Titration curves, conductometric hexadecyltrimethylammonium

The form of the titration curve with cetyl alcohol varied according to the hexadecyltrimethylammonium bromide-cetyl alcohol molar ratio. Figure 2 shows the conductometric titration curves for hexadecyltrimethylammonium bromide-cetyl alcohol ratios of 1 0.33 to 1 6. These curves show that, with increasing proportion of... 

The mechanism of this mini-emulsion emulsification process was investigated by the conductometric titration of aqueous hexadecyltrimethylammonium bromide-cetyl alcohol mixtures with benzene or styrene combined with transmission electron microscopic examination of the morphology of the mixed emulsifiers and the styrene droplets formed (2,8). Figure 1 shows that the titration curves with and without cetyl alcohol are quite different that for... 

The actual solute and micellar concentrations of hexadecyltrimethylammonium bromide should be lower than the calculated values because the rodlike particles and micellar aggregates are assumed to be non-conducting. The negative value calculated for the concentration in rodlike particles for the 1 0.33 hexadecyltrimethylammonium bromide-cetyl alcohol molar ratio is essentially zero. Figure 2 shows that the benzene conductometric titration curve for the 1 0.33 hexadecyltrimethylammonium bromide-cetyl alcohol ratio is very close to that for the same concentration of hexa-decyltrimethylammonium bromide without cetyl alcohol (Figure 1). 

Figure 10 shows that varying the hexadecyltrimethylammonium bromide concentration at the same hexadecyltrimethylammonium bromide-cetyl alcohol ratio changed the conductometric titration curve. For 0.4% hexadecyltrimethylammonium bromide at the 1 3 molar ratio, the conductometric titration curve showed no initial descending leg, suggesting that this system contained no emulsifier micelles. In comparison, the conductometric titration curve for 0.6% hexadecyltrimethylammonium bromide-cetyl alcohol at the... 

Figure 11 shows that the conductometric titration curves for 0.6% hexadecyltrimethylammonium bromide were essentially the same for molar ratios of 1 6 and 1 7. In both cases, the absence of a descending leg suggests that no micelles were present. Therefore, a further increase in the cetyl alcohol concentration resulted in an increase of that incorporated into the rodlike particles, which diminishes the crystallinity but gives no significant change in the conductometric titration curve. 

The complex variation of the conductance with added oil volume at a given hexadecyltrimethylammonium bromide concentration was shown by a three-dimensional conductance-oil volume-cetyl alcohol concentration plot. The conductometric titration curves of Figure 2 were fitted using various equations. The best fit was obtained with the following expression. 

Table VI gives the values of these thirteen coefficients for the conductometric titration curves of Figure 2 and 0.6% hexadecyltrimethylammonium bromide at molar ratios of 1 0.33, 1 0.50, 1 1, 1 3, and 1 6.

Figure 15. Three-dimensional plot of family of conductometric titration curves calculated using Equation 2 for titration at 63°C of 25 cc water containing 0.15 g hexadecyltrimethylammonium bromide and varying concentrations of cetyl alcohol with benzene at a constant rate of Icc/min viewed at a horizontal angle of 275° and a vertical angle of 50°.

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