关键词: 聚乙二醇, S2O82−, /SnO2, 固体超强酸, 酯化, 草酸二异戊酯

Abstract: A novel mesoporous S2O82?/SnO2 solid superacid catalyst was prepared using SnCl4o5H2O and polyethylene glycol 6000 as organic template. The prepared catalyst was characterized by XRD，TGA-DTA and N2-adsorption. The catalytic activity of S2O82?/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 S2O82?/SnO2 solid superacid catalyst possess tetragonal crystalline structure, and the existence of S2O82? 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 ℃, 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.

Key words: polyethylene glyco1, S2O82−, /SnO2, solid superacid, esterification, diisopentyl oxalate