Extraction chlorinated phenol

With suitable adjustments to the temperature, also subcritical water extraction (SWE) or pressurised hot water extraction (PHWE) allows selective extraction of polar (chlorinated phenols), low-polarity (PCBs and PAHs) and nonpolar (alkanes) organic compounds from industrial soils [418]. 

Microwave extractions such as that illustrated in Procedure 12.4 have been used to extract chlorinated biphenyls, phenols, sulfonylurea herbicides, and triazines from soil [7,9,13,15],... 

Tee et al. [15] described an acetone-hexane extraction procedure followed by electron capture gas chromatography for the determination of down to lpg kg-1 chlorinated phenols in sediments. 

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. 

Lee [42] determined pentachlorophenol and 19 other chlorinated phenols in sediments. Acidified sediment samples were Soxhlet extracted (acetone-hexane), back extracted into potassium bicarbonate, acetylated with acetic anhydride and re-extracted into petroleum ether for gas chromatographic analysis using an electron capture or a mass spectrometric detector. Procedures were validated with spiked sediment samples at 100,10 and lng chlorophenols per g. Recoveries of monochlorophenols and polychlorophenols (including dichlorophenols) were 65-85% and 80-95%, respectively. However, chloromethyl phenols were less than 50% recovered and results for phenol itself were very variable. The estimated lower detection limit was about 0.2ng per g. 

Kapila et al. [501] used an on-line SFE-LC to determine chlorinated phenols in wood chips over the concentration range 1-500 mg/kg. Following the extraction, the sample was loaded into a sample loop of the HPLC and chromatographed using a conventional packed LC column and UV detector. 

Supercritical C02 has also been tested as a solvent for the removal of organic contaminants from soil. At 60°C and 41.4 MPa (6,000 psi), more than 95% of contaminants, such as diesel fuel and polychlorinated biphenyls (PCBs), may be removed from soil samples (77). Supercritical C02 can also extract from soil the following hydrocarbons, polyaromatic hydrocarbons, chlorinated hydrocarbons, phenols, chlorinated phenols, and many pesticides (qv) and herbicides (qv). Sometimes a cosolvent is required for extracting the more polar contaminants (78). 

The chlorinated phenol and chlorinated biphenyls were not measured in the humic portion of the experiment because of losses from the base extraction procedure. b Caffeine data are from Experiment 2. c Insufficient data were obtained for ANOV procedure. 

M. H. Liu, S. Kapila, K. S. Nam and A. A. Elseewi, Tandem supercritical fluid extraction and liquid chromatography system for determination of chlorinated phenols in solid matrices ,/. Chromatogr. 639 151-157 (1993). 

Many of the analytical procedures for pentachlorophenol in the recent literature do not call for a hydrolysis step prior to extraction of a urine sample. During the course of our research in the development of a reliable multi-residue procedure for chlorinated phenols, we found that much more pentachlorophenol could be extracted from the urine if the sample was hydrolyzed with hydrochloric acid (23). 

Although the GC separation of methyl ethers [16] of phenols has been described, these derivatives are nowadays mainly employed only in special instances, e.g., for increasing the sensitivity of the analysis. The determination of chlorinated phenols in spent bleach liquors from paper mills was reported by Lindstrom and Nordin [17]. A water sample was extracted stepwise with diethyl ether at various pH values, after preliminary purification by means of HPLC, phenols were converted into ethyl ethers by reaction with diazoethane in isooctane—ethanol (9 1) and good reproducibility was achieved. 

As shown in Fig. 9.1.2, the phenolic fraction of a bleach plant E, effluent contains not only chlorinated phenols but also fatty acids and their esters, and even n-alkanes. The latter two classes of compounds probably are carry-over extractives from the wood during pulping or, in part, originate from defoaming agents added to the pulping liquor. 

Zhou Q-X, Liu J-F, Jiang G-B, Liu G-G, and Cai Y-Q. Sensitivity enhancement of chlorinated phenols hy continuous flow liquid membrane extraction followed hy capillary electrophoresis. J. Sep. Sci. 2004 27 576-580. 

The characterization of water-soluble components in slurries is one use of SPME with mixed solid-liquid samples. In one application, dried homogenized solid samples (10 mg of sewage sludge or sediment) were slurried in 4 ml of H,0 saturated with NaCl and adjusted to pH 2 with HCl for extraction for 1-15 h, which was followed by desorption into 4 1 methanol/ethanol over 2 min. The extracted compounds were either injected into a liquid chromatograph or fed directly via an electrospray ionization interface to a mass spectrometer with 1 s miz scans from 50-700 or selected-ion monitoring. The major components extracted included phthalates, fatty acids, non-ionic surfactants, chlorinated phenols and carbohydrate derivatives [235]. 

Pulp and paper mill sludge is a complex and changeable mixture of dozens or even hundreds of compounds. Some are well known, like natural wood extractives, organochlorines, organosulfides, and dioxins. Priority pollutants and chemicals of concern that must be analyzed in pulp mill residues include heavy metals, chlorinated hydrocarbons, chlorobenzenes, PAHs, chlorinated phenols, chlorinated catechols, chlorinated guaiacols, phthalates, resin acids, alkylphenols and alkylphenol ethoxylates, and plant sterols. 

Chlorinated phenolic compounds in air-dried sediments collected downstream of chlorine-bleaching mills were treated with acetic anhydride in the presence of triethylamine. The acetylated derivatives were removed from the matrix by supercritical fluid extraction (SEE) using carbon dioxide. The best overall recovery for the phenolics was obtained at 110°C and 37 MPa pressure. Two SEE steps had to be carried out on the same sample for quantitative recovery of the phenolics in weathered sediments. The SEE unit was coupled downstream with a GC for end analysis . Off-line SEE followed by capillary GC was applied in the determination of phenol in polymeric matrices . The sonication method recommended by EPA for extraction of pollutants from soil is inferior to both MAP and SEE techniques in the case of phenol, o-cresol, m-cresol and p-cresol spiked on soil containing various proportions of activated charcoal. MAP afforded the highest recoveries (>80%), except for o-cresol in a soil containing more than 5% of activated carbon. The SEE method was inefficient for the four phenols tested however, in situ derivatization of the analytes significantly improved the performance . 

A study was carried out for LEE by the Soxhlet method and microwave-assisted extraction for the determination of the priority phenols in soil samples. Recoveries varied from 67 to 97% with RSD between 8 and 14% for LEE, and >70% for the MAP, except for nitrophenols that underwent degradation when the latter method was applied. LOD was from 20 ngg for 2,4-dimethylphenol to 100 ngg for pentachlorophenol. The best detection method for EC was atmospheric pressnre chemical ionization MS (APCI-MS). The most abnndant ions obtained by this detection method were [M — H] for the lowly chlorinated phenols and [M — H — HCl] for tri-, tetra- and pentachlorophenols . 

Another method is extraction with methylene chloride followed by derivatization with pentafluorobenzyl bromide or diazomethane and snbseqnent GC/ECD or GC/FID analysis . The extraction solvent has to be changed before analysis. More than 50 substituted phenols have been derivatized successfully with Af-(f-butyldimethylsilyl)-Af-methyltrifluoroacetamide by forming the corresponding f-bntyldimethylsilyl derivatives. This study includes 21 chlorinated phenols, 13 nitrophenols, 3 aminophenols, 4 alkylphenols, o-phenylphenol, some other substitnted phenols inclnding 6 phenolic pesticides and the nonsnbstitnted phenol. Using SPE with polymeric adsorbents and GC/MS, phenols with very different substituents can be detected in environmental samples with high matrix content at the ppt level . 

OTHER COMMENTS used as a flame retarder and plasticizer in chlorinated rubber, nitrile rubber and resins used in coatings and adhesives based on plasticized cellulose esters used as a gasoline additive to control pre-ignition useful as a solvent in the extraction of phenol fi om gas-plant effluents and coke-oven wastewaters use as a synthetic lubricant, a waterproofing agent, a primary component of adhesives, and as an intermediate in the synthesis of pharmaceuticals. 

Extraction has to be continued until all lichen substances are dissolved (6-60 h). Often heavily soluble compounds precipitate in the extract and can be removed by filtration. One way to work up the extract is separation in an acid, a phenolic and a neutral part, by shaking successively with a solution of NaHCOj (10% in H2O) and NaOH (2% in HjO). Some compounds, e.g. chlorinated phenolics, are soluble in a solution of Na2C03 (5% in H2O). Shaking should be continued for 10-15 min. Another way is chromatography of the extract over silica gel. The ratio of product to adsorbent is about 1 30 to 1 50, and an approved sequence of eluents is n-hex-ane-diethyl ether-methanol. Many extracts are heavily soluble in n-hexane to overcome this difficulty, the mixture is dissolved in a proper... 

Add 0 2 ml of 30 per cent sodium hydroxide solution to each 0 1 g of chlorinated phenol in a platinum crucible. When solution is complete add 5 g of sodium carbonate and mix well. Dry carefully by means of a small flame and then raise to full heat for ten minutes. Extract the chloride in the re sidue w ith w ater and determine bv the Volhard method (p. 290). 

Today the sulphonation route is somewhat uneconomic and largely replaced by newer routes. Processes involving chlorination, such as the Raschig process, are used on a large scale commercially. A vapour phase reaction between benzene and hydrocholoric acid is carried out in the presence of catalysts such as an aluminium hydroxide-copper salt complex. Monochlorobenzene is formed and this is hydrolysed to phenol with water in the presence of catalysts at about 450°C, at the same time regenerating the hydrochloric acid. The phenol formed is extracted with benzene, separated from the latter by fractional distillation and purified by vacuum distillation. In recent years developments in this process have reduced the amount of by-product dichlorobenzene formed and also considerably increased the output rates. 

Extraction, employs a liquid solvent to remove certain compounds from another liquid using the preferential solubility of these solutes in the MSA. For instance, wash oils can be used to remove phenols mid polychlorinated biphenyls (PCBs) from die aqueous wastes of synthetic-fuel plants and chlorinated hydrocarbons from organic wastewater. 

Johnson and Van Emon [57] have described a quantitative enzyme based immunoassay procedure for the determination of polychlorinated biphenyls in soils and sediments and compared the results with those obtained by a gas chromatographic method. The soil is extracted with methanol, or Soxhlet extracted or extracted with a supercritical fluid. In the case of the latter two extractants good agreement was obtained between immunoassay and gas chromatographic methods. Spiking recoveries from soil achieved ranged from 104% (Aroclor 1248) to 107% (Aroclor 1242). Detection limits were 9pg kg-1 (Aroclor 1245) and 10.5pg kg-1 (Aroclor 1242). Chlorinated anisoles, benzenes or phenols did not interfere. 

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