Linear secondary alcohol ethoxylates

Linear Secondary Alcohol Ethoxylates (LSAE). The hydrophobes of LSAE are made via borate-modified oxidation of n-parafiins to form inorganic esters followed by hydrolysis. The resulting alcohols contain secondary hydroxyl groups randomly located along the linear alkyl chain. LSAE biodegrade slightly slower than LPAE (13.14). 

A Cl 1.16 linear secondary alcohol ethoxylate containing an average of 9 EO units per mole of alcohol (Cn.i6LSAE-9). 

Such as Tergitol 15-S-7, C11-C15 secondary alcohol ethoxylate (Union Carbide) or Genapol 24-L-60 linear alcohol ethoxylate (Hoechst Celanese). 

Linear internal monoolefins can be oxidized to linear secondary alcohols. The alpha (terminal) olefins from ethylene oligomerization, described earlier in this chapter, can be converted by oxo chemistry to alcohols having one more carbon atom. The higher alcohols from each of these sources are used for preparation of biodegradable, synthetic detergents. The alcohols provide the hydrophobic hydrocarbon group and are linked to a polar, hydrophilic group by ethoxylation, sulfation, phosphorylation, and so forth. 

The correlation equation obtained using the data summarized in Table 10 was 0.938. The modest correlation coefficient may be due to the use of commercial linear primary alcohol ethoxylates from two different manufacturers. Variatiofts in hydrophobe linearity, hydrophobe carbon number distribution about the average value, and EO chain length distribution about the average value were not considered in equation 8. This interpretation is supported by the observation that inclusion of data for three secondary (methyl branched at the alpha position of the hydrophobe) alcohol ethoxylates in the analysis resulted in a decrease of the correlation coefficient to <0.90. 

APG, alkyl polyglucoside FAA, fatty acid alkanolamide FAEO, fatty alcohol ethoxylate FAES, fatty alcohol ether sulfate FAGA, fatty acid glucamide FAS, fatty alcohol sulfate LAS, linear alkylbenzenesulfonate SAS, secondary alkanesulfonate. 

Steinle et al. [426] studied the primary biodegradation of different surfactants containing ethylene oxide, such as sulfates of linear primary alcohols, primary oxoalcohols, secondary alcohols, and primary and secondary alkyl-phenols, as well as sulfates of all these alcohols and alkylphenols with different degrees of ethoxylation. Their results confirm that primary linear alcohol sulfates are slightly more readily biodegradable than primary oxoalcohol sulfates and that secondary alcohol sulfates are also somewhat worse than the corresponding linear primary. 

Secondary alcohols, produced previously in small quantities from linear paraffin oxidation, have today almost disappeared from the market. The difficulties in producing the corresponding derivatives (ethoxylates, etc.) were a major drawback for their potential development. 

They are now being replaced by the polyoxyethylene derivative of straight-chain primary or secondary alcohols with C10-C18. These linear alcohol ethoxylate nonionic surfactants are more biodegradable than nonylphenol derivatives and have better detergent properties than linear alkylbenzenesulfonate. 

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