Sodium laurate, effect

Research has also been conducted in which steryl phosphonic acid (SPA) was examined in place of benzyl arsonic acid (BAA), which was used in an operating plant in China [5], In this study, several collectors were examined, including sodium laurate, sodium dodecyl sulphate, amino acids, diphosphonic acid (SPA). It was discovered that SPA was the most effective and that aliphatic alcohol (i.e. octanol) was required to maintain the effectiveness of SPA. The use of emulsifier in the mixture was required to provide a suitable emulsion of the composite collector. 

A number of cobalt(III) encapsulated cage complexes have been used as electron-transfer agents their advantage over viologens is their long-term stability in photochemical cycles. The most effective complex is [CoL] where L is l-chloro-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eico-sane at a concentration of 4 x 10 mol dm , this cage exhibits a similar ability to methylviolo-gen to produce Laser flash photolysis in sodium dodecyl sulfate and sodium laurate... 

Which would be the more effective detergent in the pH range 2 to 3, sodium lauryl sulfonate or sodium laurate Why ... 

FIGURE 2.5 Hypoglycemic effect of insulin administered orally to normal rats by means of coated soft capsules containing an absorption-enhancing formulation (8 IU porcine insulin, 4 mg sodium laurate (Ci2) and 16 mg cetyl alcohol) two capsules RSI (open stars) 2 capsules RS2 (open circles) 2 capsules RS2 + 1 capsule surfactant post-insulin administration (open square) insulin i.p. 4 IU (close circles) 2 placebo capsules (no insulin) (close stars). Each point is the mean SD of five animals for insulin administration and of four animals for controls. RSI and RS2 are capsules coated with various mixtures of Eudragits RS, S, and L. (From Touitou, E. and Rubinstein, A., Int. J. Pharm., 30, 95, 1986. With permission from Elsevier.)... 

There are only a limited number of studies comparing the systematic changes in the structure of enhancers and their influence on the oral mucosal membranes. For example, for insulin absorption in rats, it was shown that sodium glycocholate, laureth-9, sodium laurate, and sodium lauryl sulphate were approximately equipotent. Several non-ionic surfactants having a Ci2 hydrophobic tail were much less effective.P 24]... 

Aqueous emulsions of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate were polymerized with y-radiation from a Co source in the presence of sodium dodecyl sulfate or sodium laurate. The continuous measurement of conversion and reaction rate was carried out dilato-metrically. The acrylates polymerized fastest and the over-all polymerization rate increased as follows styrene < methyl methacrylate < ethyl acrylate methyl acrylate. The effects of radiation dose, temperature, and original monomer and emulsifier concentrations were studied with respect to the following factors properties of polymer dispersions, number and size of polymer particles, viscometrically determined molecular weights, monomer-water ratio, and kinetic constants. 

Several other pyrolytic studies were performed on nylon 6. In one such study [4], the influence of several aliphatic carboxylates on nylon 6 thermal degradation was studied. The carboxylates that were evaluated include sodium butyrate, sodium caproate, sodium a-ethylcaproate, sodium caprylate, sodium laurate, potassium caproate, potassium laurate, and lithium caproate. Small amounts of these aliphatic carboxylates strongly increase the thermal decomposition rate even at 280° C. The effect of aliphatic carboxylates can be explained by the deprotonation of one of the amide groups of the polymer followed by the nucleophilic substitution of a neighboring carbonyl group, in a reaction as shown below ... 

The adsorption kinetics of a mixture of surfactants (sodium dodecyl sulfate and sodium laurate) onto a vacuum-deposited AI2O3 film and diphenylchlorosi-lane [322] and phthalocyanines [323] on chemically deposited silicon oxide on silicon was also studied [324], Coated ATR was also effective in the IR spectroscopic studies of adsorption on polymers (Section 7.7). 

Peper showed [195] that in the presence of 1.8 X 10" M calcinm chloride, the adverse effect of these sodium soaps on both foamability and foam stability of a 3 X 10 M (1.0 g dm" ) sodium dodecylbenzene sulfonate solution was in the order sodium stearate sodium palmitate > sodium oleate > sodium laurate, which follows the order of solubility products of the corresponding calcinm soaps (calcium... 

In their study of the emulsifier effect on the lipolytic activity, Mozaffar et al. [28] foxmd that the activity of the extracellular lipase of Pythium ultimum was more affected by the surfactant structure than by the surface area of the oil droplets. Replacing linear alkylbenzene sulfonate (LAS) by alpha olefin sulfonate or alkyl ether sulfate severely impairs the activity of Lipolase [16]. Other lipases are strongly inhibited by LAS, but not by sodium dodecyl sulfate (SDS) and sodium laurate, or by Aerosol OT and by cetyl trimethyl ammonium bromide (CTAB) but not by SDS. At low concentration, some nonionic surfactants favor and others impair the lipolytic activity [27]. Another lipase has been reported to be inhibited by anionic surfactants [29]. 

Counterion effects (5). Experiments which have been carried out using lithium, sodium, potassium, ammonium and morpholinium laurates have shown that the effects of these five laurates upon mechanical and chemical stability are broadly similar, although such differences as are observed are statistically significant. 

Some data are also available for the effect of the counterion of a dodecyl sulphate upon its ability to enhance the mechanical stability of natural rubber latex. As in the case of the laurates the lithium, sodium, potassium and ammonium salts are similar in behaviour, but the morpholinium salt is slightly less effective. Again, the latter effect is attributed to specific adsorption of the morpholinium cation. Calcium and magnesium dodecyl sulphates are also effective in enhancing mechanical stability, their abilities being similar to that of morpholinium dodecyl sulphate. 

The effect of micellar solutions of sodium dodecanoate (laurate) and n-dodecyltrimethylammonium bromide on the rate of alkaline hydrolysis of p-nitrophenyl acetate, mono-p-nitrophenyl dodecanedioate, and p-nitrophenyl octanoate has been investigated by Menger and Portnoy... 

The most effective additives for increasing the stability of the foam produced by surfactant solutions appear to be long-chain, often water-insoluble, polar compounds with straight-chain hydrocarbon groups of approximately the same length as the hydrophobic group of the surfactant. Examples are lauryl alcohol for use with sodium dodecyl sulfate, Af,/V-bis(hydroxyethyl) lauramide for use with dodecylbenzenesulfonate, lauric acid for use with potassium laurate, and N,N-dimethyldodecylamine oxide for use with dodecylbenzenesulfonate and other anionics. 

It may be mentioned that the stearate above i 5 normal is hardly a solution, 1 5N sodium stearate at 90° is a viscid gum On the other hand, 2 oN potassium laurate solution with a similarly shaped curve is a clear oily liquid The form of the curve is thus due to the constituents in the system and is not due to mechanical effects, eg gel formation, skins on the surface, or other changes of state The effect is also not due to hystensis, as is the case m the dehydration of certain gels, for it is independent of the age or method of preparation of the soap solution or whether water may have been previously added or taken away It will be pointed out later that the existence of the minimum m the boiling pomt nse is due to dehydration of the colloidal constituents, thereby releasing a quantity of solvent which effectively dilutes the solution and thus produces a diminished nse in the boiling point Were it not for this, the boiling point would nse steadily all the way with increase m concentration... 

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