Metal Oleate Research Articles

In situ study of metal oleate friction modifier additives

There has been debate for many years as to whether long-chain surfactant friction modifier additives reduce friction by forming adsorbed films of monolayer thickness or whether they form films equivalent to several or many multilayers thick. In the work described in this paper, a series of metal oleate friction modifier additives has been synthesized and their film-forming properties compared in rolling-contact conditions by means of ultrathin film interferometry. It has been found that some of these additives form thick boundary films while others do not. It is concluded that thick boundary-film formation results from the formation of insoluble iron(II) oleate on the rubbing surfaces and that, for metal oleates, this occurs only for metals lower than iron in the electrochemical series and is due to a redox reaction involving iron from the steel surface and the metal oleate.

Micellization and conductometric investigation on some lanthanide metal oleates

Determination de la concentration critique micellaire, des parametres thermodynamiques de dissociation et de micellisation de l'oleate de lanthane, de l'oleate de cerium et de l'oleate de neodyme

Adsorption, precipitation, and electrokinetic processes in the iron oxide (Goethite)—oleic acid—oleate system

Detailed adsorption isotherms based on radiochemical analyses for adsorption of oleate aqueous species on α-FeOOH (goethite) are reported. The range of total oleate and pH conditions are shown, from detailed analysis of oleate solution chemistry, to be in a domain free of liquid oleic acid or metal oleate precipitation. The form of the isotherms indicates that down to 10 −7 mole·dm 3 the adsorption is controlled by coulombic plus hydrophobic effects together with a specific adsorption component that is considered to be neutral oleic acid coadsorption with oleate anions, or acid soap dimer adsorption. The electrokinetic data also indicate a specific contribution beyond coulombic plus hydrophobic effects. For regions where precipitation of liquid oleic acid occurs a model of the surface film akin to a two-dimensional microemulsion is proposed.

The mechanism of fatty acid adsorption in the presence of fluorite, calcite and barite

The interaction of oleic acid with fluorite, calcite and barite has been studied using solubility, oleate abstraction, electrophoretic mobility and Hallimond-tube flotation measurements. Abstraction of oleate from aqueous solution corresponds to the precipitation of the metal oleate. Multilayers of metal oleate inhibits the dissolution of the minerals and prevents true equilibrium from being obtained. Flotation is not only dependent on the amount of oleate abstracted but also on the strength of adhesion of the precipitated metal oleate to the minerals. Selectivity between the flotation of calcite, fluorite and barite is unlikely to be obtained by varying the pH because similar responses are observed.

Nuclear Magnetic Resonance Studies of Molecular Motion in a Number of Stearates and Oleates

The broad line p.m.r. spectra of the alkali metal oleates have been observed from 77 °K up to or beyond the crystalline to waxy phase transition. Lower phase transition temperatures are observed in the oleates than in the stearates. This fact is attributed to larger entropies of transition in the oleates than in the stearates. The n.m.r. second moments indicate that in the stearates the packing of chains is probably not closer than in the oleates and consequently that the barriers to chain reorientation are not significantly higher in the stearates than in the oleates. Sodium oleate and stearate both appear to behave irregularly in the series of alkali metal soaps. Spin-lattice relaxation times have been measured by adiabatic rapid passage methods for both alkali metal oleates and stearates. Values of T1 and of the activation energy barrier for the reorientation of end methyl groups are compared with values obtained by other workers. No significant difference is seen between relaxation processes in stearates and oleates, at least in the lower temperature range. Soaps which seem to have some amorphous character have a second relaxation mechanism, in addition to end methyl group rotation, which is evidently important in the region of about 150–250 °K.

Studies on the Alcoholysis Reaction of Fatty Oils with Fentaerythritol

In the alcoholysis reaction of fatty oils with pentaerythritol, the effects of reaction conditions on the reaction rate and the composition of reaction products were investigated and the reaction mechanism was discussed.Reaction products consist of glycerol, pentaerythritol, and their esters as shown Fig.-1 These compounds were clearly separated by means of the thin layer chromatography, using silica gel as absorbent and diethylether as solvent. The composition of reaction products was determined by the measurement of the concentration of spots using densitometer.The effects of reaction conditions on the reaction rate were investigated and the following results were obtained.1) In the system of soybean oil-pentaerythritol, the apparent activation energy of this reaction was about 27 kcal/mole.2) Reaction rate constants in various fatty oils were in the order of linseed oil > olive oil _??_ coconut oil _??_ dehydrated castor oil > soybean oil, and the apparent activation energies were opposite to this order.3) Lead oleate was most active among the various catalysts tested and litharge (PbO) was the second.The order of catalytic activity in metal oleates was as follows.Pb >> Ca > Zn _??_ Mn > Li _??_ K > FeReaction was obviously the second-order reaction and it was supposed that alkoxy anion which was formed by the reaction of pentaerythritol with catalyst attacked carbonyl group of fatty oils.Furthermore, it was found that the composition of reaction products was almost independent of various reaction conditions and was consistent with the calculated values assuming the random distribution of fatty acid groups.

Anomalous Effect of the Concentration of Metal-salt Catalysts in the Liquid-phase Oxidation of p-Xylene and Toluene

Abstract By studying the relation between the concentration and the oxidation activity of various metal catalysts, mostly naphthenates, oleates, linoleates, and caprates of manganese, cobalt, and nickel salts, as well as mixed catalysts of two kinds, it has been established that, in general, there is an anomalous effect of the catalyst concentration-namely, the catalytic activity disappears above a certain point in the concentration of the catalyst. The anomalous concentration effect of a catalyst is observed in the oxidation of toluene and p-xylene with all the catalysts, but chromium naphthenate is a lone exception in the oxidation of p-xylene. It has been shown that the anomalous effect is due to the association of the catalyst in the hydrocarbon solvent to be oxidised, and that the associated catalyst does not act to promote oxidation. The association is reversible, being dependent on the concentration of the catalyst, so the anomalous concentration effect of a catalyst disappears on dilution.

Solutions of metal soaps in organic solvents. Part IV. Direct-current conductivity in solutions of some metal oleates in toluene

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