Polycyclic aromatics formation in HSAPO-34 during methanol-to-olefin catalysis : ex situ characterization after cryogenic grinding

Cryogenic grinding using a freezer mill is shown to be a useful adjunct to acid digestion for the ex situ analysis of aromatic hydrocarbons entrained in microporous catalysts. In the course of converting methanol to olefins, HSAPO-34 contains first methylbenzenes and later methylnaphthalenes. As the catalyst deactivates, significant amounts of phenanthrene and pyrene form as well.