Dinitrotoluene Synthesis Using Solid State Catalysts - MoO3/SiO2 and H3PO4/MoO3/SiO2

Dinitrotoluene (DNT) has a lot of applications. It is mainly used in the production of polyurethane forms. Other uses include the explosives industry. It is converted to trinitrotoluene (TNT), or used as an additive in propellants. The main aim of these researches was to obtain DNT in one stage process with solid acid catalyst and nitric acid. The solid catalysts were composed of transition metal oxide (MoO3) and silica gel. One of them was modifed by phosphoric acid (H3PO4/MoO3/SiO2). The addition of phosphoric acid to these catalysts enhances catalytic properties and gives new structures on the surface – mixture of MoO3 and 12-molybdophosphoric acid. The activity of two catalysts in toluene nitration was compared. Higher yields of DNT were obtained in shorter time and with lower excess of HNO3 using modifed catalyst H3PO4/MoO3/SiO2 than using catalyst MoO3/SiO2. The very high yield of DNT (85%) was obtained in the reaction with only tenfold excess of nitric acid with 10 g of H3PO4/MoO3/SiO2. The way of regeneration of the catalyst system H3PO4/MoO3/SiO2 was found and time of storing was examined.