Shape-selective synthesis of methylamines over the RRO zeolite Al-RUB-41

Aluminum was incorporated into the layered silicate RUB-39, which is transformed by calcination into RUB-41. This new zeolite with RRO topology contains 8- and 10-ring pores, and the acid sites in the aluminated material catalyze the synthesis of methylamines, in particular mono- and dimethylamine, by amination of methanol. Owing to the shape-selective catalytic properties of (H)Al-RUB-41, low selectivity to the thermodynamically favored trimethylamine product is obtained in comparison with results on RUB-39 or non-shape-selective materials. Both activity and selectivity are highest for RUB-41 catalysts with a high Si to Al ratio. Silylation reduces the number of unselective sites and results in a further suppression of trimethylamine formation. The introduction of acidity in the intact RUB-41 structure is supported by Al-MAS NMR and NH3-TPD data. Additional characterization by XRD and SEM is provided.

Graphical abstractShape-selective amination of methanol over Al-RUB-41 with selectivities up to 87% towards monomethylamine and dimethylamine.Figure optionsDownload full-size imageDownload high-quality image (137 K)Download as PowerPoint slideResearch highlights► Aluminum was incorporated into the layered silicate precursor of RUB-41. ► (H)Al-RUB-41 is a shape-selective catalyst for the methylamine synthesis. ► Highest activity and selectivity are attained at high Si/Al ratios. ► Silylation resulted in an increase in selectivity toward MMA and DMA.