Liquid viscosities for methyl hexanoate, methyl heptanoate, methyl caprylate, and methyl nonanoate at high pressures

The experimental measurements for liquid viscosities of four fatty acid methyl esters, including methyl hexanoate, methyl heptanoate, methyl caprylate, and methyl nonanoate, were carried out with a falling-cylinder viscometer. For the present measurement, the temperature ranges were from 292 K to 362 K and the pressure was reached to 30 MPa. The combined expanded relative uncertainty of the viscosity measurements was within 0.03 with 0.95 confidence level. The viscosity data for each studied esters were correlated by Andrade-Tait equation, and the average absolute relative deviation between the experimental data and calculated values is 0.31%, 0.44%, 0.38%, and 0.25% for methyl hexanoate, methyl heptanoate, methyl caprylate, and methyl nonanoate, respectively. The maximum absolute relative deviation is 1.09%, 1.28%, 1.28%, and 0.75%.