Potential Correlation between Spontaneous Emulsification and the Plait Point in the System Water/Benzene/Ethanol: A Phase Diagram Approach

Stig E Friberg

doi:10.4236/soft.2013.21001

Abstract

The separation of phases after the stability composition at a plait point is exceeded has significant effect on the reactions during spontaneous emulsification, but experimental efforts to obtain accurate information are extremely difficult, because even the smallest scattering of the numbers has a large effect on the result. In the present contribution a model system was applied that closely mirrored experimental values and the mass ratio of the two phases could be calculated with high accuracy. Extrapolation of the ratio between phase masses towards the critical composition showed the two phase masses each close to 0.5, while a composition with a miniscule difference from this composition extrapolated to 1.0. The results showed spontaneous emulsification between solutions at the plait point and water to consist of two processes; an initial extremely fast reaction and a slower process between the aqueous phase formed in the primary emulsification and water.

Highlights

The criterion for achieving spontaneous emulsification is that sufficient internal excess energy exists to compensate for the energy to form the emulsion
A recent investigation [8] of this kind gave counterintuitive results, revealing cases of addition of water leading to an initial reduction of the aqueous phase. These findings demonstrated the need to clarify the spontaneous emulsification for compositions close to the plait point, but experimentally the necessary accuracy is difficult to attain and Wheeler and Widom [9] instead calculated the interactions between di-functional (“diatomic”) molecules of the types AA, AB and BB, postulating interactions favoring the contacts of A ends with A
The present numerical calculation is based on extensive experimental information on the system water/benzene/ethanol [10,11,12,13,14,15,16], which has been characterized by algebraic expressions using probability curve functions with the Weibull approach [13,14]

Summary

Introduction

The criterion for achieving spontaneous emulsification is that sufficient internal excess energy exists to compensate for the energy to form the emulsion. A recent investigation [8] of this kind gave counterintuitive results, revealing cases of addition of water leading to an initial reduction of the aqueous phase. These findings demonstrated the need to clarify the spontaneous emulsification for compositions close to the plait point, but experimentally the necessary accuracy is difficult to attain and Wheeler and Widom [9] instead calculated the interactions between di-functional (“diatomic”) molecules of the types AA, AB and BB, postulating interactions favoring the contacts of A ends with A ends and of B ends with B ends over the contacts of A ends with B ends. For the present problem, these modeling attempts do not provide sufficient accuracy and a different algebra[17,18] was utilized in order exactly to calculate the conditions in the plait point range of the diagram, Figure 1(c)

Fundamental Basis

Basic Equations

Numerical Calculations

Discussion

Findings

Summary