3-Chlorophenol, fractionation

Dichlorodibenzo-p-dioxin was prepared from isotopic potassium 2,4-dichlorophenate uniformly labeled with Ullman conditions gave a 20.5% yield. Small amounts of dichlorophenoxy chlorophenol were removed from the product by extraction with sodium hydroxide before purification by fractional sublimation and recrystallization from anisole. Chlorination of 2,7-dichlorodibenzo-p-dioxin in chloroform solution containing trace amounts of FeCls and 12 yielded a mixture of tri-, tetra-, and pentachloro substitution products. Purification by digestion in boiling chloroform, fractional sublimation, and recrystallization from anisole was effective in refining this product to 92% 2,3,7,8-tetrachloro isomer, which also contained 7% of the tri- and 1% of the penta-substituted dibenzo-p-dioxin. Mass spectroscopy was used exclusively to monitor the quality of the products during the synthesis. 

Uniformly labeled 2,4-dichlorophenol- C (purchased from New England Nuclear Corp, Boston, Mass.) was used in the tracer preparation. This provided a label at all carbon positions in the dibenzo-dioxin structure. 2,7-Dichlorodibenzo-p-dioxin- C after initial cleanup by fractional sublimation, contained approximately 5% of an impurity, detected by thin layer chromatography (TLC) which gave mass peaks at 288, 290, 292, and 294 in the mass spectrometer, consistent with a trichloro-hydroxydiphenyl oxide. This is probably the initial condensation product of the Ullman reaction and is most likely 2-(2,4-dichlorophenoxy)-4-chlorophenol. It was removed easily by extractions with aqueous... 

Fig. 54. Specific refractive index increments at constant composition (o) and constant chemical potential ( ) for solutions of nylon-6 in 2,2,3,3-tetrafluoropropanol/l-chlorophenol binary mixtures, is the volume fraction of l-chlorophenol and filled circles refer to the two pure single solvents161)...

The present paper deals with a relation between toxicity and accumulation of chlorophenols in goldfish, Carassius auratus, PCP metabolites and their amounts excreted by the three major routes (branchial, renal and biliary) in the fish, and also with effects of pre-exposure to PCP on PCP-tolerance and on sulfate conjugation with phenol by the liver soluble fraction of the fish. 

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. 

The only other effect possibly attributed solely to humic acid involved 2,4-dichlorophenol, the most broadly distributed compound tested in this study. In columns 108 and 109, the humic acid apparently decreased the ease of elution of the chlorophenols because lower overall recoveries were obtained from column 109, which included the humate, than from column 108, which was humate-free. Also, recovery was detected in F6 of column 109 but not in F6 of column 108. This result suggests that humate enhanced binding of the phenol to the column. The reproducibility of 2,4-dichlorophenol recovery among the various parfait fractions was poor, as illustrated by the results from replicate columns 117, 118, and 120. Because of the variability, the differences in... 

Organochlorine pesticides (OCP), acid herbicides, chlorophenols Florisil Hexane, dichloromethane Fractionation... 

The reaction mixture is then distilled in vacuum through a fractionating column. At a pressure of 20 mm., the o-chlorophenol goes over at 75-90°, the para isomer at 110-115°. About 130 grams of o-chlorophenol (25 per cent) and 320 grams of p-chlorophenol (62 per cent) are obtained. 

Bulk matrix removal aims to remove material such as lipids which can disturb final analysis. This can be performed by acid treatment of the extract or by liquid-solid chromatography. Alumina fractions of chlorophenol extracts have been purified with concentrated sulfuric acid [37,38] and it has been used to remove lipid and organic coextractives in sediment, biota, and human extracts [33,43,57,58,113,114,120,122-125]. The sulfuric acid treatment of PCDEs has been reported not to affect their recoveries [58]. 

Activated alumina (260 °C) column has been used for isolation of PCDEs, PCDDs, and PCDFs from chlorophenol extracts [37,38]. Four fractions were collected from an alumina column (50 g) petroleum ether (400 ml), 5% ethyl ether in petroleum ether (200 ml), 25% ethyl ether in petroleum ether (400 ml), and ethyl ether (400 ml). PCDEs, PCDDs, and PCDFs were determined in the third and fourth fractions after sulfuric acid cleanup. 

FIGURE 14.1.2.1.1 Logarithm of mole fraction solubility (In x) versus reciprocal temperature for 2-chlorophenol. 

Bromine (200 g., 1.25 moles) is slowly added with stirring to a solution of 150 g. (1.17 moles) of o-chlorophenol in 4 volumes of carbon tetrachloride. (Hood.) The mixture is allowed to stand overnight, and the solvent is then removed by distillation. Fractional distillation... 

Laboratory experiments on sorption have shown that even over a short period of time sorption may be irreversible or exhibit hysteresis illustrative examples are provided by chlorophenols in sediment fractions (Isaacson and Frink 1984), naphthalene and... 

Tris[3-tert-butyl-4-(hydroxybenzyl)]mesitylene (III) was synthesized starting from 2-fert-butyl-6-chlorophenol, which in turn was prepared by the method of Kolka et al. (10). The 2-ferf-Butyl-6-chlorophe-nol was alkylated with a1,a3,a5-(trihydroxyhexamethyl)benzene (Aldrich) with the use of boron trifluoride etherate catalyst (II). A mixture of I and II was obtained, separated by fractional crystallization from methyl-cyclohexane. The structures of the two products were assigned on the... 

Chlorophenol is obtained by use of S02C12 as follows 447 Molar amounts of phenol and S02C12 are mixed at room temperature and the mixture is set aside until reaction sets in with lively evolution of S02 and HC1. After this, the mixture is warmed on the water-bath until gas evolution ceases, then washed with sodium carbonate solution, dried by CaCl2, and fractioned. The product, obtained in almost 100% yield, has b.p. 216-218° and m.p. 37°. 

Chlorophenol [95-57-8] M 128.6, m 8.8 , b 61-62°/10mm, 176 /760mm, pK 8.34. Pass 2-chlorophenol at least twice through a gas chromatography column. It has also been purified by fractional distillation. 

Figure 4.12 Removal of aqueous 4-chlorophenol for various size fractions of Degussa P25. Data presented refer to reduction of 4-chlorophenol only. For details on further reactions of 4-chlorophenol on Degussa P25, see [38],...

Dichlorophenol is produced by chlorination of phenol in a polar solvent such as water or acetic acid at temperatures from 70 to 80 °C to minimize further chlorination (when using non-polar solvents with an excess of chlorine, 2,4,6-tri-chlorophenol is the main reaction product). The crude product is purified by fractional distillation. West European production of 2,4-dichlorophenol is around 20,000 tpa. 2,4-Dichlorophenol is used mainly to produce 2,4-dichlorophenoxy-acetic acid (2,4-D), first used as a herbicide in 1942 and obtained by the reaction of 2,4-dichlorophenol and monochloroacetic acid at 80 to 100 °C and a pH value of 7 to 11. 

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