Solid state modification of as-synthesized SAPO molecular sieves withindium

Abstract

Solid state ion exchange of the protonic acid sites in SAPO-5, SAPO-34 and SAPO-37 molecular sieves with indium can be accomplished via thermal treatment of mechanical mixtures of as-synthesized SAPO's with In 2 O 3 in an inert gas. The organic template acts as a reducing agent in respect to the indium oxide and the volatile In 2 O is likely the intermediate species that further interacts with the SAPO protonic sites. The catalysts produced by this procedure possess very similar properties to the materials obtained through reductive solid state ion exchange of template free SAPO's that have been converted in an H + form and mixed with In 2 O 3 prior to the reduction with H 2 . Both acidity and catalytic activity in proton catalyzed reactions such as m-xylene and methanol conversions strongly decrease upon modification with indium. The novel procedure of template induced solid state ion exchange may be useful for modification of materials like SAPO-37 whose template free forms are less stable than the corresponding as-synthesized form.