Alcohol ethoxylates alkyl distribution

Alkyl ether sulphates can be analysed on a 2.5 cm x 2 mm i.d. column of CIS reverse phase material with a water/tetrahydrofuran gradient system [20]. In this example the detector was the evaporative light scattering detector, as a gradient system was being used with a molecule with no strong chromophore. Alternatively, to obtain more detailed distributions, the molecule could be desulphated and analysed as described for alcohol ethoxylates. 

Sulfated C12-C15 alcohol 3-mole ethoxylate homolog distribution separation by both alkyl and ethoxy chain length... 

Sulfated C12-C15 alcohol 3-mole ethoxylate homolog distribution separation by both alkyl and ethoxy chain length Sulfated C12-C15 alcohol 3-mole ethoxylate determination of alkyl chain length distribution Sulfated C12-C14 alcohol ethoxylate determination of alkyl chain length distribution Sulfated C10-C14 alcohol ethoxylate determination of alkyl chain length distribution separation of isomers... 

Phosphated C 2-C j alcohol ethoxylate determination of alkyl chain length distribution separation of isomers... 

Cs-Cjji alcohol ethoxylates and EO/PO adducts determination of alkyl chain length distribution, %EO, %PO... 

Ethoxylated glycerol and sorbitan C14-C18 alkyl esters identification of alcohol and alkyl moieties determination of alkyl chain distribution... 

The dodecyl penta(oxyethylene glycol) monoether was synthesized from Aldrich dodecyl alcohol (98%) by adding 5 mol of ethylene oxide per mol of alcohol this reaction produces the typical distribution in degree of ethoxylation. The synthesis of nonylphenyl methacrylate was by a straightforward reaction of methacryloyl chloride (Aldrich) and nonylphenol (Kodak). Proton NMR spectroscopy just before use indicated 77% double bonds the rest were alkyl hydrogens, presumably because of polymerization. 

Alkylphenol ethoxylates are important kinds of nonionic surfactants. A characteristic feature of the catalytic ethoxylation of alkylphenols is the enhanced reactivity of phenol hydroxyl for ethylene oxide in comparison with alcohols. Esters of ethylene glycol and alkylphenol behave already as an alcohol. Therefore di-, tri-, and m-mers are allowed to form only after the complete consumption of the starting material. All commercial ethoxylated alkylphenols are mixtures of oligomer-homologues having a Poisson-like distribution with some PEG and catalyst as impurities. Both alkylphenols and dialkylphenols are useful for ethoxylation as a hydrophobic moiety. Among the alkylphenols, isooctylphenol and isononylphenol are most widely used. They are synthesized by the Friedel-Crafts alkylation of phenol with butene dimer and mixture of propene trimers, respectively. 

Ethoxylated alcohols were reacted with 50% HBr in glacial acetic acid to give their alkyl bromides. These were separated on a column (9 m x 50 micron) of SE-52XL at 140 C with density programmed carbon dioxide and FID. This analysis gives the alkyl chain distribution and total nonionic [51]. 

Oxyethylated alcohols are prepared at 130°C-180°C in the presence of a catalyst whose concentration is on the order of a few tenths of a percent. Various kinds of catalysts are used. Earlier, basic catalysts (sodium hydroxide) were commonly used, which yielded a wide distribution of ethoxymers. Currently, acidic catalysts with a considerably narrower distribution of ethoxymers and a lower content of unreacted alcohol are used. It follows from this comparison that products obtained by means of different syntheses may have different compositions due to the presence of both different ethoxymers and residual free alcohol, which is often hard to vaporize. Additionally, alcohol as a reactant may be a mixture of compounds with various alkyl chain lengths. Therefore, particularly in the case of ethoxylates prepared from natural sources on an industrial scale, one may have to deal with a mixture of compounds with various ethylene oxides (m) and alkyl (n) chain lengths. 

Description. Alkyl ether sulfates (AES), which are also called alcohol ethoxy sulfates (AEOS), result from the sulfation of an ethoxylated alcohol. As will be mentioned in a later section covering the ethoxylated alcohols, there is usually, and more especially in industrial-grade raw materials, a rather broad distribution in the ethoxylation degree. The ether sulfates are stable under alkaline conditions but are rapidly hydrolyzed under acidic conditions and even under neutral conditions this hydrolysis is ascribed to an autocatalytic acidification process that progressively takes place and continues growing. 

The determination of alkyl chain distribution of alcohol ether sulfates can be most easily performed by gas chromatography after cleavage of the sulfated ethoxy moiety with hydri-odic acid. This procedure is similar to that described under the analysis of ethoxylated nonionic surfactants. The alkyl iodides from cleavage may also be determined by HPLC (72). An alternative approach requires the decomposition of the sulfate and ethoxy groups with the mixed anhydrides of paratoluenesulfonic and acetic acid, followed by GC determination of the alcohol acetates (73). 

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