SEPARATION OF HIGHER MOLECULAR-WEIGHT ORGANIC-COMPOUNDS BY PERVAPORATION

Two-liquid phase bioconversions can be used to produce medium and long -chain 1-alkanols from the corresponding n-alkanes. A pervaporation pr ocess has been investigated for the separation of the product accumula ted in the apolar phase of such a two-liquid fermentation system. The separation characteristics of various dense membranes towards organic mixtures (octane/1-octanol) were determined. The performance of eighte en membranes in separating 1-octanol from a large excess of octane has been tested. The different membranes showed either reasonably high se lectivity (alpha) and low permeation rates or low selectivities and hi gh fluxes. Minimal requirements of the pervaporation process for a des ired selectivity with one and multistage pervaporations are presented. The results indicate that it should be possible to separate economica lly interesting organic products from higher molecular weight organic mixtures, by tailoring suitable membranes with a reasonably good selec tivity and high flux for single or for multistage pervaporation system s. (C) 1997 Elsevier Science S.A.