Interfacial kinetics in octane based emulsions. Effects of surfactant concentration on the reaction between 16-ArN2+ and octyl and lauryl gallates

Physical evidence that the variations in the efficiency of homologous series of antioxidants in emulsions are a result of differences in their distribution

“…Alternatively, AOs with high P W O values are hydrophobic and essentially water insoluble and, in emulsions, they mainly distribute between the oil and interfacial regions . AOs with moderate P W O values are of medium hydrophobicity and can be distributed between the oil, water and interfacial regions of emulsions, whereas those with very high P O I and P W I values are exclusively located in the interfacial region of the emulsion …”

“…26 AOs with moderate P W O values are of medium hydrophobicity and can be distributed between the oil, water and interfacial regions of emulsions, 7,8,19 whereas those with very high P O I and P W I values are exclusively located in the interfacial region of the emulsion. 27,28 The values of the partition constant (P W O ) for CA and its alkyl esters were determined in binary soybean oil-water mixtures, in the absence of surfactant, as indicated in the present study at t = 25 ∘ C ( Table 2). P W O values increase by approximately 2 x 10 3 fold with increasing hydrophobicity of the AO, ranging from P W O ≈ 0.09 for CA to 314 for the C 16 ester.…”

Interfacial Engineering of Pickering Emulsion Co-Stabilized by Zein Nanoparticles and Tween 20: Effects of the Particle Size on the Interfacial Concentration of Gallic Acid and the Oxidative Stability

“…Equations (2) and (3) describe the relationship between P W I and k obs , where [GA T ] is the GA concentration in total emulsion volume; k I indicates a second-order rate constant in interfacial region; and Φ w is the volume fraction of the aqueous phase. Readers may refer to Reference [30] for detailed calculations. Moreover, the partition constants P W I could be assessed by fitting the experimental data to Equation (3) (1/k obs vs. Φ I ).…”

Biphasic Epoxidation Reaction in the Absence of Surfactants—Integration of Reaction and Separation Steps in Microtubular Reactors

“…Careful consideration of the different chemical and physical steps taking place in the biphasic system and modeling of the observed reactivity using a pseudophase kinetic model previously applied to emulsion systems , provides some insight into the system. The different steps taking place in the biphasic epoxidation of sunflower oil using Na 2 WO 4 as catalyst are schematically represented in Figure .…”

“…The rate of reaction in biphasic systems is independent of the contact area when any of the chemical (reaction) steps taking place either in the oil or in the aqueous phase is kinetically slower than the diffusion steps, including bulk diffusion of molecules in the oil and aqueous phase or across the phases. Careful consideration of the different chemical and physical steps taking place in the biphasic system and modeling of the observed reactivity using a pseudophase kinetic model previously applied to emulsion systems 21,22 provides some insight into the system. The different steps taking place in the biphasic epoxidation of sunflower oil using Na 2 WO 4 as catalyst are schematically represented in Figure 3.…”