摘要
采用分别沉淀-混合-浸渍法制备了稀土固体S2O82-/ZrO2-SiO2-Sm2O3催化剂。分别以乙酸丁酯和乳酸丁酯的合成为探针反应,考察了不同制备条件对催化剂活性的影响及催化剂的稳定性,并采用IR,XRD,DTA/TGA,TEM,BET和XPS等手段对催化剂进行了表征,结果表明:本文制得的催化剂属无定型、桥式结构为主的固体超强酸,且其稳定性及活性均比SO42-/ZrO2-SiO2有较大的提高。
A new kind of catalyst S2O82-/ZrO2-SiO2-Sm2O3 was prepared by the precipitation-mixing/co-precipitation method separately.The activity and stability of this catalyst which was prepared in different conditions were evaluated by the esterification of acetic acid with butanol and lactic acid with butanol.The structure of this catalyst was characterized by XRD,IR,DTA/TGA,TEM,BET and XPS.The IR spectrum indicates that the catalyst has the property of super acid.The result of XRD investigation shows an amorphous structure of the catalyst.The XPS analysis indicates that the electron bonding energy of S2p and Zr3d is increased caused by the addition of Sm2O3.This modification changed the chemical morphology of the surface of the catalyst and increased the content of sulfur in the surface layer,so as to improve the stability and prolong the life of the catalyst.From the conclusion of characterization,it can be deduced that the super acid center is formed by sulfur with high chemical valence which combined with zirconium in bridge bond in stead of combined with SiO2.The function of SiO2 is just to enlarge the specific surface area.TG-DTA results show that three main reasons are related to the inactivation of the catalyst: shedding of the sulfate group from the surface of the catalyst,covering of the organic materials coming from reacting reagent on activate sites and depositing of carbon.TEM show that the size of catalyst particles is in range of nano scale.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2006年第z1期53-57,共5页
Journal of the Chinese Society of Rare Earths
基金
内蒙古自治区自然科学基金项目(20010901-13)资助
关键词
固体超强酸
催化剂
表征
稀土
solid super acid
catalyst
characterization
rare earths
