GB1017632A - Process for the extraction in liquid phase of aromatic hydrocarbons from hydrocarbon mixtures containing them - Google Patents

Abstract

C6-C10 aromatic hydrocarbons are separated from mixtures thereof with one or more aliphatic, cycloaliphitic and olefinic hydrocarbons by contacting the mixture at 50-170 DEG C. with one or more anhydrous solvents whose selectivity for the aromatics is affected by the addition of water and variation of temperature, adding water to the extract and varying the temperature if necessary to obtain a separation into two layers, separating the upper aromatic layer and bringing it into counter-current contact with the lower layer at a temperature not less than the temperature at which separation was carried out and separating the aromatics from the final extract. The light hydrocarbon phase separated from the first extract may be partially recycled to the first stage and/or only partially contacted with the lower layer in the counter-current extraction. Light paraffins and/or an aromatic reflux may be added to the counter-current extraction. The raffinate from the counter-current extraction may be partially or completely recycled to either the first stage or the separated light hydrocarbon phase. The amount of water added after the first extraction may be 1-30 vol. per cent of the solvent employed. Solvents specified are alcohols, glycols, ethers of glycols or ethylenic poly-glycols, phenyl ethanolamine, ethanolamines, amides, nitriles, dinitriles, oxydinitriles, phenol, nitrophenols, cresols, nitrocresols, acetophenone, dioxane, benxophenone and formamides. The examples describe the separation of xylenes from n-heptane and the aromatics from various gasolines.