Synthesis Of Tirbutyl Citrate Over Rare Earth Doping MCM-41Catalyst

Ce-MCM-41, Y-MCM-41Mesoporous Molecular Sieve with different Si/Ce(mol),Si/Y(mol) ratio were synthesized by hydrothermal method doping rare-earth metal. hecomposition and structure of the samples were characterized by X-ray (EDS) analysis,Infrared analysis (IR), Pyridine adsoption(Py-IR), N2adsorption-desorption, NH3temperatureprogramming(NH3-TPD), small-angleX-raydiffraction(XRD), themogravi metri canalysis(TG/DSC), transmission electron micropy(TEM), scanning electronic microscope(SEM)etc.The results of TEM and SEM showed that Ce-MCM-41of rare earth modified had the ordered hexagonal mesopore structure and ordered arrangement with the shapeof worm-like. The results of EDS showed that cerium ion have dopinged MesoporousMolecular Sieve, Doped and calculated value have slightly different.The resultsof TPD showed that The acid quantity decrease with the increase of Si/Ce(mol) ratio, TPD acid of Ce-MCM-41(30) reached0.0369mmol/g.The BET surface area of Ce-MCM-41(30) reached868.7m2/g, pore volume0.8903mL/g, bore diameter4.028nm; Fy-IR analysis Showed that there are both Bnsted acid and Lewis acid in thesurface of Ce-MCM-41(30), acid strengty of Bnsted acid more than Lewis acid.The results of TEM and SEM showed that Y-MCM-41of rare earth modified had the ordered hexagonal mesopore structure and ordered arrangement with the shape of worm-like. The results of EDS showed that cerium ion have dopinged MesoporousMolecular Sieve, Doped and calculated value have slightly different.The results of TPD showed that The acid quantity decrease with the increase of Si/Y(mol) ratio, TPDacid of Y-MCM-41(30) reached0.0244mmol/g. The BET surface area of Y-MCM-41(30) reached793.0m2/g, pore volume0.8345mL/g, bore diameter4.209nm. Fy-IR analysis Showed that there are both Bnsted acid and Lewis acid in thesurface of Y-MCM-41(30), acid strengty of Bnsted acid more than Lewis acid.Catalytic character of Ce-MCM-41(30) and Ce-MCM-41(30) sieve were evaluatedusing esterification reaction of n-butyl alcohol and citric acid as a probe. The resultsshowed that The esterificatin yield of tirbutyl citrate decrease with the increase of Si/Ce(mol), Si/Y(mol) ratio, Esterification rate be connected with acid amount and pore structure.When n(acid):n(alclhol)=1.0:5.0, w(cat)%=5%, reaction time7h, reaction tempera ture1400C. they were good catalysis results, esterificatin yield of Ce-MCM-41(30) was91.2%, when the catalysts were used five times repeatly, the esterification yield was stillapproach77.3%, when n(acid):n(alcohol)=1.0:5.0, w(cat)%=5%, reactiontime7h, reaction temperature1400C, esterifiatin yield of Y-MCM-41(30) was90.2%, when the catalysts were used five times repeatly, the esterification yield was still appraach75.2%.