Linear alkylbenzenesulfonates higher

AH detergent proteases are destabilized by linear alkylbenzenesulfonate (LAS), the most common type of anionic surfactant in detergents. The higher the LAS concentration and wash temperature, the greater the inactivation of the enzyme. The presence of nonionic surfactants, however, counteracts the negative effect of LAS. Almost aH detergents contain some nonionic surfactant therefore, the stabHity of proteases in a washing context is not problematic. 

Linear alkylbenzenes are made from linear terminal olefins and benzene and are important precursors of biodegradable anionic surfactants (LAS, linear alkylbenzenesulfonates). The conventional catalyst is HF, first to be replaced by a fluorinated silica-alumina in the DETAL process. The DETAL process is safer than the HF process and also more cost-effective because no special metallurgy is required and no calcium fluoride waste stream exists.52 Zeolites such as Beta may come to the fore here because they display a higher selectivity to the desired 2-phenyl isomers.55... 

Figure 3 illustrates the detergency performance of a linear C,g alkyidiphenyl oxide disulfonate compared to a typical monosulfonated surfactant, Cjj linear alkylbenzenesulfonate. The alkyidiphenyl oxide disulfonate was observed to yield a higher detergency score than the monosulfonated surfactant over a broad concentration range. The results illustrated in Figure 3 represent a direct comparison between a mono- and disulfonated surfactant in an unformulated system at a hardness level of 150 ppm Ca. ... 

The term alkylbenzenesulfonate (ABS) is generally applied to the branched-chain products, which are only biodegradable with difficulty. ABS is not used in developed countries except for specialty applications where it will not reach natural waters (e.g., as an emulsifier for agricultural chemicals). As opposed to ABS, linear alkylbenzenesulfonate (LAS) is rapidly biodegradable under aerobic conditions. The feedstocks are synthesized by Friedel-Crafts alkylation of benzene. Depending on the alkylation catalyst, phenyl substitution may be uniform on the secondary carbons, or higher in the 2 position. (The 1-phenyl isomer is not found.) Subsequent sulfonation with oleum or sulfur trioxide produces mainly the para isomers. LAS has the lowest cost of any surfactant and is used throughout the world. It is sensitive to water hardness. 

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