Alkylbenzenes. biodegradable

Hutchins, S. R. (1992). Inhibition of alkylbenzene biodegradation under denitrifying conditions by using the acetylene block technique. Applied and Environmental Microbiology, 58(10), 3395-8. 

Linear paraffins in the C q to range are used for the production of alcohols and plasticizers and biodegradable detergents of the linear alkylbenzene sulfonate and nonionic types (see Alcohols Plasticizers Surfactants). Here the UOP Molex process is used to extract / -paraffins from a hydrotreated kerosine (6—8). 

Of interest is the relative composition of the LABs, particularly the different amount of 2-phenyl isomer and of nonlinear alkylates, given in Table 8. Branched alkylbenzene (BAB) formed by the AlCl3-catalyzed reaction between propylene, condensed to its tetramer, and benzene are less biodegradable and are termed biologically hard. LABs have to a large extent replaced BABs in the domestic markets because of their improved biodegradability. 

Boeije GM, Schowanek DR, Vanrilleghem A (2000) Incorporation of biofilm activity in river biodegradation modeling a case study for linear alkylbenzene sulphonate (LAS). Wat Res 34 1479... 

Alkylator, side reactions in, 23 329 Alkylbenzene(s), 12 162, 163, 169 23 329 from benzene, 3 619t, 620 biodegradation, 3 763t by-products, 23 335 dispersant moieties, 8 706t formylation of, 12 178 oxidation of, 26 894-896 Alkylbenzenesulfonates, rat oral LD50 values, 3 445... 

BIODEGRADATION OF LINEAR ALKYLBENZENE SULFONATES IN THE MARINE ENVIRONMENT... 

Although the marine environment can generally be considered the final destination of industrial and urban wastewater effluents, studies of biodegradation of linear alkylbenzene sulfonates (LAS) in this compartment have been scarce until recently [1—8]. The removal of LAS from the marine medium seems to be an efficient process, as shown by the low levels of LAS detected in samples of both water and sediment [9—11]. High values have only been found in zones close to the direct wastewater effluent discharge points of urban areas [11]. 

Elshahed et al. (2001) investigated the pathways of anaerobic biodegradation of alkylbenzenes by sediment-associated microorganisms from a gas-condensate-impacted aquifer under laboratory conditions. Stoichiometric amounts of sulfate were consumed and methane produced. Two intermediate compounds identified via GC/MS were 3-phenyl-l,2-butanedicarboxylic acid and benzoic acid. Both metabolites identified in the laboratory incubations were also identified in the contaminated aquifer from which the microorganisms were obtained. 

The household laundry detergents were reformulated to become more biodegradable in the 1960s. The principal detergents used in households were alkylbenzene sulfonates, R-G-SG Na" ", where the alkyl group R has 9 to 17 carbon atoms and can have many... 

The linear olefins are used in the production of biodegradable detergents. The Cq to cuts are fed to alkylation units where the olefins react with benzene to form alkylbenzenes which are subsequently sulphonated. The paraffins present in the feed pass through unconverted. These are then chlorinated and used as plasticizers. The linear olefins can also be converted to linear aldehydes and alcohols by hydroformylation. 

The three transitions mentioned above, replacement of branched alkylben-zene sulfonates by linear alkylbenzene sulfonates, replacement of alkylphenol ethoxylates by alcohol ethoxylates and substitution of ester quats for stable quats are all driven by environmental concerns. Rate of biodegradation and aquatic toxicity are the major parameters taken into account, and, in order to pass the regulations that the European Union has adopted, a surfactant must pass the criteria of showing ... 

It is common practice to put the experimentally obtained values for biodegradation and aquatic toxicity into a kind of matrix, as is illustrated by Fig. 2. The shaded areas in the matrix are the approved areas . Out of the six product types discussed above linear alkylbenzene sulfonates, alcohol ethoxylates, and ester quats lie within the shaded areas, while branched alkylbenzene sulfonates, alkylphenol ethoxylates and stable quats do not. 

Spormann, A. M., and F. Widdel, Metabolism of alkylbenzenes, alkanes, and other hydrocarbons in anaerobic bacteria , Biodegradation, 11, 85-105 (2000). 

Angley, J.T., Brusseau, M.L., Miller, W.L. Delfino, J.J. (1992). Nonequilibrium sorption and aerobic biodegradation of dissolved alkylbenzenes during transport in aquifer material column experiments and evaluation of a coupled-process model. Environmental Science Technology, 26(7), 1404-10. 

Roberts, D.W., Application of QSAR to biodegradation of linear alkylbenzene sul-phonate (LAS) isomers and homologues, Sci. Total Environ., 109/110, 301-306, 1991. 

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