxybenzene (catechol), methyl (9-dihydtoxybenzene, (methyl catechol), and y -dihydroxybenzene (resorcinol). The monohydric phenol fraction is added to the cmde tar acids extracted from the tar for further refining, whereas the dihydric phenol fraction is incorporated in wood-preservation creosote or sold to adhesive manufacturers. Naphthalene Oils. Naphthalene is the principal component of coke-oven tats and the only component that can be concentrated to a reasonably high content on primary distillation. Naphthalene oils from coke-oven tars distilled in a modem pipe stiU generally contain 60—65% of naphthalene. They are further upgraded by a number of methods. 

Ghiselli, A. et al.. Antioxidant activity of different phenolic fractions separated from an Italian red wine, J. Agric. Food Chem., 46, 361, 1998. 

Biological monitoring for exposure to phenol is possible by measuring blood or urine levels of the parent compound. However, it should be noted that phenol and metabolites of phenol may also come from other sources. For example, phenol is a metabolite of benzene and of protein metabolism. Urine samples taken from male workers employed in the distillation of high-temperature phenolic fractions of tar revealed a phenol excretion rate of 4.20 mg/hour compared to a control rate of 0.53 mg/hour for non-exposed workers (Bieniek 1994). Samples were taken 4 hours into the workers workday, but the worker exposure levels were not reported. 

Bieniek G. 1994. Concentrations of phenol, o-cresol, and 2,5-xylenol in the urine of workers employed in the distillation of the phenolic fraction of tar. Occup Environ Med 51 354-356. 

Pool PL, Lin PZ. 1982. Mutagenicity testing in the Salmonella typhimurium assay of phenolic compounds and phenolic fractions obtained from smokehouse smoke condensates. Food Chem Toxicol 29 383-391. 

Anti-implantation effect. Chloroform extracts of the dried leaf, twig, and stem, administered intragastrically to pregnant rats at a dose of 0.58 g/kg for 10 days, were active. The phenolic fraction, at a dose of 0.52 g/kg and methanol extract at a dose of 0.70 g/kg, were active. Water extract, at a dose of 1 g/kg and petroleum ether extract at a dose of 0.38 g/kg, were inactive Anti-tumor activity. Water extract of the dried root, administered intraperitoneally to mice at a dose of 400 mg/kg, was inactive on Leuk (friend virus-solid) and Leuk-L1210. A dose of 500 mg/kg was inactive on sarcoma 180(ASC) - . 

Moree- Testa, P., M. Donzel, M. H. Bergerol, and M. M. Luzinier. Determination of pyridinic and pyrazinic compounds in tobacco and cigarette smoke. Ann Tab Sect 1974 1(12) 27. Richter, M. Composition of essential oils in tobacco. III. Analysis of phenolic fraction. Ber Inst Tabakforsch (Dresden) 1974 21 52. 

OE074 Balic, V., and O. Cera. Acidic phenolic fraction of the juice of olives de- OE086 termined by a gas chromatographic method. Grasas Aceites (Seville)... 

Sample preparation is included in sample handling and is rapidly becoming a science in itself. The initial treatment of the sample is a critical step in chemical and biochemical analyses it is usually the slowest step in the analysis. In the case of food and plant samples, the number and diversity of analytes is very high and efficient pretreatment is required to obtain enriched phenolic fractions. 

Blanchard, L., Darriet, P., and Dubourdieu, D. (2004). Reactivity of 3-mercaptohexanol in red wine Impact of oxygen, phenolic fractions, and sulfur dioxide. Am.. Enol. Vitic. 55, 115-120. 

Methods of analysis are needed to determine total phenolic content and the relative content of phenolic fractions by means of their different characteristics. Many analytical methods used for phenols have been empirical and not easily reproduced or rationalized (I). Procedures that are based on sound chemical principles and that are sufficiently verified deserve wider application. We are concerned here with recent work on such analyses for phenols in wines. Application cf these results may help solve a major problem in phenol research—the many different, too empirical, unrelatable values (ml KMn04, vanillin-to-leucoantho-cyanin ratio, etc.) obtained in different ways by different researchers. Uniform use of verified methods and uniform standards and methods of expressing results will aid in developing an understanding in this field. 

Hydroxy derivatives of benzofuran are also found in the phenolic fractions of shale oil tar such compounds are formed by thermal ring closure of phenol ethers with unsaturated side chains.113-115 2-(4-Methoxyphenyl)benzofuran has been isolated in small amounts from the depolymerization products of some tars (in the presence of phenol).114,115... 

CK Shu, BD Mookherje. Volatile components of the phenolic fraction of cooked bacon. J Agric Food Chem 33 1107-1109,1985. 

A Ghiselli, M Nardini, A Baldi, C Scaccini. Antioxidant avtivity of different phenolic fractions separated from Italian red wine. J Agric Food Chem 46 361-367, 1998. 

Sanchez-Monedero, M. A., Roig, A., Cegarra, J., and Bernal, M. P. (1999). Relationships between water-soluble carbohydrate and phenol fractions and the humification indices of different organic wastes during composting. Bioresource Technol. 70,193-201. 

We found that the ether and ethyl acetate extracts of chicory roots exhibited the best nematicidal activities. The extracts were separated according to their acidity to give organo-acidic, phenolic, basic and neutral fractions. The phenolic fraction was found... 

Table I. Phenolic Fraction (GPC Fraction 3 From SO2 - Solubles)...

We had shown that it was possible to extract both A9-THC and ll-hydroxy-A9-THC from plasma with toluene. The next question was the problem of lipophiles. Again we found that in order to remove interferences to A9-THC determinations it was necessary to fractionate the toluene extract with Claisen s alkali in order to obtain the phenol fraction of plasma. We found that the extractions of A9-THC from toluene with Claisen s alkali is not quantitative, but it is reproducible. The loss of A9-THC in this reaction however, is compensated for by removal of interferences which were the limiting factors in the single extraction step. 

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