The essential oil of Stachys lavandulifolia Vahl (Lamiaceae) was isolated by hydrodistillation of the aerial parts of the plant, with a yield of 0.25%. The chemical composition of volatile oil was analyzed by capillary GC and GC/ MS. The main components were germacrene-D (13.2%), ?-phellandrene (12.7%), ?-pinene (10.2%), myrcene (9.4%), ?-pinene (8.4%) and Z-?-ocimene (5.8%).

Common mass transfer models for multistage distillation show significant deviations between calculated and experimental height equivalent to a theoretical plate (HETP) values viscous feed mixtures. This is due limited transferability of the available data which were mainly obtained from experiments with inviscid Separation efficiency measurements at elevated viscosities can be conducted polymer...