Sulfamic: acid incorporated tin oxide: Acidity and activity relationship

Herein we study the activity and acidity relationship, Sulfamic acid (SA) has been incorporated with tin oxide (Sn). Acidity measurement confirmed the presence of dual-acidic sites. SA hinders the crystallization and inhibits SnO₂ crystal growth. The particle size of SnO₂ (2.1–8.2 nm) and the SBET values of samples were found to be dependent on the SA content and calcination temperatures. The increase in the surface acidity was found to occur with increasing the thermal treatment up to 450 °C, while further increasing of calcination temperature is accompanied by a decrease in the surface acidity. Lewis and Bronsted acid sites play important role in the catalytic activity, The SA-Sn nanoparticles are efficient for the synthesis of 14-aryl-14H-dibenzo[a,j] xanthene under solvent-free conditions in good to excellent yields and the sample contains 25 wt% SA has the highest activity than the others under the same reaction conditions.