The dimensions of different copper species on Cu/SiO2 catalysts in the one-step condensation of isoprene via formaldehyde and isobutene

The one-step condensation of isoprene from vapor-phase formaldehyde and isobutene is an environmental-friendly synthesis technology in the chemical industry. This work reports the synthesis of isoprene in presence of Cu/SiO 2 catalysts with different size of copper species using an impregnation method. The catalysts were characterized by UV–vis absorption spectra, Py-IR, H 2 -TPR, NH 3 -TPD, XRD, XPS techniques to better understand the catalytic performance. The increasing activity of the catalysts follows the order of the particle size of copper species from large to small. The smaller particle results more exposed Cu + sites which might active the Carbonyl in formaldehyde. In addition, the medium strong Lewis acid sites on the dry catalysts might take the mainly effect in this Prins reaction.