Salts, colloidal

Flochart, B.D. (1961) The effect of temperature on the critical micelle concentration of some paraffin-chain salts. /. Colloid Sci., 16, 484-92. 

Evans, D.F., Yamauchi, A., Roman, R. and Casassa, E.Z. (1982) Micelle formation in ethylam-monium nitrate, a low-melting fused salt. /. Colloid Interface Sci., 88, 89-96. 

Barium fluorosilicate Barium fluosilicate Barium hexafluorosilicate Barium hexafluorosilicate 2-) Barium silicofluoride Barium silicon fluoride Barium-silicofluorid Caswell No. 070 EINECS 241-189-1 EPA Pesticide Chemical Code 075302 Flosol Hexafluorasilicate 2-) barium (1 1) Silicate(2-), hexaftuoro-, barium (1 1) Silicon fluoride barium salt. Colloidal barium silicofluoride, used as a horticultural pesticide. Needles dl - 4.29 soluble in H2O (0.0235 g/100 ml). 

Rate measurements on fine amorphous powder and colloids have been made by Doremus et al. (224) and by Friedberg (225). The effects of pH, temperature, and presence of salts were similar to those reported by others. More than 50 years ago, Dienert and Wandenbulcke (226) reported the basic facts that colloidal silica passed into solution as soluble silica, which was detectable colorimetrically with molybdic acid, and that alkalinity and salts were good catalysts for dissolution. They made an observation which apparently has never been followed up. They claimed that when salt is present, the dissolution rate is faster in a quartz container than in platinum and that in the absence of added salt, colloidal silica would pass into the soluble state when heated with water in quartz, but not in platinum. However, pH measurements were not made. 

Dumanski has determined the molecular weight of the crystalloidal blue molybdenum oxide obtained by the method of G. Marchetti,1f and has found the value 440. The formula is supposed to be MosOs 5 H2O. When this solution is treated with salt colloidal molybdic acid is formed. 

Mounangaa, T., Gerardin, P., Poaty, B. et al. (2008) Synthesis and properties of antioxidant amphiphilic ascorhate salts. Colloids Surf. A Physicochem. Engng Aspects, 318, 134-140. 

Kakehashi R, Yamazoe H, Maeda H (1998) Osmotic coefficients of vinylic polyelectrolyte solutions without added salt. Colloid Polym Sci 276 28 33... 

Menger, F.M., Williams, D.Y, Underwood, A.L., Anacker, E.W. Effect of counterion geometry on cationic micelles. /. Colloid Interface Sci. 1982,90(2), 546-548. Loughlin, J.A., Romsted, L.S. A new method for estimating counter-ion selectivity of cationic association colloid trapping of interfacial chloride and bromide counterions by reaction with micellar bound aryldiazonium salts. Colloids Surf. 1990, 48(1-3), 123-137. 

The reaction mechanism for these products is not clearly understood, but the introduction of organo-metallic compounds (barium or iron salts in colloidal suspension) has been shown to have a beneficiai action on the combustion of diesel fuel in engines and reduce smoke. However, these products cause deposits to form because they are used in relatively large proportions (on the order 0.6 to 0.8 weight %) to be effective. 

The reports were that water condensed from the vapor phase into 10-100-/im quartz or pyrex capillaries had physical properties distinctly different from those of bulk liquid water. Confirmations came from a variety of laboratories around the world (see the August 1971 issue of Journal of Colloid Interface Science), and it was proposed that a new phase of water had been found many called this water polywater rather than the original Deijaguin term, anomalous water. There were confirming theoretical calculations (see Refs. 121, 122) Eventually, however, it was determined that the micro-amoimts of water that could be isolated from small capillaries was always contaminated by salts and other impurities leached from the walls. The nonexistence of anomalous or poly water as a new, pure phase of water was acknowledged in 1974 by Deijaguin and co-workers [123]. There is a mass of fascinating anecdotal history omitted here for lack of space but told very well by Frank [124]. 

The traditional association colloid is of the M R" type where R" is the surfactant ion, studied in aqueous solution. Such salts also form micelles in nonaqueous and nonpolar solvents. These structures, termed inverse micelles, have the polar groups inward if some water is present [198] however, the presence of water may prevent the observation of a well-deflned CMC [198,199]. Very complex structures may be formed in nearly anhydrous media (see Ref. 200). 

For a more complete understanding of colloid stability, we need to address the kinetics of aggregation. The theory discussed here was developed to describe coagulation of charged colloids, but it does apply to other cases as well. First, we consider the case of so-called rapid coagulation, which means that two particles will aggregate as soon as they meet (at high salt concentration, for instance). This was considered by von Smoluchowski 1561 here we follow [39, 57]. 

The salts of monoalkyl sulphates are frequently encountered as commercial detergents (for example, dreft, gardinol and pentrone ) they are usually sodium salts, the alkyl components contain 12 or more carbon atoms, and give colloidal solutions. They are hydrol3 sed by boiling with dilute sodium hydroxide solution ... 

In Du Pont patents (116) the catalyst is prepared by spray-drying a mixture of colloidal siUca or other carriers and Pt/Pd salts. Aqueous hydrogen peroxide solutions up to 20 wt % ate reported for reaction conditions of 10—17°C and 13.7 MPa (140 kg/cm ) with 60—70% of the hydrogen feed selectively forming hydrogen peroxide. 

Overview. Three approaches are used to make most sol—gel products method 1 involves gelation of a dispersion of colloidal particles method 2 employs hydrolysis and polycondensation of alkoxide or metal salts precursors followed by supercritical drying of gels and method 3 involves hydrolysis and polycondensation of alkoxide precursors followed by aging and drying under ambient atmospheres. 

Hydrolysis of solutions of Ti(IV) salts leads to precipitation of a hydrated titanium dioxide. The composition and properties of this product depend critically on the precipitation conditions, including the reactant concentration, temperature, pH, and choice of the salt (46—49). At room temperature, a voluminous and gelatinous precipitate forms. This has been referred to as orthotitanic acid [20338-08-3] and has been represented by the nominal formula Ti02 2H20 (Ti(OH). The gelatinous precipitate either redissolves or peptizes to a colloidal suspension ia dilute hydrochloric or nitric acids. If the suspension is boiled, or if precipitation is from hot solutions, a less-hydrated oxide forms. This has been referred to as metatitanic acid [12026-28-7] nominal formula Ti02 H2O (TiO(OH)2). The latter precipitate is more difficult to dissolve ia acid and is only soluble ia concentrated sulfuric acid or hydrofluoric acid. 

Naphthol AS Coupling Components. Naphthol AS components are the aryhdes of either o-hydroxyarylcarboxycHc acids or acylacetic acids. They are free of sulfo and carboxyl groups, but form salts with bases these salts dissolve in water to give colloidal solutions, which couple with diazo components to form colored pigments. The whole class derives from the anilide of 3-hydroxy-2-naphthoic acid [92-70-6] Naphthol AS (85) (Cl Azoic Coupling Component 2). 

---