Vapor‐liquid equilibria from perturbation gas chromatography. Part II: Application to the polybutadiene/benzene/cyclohexane ternary system

Abstract

This work brings together recent gas chromatography experiments and theory involving multiple sorbing species at finite concentration, and theories for multicomponent polymer solutions by means of the parameter estimation procedure of Part 1. Results quantitatively describe the wide variation in peak retention times that are caused by phase equilibrium and chromatographic interference, the best solution models doing so to within or near experimental error. The chromatographic method is capable of detecting differences and peculiarities in the various polymer solution models in both the accuracy of the calculated retention times and the sensitivities of the calculations to the model parameters. Perturbation chromatography offers some unique capabilities for multicomponent vapor-liquid equilibrium determinations.

Composition profiles in multicomponent perturbation gas chromatography

“…Experimentally, in finite concentration systems, upon injecting a given species into the column, one may observe positive response peaks, negative response peaks, or both, depending upon the systems studied and upon the sorption isotherms. One such example is reported in Ruff et al (1986b). In this work we take the isotherms thus determined and use them in the model outlined above to calculate detailed species composition curves or column responses as functions of position and time.…”

“…While in binary systems with only one sorbing component the response peak is fairly uninteresting, in multicomponent systems, the responses can be very intriguing indeed. Injecting a component upstream of a column can produce responses downstream which are measured as "positive" peaks, "negative" peaks, and interesting combinations of positive and negative (Ruff et al, 1986b).…”

Modeling osmotic pressure second virial and preferential adsorption coefficient data of ternary solvent-polymer-solvent systems using equation-of-state solution theories

“…30 The multicomponent forms of the three EOS solution theories are presented in Tables I and II. 31 This choice of theories provides a variety of means for accounting for species free volume and surface contact area dissimilarities. All three theories account for free volume dissimilarities among the species.…”

Equation of State Modeling of the Solubility of CO2/C2H6 Mixtures in Cross-Linked Poly(ethylene oxide)

“…The knowledge of the solubility of fluid mixtures in polymers is essential for several industrial applications, although at the moment only a very few, time-consuming procedures have been established to measure mixed gas or vapor sorption in polymers. − Compared to pure gas solubility, the number of experimental data sets available in the literature for multicomponent sorption in polymers is rather limited. Most of the studies in this field focus on removal of solvent mixtures from polymers, and the data are obtained by inverse gas chromatography (IGC) over limited ranges of operating conditions, often with little industrial interest. − Indeed, the temperatures explored in these cases are often far above those of interest for most of the polymers considered, the pressures investigated are rather low (usually atmospheric), and the range of compositions studied are very narrow, since at least one of the penetrants is present in trace amounts in the gaseous phase.…”