Catalytic synthesis of diisopentyl oxalate over mesoporous S 2o8 2-/Sno2 solid superacid

A novel mesoporous S2O8 2-/SnO2 solid superacid catalyst was prepared using SnCl4 · 5H 2O and polyethylene glycol 6000 as organic template. The prepared catalyst was characterized by XRD, TGADTA and N2-adsorption. The catalytic activity of S2O8 2-/SnO2 solid superacid for the esterification of oxalic acid and isoamyl alcohol was studied, and the effect of catalyst calcination temperature, acid/alcohol molar ratio, catalyst dosage and reaction time on the esterification rate was investigated as well. Results indicate that the mesoporous S2O 8 2-/SnO2 solid superacid catalyst possess tetragonal crystalline structure, and the existence of S2O 8 2- tends to delay the crystallization of SnO2 and inhibits the growing of crystal, thus the catalyst exhibits good catalytic activity for diisopentyl oxalate synthesis. Under the conditions of a catalyst calcination temperature of 500 °C, n(isoamyl alcohol): n(oxalic acid) = 3: 1, a toluene adding amount of 30 mL, m (catalyst) : m(oxalic acid) = 7.5 and a reaction time of 2.5 h, the yield of diisopentyl oxalate reached 99.2%. The obtained diisopentyl oxalate was used as cetane enhancing agent and added into the FCC diesel fractions from the No. 1 Refinery of CNPC Fushun Petrochemical Company, it was found that the cetane number of this diesel fuel increased 1.2 - 3.0 units, and without significant effect on its other properties.