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

Abstract From the Canadian patent

A method is disclosed for modifying a catalytic molecular sieve for shapeselective 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 …