| abstract |
THERE IS PROVIDED A PROCESS FOR THE SELECTIVE PRODUCTION OF PARA-XYLENE WHICH COMPRISES REACTING TOLUENE WITH METHANOL IN THE PRESENCE OF A CATALYST COMPRISING A POROUS CRYSTALLINE MATERIAL HAVING A DIFFUSION PARAMETER FOR 2,2 DIMETHYLBUTANE OF ABOUT 0.1-15 SEC-1 WHEN MEASURED AT A TEMPERATURE OF 120°C AND A 2,2 DIMETHYLBUTANE PRESSURE OF 8 KPA (60 TORR). THE POROUS CRYSTALLINE MATERIAL IS PREFERABLY A MEDIUM-PORE ZEOLITE, PARTICULARLY ZSM-5, WHICH HAS BEEN SEVERELY STEAMED AT A TEMPERATURE OF AT LEAST 950°C. THE POROUS CRYSTALLINE MATERIAL IS PREFERABLY COMBINED WITH AT LEAST ONE OXIDE MODIFIER, PREFERABLY INCLUDING PHOSPHORUS, TO CONTROL REDUCTION OF THE MICROPORE VOLUME OF THE MATERIAL DURING THE STEAMING STEP. |