Colloidal behavior of cobalt monooleate soap in apolar organic solvents

Solution behaviour of lead(II) carboxylates in organic solvents

“…Results are presented in Table 4, and from extrapolation to zero concentration, a limiting effective hydrodynamic radius of 184 nm was calculated for these aggregates. This can be compared with results on cobalt hydroxy monooleate in heptane solutions, where a z-averaged radius of gyration of 320 nm was determined for dilute solutions [32]. Using the same relationships, apparent hydrodynamic radii were calculated for the fast component at various temperatures (Table 4).…”

“…Secondly, introduction of unsaturation or chain branching into the chain decreases the solubility temperature [48], and soaps, such as oleates [23,32], are frequently soluble at room temperature. Thirdly, in nonpolar or noncoordinating solvents, evidence has been presented from ebullioscopic measurements [16,18], viscosimetry [23,32], UV-vis absorption spectra [30,40] and fluorescence depo-larisation [20] for the existence of aggregates in solution. However, in contrast to the behaviour of amphiphiles in aqueous solutions [3,4] these appear to be ill-defined, and enormous variations are observed in the aggregation numbers obtained by the various techniques.…”

“…These properties may also be dramatically affected by the presence of any water [22,32,44], and in some cases, gelation may occur [32,44]. With the branched chain copper(II) 2-ethylhexanoate, gel formation has been observed even in the absence of water [35,36].…”

Cross-Section Structure of Cylindrical and Polymer-like Micelles from Small-Angle Scattering Data. 2. Experimental Results

“…Here we present experimental results from a detailed small-angle neutron scattering study of polymer-like lecithin reverse micelles. While numerous aqueous surfactant systems are known to exhibit polymer-like properties, there are only a few reports on polymer-like surfactant aggregates in organic solvents. ,,− In contrast to aqueous micellar systems, reverse micelles or water-in-oil microemulsions at moderately high values of surfactant concentration and low values of the molar ratio of water to surfactant, w 0 , are generally believed to have either a droplet-like structure or only a small degree of anisotropy. A notable exception is the system lecithin/organic solvent/water, where formation of gel-like, viscoelastic, reverse micellar solutions can be observed .…”

Reações de transferência de acila em microemulsões água/óleo: hidrólise de benzoatos de fenila catalisada pelo ânion o-iodosobenzoato.

“…A formação de micelas inversas em solventes orgânicos têm sido estudada por diversas técnicas, tais como a condutância (PERI, 1969;MARCOVITS et al, 1974), a solubilização de corantes (GUTMAN e KERTES, 1975;MUTO e MEGURO, 1973;MUTO et al, 1976;HERRMANN e SCHELLY, 1979), ressonância de spin eletrônico, ESR (KITAHARA et al, 1974), fluorescência (HERRMANN e SCHELLY, 1979;TSUJII et al, 1978), espalhamento de nêutrons e de luz (RAVEY et al, 1984;CAPONETTI et al, 1986;KOTLARCHYK, 1985), RMN (FENDLER et al, 1973;EL SEOUD e EL SEOUD, 1982;EL SEOUD e EL SEOUD, 1983), aniquilação de pósitrons (JEAN e ACHE, 1978;FUCUGAUCHI et al, 1979), espectroscopia UV-vis (KITAHARA, 1958), osmometria de pressão de vapor (INOUE et al, 1977;TAMURA e SCHELLY, 1981), e viscosidade (PERI, 1969;MARCOVITS et al, 1974;ZHUO et al, 1987).…”