In the present work, a group contribution model is proposed for estimating the dynamic viscosity of fatty compounds. For the major components involved in the vegetable oil industry (such as fatty acids, esters and alcohols, triacylglycerols, and partial acylglycerols), the optimized parameters are reported. In order to improve the data bank gathered from the literature, viscosity data were measured as a function of temperature for three saturated and three unsaturated fatty esters, one unsaturated fatty acid, and one unsaturated triacylglycerol. These last two are unavailable data in the literature (linolenic acid and trilinolenin). A simple method of calculation is also proposed to predict the dynamic viscosity of vegetable oils as an extended applicability of our equation. The model can be a valuable tool for designing processes and equipment for the oil industry, including edible and non-edible compounds, such as biodiesel.

Viscosity data have been measured as a function of temperature for two pure polyunsaturated fatty compounds (linoleic acid and trilinolein), for two multicomponent fatty systems, for a commercial-grade oleic acid (approximately 80% pure), and for canola oil. The measurements were performed in Cannon Fenske glass capillary kinematic viscometers. The contents of a large data bank, containing viscosity data for saturated, monounsaturated, and polyunsaturated pure fatty substances, were correlated by an equation based on the number of carbon atoms and double bonds. By using this equation for pure compounds and the UNIMOD group contribution method for mixtures, the viscosity data for model fatty systems, commercial oleic acid, and canola oil were predicted. The good results obtained in the present work indicate that this approach can be a valuable tool for designing or evaluating chemical process equipment for the oil industry.

Viscosity data of fatty compounds and their mixtures are important for designing equipment for the oil industry, including edible, as some vegetable oils, and nonedible purposes, as biodiesel. To expand the data bank gathered from the literature, the present work reports viscosity data of fatty mixtures found in the oil and fat industry, such as mixtures of fatty acids, methyl esters, and triacylglycerols, over a large range of temperatures. Viscosities of these fatty mixtures as well as viscosity data taken from the literature were predicted by known methods, such as the modified Kay's rule, the Kendall and Moore model, and GC-UNIMOD. In general, the three models presented a good representation of the kinematic viscosity of fatty mixtures. For the majority of cases (or 77.1 %), the average relative deviations (ARD) obtained were not higher than 10 %.