Elastic and Inelastic Light Scattering from Distilling Microdroplets for Thermodynamic Studies

• Published in: Industrial & engineering chemistry research Vol. 35; no. 9; pp. 2834 - 2841
• Main Authors: Aardahl, Christopher L, Foss, Willard R, Davis, E. James
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 1996
• Subjects: Applied sciences; Chemical engineering; Distillation; Exact sciences and technology; Distillation; Particle size; Multicomponent mixture; Elastic scattering; Theoretical study; Evaporation; Experimental study; Droplet; Halocarbon; Binary mixture; Inelastic scattering; Chemical composition; Raman spectrometry; Kinetics; Thermodynamic properties
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie950443p

The evaporation rates of single-component droplets and the related thermodynamics of binary component droplets consisting of 1-iodododecane and 1-bromotetradecane have been explored using elastic and inelastic (Raman) light-scattering to determine the droplet size and chemical composition as diffusion-controlled evaporation proceeded. Single droplets were levitated electrodynamically in a chamber and exposed to a vapor-free nitrogen gas stream. Elastic scattering data for the single components, obtained at the same temperature, were used to determine the optical parameters and transport process parameters needed to interpret binary droplet Raman data for mixtures of the halogenated hydrocarbons. Evaporation rate theory coupled with a UNIFAC thermodynamic model for activity coefficients was shown to agree very well with experimental data collected from binary droplets. Results indicate that Raman intensity ratios associated with the C−I and C−Br bonds can be used to follow changes in composition quantitatively, but for greater accuracy more detailed analysis of the effects of morphology-dependent resonances on the Raman effect is needed.