Alkylbenzenes, degradation

Simoni S, S Klinke, C Zipper, W Angst, H-P E Kohler (1996) Enantioselective metabolism of chiral 3-phenyl-butyric acid, an intermediate of linear alkylbenzene degradation, by Rhodococcus rhodochrous. Appl... 

Beller H. R. (2000) Metabolic indicators for detecting in situ anaerobic alkylbenzene degradation. Biodegradation 11(2-3), 125-139. 

The benzylic position of an alkylbcnzene can be brominated by reaction with jV-bromosuccinimide, and the entire side chain can be degraded to a carboxyl group by oxidation with aqueous KMnCfy Although aromatic rings are less reactive than isolated alkene double bonds, they can be reduced to cyclohexanes by hydrogenation over a platinum or rhodium catalyst. In addition, aryl alkyl ketones are reduced to alkylbenzenes by hydrogenation over a platinum catalyst. 

When comparing secondary alkanesulfonates (SAS) and linear alkylbenzene-sulfonates (LAS), it is obvious that SAS are more readily degraded than LAS. This is somewhat more pronounced at lower temperatures (Table 34). 

There is an additional problem that has important implications for the bioremediation of contaminated sites when two substrates such as a chlorinated and an alkylated aromatic compound are present. The extradiol fission pathway is generally preferred for the degradation of alkylbenzenes (Figure 9.17), although this may be incompatible with the degradation of chlorinated aromatic compounds since the 3-chlorocatechol produced inhibits the activity of the catechol-2,3-oxygenase (Klecka and Gibson 1981 Bartels et al. 1984). 

The thermal degradation of alkylbenzene sulfonates in alkaline media is important because of the application at elevated temperatures. The half-lives, with respect to thermal degradation, of several commercially available sulfonates were estimated at hundreds to thousands of years at 204° C. The degradation mechanism was predominately a clipping of the alkyl chain to yield an alkylbenzene sulfonate with the phenyl group attached to the a-carbon however, desulfonation also occurred [1624]. 

R. D. Shupe and T. D. Baugh. Thermal stability and degradation mechanism of alkylbenzene sulfonates in alkaline media. J Colloid Interface Sci, 145(l) 235-254, August 1991. 

PLE pressurized liquid extraction, SPE solid phase extraction, UE ultrasonic extraction, DSPE dispersive solid phase extraction, SBSE stir bar sorptive extraction, TD-GC-MS thermal desorption-gas chromatography-mass spectrometry, LAS linear alkylbenzene sulfonates, CDEAs coconut diethanol amides, NPEOs nonylphenol ethoxylates, DP degradation products, SPC sulphenyl carboxylates, PCDD dibenzo-p-dioxins (PCDD), PCDF dibenzofurans, PCBs biphenyls... 

Gonzalez S, Petrovic M, Barcelo D (2004) Simultaneous extraction and fate of linear alkylbenzene sulfonates, coconut diethanol amides, nonylphenol ethoxylates and their degradation products in wastewater treatment plants, receiving coastal waters and sediments in the Catalonian area (NE Spain). J Chromatogr A 1052(1-2) 111-120... 

Navas JM, Gonzalez-Mazo E, Wenzel A, Gomez-Parra A, Segner H (1999) Linear alkylbenzene sulphonates and intermediate products from their degradation are not estrogenic. Mar Pollut Bull 38 880-884... 

Surfactants, such as linear alkylbenzene sulfonates (LAS) and alkylphenol ethoxylates, are present in whitewaters because of their use as cleaning agents or as additives in antifoamers, deinkers, dispersants, etc. The non-ionic surfactants alkylphenol ethoxylates (APEO) degrade to nonylphenol (NP) or to a... 

OCCURRENCE OF SURFACTANTS IN SURFACE WATERS AND FRESHWATER SEDIMENTS—II. LINEAR ALKYLBENZENE SULFONATES AND THEIR CARBOXYLATED DEGRADATION PRODUCTS... 

Surfactants and their biotransformation products enter surface waters primarily through discharges from wastewater treatment plants (WWTPs). Depending on their physicochemical properties, surface-active substances may partition between the dissolved phase and the solid phase through adsorption onto suspended particles and sediments [1,2]. Several environmental studies have been dedicated to the assessment of the contribution of surfactant residues in effluents to the total load of surfactants in receiving waters. This contribution reviews the relevant literature describing the presence of linear alkylbenzene sulfonates (LASs) and in particular of their degradation products in surface waters and sediments (Table 6.3.1). 

Although a substantial body of data is available on the levels of linear alkylbenzene sulfonates (LASs) in rivers and estuaries, fewer studies have been conducted on their environmental behaviour, with reference to the mechanisms involved in their transport and to the reactivity they undergo. Studies of LAS in subterranean water and in the marine medium are scarce and have mainly been conducted in the last decade [2-6], coinciding with the development of new techniques of concentration/separation and analysis of LAS at ppb levels or less. Data on concentrations of sulfophenyl carboxylates (SPCs) are very scarce and the behaviour of these intermediates has hardly received any study. This chapter provides an overview of the current knowledge on behaviour of LAS and their degradation products in coastal environments. 

In the E-Screen bioassay, LAS was not effective in promoting cell proliferation (Table 7.3.3). This compound was tested at concentrations of up to 100 pM with no evidence of cellular toxicity. The antiestrogenic effect of this compound was also measured but all samples tested were negative. Because it has been suggested that surfactants of the alkylbenzene sulfonate type are readily degradable and transformed into sulfophenyl carboxylates or SPCs, an important number of SPCs were assayed in the E-Screen test. These SPCs did not induce cell proliferation of MCF7 cells. 

Do not use enzymes in formulations containing cationic surfactants, anionic surfactants like alkylbenzene sulfonates, and bleaches like hypochlorite and percarboxy lie acids, since they can degrade enzymes. 

In activated sludge, 80.6% degraded after a 47-h time period (Pal et al., 1980). Chemical/Physical. Zhang and Rusling (1993) evaluated the bicontinuous microemulsion of surfactant/oil/water as a medium for the dechlorination of polychlorinated biphenyls by electrochemical catalytic reduction. The microemulsion (20 mL) contained didodecyldi-methylammonium bromide, dodecane, and water at 21, 57, and 22 wt %, respectively. The catalyst used was zinc phthalocyanine (2.5 nM). When PCB-1221 (72 mg), the emulsion and catalyst were subjected to a current of mA/cm on 11.2 cm lead electrode for 10 h, a dechlorination yield of 99% was achieved. Reaction products included a monochlorobiphenyl (0.9 mg), biphenyl, and reduced alkylbenzene derivatives. 

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