High-temperature and high-pressure density and liquid–vapor phase transition properties of methyl octanoate as main biofuel component

High-Temperature and High-Pressure PVT Measurements of the Binary n-Hexane + Methyl Octanoate Mixture near the Critical Point of the Pure Solvent (n-Hexane)

“…The experimental details, physical bases of the method, design of the high-temperature and high-pressure constant-volume measuring cell (piezometer) and PVT apparatus, procedure of measurements, and uncertainty assessment have been described in our previous several publications. ,,− A brief review is given here. The experimental PVT apparatus included a high-temperature and high-pressure constant-volume piezometer (measuring cell, the main part of the PVT apparatus); the system for the temperature control; the pressure measurement unit; and the sample filling unit.…”

“…A literature survey revealed that there are no any thermodynamic property data for the binary n -hexane + methyl octanoate mixture reported in the literature at high temperatures and high pressures, especially near the critical point, except our previous publication . Pure components of the mixture ( n -hexane and methyl octanoate) are well-studied (see our previous publication). There are a series of publications on density measurements for the related mixtures such as n -heptane + FAMEs. ,− A detailed review of these papers is reported in our previous publication …”

“…This work is part of a long-term research project ,,− dealing with the experimental study of thermodynamic and transport properties of pure liquids and liquid mixtures near and at supercritical conditions. The aim of these studies is to deeply understand and improve our understanding of the molecular interactions, which define the phase behavior and thermodynamic properties of complex liquid mixtures with different shapes, size, and chemical nature near the critical point of the pure solvent ( n -hexane).…”

“…The aim of these studies is to deeply understand and improve our understanding of the molecular interactions, which define the phase behavior and thermodynamic properties of complex liquid mixtures with different shapes, size, and chemical nature near the critical point of the pure solvent ( n -hexane). The method and experimental high-pressure and high-temperature constant-volume PVT apparatus has successfully been used previously to accurately measure the PVT and phase transition properties ( P S ,ρ S , T S ) of main components of biofuel, ,, aqueous hydrocarbon solutions, ,− and other molecular liquids (alcohols and hydrocarbons) . In our previous publications, , we have reported PVT , phase transition ( P S ,ρ S , T S ), and the critical ( P C ,ρ C , T C ) properties of pure methyl octanoate and binary n -hexane + methyl octanoate ( x = 0.028 mol fraction of methyl octanoate) over a temperature range from 293 to 623 K at pressures up to 18 MPa using the same high-temperature and high-pressure constant-volume PVT apparatus.…”

“…The method and experimental high-pressure and high-temperature constant-volume PVT apparatus has successfully been used previously to accurately measure the PVT and phase transition properties ( P S ,ρ S , T S ) of main components of biofuel, ,, aqueous hydrocarbon solutions, ,− and other molecular liquids (alcohols and hydrocarbons) . In our previous publications, , we have reported PVT , phase transition ( P S ,ρ S , T S ), and the critical ( P C ,ρ C , T C ) properties of pure methyl octanoate and binary n -hexane + methyl octanoate ( x = 0.028 mol fraction of methyl octanoate) over a temperature range from 293 to 623 K at pressures up to 18 MPa using the same high-temperature and high-pressure constant-volume PVT apparatus. In the present work, we reported new PVT and phase transition ( P S ,ρ S , T S ) and critical ( P C ,ρ C , T C ) property data for the binary mixture with the composition of x = 0.057 mol fraction of methyl octanoate in order to accurately determine the initial slopes of the critical lines P C ( x ), ρ C ( x ), and T C ( x ) to estimate the Krichevskii parameter and other physically meaningful characteristic parameters, which define the critical behavior of the thermodynamic properties of the binary mixture (0.943 n -hexane + 0.057 methyl octanoate).…”