Abstract: 5-Nitrosalicylaldehyde was synthesized by the nitration of salicylaldehyde with nitric acid over H6PMo9V3O40 supported on silica gel. The effects of parameters were investigated, such as H6PMo9V3O40 loading, reaction time, temperature, solvent, and so on. Under the optimal conditions:m(salicylaldehyde)∶m(65%HNO3)∶m(20%H6PMo9V3O40/SiO2)=2.44∶3.00∶3.00, in petroleum ether at 45 ℃ for 2.5 h, the conversion of salicylaldehyde was 98%, the selectivity of 5-nitrosalicylaldehyde was up to 96.8%. The catalyst could be recovered easily and reused for five times without noticeable drop in activity.

Key words: nitrosalicylaldehyde, H6PMo9V3O40 supported on silica gel, nitration, salicylaldehyde