Frenkel Line and Solubility Maximum in Supercritical Fluids

TL;DR

This paper maps the Frenkel line in supercritical fluids like CO2, H2O, and CH4, revealing its relation to solubility maxima and providing insights into the physical state transitions in these systems.

Contribution

It introduces the first mapping of the Frenkel line for real fluids and explores its connection to solubility maxima, advancing understanding of supercritical fluid behavior.

Findings

Frenkel line can be mapped for CO2, H2O, and CH4.

Frenkel line trends similar to melting line above critical pressure.

Frenkel line may indicate optimal conditions for solubility.

Abstract

A new dynamic line, the Frenkel line, has recently been proposed to separate the supercritical state into rigid-liquid and non-rigid gas-like uid. The location of Frenkel line on the phase diagram is unknown for real uids. Here, we map the Frenkel line for three important systems: CO2, H2O and CH4. This provides an important demarcation on the phase diagram of these systems, the demarcation that separates two distinct physical states with liquid-like and gas-like properties. We find that the Frenkel line can have similar trend as the melting line above the critical pressure. Moreover, we discuss the relationship between unexplained solubility maxima and Frenkel line, and propose that the Frenkel line corresponds to the optimal conditions for solubility.