Alcohol ethoxysulfates

Alcohol ethoxysulfates have been used in field tests as nitrogen (177) and carbon dioxide (178) foaming agents. Field use of alcohol ethoxysulfates is restricted to low temperature formations owing to its limited hydrolytic stabihty at low pH and elevated temperature (179). It has been reported that some foams can reduce residual oil saturation, not by oil displacement, but by emulsification and imbibition of the oil into the foam (180). 

Surfactants evaluated in surfactant-enhanced alkaline flooding include internal olefin sulfonates (259,261), linear alkyl xylene sulfonates (262), petroleum sulfonates (262), alcohol ethoxysulfates (258,261,263), and alcohol ethoxylates/anionic surfactants (257). Water-thickening polymers, either xanthan or polyacrylamide, can reduce injected fluid mobiHty in alkaline flooding (264) and surfactant-enhanced alkaline flooding (259,263). The combined use of alkah, surfactant, and water-thickening polymer has been termed the alkaH—surfactant—polymer (ASP) process. Cross-linked polymers have been used to increase volumetric sweep efficiency of surfactant—polymer—alkaline agent formulations (265). 

Several surfactants were studied in ambient-pressure foam tests, including alcohol ethoxylates, alcohol ethoxysulfates, alcohol ethoxyethylsulfonates, and alcohol ethoxyglycerylsuUbnates [210]. Surfactants that performed well in the 1-atm foaming experiment were also good foaming agents in site cell and core flood experiments performed in the presence of CO2 and reservoir fluids under realistic reservoir temperature and pressure conditions. 

Both nonionic and anionic surfactants have been evaluated in this application (488,489) including internal olefin sulfonates (487, 490), linear alkylxylene sulfonates (490), petroleum sulfonates (491), alcohol ethoxysulfates (487,489,492). Ethoxylated alcohols have been added to some anionic surfactant formulations to improve interfacial properties (486). The use of water thickening polymers, either xanthan or polyacrylamide to reduce injected fluid mobility mobility has been proposed for both alkaline flooding (493) and surfactant enhanced alkaline flooding (492). Crosslinked polymers have been used to increase volumetric sweep efficiency of surfactant - polymer - alkaline agent formulations (493). 

Alcohol ethoxysulfates (AES) are made by reaction of 3-7 mol of ethylene oxide with a linear C12-C14 primary alcohol to give a low molecular weight ethoxylate, followed by the usual sulfonation. 

The shift to oleochemicals has been supported by increasing environmental concerns and a preference by some consumers, especially in Europe, for materials based on natural or renewable resources. Although linear alkylbenzenesulfonates (LASs) are petrochemically based, alcohol ethoxylates, alcohol ethoxysulfates, and primary alcohol sulfates are derived from long-chain alcohols that can be either petrochemically or oleochemically sourced. There has been debate over the relative advantages of natural (oleochemical) vs synthetic (petrochemical) based surfactants. However, detailed analyses have shown there is litde objective benefit for one over the other. 

Amnionic surfactants used in shampoos, cosmetics, toothpaste, and laundry products include linear alkylbenzenesulfonates (LAS), alcohol sulfates (AS), alcohol ethoxysulfates (AES), alcohol glycerol ether sulfonates, and alpha-olefin sulfates. Household end use of anionic surfactants in the United States was 7.3 X 105 metric tons in 1987 LAS, AS, and AES accounted for 98% of the total (I). 

Equation 5 was used to analyze the cmc properties for a series of alcohol ethoxysulfates (Table 8). While a "fair" correlation coefficient of 0.946 was obtained, it should be noted that the range of hydrophobe carbon chain lengths studied was limited. AES surfactants are prepared by sulfation of alcohol ethoxylates and can contain unreacted alcohol ethoxylate. Variation in the concentration of unreacted AE, which is not considered in equation 5, could reduce the correlation coefficient. 

Salt and alkali solutions were prepared from reagent grade chemicals. The anionic surfactant used was Neodol 25-3S, a commercial alcohol ethoxysulfate obtained from Shell Chemical Company as a 60 wt% active solution. The nonionic surfactant examined was Triton X-100, obtained from J.T. Baker Inc. as a 100 wt% active solution. 

Chem. Descrip. Alkylbenzene sulfonate and primary alcohol ethoxysulfate Uses Detergent used in dishwashing and general cleaning appiics. 

Chem. Descrip. Primary alcohol ethoxysulfate (sodium cation)... 

Alkyl ether sulfates, also called alcohol ethoxysulfates, are prepared by addition of one to four oxyethylene groups to an alcohol which is then sulfated. Oxyethylation enhances water solubility and foaming over the analogous alcohol sulfate, giving a product useful in shampoos and in liquid and powdered detergents. The raw material for these products can be either natural fatty alcohols or primary or secondary synthetic alcohols, usually of C12-C18 chain length. The analogous alkylphenol ether sulfates are found in industrial applications. Ether sulfates are not as sensitive to water hardness as are other anionic surfactants. 

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