Selective Natration Of Toluene On Molecular Imprinted Polymers

One of a main goal of modern nitration methodology is to increase its regioselectivity in order to meet desirable environments, and clean synthesis of nitro aromatic compounds is an important trend in the development of nitration. The traditionally industrial nitration involving concentrated mineral acids as the catalysts have become one of the most environmentally harmful processes. In this thesis, a non-acid nitration methodology using nitrogen dioxide was discussed as compared with commercially strong acid mtration. A novel bio-mimic catalyst, the molecularly imprinted polymers (MIPs), was examined for improving the regioselection of aromatic nitration by using nitrogen dioxide as nitrating agent.Aromatic hydrocarbons could be selectively nitrated with nitrogen dioxide in the presence of MIPs. MIPs were characterized by means of modern analyses. And such successes stem from combination of factors involved in this type of heterogeneous catalysis. It was found that a good activity and regioselectivity in nitration were achieved by using an acidic functional group monomer, and a polymer of a high degree cross-linking. Compared with the nitration using sulfuric-nitric acids, the non-acid method was of better para-selectivities for the nitration of mono-substituted arenes. For toluene nitration, the ortho/para isomer ratio of nitro products could improve to 0.89 on MIPs, which were synthesized by methacrylic acid as functional monomer. The regioselectivity appeared in various simple aromatic compounds at the same mtration processes.