Chlorophenolate ions

The equilibrium constant for formation of 4-chlorophenyl acetate from 4-chlorophenolate ion and acetyl 4-methylpyridinium ion is given by ... 

Dichlorodibenzo- -dioxin. 2-Bromo-4-chlorophenol (31 grams, 0.15 mole) and solid potassium hydroxide (8.4 grams, 0.13 mole) were dissolved in methanol and evaporated to dryness under reduced pressure. The residue was mixed with 50 ml of bEEE, 0.5 ml of ethylene diacetate, and 200 mg of copper catalyst. The turbid mixture was stirred and heated at 200°C for 15 hours. Cooling produced a thick slurry which was transferred into the 500-ml reservoir of a liquid chromatographic column (1.5 X 25 cm) packed with acetate ion exchange resin (Bio-Rad, AG1-X2, 200-400 mesh). The product was eluted from the column with 3 liters of chloroform. After evaporation, the residue was heated at 170°C/2 mm for 14 hours in a 300-cc Nestor-Faust sublimer. The identity of the sublimed product (14 grams, 74% yield) was confirmed by mass spectrometry and x-ray diffraction. Product purity was estimated at 99- -% by GLC (electron capture detector). 

Kuo, C. and Genthner, B., Effect of added heavy metal ions on biotransformation and biodegradation of 2-chlorophenol and 3-chlorobenzoate in anaerobic bacterial consortia, Appl Environ Microbiol, 62 (7), 2317-2323, 1996. 

Renberg [35] used an ion-exchange technique for the determination of chlorophenols and phenoxy acetic acid herbicides in soil. In this method the soil extracts are mixed with Sephadex QAE A-25 anion exchanger and the adsorbed materials are then eluted with a suitable solvent. The chlorinated phenols are converted into their methyl ethers and the chlorinated phenoxy acids into their methyl or 2-chloroethyl esters for gas chromatography. 

Photolytic. Under artificial sunlight, river water containing 2-5 ppm chlorobenzene degraded to phenol and chlorophenol. The lifetimes of chlorobenzene in distilled water and river water were 17.5 and 3.8 h, respectively (Mansour et al, 1989). In distilled water containing 1% acetonitrile exposed to artificial sunlight, 28% of chlorobenzene photolyzed to phenol, chloride ion, and acetanilide with reported product yields of 55, 112, and 2%, respectively (Dulin et al., 1986). 

The preferential sorption-capillary flow mechanism of reverse osmosis does that. In the NaCl-H20-cellulose acetate membrane system, water is preferentially sorbed at the membrane-solution Interface due to electrostatic repulsion of ions in the vicinity of materials of low dielectric constant (13) and also due to the polar character of the cellulose acetate membrane material. In the p-chlorophenol-water-cellulose acetate membrane system, solute is preferentially sorbed at the interface due to higher acidity (proton donating ability) of p-chlorophenol compared to that of water and the net proton acceptor (basic) character of the polar part of cellulose acetate membrane material. In the benzene-water-cellulose acetate membrane, and cumene-water-cellulose acetate membrane systems, again solute is preferentially sorbed at the interface due to nonpolar... 

In particular, the priority pollutant phenols (PPP), identified by EPA since the 1970s are widespread water pollutants that must receive the greatest attention due to their recognized toxicity. For the separation of eleven PPP, an ion-interaction reagent (HR) RP HPLC/UV method has been developed that allows limits of detection lower than 30 J,g in river waters, after LLE in dichlo-romethane and a 500-fold pre-concentration [82]. Through on-line SPE followed by both UV and electrochemical detection [83], 16 priority phenols have been determined in water samples with the LOD value for chlorophenols lower than 1 ng L [84]. LODs at ng L levels were obtained for all the PPPs in samples of river water, employing a relatively small volume of sample through an on-line SPE HPLC/MS method with an APCI source. 

Thus far, SPME methods have had only limited success in isolating polar organics (e.g., chlorophenols [30] and formaldehyde [31]) or ions [32,33] from aqueous mixtures. However, the tunable hydrophobicity and multimodal potential interaction chemistries of ILs suggest potential applications in LPME. Further, their high viscosity coupled with their minimal vapor pressure promotes stable droplet formation. Figure 5.2 illustrates the experimental setup for LPME. In addition, analyte recovery can be performed simply by injecting the droplet onto a liquid chromatographic column. 

It should be recognized, however, that dioxins also occur naturally, from forest fires (trees contain chloride ions) and the action of peroxidase enzymes on chlorophenols. 

When 5 moles of benzene and 1 mole of II competed in concentrated sulfuric acid for the nitronium ion, the nitration of the first ring proceeded about 300 times faster than the nitration of benzene (Table II). Similarly the nitration of II proceeded about 150 times faster than that of toluene and comparable to that of p-chlorophenol. 

The mass spectra of DNS derivatives of chlorophenols [192] and hydroxybiphenyls [194] have been recently reported, and intense ions similar to those from the amine derivatives were observed at m/e 170 (Fig.4.73). 

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