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Haze point

On the other hand, if one starts from the oil phase with dissolved surfactant and add water, solubilisation of the latter takes place and hence solubilisation increases rapidly with reduction of temperature near the haze point of the surfactant. This is illustrated in Figure 2b which shows both the haze point and solubilisation curve. Between the two curves, an isotropic region of w/o solubilised system exists. At any given temperature, any increase in water weight fraction above the solubilisation limit results in water separation, i.e. w/o solubilised + water, whereas at a given surfactant concentration, any decrease in temperature below the haze point result in separation into water, oil and surfactant. [Pg.157]

The temperature at which clarity begins to develop he defined as the haze point. ... [Pg.155]

A slightly higher temperature than the haze point, where there is a marked increase in strength and elongation which could readily be noticed by simple manual stressing, he defined as the elastomeric point. ... [Pg.155]

Six transition points in all were defined by Greenhoe which, with rising temperatures, were fluid point dry point gel point haze point elastomeric point and fusion point. [Pg.156]

The term haze point has been used to describe the temperature at which cloudy material begins to form in a cooled sample. Fallout is another confusing term. In the metalworking industry, a 4-oz. glass bottle containing the sample is allowed to sit at room temperature for 48 hours. The fallout percent can be estimated volumetric ally. It is suggested that suppliers and users abide by industry standard methods when describing this aspect of rendered fats (23). [Pg.3070]

Haze point is another quality assurance tool that can be used in conjunction with cloud point. Haze point is defined as the point at which the sample starts to become hazy as it is cooled to the cloud point. In a study of partially reacted versus fully reacted methyl esters of tallow and lard, it was found that fully reacted methyl esters exhibit haze points much higher on esters in which approximately 95% of the original fatty acids as acylglycerols had been reacted to methyl ester, the haze points ranged from 5-8°C higher than the cloud points. As measured in this manner, haze points are not approved methods by AOCS standards however, the manufacturer or user of methyl esters may find these data useful. [Pg.3071]

FIG. 3.11 (a) Haze point temperature (CP, critical point amph, amphiphile). (b) Haze... [Pg.53]

The critical temperature Ta is often referred to as the haze point temperature, and the miscibility gap between oil and amphiphile plays an essential role in the ternary phase diagram. [Pg.53]

From the phase behavior of both binary mixtures (water-amphiphile and oil— amphiphile), it is now possible to account, at least qualitatively, for the three-component phase diagram as a function of temperature. The presence of a haze point on the oil-amphiphile phase diagram (critical point a) at temperature Ta shows that the surfactant is more compatible with the oil at high than at low temperature. The presence of a cloud point on the water-amphiphile phase diagram (the lower critical point (>) at temperature Tjj shows that (at least in the neighborhood of the temperature domain) the amphiphile is less compatible with water at high than at low temperature. As a consequence (the other parameters being kept constant), the amphiphile behavior depends on temperature. [Pg.57]

If the temperature at which the phase diagram is recorded is above Ta (the haze point), a critical point CPa is present near the oil vertex (although pure amphiphile and pure oil are miscible, the presence of a small amount of water recalls the lack of compatibility between amphiphile and oil). If the temperature is below Ta, no critical point appears in the three-component phase diagram (it would be positioned at a negative water concentration). [Pg.59]

A question that arises from data such as those in Fig. 2 concerns the mechanism by which the pressure-driven phase separation occurs. Two types of phase transitions are known from studies of liquid systems. At the solubilization phase boundary, reverse micelles expel excess water to form a second phase. Its location is determined by the natural curvature of the surfactant interface. The natural curvature is the preferred curvature of the interface when no interactions between droplets are present. At the haze point boundary, surfactant and water precipitate together to form a surfactant-rich second phase. This phase transition is driven by micelle-micelle interactions. It is analogous to the cloud point transition seen with increasing temperature in an aqueous micellar system. [Pg.283]

Figure 3 Phase behavior of a heptane-water -Ci 2 EO5 reverse micelle system. Open circles indicate solubilization boundary closed circles indicate haze point boundary. (From Ref. 12.)... Figure 3 Phase behavior of a heptane-water -Ci 2 EO5 reverse micelle system. Open circles indicate solubilization boundary closed circles indicate haze point boundary. (From Ref. 12.)...
An example of surfactant behavior in conventional liquid solvents is shown in Fig. 3 for the nonionic C12EO5-water-heptane system [12]. The upper boundary of the narrow one-phase region, shown by open circles, is the solubilization boundary. The lower boundary, shown by filled circles, is the haze point curve. AOT systems have the same kind of phase behavior, but since AOT is anionic the relative positions of the solubilization and haze point... [Pg.284]

An important issue in this type of behavior is the nature of the phase boundaries in the light solvents. In the case of the pentane and butane systems, the upper temperature phase boundary is marked by a gradual fogging of the solution due to precipitation of water, which is consistent with a natural curvature (solubilization) mechanism. The lower temperature boundary is marked by a sudden precipitation of both water and surfactant, which indicates a haze point (micelle-micelle interaction) transition. In the propane system it is difficult to determine the phase transition mechanism because of the low solubilization of water [12]. Nonetheless, it appears that the relative location of haze point and solubilization boundaries are the same in both light and heavy alkanes. [Pg.295]

A similar observation of increasing A gx when the temperature is increased toward the haze point was made in a comprehensive study by Lang et al. [29]. The results were later correlated with the percolation phenomenon of microemulsions as revealed by conductivity measurements [33]. Surprisingly high values of the second-order exchange rate constant... [Pg.617]

It is also important that the interaction between the droplets becomes more attractive with increasing temperature (approaching the haze point), so that the cluster lifetime should increase. Three factors determining the overall rate of solute exchange between clusters—namely, the collision rate, the lifetime of the cluster, and the exchange within the cluster—would then all increase with temperature and contribute to the activation energy determined in the stopped-flow experiments [34],... [Pg.620]

Is an amphoteric surfactant prepared from coconut oil with excellent electrolytic tolerance and is stable over a wide pH range. It exhibits very good foaming properties, a low haze point, and complexes with certain anionic surfactants to form clear, stiff gels. [Pg.255]

Nonionic ethoxylated surfactants can also be used to produce isotropic W/O microemulsions. A low HLB number surfactant may be dissolved in an oil, and such a solution can solubilize water to a certain extent, depending on surfactant concentration. If water is added above the solubilization limit, the system separates into two phases W/O solubilized - - water. If the temperature of such a two-phase system is reduced an isotropic W/O microemulsion is formed below the solubilization temperature. If the temperature is then further reduced below the haze point, sep-... [Pg.561]

Fuels more viscous than 550 sec Saybolt Universal at the starting temperature cannot be handled by some fuel-ignition pumps. Plugging of screens or cloth filters tends to occur at the cloud or haze point, which is usually about 10°F above the pour point. Finally, the cetane number... [Pg.58]


See other pages where Haze point is mentioned: [Pg.170]    [Pg.3070]    [Pg.4]    [Pg.294]    [Pg.617]    [Pg.205]    [Pg.562]   
See also in sourсe #XX -- [ Pg.148 ]

See also in sourсe #XX -- [ Pg.6 , Pg.90 ]




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