2. Experimental
Transesterification of vegetable oils with supercritical methanol
was performed in a laboratory setup using a tubular flow reactor as
described in details in ref. [36]. The reactor volume was ∼23.5 cm3.
The reaction mixture was obtained by mixing two independent
flows of liquid reagents at the reactor inlet. The first flow was pure
methanol; it was fed to the mixer by a piston pump through a heat
exchanger, where it was heated to the reaction temperature. The
second flow was vegetable oil; it was fed directly to the mixer by
a syringe pump. The methanol/oil parameter was calculated as a
ratio of methanol to oil volume flow rates (cm3/min) at the reactor
inlet.
For experiments in this work, refined edible oils, namely, rapeseed,
sunflower, corn and cameline, and methanol (>99.8%) were
used.
The reaction products were sampled at fixed time intervals.
After several minutes, the sampled mixture simultaneously separated
into two phases: top and bottom ones. The top (less dense)