Zeolitic materials with modified surface composition, crystal structure, crystal size, and/or porosity, methods for making the same, and methods for converting oxygenates to olefins via reactions catalyzed by the same

Abstract

Zeolitic materials with modified surface composition, crystal structure, crystal or particle size, and/or porosity, methods for making the same, and methods for converting oxygenates to olefins using the same are provided herein. In an exemplary embodiment, a method for reducing a surface silicon content of a silicon-containing zeolitic material is provided that includes providing a silicon-containing zeolitic material; and contacting the silicon-containing zeolitic material with a modifying solution comprising one or more of an amine, an alcoholamine, and an amino acid. In this embodiment, the contacting occurs under conditions suitable for the modifying solution to reduce a surface silicon content, increase the porosity, and/or decrease an average crystal or particle size of the silicon-containing zeolitic material.

1 . A composition of matter comprising a zeolitic material having a pore structure comprising micropores, wherein the zeolitic material has a % porosity as measured by mercury porosimetry of about 65% to about 80%; and wherein the zeolitic material comprises silicon at a first concentration within a depth of about 2 nm from a surface and a second concentration at a depth of about 40 nm or more from the surface; the first concentration being about 0.9 to about 1.6 times the second concentration. 
     
     
         2 . The composition of  claim 1 , wherein the zeolitic material comprises a silico-alumino-phosphate (SAPO) or a metal-substituted silicoaluminumphosphate (MeAPSO). 
     
     
         3 . The composition of  claim 1 , wherein the zeolitic material comprises SAPO-34, metal-substituted SAPO-34, SAPO-18, metal-substituted SAPO-18, or mixtures or intergrowths thereof. 
     
     
         4 . The composition of  claim 1 , wherein the zeolitic material comprises a bulk silicon content of about 0.01 wt. % to about 2.7 wt. % silicon. 
     
     
         5 . A composition of matter comprising a zeolitic material having a pore structure comprising micropores, wherein the zeolitic material has a % porosity as measured by mercury porosimetry of about 65% to about 80%; and wherein the zeolitic material comprises a crystalline material with an average crystal or particle size as measured by light scattering of about 400 nm to about 2500 nm. 
     
     
         6 . The composition of  claim 5 , wherein the zeolitic material comprises a silico-alumino-phosphate (SAPO) or a metal-substituted silicoaluminumphosphate (MeAPSO). 
     
     
         7 . The composition of  claim 5 , wherein the zeolitic material comprises SAPO-34, metal-substituted SAPO-34, SAPO-18, metal-substituted SAPO-18, or mixtures or intergrowths thereof. 
     
     
         8 . The composition of  claim 5 , wherein the zeolitic material comprises a bulk silicon content of about 0.01 wt. % to about 2.7 wt. % silicon.