One-pot two-step process for direct propylene oxide production catalyzed by bi-functional Pd(Au)@TS-1 materials

• Bi-functional catalysts based on palladium and gold nanoparticles supported onto active nanocrystalline TS-1 zeolite are prepared and characterized.
• Active and reusable catalysts for the direct PO production from H2, O2 and C3= with the in-situ generation of intermediate H2O2 are evaluated.
• One-pot two-step consecutive process is carried out using only one stable catalyst with high selectivity for PO production.
• Modification of suitable reaction parameters, working under safety supercritical CO2 conditions, allowed the optimization of catalytic results.

Different bi-functional materials (Pd(Au)@TS-1) based on metallic nanoparticles supported onto active nanocrystalline titanium silicalite (TS-1) zeolites were synthesized, characterized and used as recyclable heterogeneous catalysts for direct propylene oxide production from hydrogen, oxygen and propylene through one-pot two-step consecutive process. These catalysts allowed carrying out the combined reaction where metallic nanoparticles catalyzed the formation of in situ H2O2 that was the necessary intermediate for propylene epoxidation catalyzed by active TS-1 nanocrystalline support. Several variables were considered such as use of supercritical CO2 conditions, modifiable content of metallic species, and presence of additional co-solvents, surface acidity inhibitors and H2O2 stabilizers. Reusability and stability of the bi-functional catalyst was showed through consecutive catalytic cycles.

Figure optionsDownload high-quality image (153 K)Download as PowerPoint slideReusable bi-functional catalysts based on Pd and Au nanoparticles supported onto active TS-1 nanocrystalline matrix for direct propylene oxide production by one-pot two-step consecutive reaction under safety CO2 supercritical conditions.