Alkyl sulfates separation

C -Ci4 linear alkanesulfonates and C4-C16 alkyl sulfates separation by alkyl chain length... 

Polyphosphoric acid, P2O5, POCl, and PCl are suitable phosphorylatiag agents. Reaction of an alkyl sulfate with sodium pyrophosphate has also been reported for preparation of alkyl pyrophosphates (77). In general, phosphorylation leads to a mixture of reaction products that are sold without further separation. Thus, when lauryltri(ethyleneoxy)ethanol reacts with 0.3 mol of P2O5 at 50°C and is neutralized with 50% aqueous NaOH, the reaction mixture contains the foUowiag products ... 

Zhou and Pietrzyk [41] found that increasing the mobile-phase ionic strength not only increases the retention of AS and AES on a reversed stationary phase, but also improves the resolution since the peak widths are significantly reduced. The authors achieved baseline separation of a multicomponent alkane sulfonate and alkyl sulfate mixture from C2 to Cis using a mobile-phase gradient whereby acetonitrile concentration increases and LiOH concentration decreases. 

Mannitol hexanitrate is obtained by nitration of mannitol with mixed nitric and sulfuric acids. Similarly, nitration of sorbitol using mixed acid produces the hexanitrate when the reaction is conducted at 0—3°C and at —10 to —75°C, the main product is sorbitol pentanitrate (117). Xylitol, ribitol, and L-arabinitol are converted to the pentanitrates by fuming nitric acid and acetic anhydride (118). Phosphate esters of sugar alcohols are obtained by the action of phosphorus oxychloride (119) and by alcoholysis of organic phosphates (120). The 1,6-dibenzene sulfonate of D-mannitol is obtained by the action of benzene sulfonyl chloride in pyridine at 0°C (121). To obtain 1,6-dimethanesulfonyl-D-mannitol free from anhydrides and other by-products, after similar sulfonation with methane sulfonyl chloride and pyridine the remaining hydroxyl groups are acetylated with acetic anhydride and the insoluble acetyl derivative is separated, followed by deacetylation with hydrogen chloride in methanol (122). Alkyl sulfate esters of polyhydric alcohols result from the action of sulfur trioxide—trialkyl phosphates as in the reaction of sorbitol at 34—40°C with sulfur trioxide—triethyl phosphate to form sorbitol hexa(ethylsulfate) (123). 

Methyl- or 2-ethyl-benzo[Z> ]thiophenes are conveniently prepared by treatment of 2-benzo[6]thienyllithium with the appropriate alkyl sulfate <70AHC(11)177). Clemmensen or Wolff-Kishner reductions of the 2-acylbenzo[Z>]thiophenes are useful, but since acylation produces a mixture of the 2- and 3-acyl isomers (Section 3.14.2.4), these must be separated. Cyclization of phenyl phenacyl sulfide with hydrofluoric acid leads exclusively to 2-phenyl-benzo[6]thiophene, and 3-phenylbenzo[6]thiophene can be rearranged to the 2-isomer in hydrofluoric acid (Section 3.15.2.3.2). Aromatization of 2-cycIohexenylbenzo[6]thiophene, obtained by condensation of the 2-lithio reagent with cyclohexanone, gives 2-phenyl-benzo[6]thiophene, and the reaction is adaptable to the 2-(l-naphthyl) derivative also. 

Polypyrrole can be prepared with n-alkyl sulfates and sulfonates as anions 490), forming layered structures with a bilayer of the detergent separating layers of polypyrrole. 

To obtain oiehns in the pure state, intended for other uses than alkylation (oxo synthesis, alkyl sulfates), ffiey can be separated by selective and leversiUe adsorption on sc ds. UOP employs a tedinique designated Olex , whidi is similar in principle to that of its Molex and Parex processes. 

A number of so-called double ion-pair methods have been described for the analysis of hydrophobic amines in which the mobile phase contains both a quaternary ammonium ion and an alkyl sulfate or sulfonate. At first glance, this combination of mobile phase additives is counterintuitive because one would expect the effect of the anionic and cationic additives to cancel. However, the combination of cationic masking agents to reduce peak tailing and an anionic ion-pairing agent to enhance retention is sometimes necessary for the reversed-phase separation of hydro-phobic amines. 

Separation. — The separation of thorium from the rare earth metals with which it is still mixed may be accomplished by three methods (1) the carbonate separation depends on the fact that thorium carbonate is much more soluble in sodium carbonate than the carbonates of the rare earth metals (2) by the fractional crystallization of the mixed sulfates at 15°-20°, crystals of Th(S04)2 8 H20 are obtained at the insoluble end of the series (3) thorium oxalate forms a soluble double salt with ammonium oxalate, while the rare earth oxalates are almost insoluble in this reagent. Some other methods which have been suggested are fractionation of the chromates,4 of the hydrogen alkyl sulfates,5 of the acetates, by the use of sebacic add 6 and hydrogen peroxide. 

Ion flotation in the presence of surfactants for the treatment of rinses and separation of metal ions is of interest since the sixties [327, 328]. Here, we take only a few examples. The recovery of silver ions from highly diluted solutions is possible by forming a silver-thiourea complex in form of a colloidal precipitate (sublate) followed by sublate flotation with sodium dodecyl benzene sulfonate [329]. Skiylev [330] has developed methods for the removal of non-ferrous metal salts from waste waters. Subject of the investigations were 0.01 - 0.001% solutions of ferrous metal salts. Typical anionic surfactants (alkyl sulfates, alkyl phosphates, alkyl xanthogenates of potassium) or cationic surfactants (quaternary ammonium salts) were used as collectors in ion flotation from diluted solutions. At certain pH, a sublate containing a non-ferrous metal ion was formed, followed by a sublate film formation at the surface due to the rise of the complexes with air bubbles stabilised by the surfactants. 

The effects of increasing the concentration of initiator (i.e. increased conversion, decreased and broader PDi) and reducing the reaction temperature (i.e. decreased conversion, increased M and narrower PDi) for the polymerizations in ambient-temperature ionic Uquids are the same as observed in conventional solvents. Mays et al. reported similar results and, in addition, used NMR to investigate the stereochemistry of the PMMA produced in (BMIMjlPFej. They found that the stereochemistry is almost identical to that for PMMA produced by free radical polymerization in conventional solvents [28]. The homopolymerization and copolymerization of several other monomers are also reported. Similar to vdiat was found by Noda and Watanabe, in many cases the polymer was not soluble in the ionic liquid and thus phase separated [28,29]. Free radical polymerization of n-butyl methacrylate in ionic liquids based on imidazolium, pyridinium, and alkylammonium salts as solvents was investigated with a systematic variation of the length of the alkyl substituents on the cations, and employing different anions such as tetrafluoroborate, hexafluorophosphate, tosylate, triflate, alkyl sulfates and dimethyl phosphate [31]. 

Knox and Hartwick [14] studied the effect of alkyl sulfates with different numbers of carbon atoms on the retention of cations. The amount of mobile phase additive sorbed onto the stationary phase was measured. They concluded that presorption of the alkyl sulfate and subsequent dynamic ion exchange of sample cations was the dominant mechanism and that ion pair formation in the mobile phase was not important Although the studies of Knox and coworkers are persuasive, their conclusions are based on hydrophobic additives that sorb strongly onto the stationary phase. It is hard to imagine that the same scenario applies to less hydrophobic organic and inorganic additives, especially when organic cations are to be separated. 

D. Zhou and D. J. Pietrzyk, Liquid chromatographic separation of alkane sulfonates and alkyl sulfate surfactants effect of ionic strength. Anal. Chem., 64, 1003, 1992. 

There are separate ISO standards for primary and secondary alkyl sulfates (i.e., for products made from primary or secondary alcohols). The ISO standard covering primary alkyl sulfates specifies neutral oil by extraction from ethanol/water solution, total combined alcohols by ether extraction after acid hydrolysis, pH of a 10% aqueous solution, water by titration if below 10% or by azeotropic distillation if above 5%, and chloride by titration (60). The standard covering secondary alkyl sulfates is similar, but combined alcohols are not determined. Assay is by determination of total solids after extraction of the neutral oil, corrected for the presence of other impurities (61). 

Besides the extraction procedure described in Section II, unsulfated alcohol can be determined by TLC and by HPLC, as described below. In the special case of a mixture of alkyl sulfate and alkylarylsulfonate, unsulfated alcohol can be separated from unsul-fonated alkylbenzenes by forming the urea adduct of the alcohol and separating by centrifugation (63). 

Notes Partial formation of methyl esters of the fatty acids can occur, especially during passage through column 1. Partial hydrolysis of alkyl sulfates and tau-rides can occur during elution of column 2 with HCl. This can be avoided by instead eluting with 125 mL 0.3 Ml NaOAc in 70 30 EtOH/H20. The surfactant can be separated from the NaOAc by ion exclusion chromatography or extraction. 

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