Density and conversion in Biodiesel Production with Supercritical Methanol

A. VELEZ; P. HEGEL; G. MABE; E. A. BRIGNOLE

Sorrento

Conferencia; 9th Conference on Supercritical Fluids and Their Applications; 2010

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 a given molar ratio. For each studied condition the mixture was brought to a temperature at which the system became homogeneous. The isochoric (constant volume) relation between temperature and pressure at this particular density and composition was recorded. In the temperature range of 550 – 630 K, a high conversion of the oil to the corresponding fatty esters and glycerin was obtained.  The densities of sunflower oil with methanol for two different alcohol/oil ratios: 40 and 25 were measured. Densities of coconut oil + methanol and methyl oleate + methanol mixtures were also measured.  The effect of global density on conversion was studied at long reaction times (3-4 hrs).  Strong evidence of the phase transitions of the reacting mixtures, from heterogeneous to homogeneous, was obtained from the experimental results.