Semipolar Organo Boron Surfactants. III.

The relation between hydrophobic structure and surface activity was investigated on the following oil-soluble organo boron surfactants._??_Bisglycerylborate (BGB) monoalkylateThe lowering ability of interfacial tension of BGB monoisostearate with a blanched hydrophobic group was lower than those of BGB monoalkylates with a straight hydrophobic group in the lower concentration region, but the best in tested four surfactants in the higher concentration region.In case of the type with a straight hydrophobic group, BGB monooleate and BGB monolinoleate containing the unsaturated chain showed the better lowering ability of interfacial tension than BGB monostearate with the saturated alkyl group.The result was discussed on the basis of II-A curves and water numbers of these surfactants.