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  • Partitioning behavior of an acid-cleavable, 1,3-dioxolane alkyl ethoxylate, surfactant in single and binary surfactant mixtures for 2- and 3-phase microemulsion systems according to ethoxylate head group size.

Partitioning behavior of an acid-cleavable, 1,3-dioxolane alkyl ethoxylate, surfactant in single and binary surfactant mixtures for 2- and 3-phase microemulsion systems according to ethoxylate head group size.

Journal of colloid and interface science (2010-10-01)
Javier Gomez del Rio, Douglas G Hayes, Volker S Urban
ABSTRACT

Partition coefficients for a pH-degradable 1,3-dioxolane alkyl ethoxylate surfactant, 4-CH(3)O (CH(2)CH(2)O)(5.6)-CH(2), 2,2-(CH(2))(12)CH(3), 2-(CH(2)) CH(3), 1,3-dioxolane or "cyclic ketal" surfactant, CK-2,13-E(5.6,ave), between isooctane- and water-rich phases of 2- and 3-phase microemulsion systems (K(n)) were determined as functions of the ethoxylate size, n, and temperature for the neat surfactant and its binary surfactant mixtures, to understand the partitioning of alkyl ethoxylates possessing a broad distribution of ethoxylate size and to determine conditions required for formation of 3-phase microemulsion systems at an optimal temperature where phase separation occurs rapidly, important for protein purification via proteins' selective partitioning to the middle phase, driven by affinity to the second surfactant of the binary mixture. A semi-empirical thermodynamic mathematical model described the partitioning data well, provided optimal temperature values consistent with phase diagrams and theory, and demonstrated that the tail region of CK-2,13-E(5.6,ave) is more polar than the hydrophobes of fatty alcohol ethoxylates. The addition of Aerosol-OT (AOT) removed the temperature sensitivity of CK-2,13-E(5.6,ave)s partitioning, producing 3-phase microemulsion systems between 20 °C and 40 °C. Analysis of the bottom phases of the 2- and 3-phase microemulsion systems formed by CK-2,13-E(5.6,ave) via small-angle neutron scattering demonstrated the presence of spherical, monodisperse oil-in-water microemulsions.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
2,2,4-三甲基戊烷, anhydrous, 99.8%
Sigma-Aldrich
2,2,4-三甲基戊烷, ACS reagent, ≥99.0%
Sigma-Aldrich
2,2,4-三甲基戊烷, HPLC Plus, for HPLC, GC, and residue analysis, ≥99.5%
Sigma-Aldrich
1,3-二氧戊环, anhydrous, contains ~75 ppm BHT as inhibitor, 99.8%
Sigma-Aldrich
2,2,4-三甲基戊烷, suitable for HPLC, ≥99%
Sigma-Aldrich
2,2,4-三甲基戊烷, puriss. p.a., ≥99.5% (GC)
Sigma-Aldrich
1,3-二氧戊环, ReagentPlus®, contains ~50 ppm BHT as inhibitor, 99%
Supelco
2,2,4-三甲基戊烷, analytical standard
Sigma-Aldrich
2,2,4-三甲基戊烷, ReagentPlus®, ≥99%
Sigma-Aldrich
2,2,4-三甲基戊烷, puriss. p.a., ACS reagent, ≥99.5% (GC)
Supelco
密度标准品 692kg/m3, H&D Fitzgerald Ltd. Quality