Dialkyltetralin sulfonates

The DATs present in LAB will readily sulfonate to form dialkyltetralin-sulfonate or DATS. The foam and detergency performance properties of individual C DATS homologs are very similar to that of the corresponding C j LAS homologs [21]. Thus, even at a level of 10% DATS in the LAB, no decrease in foam or detergency performance is observed. In some liquid formulations, the presence of DATS can provide a beneficial hydrotropic effect to LAS [22]. Figure 8 illustrates that DATS are indeed surfactants, as evidenced by their surface tension vs. concentration plot. 

The simultaneous determination of LAS and their co-products (dialkyltetralin sulfonates (DATSs) and alkylbenzene sulfonates with... 

Commercial LAS blends usually contain some sulfonated impurities, mainly dialkyltetralin sulfonates (DATS) with a similar distribution of aliphatic carbons than that of LAS (C10-C13). The (- )-ESI-MS spectra of DATS display a series of equally spaced signals with A m/z 14, shown for Cn-DATS in Fig. 2.10.3, arising from the cleavage of the alkyl... 

Biodegradation of commercial surfactant mixtures is also affected by the presence of co-products with differing structures. For example, there was concern that methyl branched LAS (i.e., iso-LAS) and dialkyltetralin sulfonates (DATS) in all commercial LAS would be recalcitrant. However, studies have shown that these co-products mineralize in receiving environmental compartments such as waters and soils [47, 48]. 

Dialkyltetralins (DATs) and dialkylindanes are formed as byproducts during the alkylation process and these byproducts co-distill with LAB [9]. Examples of the unsulfonated and sulfonated dialkyltetralin are shown in Fig. 4. The level of DAT in LAB will vary depending on the type of alkylation process [10,11]. Table 3 lists the composition of several types of LABs and their DAT content as determined by gas chromatography-mass spectrometry (GCMS). It is important to note that a high level of DAT is not the result of alkylation with A1C13 catalyst. As seen in Table 3, AlCl3-catalyzed LAB can have a very low DAT content. 

Linear alkylbenzene produced from chloroparaffms contains 6-8% dialkyltetralin and dialky lindane. Alkylbenzene produced from olefins contains about 1% of these compounds. Thus, LAS may contain about 1%, or about 7% of the sulfonated indanes and tetralins, with the indanes being at very low concentration compared to the tetralins. These byproducts are surfactants, and their presence is beneficial in liquid formulations since they act as hydrotropes and viscosity improvers. They can be determined by GC or GC/MS by the same methods as are used for determining the alkyl chain distribution. The compounds are made volatile by desulfonation or by derivatization as discussed in Chapter 8 (58,59). 

---