Thermophysical characterization of Brazil nut oil in pressurized solvents: Density modeling and barocaloric effect for sustainable process development

In this work, we present a comprehensive thermophysical characterization of Brazil nut oil, emphasizing its potential for sustainable applications involving pressurized fluids. Density measurements were conducted for the binary systems of Brazil nut oil + n-propane and Brazil nut oil + ethanol using a vibrating tube densimeter. The measurements were taken at elevated pressures, varying temperatures, and different mass ratios. Systems with ethanol showed higher absolute densities, and increasing the oil mass fraction led to a consistent rise in system density. The experimental data were accurately described using the Peng–Robinson equation of state with volume translation, reinforcing their applicability in designing and optimizing high-pressure extraction processes. Beyond density modeling, Brazil nut oil was found to exhibit a large barocaloric effect, with an isothermal entropy-driven temperature change (ΔT_s) of approximately (12 at 323) K and 174 MPa and a merit index of 65 K·GPa⁻¹ . This remarkable barocaloric behavior reveals this natural oil's previously unexplored thermophysical feature. The combined analysis of high-pressure density behavior and barocaloric response highlights the dual potential of Brazil nut oil as a feedstock for green extraction technologies using pressurized solvents such as n-propane and ethanol and as a promising candidate for solid-state refrigeration systems. These findings offer novel insights into the valorization of Brazil nut oil and support its integration into environmentally conscious process development within the scope of biorefinery and clean technology platforms.