Preparation,characterization of nanosolid superacid TiO_2/SO_4~(2-) and regioselective nitration of toluene by catalysis

The new nanosolid superacid TiO_2/SO_4~(2-)is prepared by using sol-gel method.Samples were characterized by XRD and TEM.The results showed that TiO_2/SO_4~(2-) is superfine solid belong to nanocrystal and its average size is 34 nm with good distribution.The regioselection and activity of toluene nitration was raised,when the nanosolid superacid TiO_2/SO_4~(2-) was taken as the catalyst.The optimnm reaction conditions were found out.Thus activated temperature of catalyst was 600℃,the reaction was carried out at 60℃ for 4h with n(nitric acid)/n(toluene) is 2.0 and w(toluene)/w(catalyst)=35 to get toluene conversion of 87.4%,the ratio between para-and ortho-nitrotoluene reaching up to 1.52.