Process for co-producton of metaxylene and paraxylene

A process for co-production of metaxylene and paraxylene from a hydrocarbon feedstock wherein the process comprises a separation stage of the feedstock in a simulated moving bed in at least one chromatographic column containing a plurality of beds of an adsorbent, interconnected in a loop, said column comprising an injection of the feedstock, a draw-off of a first raffinate, a draw-off of a second raffinate comprising metaxylene, an injection of desorbent and a draw-off of an extract comprising paraxylene, whereby the process comprising simultaneous periodic offsetting of injection positions and draw-off position of the extract of a bed in the direction of flow of the main flux that circulates in the column, wherein a first raffinate comprising desorbent, orthoxylene, metaxylene and ethylbenzene is drawn off continuously or intermittently, a second raffinate R2 comprising orthoxylene and metaxylene is drawn off intermittently, and the second raffinate is distilled to recover orthoxylene and metaxylene separately with at least 99% purity, and with an improved yield.