A novel and effective palladium catalyst loaded on polymer microspheres modified with magnesium oxide for the telomerization of 1,3-butadiene with CO2 (carbon dioxide) was prepared by using the Shirasu Porous Glass (SPG) membrane emulsification technique. A series of characterizations were carried out on the catalyst, such as CO2-TPD (Carbon Dioxide Temperature-Programmed Desorption), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), XPS (X-ray Photoelectron Spectroscopy), etc., to verify that the introduction of magnesium oxide enhances the catalyst's ability to adsorb and activate carbon dioxide. The electron transfer between magnesium oxide and palladium stabilizes the palladium active species, and the surface-formed magnesium oxide can improve the mechanical strength of the catalyst and reduce its breakage. Only 0.025 mol % of catalysts were needed to obtain δ-lactones (E)-3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one with 57% yield and 95% selectivity under 60 °C conditions using acetonitrile as the solvent. With simple filtration and drying, the catalyst can be reused five times and still has a good catalytic effect.
Song et al. (Thu,) studied this question.