The additive effect of amines on the dihydroxylation of buta-1,3-diene into butenediols by supported Pd catalysts

The additive effect of amines on the supported PdO catalyzed-dihydroxylation of buta-1,3-diene is first examined. The significant enhancement of the synthetic efficiency for the diol products is achieved by the addition of less hindered strong bases, such as morpholines and N-methylimidazole. Notably, we found that the amine additive is indispensable to keep the catalytic activity during the recycling test, which is never mentioned in previous reports. Furthermore, both the fresh and spent catalysts are characterized by attenuated total reflection infrared (ATR-IR) observation and X-ray absorption fine structure (XAFS) measurements.