Synthesis of Triethyl Citrate Catalyzed by Solid Acid Catalyst
Li Fanhua Chai Yanfeng(Rizhao Kumho Jinma Chemical Co.,Ltd.,Rizhao 276825)
Mesoporous zirconium oxide and titanium oxide were prepared by hydrothermal synthesis method,and S2O82-was introduced onto surface of mesoporous oxides by impregnation method.The effects of the molar ratio of ethyl alcohol to citric acid and the reaction time on the esterification rate were investigated in the presence of 5% S2O82-/M-ZrO2 as catalyst (based on the total mass of reactants). The optimum reaction conditions of esterification were as follows:n(ethyl alcoho1):n(citric acid) 6.0:1,toluene as water-carrying agent,reaction temperature 80-120 ℃,and reaction time 7 hours.Under these conditions,S2O82-/M-ZrO2 could be repeatedly used 5 times without any treatments,with the yield still kept over 94%. The surface area and structure of the catalysts were determined by XRD and nitrogen adsorption-desorption method.The structure of product was characterized by FT-IR and 1HNMR.