Photodegradative surfactants: photolyses of p-alkylbenzyltrimethylammonium and alkylbenzyldimethylammonium halides in aqueous solution

Abstract

A series of benzyl-containing ammonium salts, p-alkylbenzyltrimethylammonium halides (C(n)BA: 1a-c) and alkylbenzyldimethylammonium halides (C(n)AB: 2a-d), have been prepared and their photodegradabilities in aqueous solutions have been compared. The photolytic decomposition proceeded by heterolytic and homolytic cleavages of the benzyl-nitrogen bond. The conversion yields were almost the same for all surfactants, whereas the product yields were slightly dependent on the alkyl-chain length. After irradiation, C(8)BA (1b) and C(12)BA (1c) were converted to non-surfactants, whereas C(12)AB (2c) and C(16)AB (2d) still remained surface-active. Their solution properties were concomitantly changed.

Surface-Active and Photochemical Properties of Sodiump-Dodecylbenzylsulfate in Aqueous Solution

“…These facts are in contrast to our previous result that the corresponding ammonium salts, p-alkylbenzyltrimethylammonium chlorides, undergo both homolytic and heterolytic cleavages to give certain amounts of p-alkyltoluene, p-alkylbenzaldehyde, and p-alkylbenzyl alcohol. [6,8] It should be noted that the conversion yield of C 12 BS is remarkably higher than that of C 1 BS (Table 2). However, we have no clear evidence for the higher photo-degradability of C 12 BS.…”

“…HPLC was performed on a Jasco liquid chromatography system, as reported previously. [8] Krafft temperature was determined as the temperature above which a 1 wt% of surfactant was soluble in water. Critical micelle concentration (CMC) was determined fluorometrically by observing the vibrational peak ratio (I 3 /I 1 ) of pyrene fluorescence.…”

“…Critical micelle concentration (CMC) was determined fluorometrically by observing the vibrational peak ratio (I 3 /I 1 ) of pyrene fluorescence. [8,12] Solubilizing power was estimated from the concentration of Oil Orange SS…”

“…[8] A 10 mM of aqueous solution (4 ml) was placed in a quartz tube (13 mmφ) and irradiated for 10 min at 25 o C under argon, air, or oxygen atmosphere.…”

“…[7] We also emphasize that this type of surfactants are stable under usual conditions (e.g., stable to solar irradiation and non-hydrolysable in acidic and basic solutions) and are surface-active as good as commercially available cationic surfactants. [6,8] Here we report the surface-active and photochemical properties of a novel anionic surfactant, sodium p-dodecylbenzylsulfate (C 12 BS), which is expected to be an alternative to one of the most commercially available and the most important synthetic detergents, linear alkylbenzenesulfonate (LAS).…”