New Catalytic Materials for the Direct Epoxidation of Propylene by Molecular Oxygen

The direct vapor-phase production of propylene oxide (PO) from propylene and molecular oxygen without the use of a coreactant remains a challenging problem in industrial catalysis, in spite of several decades of research. Herein, the discovery of a new class of silica-supported multimetallic RuO2-CuOx-NaCl catalysts for the direct synthesis of PO from propylene and molecular oxygen is reported. This trimetallic catalyst exhibits durability and delivers PO selectivities of 40-50% at propylene conversions of 10-20% within 240-270 degrees C and at atmospheric pressure. The best performing catalysts are characterized by powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM) and are determined to be composed of nanocrystalline domains of the three phases of RuO2, CuOx, and NaCl.