Ortho ester‐based cleavable cationic surfactants

Abstract

A new type of cleavable cationic surfactant, based on the ortho ester link, is described. Ortho ester amines with alkyl chain lengths from C 8 to C 16 were synthesized from a short-chain ortho ester, a fatty alcohol, and an amino alcohol. The ortho ester amine was subsequently quaternized with methyl chloride, yielding a cationic surfactant. The structures were confirmed by 1 H and 13 C nuclear magnetic resonance and the surface chemical properties were investigated by measuring both static and dynamic surface tensions. The results were compared to standard n-alkyl trimethyl ammonium bromides. The critical micelle concentrations were found to vary rather widely, whereas the surface tensions in some cases were comparatively low. The short alkyl chain ortho ester quaternaries were found to have low surface tensions at short surface ages and to induce rapid wetting of a hydrophobic surface in dynamic tests. Additionally, the new surfactants were found to hydrolyze rapidly under mild acidic conditions, as measured by both titation and monitoring of the dynamic surface tension. Further, they showed excellent long-term stability at pH 10 in dilute aqueous solutions. The effect of added electrolyte on rate of hydrolysis was also investigated. A marked enhancement in the hydrolysis rate was found when NaBr was added, whereas NaCl did not have the same effect. The new surfactants could potentially be used to provide temporary surfactant action in application areas such as disinfection, fabric care, personal care, chain lubrication, and mineral flotation as well as in textile processes such as dyeing or scouring. a As shown in Scheme 1, x refers to the ethyl substituent, y to the fatty alcohol substituent, and z to the short-chain amine substituent. See text for details. Abbreviation: NMR, nuclear magnetic resonance.FIG. 6. Hydrolysis characteristics for an n-C 10 -trimethylamino ortho ester quat. Bulk surface activity was measured by the bubble pressure method. Temperature was 21 or 50ºC. Surface ages were 3-18 s. Initial concentrations were ca. 1 g/L of solvent-containing product.

Surfactants Containing Hydrolyzable Bonds

“…Cationic ortho ester surfactants have also been described [66]. They can be synthesized by a route analogous to that used for nonionic ortho ester surfac-tants (Fig.…”

“…17), using an amino alcohol, such as N,N-dimethylaminoethanol, instead of the methyl-capped PEG. Cationic ortho esters have been suggested for use as surfactant or as a bactericidal agent with a pH-dependent halflife [63,66]. The surfactants are completely stable at pH 10 while they break down readily under mild acidic conditions.…”

Synthesis and surface activities of multi-ammonium cationics derived from n-octadecyl glycidyl

“…however, demonstrate poor primary biodegradation and no evidence of ultimate biodegradation. Increas ing usage of cationic surfactants in industrial and household products has been causing environmental problems owing to poor biodegradability and thus much attention has been paid to develop environmen tal friendly, nontoxic and biodegradable compounds of this kind [18][19][20][21][22][23][24].…”

Syntheses and surface active properties of cationic surfactants having multi ammonium and hydroxyl groups

“…primary biodegradation and no evidence of ultimate biodegradation. Increasing usage of cationic surfactants in industrial and household products has been causing environmental problems owing to poor biodegradability and thus much attention has been paid to develop environmental friendly, nontoxic and biodegradable cationic surfactants [9][10][11][12][13][14].…”