Halogenated Phenolic Compounds

T0025 Akzo Nobel MPP Systems, Macro Porous Polymer (MPP) 

T0144 Cams Chemical Company, CAIROX Potassium Permanganate T0161 Chemical Oxidation—General 

T0288 Enviro-Sciences, Inc., Low-Energy Extraction Process (LEEP) 

T0354 Grace Bioremediation Technologies, Daramend Bioremediation Technology 

T0361 H H Eco Systems, Inc., Solid-State Chemical Oxidation 

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Halogenated Aromatic Compounds Halogenated Cresols Halogenated Ethers and Epoxides Halogenated Phenolic Compounds Halophenols Chlorophenol Dichlorophenol Halophenols Pentachlorophenol PCP Tetrachlorophenol Trichlorophenol... 

Berger U, Herzke D, Sandanger TM. 2004. Two trace analytical methods for determination of hydroxylated PCBs and other halogenated phenolic compounds in eggs from Norwegian birds of prey. Anal Chem 76 441 -52. 

Some naturally occurring organohalogen compounds are produced in massive quantities. Forest fires, volcanoes, and marine kelp release up tx>SmiUimi tons oTCHj,Cl pt r yejir. for example, while annual industrial emissions total only about 26,000 tons. A detailed examination of one species of Okinawan acorn worm in a 1 km study urea showed that tl>ey released nearly IQO pounds per day of halogenated phenols, compounds previously thought to be nonnatural pollutants. 

Further details of the pathways for the degradation of PAFIs are described in Chapter 6, Section 6.2.1 and in a review (Neilson and Allard 1998). It seems that most of the degradative enzymes are inducible, and this is consistent with the fact that most strains have been isolated after specific enrichment with the xenobiotic. The case of the partially constitutive synthesis of catechol 1,2-dioxygenase in the yeast Trichosporon cutaneum (Shoda and Udaka 1980) has been noted (Section 4.5.2). In the case of biotransformation, however, there are sporadic examples of the constitutive synthesis of enzymes. For example, the system carrying out the O-methylation of halogenated phenolic compounds was apparently constitutive (Neilson et al. 1988) this observation is consistent with the isolation of the strains by enrichment with Q compounds structurally unrelated to the halogenated substrates. The O-methylation reaction may function primarily as a detoxification system, so that in this case constitutive synthesis of the enzyme would clearly be advantageous to the survival of the cells. 

The O-methylation of halogenated phenolic compounds by both Gram-positive and Gram-negative bacteria has been demonstrated (Allard et al. 1987), and in cell extracts of representatives of these bacteria, it appears that the methyl group is provided as expected by S-adenosyl methionine (Neilson et al. 1988b). 

Figure 7.54 2,4,6-Tribromophenol is the main halogenated phenolic compound in red algae.

As recently as 1970, only about 30 naturally occurring organohalogen compounds were known. It was simply assumed that chloroform, halogenated phenols, chlorinated aromatic compounds called PCBs, and other such substances found in the environment were industrial pollutants. Now, only a third of a century later, the situation js quite different. More than 5000 organohalogen compounds have been found to occur naturally, and tens of thousands more surely exist. From a simple compound like chloromethane to an extremely complex one like vancomycin, a remarkably diverse range of organohalogen compounds exists in plants, bacteria, and animals. Many even have valuable physiological activity. Vancomycin, for instance, is a powerful antibiotic produced by the bacterium Amycolatopsis orientalis and used clinically to treat methicillin-resistant Staphylococcus aureus (MRSA). 

Halogenated phenols, particularly 2-bromo-, 2,4-dibromo-, and 2,4,6-tribromophenol, have been identified in automotive emissions and are the products of thermal reactions involving the dibromoethane fuel additive (Muller and Buser 1986). It could therefore no longer be assumed that such compounds are exclusively the products of biosynthesis by marine algae. 

Since the aerobic degradation of halogenated phenols takes place by monooxygenation and is discussed in Part 2 of this chapter, it is not discussed here except to note the production of chlorocat-echols from chlorophenols and chloroanilines. Emphasis is placed on chlorinated substrates, and reference may be made to a review (Allard and Neilson 2003) for details of their brominated and iodinated analogs. The degradation of aromatic fluorinated compounds is discussed in Part 3 of this chapter. 

Resin cures utilise phenol-formaldehyde resins with reactive methylene groups and a small added amount of either a chlorinated rubber, e.g., polychloroprene, or stannous chloride. If halogenated phenolic resins are used the additional source of a halogen may not be required. Resin cures give butyl compounds excellent heat stability and are used to good effect where this is required, e.g., in tyre curing bags which have to resist service at 150 °C in a steam atmosphere. 

Such xenobiotics as aliphatic hydrocarbons and derivatives, chlorinated ahphatic compounds (methyl, ethyl, methylene, and ethylene chlorides), aromatic hydrocarbons and derivatives (benzene, toluene, phthalate, ethylbenzene, xylenes, and phenol), polycyclic aromatic hydrocarbons, halogenated aromatic compounds (chlorophenols, polychlorinated biphenyls, dioxins and relatives, DDT and relatives), AZO dyes, compounds with nitrogroups (explosive-contaminated waste and herbicides), and organophosphate wastes can be treated effectively by aerobic microorganisms. 

Halogenated phenols correlate well with Hammett s constant (a). Figure 6.24 shows the linear trend of the c values of 3-chlorophenol, 4-chlorophenol, 3,4-dichlorophenol, and 3,5-dichlorophenol with respect to their first-order reaction rate constants. Aromatic compounds with substituents in the meta and para positions have pronounced steric differences and result in a well-defined trend. Table 6.9 summarizes all the QSAR models discussed above. 

The total phenolic compounds in an aqueous sample can be determined by a colorimetric method using 4-aminoantipyrine. This reagent reacts with phenolic compounds at pH 8 in the presence of potassium ferricyanide to form a colored antipyrine dye, the absorbance of which is measured at 500 nm. The antipyrine dye may also be extracted from the aqueous solution by chloroform. The absorbance of the chloroform extract is measured at 460 nm. The sample may be distilled before analysis for the removal of interfering nonvolatile compounds. The above colorimetric method determines only ortho- and meta-substituted phenols and not all phenols. When the pH is properly adjusted, certain para-substituted phenols, which include methoxyl-, halogen-, carboxyl-, and sulfonic acid substituents, may be analyzed too. 

The individual phenolic compounds may be determined by GC-FID or GC/MS. Alternately, the phenol may be derivatized to a halogen derivative and measured by GC-ECD. 

Almost all classes of compounds non-selective Flame ionization detector Non-halogenated volatile compounds (EPA 8015) Phenols (EPA 8041) PAHs (EPA 8100) —All other chemical compounds present in the sample will interfere with the target analytes. —TPH analyses are affected by naturally occurring organic compounds in soils with high humic substance content. 

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