羟基磷灰石负载固体酸的制备及其催化酯化反应性能

Preparation of Hydroxyapatite Supported Solid Acids and Their Catalytic Activity in Esterification

采用回流法将FeCl3和ZnCl2负载在羟基磷灰石(HAP)上制备了负载型固体酸催化剂FeCl3/HAP和ZnCl2/HAP;比较研究了两者催化乙酸与异丁醇酯化反应的活性及其稳定性;通过XRD初步分析了催化剂表面酸位的形成机理,并用FTIR表征了反应产物的结构。实验结果表明,FeCl3/HAP催化酯化反应的活性高于ZnCl2/HAP,但后者的活性比前者稳定;HAP负载FeCl3或ZnCl2后未改变其晶体结构,活性组分高度分散在HPA载体中;催化合成乙酸异丁酯的适宜条件为:乙酸与异丁醇的摩尔比1∶1.3、催化剂用量(相对于反应物的质量)5%、反应时间1.5 h,在此条件下,FeCl3/HAP和ZnCl2/HAP催化酯化反应的酯化率分别为95%和91%。

Novel HAP（HAP： hydroxyapatite） supported solid acids, FeCl3/HAP and ZnC12/HAP, were prepared by a refluxing method. Their catalytic activity and stability in the esterification of acetic acid with isobutanol were examined. The prepared catalysts were characterized by XRD, and the chemical structures of the esterification products were confirmed by FTIR. The mechanism of the acid site formation on the catalyst surface was described by means of XRD. The experimental results show that the catalytic activity of FeCl3/HAP is higher than that of ZnCl2/HAP, but the latter exhibits much better stability; both of them have the same crystal structure as HAP, and the active components in the catalysts are highly dispersed on HAP. Under the optimum conditions for the catalytic synthesis of isobutyl acetate： mole ratio of acetic acid to isobutanol of 1 ： 1.3, catalyst dosage（based on the reactants mass） of 5% and reaction time of 1.5 h, the esterification rates on FeC13/HAP and ZnCl2/ HAP are 95% and 91%, respectively. The prepared solid acids are the environmental-friendly.