Chlorophenols tolerance

The tolerance of the strains to high concentrations of pentachlorophenol—S. chlorophenolica appears to be less sensitive than M. chlorophenolicus (Miethling and Karlson 1996). This may be attribnted to the ability of the cells to adapt their metabolism to avoid synthesis of toxic concentrations of chlorinated hydroquinones, and is consistent with the low levels of these metabolites measnred in the cytoplasm of cells metabolizing pentachlorophenol (McCarthy et al. 1997). Inocnla have also been immobilized on polyurethane that, in addition, ameliorates the toxicity of chlorophenols (Valo et al. 1990). 

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. 

Microorganisms (especially bacteria) are capable of producing strains which are tolerant to normal chlorine treatment levels. This can be overcome by employing higher chlorine levels however, this can lead to the formation of unpleasant flavours and odours due to the formation of chlorophenols and other halocarbons. 

An alternative method to make PAEs is the acyclic diyne metathesis (ADIMET) shown in Scheme 2. It is the reaction of a dipropynylarene with Mo(CO)6 and 4-chlorophenol or a similarly acidic phenol. The reaction is performed at elevated temperatures (130-150 °C) and works well for almost any hydrocarbon monomer. The reaction mixture probably forms a Schrock-type molybdenum carbyne intermediate as the active catalyst. Table 5 shows PAEs that have been prepared utilizing ADIMET with these in situ catalysts . Functional groups (with the exception of double bonds) are not well tolerated, but dialkyl PPEs are obtained with a high degree of polymerization. The progress in this field has been documented in several reviews (Table 1, entries 2-4). Recently, a second generation of ADIMET catalyst has been developed that allows... 

A strain of Rhodococcus sp. that degrades benzene is able to tolerate concentrations of 2% (v/v) per day in continuous culture (Paje et al. 1997), and strains of rhodococci that degrade aromatic compounds including phenols, 4-chlorophenol, and benzene synthesized concentrations of 10-methyl-fatty acids apparently at the expense of unsaturated fatty acids (Tsitko et al. 1999). 

It was discovered (Scheme 6.11) that in situ alkyne metathesis catalysts tolerate the presence of double bonds. Reaction of dipropynylstilbene 5 with the in situ catalyst system furnished the PPE-PPV-hybrid 6 [39]. However, instead of 4-chlorophenol the more active cocatalyst 4-trifluoromethylphenol has to be... 

The specifications for the quality of phenol are based on its downstream application. The phenol content is generally over 99%, the water content below 0.1%. For 8-caprolactam and bisphenol A production, only a low level of carbonyl compounds is in fact tolerable. The nature of by-products accordingly depends on the respective synthesis route. Phenol produced from cumene contains acetophenone and a-methylstyrene as co-products. Phenol manufactured by the Raschig method contains small amounts of chlorophenol tar phenols contain minor proportions of nitrogen and sulfur components. 

In Fiirstner et al. s reportsthey demonstrated that Schrock alkylidyne complex [W]-I (4—6mol%) showed a high activity for the RCM between two alkynes to cyclic alkynes at 80°C (Scheme 24.78) in comparison with the Mortreux system [Mo(CO)e (5-10 mol%), p-chlorophenol or 4-trilluoromethylphenol (50-150mol%)]. Furthermore, the authors provided additional features of [W]-I or [Mo]-Vn-catalyzed alkyne RCM reactions as follows 1) Functional groups such as ether, ester, enoate, amide, sdyl ether, sulfonamide, carbamate, and sulfone are tolerable. 2)... 

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