VOLUMETRIC PROPERTIES OF REACTING MIXTURES IN BIODIESEL PRODUCTION WITH SUPERCRITICAL ALCOHOLS: EXPERIMENTAL MEASUREMENTS AND CORRELATION

A. VELEZ; P. HEGEL; S. ESPINOSA; E.A. BRIGNOLE

Natal, Brasil

Conferencia; II Iberoamerican Conference on Supercritical Fluids PROSCIBA; 2010

Universidade Federal do Rio Grande do Norte ? UFRN

In the current work the densities of vegetable oils + methanol reacting mixtures were measured by loading a closed vessel with a known amount of an oil/alcohol mixture of known molar ratio. The mixture is brought to a temperature above its critical conditions and the isochoric relation between temperature and pressure for this particular density and composition is recorded. In the temperature range studied 550 - 630 K, a high conversion of the oil to the corresponding fatty esters and glycerin is obtained. Under the isochoric conditions the densities of sunflower oil with methanol for two different alcohol/oil ratios: 40 and 25 were measured. Also densities of coconut oil + methanol and methyl oleate + methanol mixtures were measured. The densities of pure methanol were measured for calibration purposes. The volumetric properties in the supercritical region were compared with predictions obtained by a cubic three parameter equations of state. On this base a correlation for the volumetric properties of the reacting mixtures is proposed.