Several Technologies for In Situ HPPO with TS-1-Supported Pd Catalysts

1 Several Technologies for In Situ HPPO with TS-1-Supported Pd Catalysts 

A process for the epoxidation of propene with in situ generation of H P was proposed in the 1990s by the Tosoh Corporation [23]. It was suggested that PO could be made via a direct reaction between hydrogen and oxygen in the presence of propene, using a catalyst made of Pd supported on crystalline titanium silicate, in a flow system. The solvent for the reaction was f-butanol, and the reaction temperature was 45 °C. A conversion of 0.8% was reported, with a selectivity for PO of 99%. 

ARCO Chem Tech (now Lyondell) has reported catalysts that show enhanced selectivity and yield for PO [24]. Again, the catalyst was made of Pd impregnated over TS-1, but the addition of either NH4OH, benzothiophene or triphenylphosphine in the reaction medium enabled an increase in the PO yield with respect to propene and H2. Selectivity was also improved due to the suppression of the propene hydrogenation reaction. 

BASF has also claimed the use of metal-modified TS-1 catalysts [25]. Various catalyst compositions have been described, including (i) titanium or vanadium silicalites containing rare earth ions [25a] and (ii) titanium or vanadium silicalites containing noble metals (Ru, Rh, Pd, Os, Ir, Pt, Re, Au, Ag). In these systems the 

Catalyst C3Hg conversion (%) Selectivity PO/C3H8 (%) Solvent Reaction time (h) 

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