Mass transport characteristics of alkyl amines in a water/n-decane system

• Published in: Journal of colloid and interface science Vol. 372; no. 1; pp. 164 - 169
• Main Authors: Winkelmann, Marion, Schneider, Lena, Gerlinger, Wolfgang, Sachweh, Bernd, Miller, Reinhard, Schuchmann, Heike Petra
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.04.2012; Elsevier
• Subjects: adsorption; Alkyl amines; Amines; chemical structure; Chemistry; Colloidal state and disperse state; Diffusion; Diffusion coefficient; diffusivity; Droplets; Effective diffusion coefficient; Emulsifiers; Emulsions; Emulsions. Microemulsions. Foams; Exact sciences and technology; General and physical chemistry; Interfacial tension; mass transfer; nanoparticles; oil fields; oils; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Surface chemistry; Surface physical chemistry; surface tension; Two phase system; Alkyl amines; Two phase system; Interfacial tension; Effective diffusion coefficient; Water; Molecular structure; Interface tension; Nanoparticle; Emulsifier; Mechanism; Particle; Precipitation; Amine; Emulsion; Alkyl; Diffusion coefficient; Diffusion; Surface activity; Stability; Droplet; Continuous phase; Mass transfer; Drop; Water soluble compound; Decane; Oil; Adsorption; Diffusion barrier; Transport; Physicochemical properties; Interface
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2012.01.006

[Display omitted] ► A photometrical method is applied to determine effective diffusion coefficients. ► We investigated alkyl amines at the water/n-decane interface. ► The effective diffusion coefficient depends on the adsorption behaviour of the amines. ► Additional surface active compounds influence the effective diffusion coefficient. Water-in-decane emulsions can be applied as reaction system for the precipitation of nanoparticles. Herein the precipitation reaction is induced once an oil as well as water soluble compound (here: alkyl amines) diffuses from the continuous oil phase into a water based droplet, loaded with the reaction partner. Thus, the mass transfer and adsorption characteristics of the alkyl amine at the interface are key parameters to understand particle formation in emulsion droplets. For this reason, the effective diffusion coefficients and the interfacial tension of different alkyl amines in a water/n-decane system were estimated. Furthermore, emulsifiers necessary for the stability of the emulsion might represent a diffusion barrier. In order to determine its influence, diffusion experiments were also conducted in the presence of emulsifier. The effective diffusion coefficients were measured using an adapted photometric method. To identify relevant adsorption characteristics of the water/n-decane/alkyl amine systems, the interfacial tension was studied with the pendant drop technique. According to the results, we can draw three conclusions: First, the effective diffusion coefficient depends on the molecular structure of the amines. Second, regarding our materials, the surface activity and surface coverage proved to be a governing parameter to describe differences in the transport mechanism. And third, the presence of additional surface active compounds leads to a decrease of the effective diffusion coefficient.