Molecular dynamics simulation of a binary mixture near the lower critical point

TL;DR

This study uses molecular dynamics simulations to investigate the phase behavior of a 2,6-lutidine/water mixture near its lower critical point, successfully matching experimental data and critical exponents.

Contribution

The paper develops and validates an atomistic model for 2,6-lutidine, accurately locating the lower critical point and confirming the universality class through simulation.

Findings

Lower critical point close to experimental value

Critical exponents agree with 3D Ising universality class

Validated atomistic model for 2,6-lutidine/water mixture

Abstract

2,6-lutidine molecules mix with water at high and low temperatures but in a wide intermediate temperature range a 2,6-lutidine/water mixture exhibits a miscibility gap. We constructed and validated an atomistic model for 2,6-lutidine and performed molecular dynamics simulations of 2,6-lutidine/water mixture at different temperatures. We determined the part of demixing curve with the lower critical point. The lower critical point extracted from our data is located close to the experimental one. The estimates for critical exponents obtained from our simulations are in a good agreement with the values corresponding to the $3D$ Ising universality class.