High temperature calcination of selectivated molecular sieve catalysts for activity and diffusional modification

• Main Author: BECK JEFFREY SCOTT,BORGHARD WILLIAM G.,CHESTER ARTHUR WARREN,KENNEDY CARRIE L.,STERN DAVID LAWRENCE
• Format: Patent
• Language: English
• Published: 20.09.2006
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; CRACKING HYDROCARBON OILS; FUELS; LUBRICANTS; METALLURGY; MINERAL WAXES; ORGANIC CHEMISTRY; PEAT; PERFORMING OPERATIONS; PETROLEUM, GAS OR COKE INDUSTRIES; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVEHYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, ORGASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; TECHNICAL GASES CONTAINING CARBON MONOXIDE; THEIR RELEVANT APPARATUS; TRANSPORTING

A method is disclosed for modifying a catalytic molecular sieve for shape-selective hydrocarbon conversions comprises: a) selectivating said catalytic molecular sieve by contacting with a silicon-containing selectivating agent; and b) calcining the selectivated catalytic molecular sieve at high temperature calcination conditions comprising temperatures greater than 700° C., which conditions are sufficient to reduce acid activity as measured by alpha value and increase diffusion barrier of said catalytic molecular sieve as measured by the rate of 2,3-dimethylbutane uptake, as compared to the selectivated catalyst. Catalytic molecular sieves thus prepared, such as silica-bound ZSM-5, and their use in hydrocarbon conversion processes such as aromatics isomerization, e.g., xylene isomerization, ethylbenzene conversion and aromatics disproportionation, e.g., toluene disproportionation are also disclosed.