Enhanced Activity of 12-Tungstophosphoricacid Supported on Silica Nanoparticle forAlkylation of Aniline with tert-butanol

摘要

Alkylation of aniline is an industrially important reaction. The homogeneous catalysts foralkylation of aniline can be eliminated by a more effective heterogeneous catalytic method from theenvironmental viewpoint. Among the solid acid catalysts, supported heteropolyacids (HPA) representan attractive alternative with economic and environmental advantages. Supported heteropolyacids(HPA) are promising solid-acid catalysts for the Friedel–Crafts reactions. The reduction of particlesize of HPA/SiO2 improves the surface area and acidity of the nanoparticle. In the current work, asimple process was developed based on the use of 12-Tungstophosphoricacid supported on silicananoparticle catalysts. The synthesized catalyst was characterized by XRD and TEM technique.Liquid phase alkylation of aniline with tert-butyl alcohol was carried under autogenous pressureusing fresh as well as steamed catalyst under mild conditions. The catalytic activity of steam treated12-Tungstophosphoricacid supported on silica nanoparticles show high activity in terms ofconversion and selectivity for the desired product. Only C-alkylated products were obtained.