Chlorophenols effect

Lin, K. and Wang, H. (1999). Shape selectivity of trace by-products for supercritical water oxidation of 2-chlorophenol effected by CuO/ZSM-48, Appl. Catal. B Environ, 22, pp. 261-267. 

The interaction between organic pollutants and N4 compounds has been addressed in several papers, among which we can highlight that of Jung et al. [5], in which resins such as Amberlite XAD-2 and XAD-4 were modified with macro-cyclic protoporphyrin IX (PPIX) or tetrakis(p-carboxyphenyl)porphyrin (TCPP) in order to enhance the adsorption capacity of the resins for phenol and chlorophenols. Effectively, the adsorption capacity of the resins was increased by the porphyrins, which can be attributed to an increase of the i- i aromatic bond, that is to say, to a hydrophobic interaction between the chlorophenols and the modified resins. 

Therefore, hplc methods seem more effective. By usiag a combiaed uv and electrochemical detection technique (52), the gem-chlotinated cyclohexadienones, the chlorophenols, and the phenoxyphenols present ia the chlorination mixtures can be determined with great accuracy. 

Effects in Animals. The LD ia rats for all light chlorophenols, irrespective of the administration route, ties between 130 and 4000 mg/kg body weight. The toxicity of these compounds ia order of increasing strength is tetrachlorophenols > monochloropheno1 s > dichlorophenols > trichlorophenols when the chlorophenol is administered either orally or by subcutaneous iajection. 

Effects in Humans. In chlorophenol production, irritation symptoms of the nose, eyes, respiratory tract, and skin resulting ia chloroacne have been observed. The results of epidemiology studies on the long-term effects of chlorophenols are quite contradictory and have not allowed the experts to reach any firm conclusions (54). 

Acetal homopolymer resins show outstanding resistance to organic solvents, no effective solvent having yet been found for temperatures below 70°C. Above this temperature some phenolic materials such as the chlorophenols are effective. Stress cracking has not been encountered in organic solvents. Swelling occurs with solvents of similar solubility parameter to that of the polymer (8 = 22.4 MPa ). 

Skin is also important as an occupational exposure route. Lipid-soluble solvents often penetrate the skin, especially as a liquid. Not only solvents, but also many pesticides are, in fact, preferentially absorbed into the body through the skin. The ease of penetration depends on the molecular size of the compound, and the characteristics of the skin, in addition to the lipid solubility and polarity of the compounds. Absorption of chemicals is especially effective in such areas of the skin as the face and scrotum. Even though solid materials do not usually readily penetrate the skin, there are exceptions (e.g., benzo(Lt)pyrene and chlorophenols) to this rule. 

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. 

PCP presents a different picture from that of the lower chlorophenols and their derivatives. The corresponding dioxin shows much more stability to light than does TCDD, enough to permit its prolonged existence at low concentrations in a photoreactor. As a phenol it can directly yield dioxins, a process favored by its normal mode of application as the sodium salt. Although octachlorodibenzo-p-dioxin has much lower mammalian toxicity than TCDD (6), its formation, properties, and effects demand additional investigation. Technical preparations of PCP are frequently mixtures of tetra- and pentachlorophenols consequently, hepta-and possibly hexachlorodibenzo-p-dioxins might be expected as photolysis products in addition to the octachloro derivative. 

The objectives of the soil persistence experiments were (1) to learn the effect of soil type and concentration on the TCDD degradation rate, (2) to isolate and characterize degradation products from DCDD and TCDD, and (3) to determine whether chlorodioxins could be formed from chlorophenol condensation in the soil environment. This last study was essential since quality control at the manufacturing level could reduce or eliminate the formed dioxin impurity. But the biosynthesis of chlorodioxins by chlorophenol condensation in the soil environment could not be controlled and would have connotations for all chlorophenol-de-rived pesticides if formation did occur. The same question needed to be answered for photochemical condensation reactions leading to chloro-... 

Steiert JG, WJ Thoma, K Ugurbil, RL Crawford (1988) P nuclear magnetic resonance studies of effects of some chlorophenols on Escherichia coli and apentachlorophenol-degrading bacterium. J Bacterial 170 4954-4957. 

Laine MM, KS Jorgensen (1997) Effective and safe composting of chlorophenol contaminated soil in pilot scale. Environ Sci Technol 30 371-378. 

An apparent particle size effect for the hydrodechlorination of 2-chlorophenol and 2,4-dichlorophenol was observed by Keane et al. [147], Investigating silica supported Ni catalysts (derived from either nickel nitrate or nickel ethane-diamine) with particles in the size range between 1.4 and 16.8 nm, enhanced rates for both reactions were observed with increased size over the full range (Figure 13). As electronic factors can be ruled out in this dimension, the observed behavior is traced back to some sort of ensemble effect, known from CFC transformations over Pd/Al203... 

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. 

Cho, N.S., Rogalski, J., Jaszek, M., Luterek, J., Wojtas-Wasilewska, M., Malarczyk, E., Fink-Boots, M., and Leonowicz, A., Effect of coniferyl alcohol addition on removal of chlorophenols from water effluent by fungal laccase, J. Wood Sci., 45, 174-178, 1999. 

A number of carboxylic acids other than acetic were investigated as solvents or promoters. All of these acids which were stable to reaction conditions were found to be effective in promoting glycol ester production (e.g., propionic, pivalic, benzoic, etc.). However, other Br nsted acids of non-carboxylic nature were not found to be effective promoters. Thus penta-chlorophenol, although it has a pKa value (4.82) very close to that of acetic acid (4.76), is not a comparable promoter (Table I, reaction 13). Likewise, phosphoric acid (pK 2.15) is not an effective solvent or co-solvent with acetic acid (Table I, reaction 8). Experiments with lower concentrations of these acids in sulfolane solvent also showed that carboxylic acids are unique in promoting glycol formation. The promoter function of carboxylic acids thus appears not to be dependent (only) upon their acidity, but on some other chemical or structural property. 

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. 

Renal Effects. Although not adverse, dark urine (as a result of oxidation products of phenol or a result of hemoglobin or its breakdown products in the urine) is a common symptom observed in humans exposed to phenol. In persons exposed to about 0.14-3.4 mg/kg/day phenol in drinking water for several weeks after an accidental spill, dark urine was reported by 17.9% of the most highly-exposed individuals, while only 3.4% of the controls reported the effect (Baker et al. 1978). This difference was not statistically significant. A 3.3-fold increase in the prevalence of dark urine was reported by persons exposed to unspecified doses of phenol after an accidental spill in Korea (Kim et al. 1994). It is not known if the chlorination process, which may have converted a majority of the phenol to chlorophenol, contributed to this effect. 

---