Disproportionation of xylenes

Claim 1

A PROCESS WHICH COMPRISES CONTACTING AT LEAST ONE XYLENE IN THE ABSENCE OF ANY SUBSTANTIAL PROPORTION OF BENZENE IN A REACTION ZONE WITH BETWEEN ABOUT 3 MOLS OF ABOUT 20 MOLS OF LIQUID HYDROGEN FLUORIDE PER MOL OF SAID XYLENE AND BETWEEN ABOUT 0.01 AND ABOUT 3 MOLS OF BF3 PER MOL OF SAID XYLENES AT A TEMPERATURE BETWEEN ABOUT 250* F. AND ABOUT 600* F., UNDER A PRESSURE SUFFICIENT AT LEAST TO MAINTAIN A LIQUID PHASE TO PRODUCE A MIXTURE OF ISOMERIC XYLENES AND TO EFFECT DISPROPORTIONATION OF A XYLENE TO FORM TOLUENE AND MESITYLENE, SUBJECTING THE REACTION PRODUCTS TO SELECTIVE EXTRACTION WITH LIQUID HYDROGEN FLUORIDE IN MOLAR EXCESS, BASED ON TOTAL XYLENES IN SAID REACTION PRODCUTS, AND WITH BF3 IN AN AMOUNT BETWEEN ABOUT 0.2 AND ABOUT 0.8 MOL PER MOL OF XYLENES AND MESITYLENE IN SAID REACTION PRODUCTS AT A TEMPERATURE BETWEEN ABOUT 0* F. AND ABOUT 150* F. UNDER A PRESSURE SUFFICIENT AT LEAST TO MAINTAIN A LIQUID PHASE, SEPARATING THE EXTRACTION MIXTURE INTO A LIQUID HYDROCARBON LAYER SUBSTANTIALLY ENRICHED IN ORTHO- AND PARAXYLENES AND TOLUENE, AND A SOLUTION OF METAXYLENE AND MESITYLENE IN LIQUID HYDROGEN FLUORIDE AND BF3, AND RECYCLING AT LEAST A PORTION OF SAID HYDROCARBON LAYER TO SAID REACTION ZONE.