Catalytic Synthesis Of Tri-Ester Of Citric Acid By Novel Water-Tolerant Solid Acid Catalyst

Water-tolerant solid acid catalysts have excellent catalytic activity, high surface area and hydrophobicity, ease of separation and reusability. Water-tolerant solid acid catalysts achieved single reaction multiphased by applying it to water-concerning reactions.Triethyl citrate was catalytically synthesized by novel water-tolerant solid acid catalyst. The preparation conditions of novel hydrophobic solid acid catalysts (carrier, mesh of active carbon, ZS loading on the AC, processing temperature) were optimized. And the catalysts were characterized by XRD, FTIR and in situ FTIR. The results showed that zirconium was well dispersed on the support surface, the bands assigned acid sites at1530cm-1and1693cm-1were observed in situ FTIR of catalytic after adsorbing ammonia, indicating catalytic had Lewis acid sites and Br(?)nsted acid sites. The effects of molar of reactants, dosage of toluene, reaction time, dosage of catalyst on the TEC were investigated. Under the optimized conditions, the conversion of citric acid was99.3%, the yield of TEC reached98.25%. After catalyst was recycled successively4times, the conversion of citric acid kept at95%, and the yield of TEC kept at93%.Novel hydrophobic solid acid catalysts were used as catalysts in the synthesis of tributyl citrate. The preparation conditions of novel hydrophobic solid acid catalysts (carrier, mesh of active carbon, ZS loading on the AC, processing temperature) were optimized. The effects of molar of reactants, the refluxing agen, reaction time, dosage of catalyst on the TEC were investigated. Under the appropriate conditions, the conversion of citric acid was99.6%, the yield of TBC reached to99.3%. After catalyst was recycled successively4times, the conversion of citric acid kept at95.7%, and the yield of TBC kept at94%.Trioctyl citrate was catalytically synthesized by using novel water-tolerant solid acid catalyst. The effects of preparation conditions of Novel hydrophobic solid acid catalysts and the synthesis conditions on the yield of TOC were optimized. Under the optimized conditions, the conversion of citric acid was100%, the yield of TOC reached to98.69%. After catalyst was recycled successively4times, the conversion of citric acid kept at99.7%, and the yield of TOC kept at98.5%.Three synthesis reactions catalyzed by water-tolerant solid acid catalysts were compared. The results showed that water-tolerant solid acid catalysts not only had excellent catalytic activity but also had hydrophobicity. Water-tolerant solid acid catalysts succeeded in synthesizing tri-ester of citric acid, achieving single reaction multiphased, and being separated easilly and reusability. The results also showed that the preparation conditions of novel hydrophobic solid acid catalysts for triethyl citrate and tributyl citrate was easy, while to trioctyl citrate it was rigorous.Novel hydrophobic solid acid catalysts were also used as catalysts to synthesis guaiacul under normal atmospheric pressure and lower temperature. The effects of preparation conditions of novel hydrophobic solid acid catalysts on the yield of guaiacul were optimized. The effects of molar of reactants, reaction time and dosage of catalyst on the guaiacul were investigated. Under the appropriate conditions, the conversion of catechol reached to29%, the selectivity of guaiacul was96%. The conversion of catechol and the selectivity of guaiacul kept at primary level after catalytic was recycled successively4times.The purification of tri-ester of citric acid and guaiacul was researched. The results showed that purity of tri-ester of citric acid and guaiacul after purification was much higher than97.5%analyzed by GC.