Synthesis, characterisation and catalytic performance of a mesoporous tungsten silicate: W-TUD-1

• Tungsten was incorporated into siliceous TUD-1, a mesoporous material.
• 2 Different incorporation methods for tungsten were compared.
• Due to its size tungsten was not framework incorporated but formed clusters.
• Tungsten containing TUD-1 is acidic and a good catalyst for the Prins reaction.

Tungsten containing TUD-1 catalysts with Si/W ratios of 10–50 were synthesised by a two-step impregnation method and a direct one-step sol–gel method. The one-step method yielded finely dispersed catalytically active tungsten oxide nano-particles (<1 nm) (at Si/W ratio above 20), while the two-step method yielded both tungsten oxide nano-particles and bulk tungsten oxide. This was established using INAA, N2 physisorption, powder XRD, Raman spectroscopy, TEM, diffuse reflectance UV–vis, FT-IR, H2-TPR and NH3-TPD analysis. Both types of catalyst preparation resulted in active acidic catalysts for the Prins cyclisation of citronellal. It was demonstrated that the finely dispersed tungsten oxide nano-particles were responsible for the catalytic activity.

Figure optionsDownload high-quality image (134 K)Download as PowerPoint slide