Inter-relationships among the properties of fatty oils

Abstract

Properties of fatty oils, such as viscosity (η), iodine value (IV) and saponification value (SV), are useful in the design of methods and equipments for the processing of the fatty oils to value-added products. This investigation is aimed at the development of generalized empirical relationships based on a model similar to the Antoine equation for vapor pressure. Two equations resulted. The first equation: log η = [−1.4 + 1.25 (IV/SV)] + [500 − 375 (IV/SV)]/ [(t + 140) − 85 (IV/SV)] relating the logarithm of viscosity to the ratio of iodine value to saponification value (IV/SV) and temperature in degrees centigrade (t), gives an average absolute deviation of 13.0% at 77 data points of several fatty oils. The second equation, somewhat simpler in form: log η = −0.6298 + [273.66/ (t + 88.81) ] relating the logarithm of viscosity directly to the temperature in degrees centigrade (t), gives an average absolute deviation of 14.5% at 89 data points of a larger group of fatty oils ranging from almond to tallow.

The two equations can be used conveniently to predict either viscosity, iodine value or saponification value, when the other two properties are known, for design purposes.