Solubilization of Dimethiylaminoazobenzene in Solutions of Detergents. I. The Effect of Temperature on the Solubilization and upon the Critical Concentration

Abstract

In a preliminary note ( 14) it has been shown that the critical concentration of various detergents is found easily from solubilization data of a water-insoluble dye like dimethylaminoazobenzene by plotting the amount of dye solubilized against the concentration of detergent. Graphs are obtained like those represented in figures 2 to 14. AIATERIALS Dimethylaminoazobenzene (DMAB), an Eastman Kodak technical product, was recrystallized from hot petroleum ether solutions (about 20 g./h). During the crystallization care was taken not to obtain too small sized crystals. The recrystallized dye was dried at 80°C. in a vacuum.The crystals were coarse enough to permit a ready separation of the dye from the detergent solution by filtration in the solubilization experiments.Orange OT (F. D. and ('., Orange No. 2; l-o-tolylazo-2-naphthol), a Calco product, was purified according to directions received from Prof. J. W. McBain.The amorphous powder was recrystallized from alcohol and dried. The dye was found to be virtual!}' insoluble in water at 30°C. and 50°C.Potassium and sodium laurates: Solutions of these soaps were prepared by neutralization of Eastman Kodak white label lauric acid with standardized potassium hydroxide and sodium hydroxide solutions, respectively. The potassium and sodium hydroxides were Baker r.r. products. Solutions which rvere 1 .Y in alkali hydroxide were heated on the steam bath with the equivalent amount of lauric acid until the acid had dissolved. The stock solutions were 0.75 .1/ (moles per liter) in potassium laurate and 0.375 d/" in sodium la urate, respectively. The more dilute solutions were obtained by proper dilution of the stock solutions.Potassium and sodium cuprates, potassium and sodium oleates, potassium stearate, palmitate, and myristate: Solutions of these soaps were prepared in the same way as given for the laurates. The fatty acids used were also Eastman Kodak white * Experiments reported in J. Phys. Chem. 50, 440 (1946).immediately after the cell with the solution had been placed into the cell compartment of the spectrophotometer. After 8 min. the extinction was 0.330, alter 10 min. 0.331, and after 20 min. 0.332, after which time it remained constant for

A Phthalocyanine Dendrimer Capable of Forming Spherical Micelles

“…This self-assembled Pc dendrimer micelle has the following features with respect to conventional anionic surfactants: 1) our spherical micelle can be formed by only~10 (WG3-K)SiPcs, while several tens of surfactants are required to generate spherical micelles; [47] and 2) the concentration of (WG3-K)SiPc eluted from the Sephadex G-100 column is very low (10…”

“…[47] That is, this self-assembly of dendrimers is prone to form a spherical micelle much more readily than general anionic surfactants, and is intermediate between unimolecular micelles and self-assembled surfactants. This originates from the mushroom-type molecular shape of (WG3)SiPc and demonstrates a distinct relationship between the self-assembly and the molecular shape of the constituents.…”

Solubilization properties of aqueous solutions of alkyltrimethylammonium halides toward a water-insoluble dye

“…While the solubilizafion of dimethylaminoazobenzene is not very different for sodium and potassium soaps [7], the solubilization power of aqueous solutions of dodecyl-2-hydro-N 237 xyethylammonium salts toward some organic solubilizates varies of the order NO7 ~-I-> Br-> C1- [9]. The solubility of phenothiazine in aqueous solution of manganese or zinc dodecyl sulfate is larger than that of sodium dodecyl sulfate [5].…”

“…The solubilizafion in micellar solution is also affected by the counterion species [5][6][7][8][9]. While the solubilizafion of dimethylaminoazobenzene is not very different for sodium and potassium soaps [7], the solubilization power of aqueous solutions of dodecyl-2-hydro-N 237 xyethylammonium salts toward some organic solubilizates varies of the order NO7 ~-I-> Br-> C1- [9].…”

“…The effect of structure of the surfactant on its solubilization behavior has been investigated by various workers [2,3,7,10,11]. The dependence on the chain length of poly(oxyethylene) group was reported for the solubilization properties of micelles of sodium dodecyl poly(oxyethylene) sulfate and poly(oxyethylene) dodecyl ether toward Yellow OB [10].…”