Abstract
Quaternary ammonium salts were prepared from alkylbenzyl chlorides and pyridine or triethylamine for the purpose of useful application of long-chain alkylbenzenes. Surface activities of these aqueous solutions were determined and compared each other in respects to surface and interfacial tensions, solubilization power and critical micelle concentration (cmc).
Pyridinium salts were found to be superior than triethylammonium compounds in surface and interfacial tensions. Surfactants containing C3-alkyl group did not show good surface activity and those with C12C16-alkyl group showed good ability to depress the both tensions. The order of effect of alkyl groups on the ability for depression of both tensions were as follows :
C8H17<C10H21<C12H25<C16H33<C14H29
Solubilization power for p-dimethylaminobenzene was determined and the results of the experiments showed that lower alkyl groups made the pyridinium salts better than the triethylammonium salts, but the reverse was the case as to the higher alkyl groups. In comparison with triethylammonium salts the pyridinium salts had lower value of cmc when alkyl groups were lower, and had higher values when alkyl groups were higher.
Thus it was concluded that surfactants containing C14-alkyl group had best surface activities in all respects.
