Patent ID: 6429347
Filing Date: 2002-08-06
Classification: C07C,Y02P,Y10S

Abstract:
A process for the production of para-xylene comprising:a) selectively precoking a catalyst in a catalyst bed by contacting the catalyst with a coke-forming feed at precoking conditions to give a temperature differential across the bed of catalyst during the selective precoking between a 3Â° C. increase and a 4Â° C. decrease to provide a selectively precoked catalyst; b) contacting an aromatics rich feedstock with the selectively precoked catalyst at disproportionation conditions comprising a hydrogen to hydrocarbon molar ratio of about 0.2 to 0.5 to obtain a para-xylene rich product containing para-xylene in excess of its equilibrium concentration; and c) carrying out step (b) until the catalyst conversion has decreased by greater than 2% of its initial conversion value and then rejuvenating the catalyst by increasing the molar ratio of free hydrogen to feedstock hydrocarbons to greater than 0.5.