Synthesis Of Multi-branch Quaternary Ammonium Amphiphiles With Surface Activity And Their Application

Dendrimers have many catalytic sites. Quaternary ammonium surfactant can be used as a micelles catalyst. Concerning with the above considerations, we designed and synthesized a class of multi-branch quaternary ammonium compounds with surface activity. Based on Behera's amine,different length of hydrocarbon chain or fluorocarbon chain as lipophilic group was introduced by using bromine acetyl bromine as connected groups, then two quaternary ammoniums and three carboxylic acid hydrolyzed from tertbutyl ester as hydrophilc groups were obtained.The molecules' stability, water absorption and surface activity were studied. Thermogravimetry-differential scanning calorimeter (TG/DSC) of the molecules revealed that the molecules are stable below 180℃. By comparing the results of water absorption properties of the catalyst in air, it was proved that the catalyst with perfluorooctyl chain have the best water resistant properties. Furthermore, it showed that the molecule could reduce the surface tension of the water obviously by studing the critical micelle concentration (CMC) values and surface tension values of different molecule in water. The result showed that the CMC value of the compound with fluorocarbon chain is the lowest.The multibranched carboxylic acid performed well in the condensation reactions of salicylaldehyde and malononitrile as Br(?)nsted acid. Moreover, carboxyl groups of these molecules were able to coordinate with rare earth metals and formed Lewis acid. The Piancatelli rearrangement catalysted by the Lewis acid prepared in-situ was studied by using 2-aminophenol and furan-2-yl(phenyl)methanol as the starting material, and the probable mechanism was proposed. Additionally, on the basis of green catalysis, Friedlander reaction under aqueous and catalyst-free conditions was also studied.