Chemistry of non-ionic detergents

SummarySurface and micellar properties of a homologous series of Octaethylene glycol-n-alkyl ethers (C,~Es; n = 9 to 15) have been studied in aqueous solutions by the surface tension measurements. The effects of the alkyl chain length comprising even and carbon numbers have been examined in order to evaluate the surface free energy A G A_ w and the standard free energy AG~ for the micellization obtained from their surface tension data. The areas per molecule and the equilibrium surface tension values at the CMC decreased with an increasing carbon number and they showed zigzag curves by the difference in even and odd carbon numbers.These findings may be attributed to the differences in the molecular orientation between the molecules with even carbon number and ones with odd carbon number on the air-water interface at CMC. A GA_w values decreased linearly with an increasing alkyl chain length but did not show a zigzag line by the differences in even and odd carbon numbers. This suggests that the molecular orientation is not influenced by the difference between their even and odd carbon numbers in the alkyl chain on the surface of the very diluted solution, and their molecules form some stable adsorbed films with an increase of the alkyl chain length. A division of A GA_ w into the contribution made both by the hydrophilic group AG~_w (-W) and by the hydrophobic group A GA-w ( -CH2 -) was attempted as follows; A GA-w (-CH2-) = -0.80 kcal/mol and AGa_w(-W) = + 0A5 kcat/mol. The free energy changes AG m of micellization were discussed on the basis of the CMC data obtained from the surface tension measurements by treating the formation of micelles as analogous to phase separation, and the contribution from the each moieties in the molecule were calculated as follows; AG m (-CH2-) =-0.68 kcal/mol and AGm(-W) = + 1.54 kcal/mol. The difference between AG~_w and AG,~ is discussed using their data. Key wordsNonionic surfactants with even and odd carton atoms, contribution of two moieties.

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“…[6] As the difference between the corresponding contributions for adsorption is (-2.18 + 0.85 = -1.33 kcal/mol), equation [5] becomes;…”

Section: Thermodynamics Of the Adsorption At Airwater Interfacementioning

confidence: 99%

“…+ acre(- [10] Using the values in equation [6], equation [11] is derived from equation [10] Each of ZIGm(-CH2-) and AGm(-W) values can be calculated to be -0.68 kcal/mol and +1.54 kcal/mol, respectively, by comparing equations [8] and [12].…”

Section: + (N-1)agm(-ch2-)mentioning

confidence: 99%

Effects of alkyl chain length on surface and micellar properties of octaethyleneglycol-n alkyl ethers

Ueno

Takasawa

Miyashige

et al. 1981

Colloid Polymer Sci

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“…The largest homogeneous detergents reported in the literature, a range of hexadecyl monoethers containing six to twenty-one ethylene units respectively, have been successfully synthesised by these routes (Elworthy & Macfarlane, 1962a ; similarly, some branched hydrocarbon chain compounds have recently been obtained by these methods (Elworthy & Florence, 1964).…”

Section: Preparation Of Ethylene Oxide Adductsmentioning

confidence: 99%

“…Corkill, Goodman & Harrold, 1964Donbrow &Jan, 1963 Ibid. Elworthy & Florence, 1964 Ibid. Corkill, Goodman & Harrold, 1964 Ibid.…”

Section: Critical Micellar Concentrationmentioning

confidence: 99%

The physical chemistry of some non-ionic detergents

Elworthy

Macfarlane

1965

Journal of Pharmacy and Pharmacology

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“…The compounds examined have been described previously (Elworthy & Florence, 1964, 1965. The straight chain detergents have a general formula Me- [CH,]x.…”

Section: Experiments A1mentioning

confidence: 99%

Partial molal volumes of some non-ionic detergents in monomeric and micellar form

Florence

1966

Journal of Pharmacy and Pharmacology

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Partial molal volumes of five synthetic non-ionic detergents have been measured above and below their critical micellar concentrations. The increases in volume on micellisation are discussed in terms of changes in hydration and hydrophobic bonding. The change in partial molal volume at the critical micellar concentration decreased with temperature. At 20" increases of 5, 9 and 17 ml mole-' were obtained for the n-butyl, n-hexyl and n-octyl hexaoxyethylene glycol ethers respectively. For comparison with the alkyl ethers, the partial molal volume of hexaoxyethylene glycol was determined at four temperatures. The utility of density measurements for the determination of the critical micelle concentration of these non-ionic detergents depended on the temperature of the system; at higher temperatures the change in slope of density-concentration plots at the critical micelle concentration decreases and sometimes is not detectable.

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Chemistry of non-ionic detergents

Cited by 44 publications

References 14 publications

Effects of alkyl chain length on surface and micellar properties of octaethyleneglycol-n alkyl ethers

Effects of alkyl chain length on surface and micellar properties of octaethyleneglycol-n alkyl ethers

The physical chemistry of some non-ionic detergents

Partial molal volumes of some non-ionic detergents in monomeric and micellar form

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