- Relationship of Structure to Properties of Surfactants. 13. Surface and Thermodynamic Properties of Some Oxyethylenated Sulfates and Sulfonates
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Surface and thermodynamic properties of the oxyethylenated anionic surfactants C10H21OC2H4SO3Na, C12H25OC2H4SO3Na, C12H25OC2H4SO4Na, and C12H25(OC2H4)2SO4Na were investigated at 10, 25, and 40 deg C in aqueous solution and in NaCl solution of 0.1 and 0.5 M total ionic strength.At all ionic strengths and temperatures studied, compounds with an oxyethylene group (EO) in the molecule are more surface-active than the corresponding compounds without an EO in the molecule.Sulfated compounds, with or without an EO, are somewhat more surface-active than the corresponding sulfonates.The introduction of the first EO does not increase the area per molecule at the aqueous solution/air interface significantly, but the introduction of the second does.In pure water, surface pressure at the cmc (?cmc) is not increased by the introduction of one EO into the molecule, but in 0.1 or 0.5 M NaCl it is.The introduction of a second EO reduces ?cmc at all ionic strengths.The first EO increases the negative value of ΔGomic by 3 kJ mol-1 and ΔG0ad by 3.6 kJ mol-1; the second EO increases the values by 0.5 and 1.4 kJ mol-1, respectively.The unusual properties of the EO-containing compounds may be due to complex formation between the ether oxygens and Na+.
- Dahanayake, Manilal,Cohen, Anna W.,Rosen, Milton J.
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- Method and Device for the Sulfonation or Sulfation of Sulfonatable or Sulfatable Organic Substances and for Performing Faster, Strongly Exothermic Gas/Liquid Reactions
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A method and a device for the sulfonation or the sulfation of organic liquid raw materials with an S03/air mixture and other reaction gases in order to perform rapid, highly exothermic gas-liquid reactions in conventional thin-layer falling-film reactors are disclosed. The introduction of the S03/air mixture occurs through several feed locations, which are located within (along) the reaction tube or reaction tubes or in the annular gap of annular-gap falling-film reactors. High peak temperatures, undesirable byproducts, worsening of the color and local oversulfation or oversulfonation, which leads to side reactions, are largely avoided.
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Page/Page column 4-5; 7; Sheet 2; Sheet 4; Sheet 5; Sheet 6
(2009/01/20)
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- Kinetics of the Acid-catalysed Hydrolysis of Dodecylsulphate and Dodecyldiethoxysulphate Surfactants in Concentrated Micellar Solutions. Part 1. - Effects of Acid and Surfactant Concentrations and of the Nature and Concentration of Counterions
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The rates of the acid-catalysed hydrolysis of sodium dodecylsulphate (SDS) and sodium dodecyldiethoxysulphate (SDE2S) have been investigated in concentrated surfactant solutions (0.035 - 0.6 mol dm-3).The acid concentration dependence of the initial rates shows a 'saturation' effect, whereas increasing surfactant concentrations above the c.m.c. lead to a maximum in the k2,obs values, beyond which they decrease sharply.These results are discussed in terms of the ion-exchange pseudophase model of the miceller reaction.The nature of the counterion has an effect on k2,obs, the values following the sequence NH4 > Li > Na >> Mg.This has been ascribed to differences in the ion-exchange constants, KH/X, of these cations in the Stern layer of the micelles with the hydrogen ion.Maintaining the total counterion concentration and the ratio of concentrations of surfactant counterion to the concentration of hydrogen ion constant (at 30, i.e. 0.6 : 0.02 mol dm-3) largely eliminates the decrease in the k2,obs values with increasing surfactant concentration, as expected from the pseudo-phase ion-exchange model.Quantitative agreement between theory and experiment is less good, however, owing at least partly to deviations from ideality in solutions of high ionic strength.
- Garnett, Christopher J.,Lambie, Alan J.,Beck, William H.,Liler, Milica
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p. 953 - 964
(2007/10/02)
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