Studies on Metal-Containing Surfactants. II.

Abstract

Surface active properties of binary aqueous solutions of dodecyl pyridinium chloride (DPC) -metal soap were investigated.Metal soaps used were ricinoleates and laurates of manganese, copper, cobalt etc., which were prepared by metatheses of the corresponding sodium salts with metal halides in alcoholic solution. The molar mixing ratios of DPC to metal soap were 5 and 10 to 1.Manganese, cobalt, zinc soaps etc. were solubilized in DPC solution in molar ratio of 1 : 31 : 10 with regard to the latter, while other metal soaps, especially iron, chromium, lead soaps etc. were less soluble.The values of surface tension and contact angle against chromium plate of the mixed aqueous solutions of laurates and of ricinoleates reached down to 24 and 30dyne/cm, and 15 and 22°θ, respectively.The specific conductances of the mixed solutions were higher than those of the solution of DPC alone and especially cobalt and zinc soap solutions showed high values.In wetting power, most remarkable synergistic effect was shown. The sinking time against felt and cotton cloth reached to 13 seconds in the case of manganese and cobalt laurate solutions. A noticeable synergistic effect was shown in foaming characteristics, too. Excellent foaming power was shown in all soap solutions, and in the foam stability every laurate and manganese ricinoleate solutions were better than the remainders. In emulsifying characteristics, emulsifying power was not so good in general, however, every laurate and manganese ricinoleate solutions were suited to kerosene which was not suitable for DPC.The rust-preventive power of mixed solutions against soft iron and brass was not so good in general, while better effects were obtained with almost soap solutions against aluminium at the higher concentrations. In anti-bacterial action, cadmium, cobalt and manganese soap solutions were effective against R. japonicus, S. cerevisiae etc.Though the effect of metal soap varies considerably with the kind of properties measured, the best effect obtained in this study was nearly equal to that caused by barium soap which was most effective among several soaps used in the previous reports.