Halogenated alkylphenols

Microbicide group (substance class) Chemical name Chemical formula Structural formula 

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Fig. 2.6.18. LC-MS-MS analysis of halogenated alkylphenolic compounds in chlorinated river water (the Llobregat river, Spain). MRM mode (a) 253 —> 167 for detection of 35C1 nonylphenolic compounds (b) 297 — 79 for 79BrNP (c) 355 —> 297 for 79BrNPE C (d) 399 — 297 for 79BrNPE2C. Reprinted with permission from Ref. [39] 2002 American...

As a rule it has to be stated that halogenated alkylphenols are more active and broader in effectiveness than the alkylphenols. It is therefore in no way astonishing that some of the most important phenol derivatives in practical application are found in this class of phenolics. Among others Klarmann et al. (1933) have carried out systematic examinations of the relationship between chemical structure and antimicrobial activity with regard to halogenated alkylphenols. However, one should not overestimate the value of the data obtained when decisions and selections have to be made for practical application, as other properties of the microbicidal compounds, such as water-solubility, partition coefficient, activity in the presence of interfering factors encountered in practice, and toxicity, are of the same or of even more importance. Although there are available a lot of data and experience, often the optimum compound and formulation must be determined by experiment. 

HALOGENATED ALKYLPHENOLS 7.3.4. 4-Chloro-6-isopropyl-3-methylphenol C10H13CIO... 

Nonylphenol ethoxylate (NPEO), octylphenol ethoxylate (OPEO), alkylphenoxy carboxylate (APEC), halogenated alkylphenols (BrOP, ClOP, BrNP, CINP), halogenated NPEOs (BrNPEOs, ClNPEOs) Bisphenol-A (BPA), bisphenol-F (BPF)... 

Quinone dioximes, alkylphenol disulfides, and phenol—formaldehyde reaction products are used to cross-link halobutyl mbbers. In some cases, nonhalogenated butyl mbber can be cross-linked by these materials if there is some other source of halogen in the formulation. Alkylphenol disulfides are used in halobutyl innerliners for tires. Methylol phenol—formaldehyde resins are used for heat resistance in tire curing bladders. Bisphenols, accelerated by phosphonium salts, are used to cross-link fluorocarbon mbbers. 

Another approach consists of an in-situ acetylation and extraction of NPEOs and further analysis of the acetyl derivatives. The method has been applied to analyse effluent water and sewage sludges [102,103], sediments [104] and river waters [105]. Silylated derivatives [106] using BSA or BSTFA have also been used to determine NPEO (n < 6) in seawater [107] and wastewater [107,108], sediments [109] and sludges from wool scour effluents [110]. Halogenated derivatives of alkylphenols (AP) can also be formed as a result of chlorination practices in water treatment or wastewater if bromide is present. Brominated OPs and NPs (BrAPEOs) have been identified by GC-MS in sewage [111] and tap water [89], respectively. 

As with Soxhlet, the preferred extraction solvent is methanol, which has been used for the extraction of alkylphenols, halogenated NPs and NPEO [13,14,36], and AEOs [37]. Other solvents that have been used are ethyl acetate for alkylphenols and short-chain NPEO [10],... 

The quantitative environmental analysis of surfactants, such as alcohol ethoxylates, alkylphenol ethoxylates (APEOs) and linear alkylbenzene sulfonates (LASs), is complicated by the presence of a multitude of isomers and oligomers in the source mixtures (see Chapter 2). This issue bears many similarities to the quantitation problems that have occurred with halogenated aromatic compound mixtures, e.g. polychlorinated biphenyls (PCBs) [1]. 

Alkylphenol ethoxylate surfactants are widely used in laundry detergents. Chlorination of these compounds results in the formation of halogenated nonylphenolic DBFs, most of them brominated acidic compounds [126],... 

Important classes of nonionic surfactants are aliphatic poly-ethoxylate alcohols (AEO), and octyl or nonyl phenol polyethoxylates (OPEO and NPEO). The alkylphenol ethoxylates (APEO) attracted special attention due to their supposedly endocrine disrupting properties (Ch. 8.3). LC-MS analysis may also involve nonylphenolethoxycarboxylates (NPEC), biodegradation products of NPEO, and halogenated analogues, generated in chlorine disinfection treatments in drinking water production plants. 

Among different nonionic surfactant classes, alkyl-phenol ethoxylates (APEOs) comprise the class meriting special attention with respect to environmental issues. The analysis of underivatized alkylphenolic compounds by GC-MS is restricted to the most volatile degradation products, such as alkylphenols and APEOs with less then 4-ethoxy groups. To overcome the problem of volatility, different offline and online derivatization protocols have been developed. Two complementary MS techniques, one using El and another using the less commonly used positive (P)CI, have been evaluated for the analysis of APEOs, their acidic (APECs) and neutral metabolites (APs), and halogenated derivatives. 

Cellulose. Cellulose has been much favored after silica gel G as a layer for phenolic separations. A wide range of alkylphenols has been studied on cellulose impregnated with ethyl oleate by reversed-phase methods with aqueous ethanol as solvent (66). Halogenated phenols have also been comprehensively examined (67). Cellulose impregnated with formamide, -methylformamide, and N,N-dimethylformamide has been used with hexane as solvent for the separation of alkylphenols, partially hindered and hindered phenols (68). Two-dimensional thin-layer separations of 40 phenols with detection by UV and with a 4-nitroaniline reagent have been described (69). 

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