SEPATATION OF XYLENE ISOMER BY PERMEATION AND EVAPORATION

摘要

PURPOSE:To separate an isomer from a mixture of various xylene isomers, by forming a eutectic crystal of the xylene isomers and carbon tetrabromide, contacting the eutectic crystal with a permeation and evaporation separation membrane, heating the crystal, and evacuating the other side of the membrane, or keeping the other side of the membrane under a low vapor pressure with the flow of an inert gas. CONSTITUTION:Various xylene isomers including p-xylene is mixed with carbon tetrabromide at 13-55 deg.C to form a eutectic crystal of xylene and carbon tetrabromide. The obtained eutectic crystal is placed on a permeation and evaporation separation membrane (preferably polyolefin film) and left at rest. The eutectic crystal is melted at a temperature higher than the temperature in the formation of the crystal, and the separation membrane is evacuated or is subjected under the flow of an inert gas to obtain a xylene component having increased p- xylene content. The ratio of the carbon tetra-bromide to the sum of the mixed xylene and carbon tetrabromide is preferably 12-90mol%.