磁性固体酸催化剂的合成及其酯化催化活性的研究

Synthesis of Magnetic Solid Acid Catalyst and Its Catalytic Activity for Esterification

研究了以磁性体为核、催化活性体为壳的固体酸催化剂制备过程的结构转化及其酯化催化活性变化。在ZrOCl2/FeCl2投料为10∶1(质量比),酸浓度为1 mol/L,浸泡时间2 h,400℃焙烧1 h的条件下,制得了具有优异的催化活性的纳米磁性催化剂ZrO2/SiO2-Fe3O4。采用IR、扫描电镜(SEM)和孔径分布等分析测试手段对催化剂的结构和性能进行了表征。IR表明催化剂存在酸性中心,并且极易吸水;BET比表面积分析说明催化剂的孔径是介孔材料,但是存在两种介孔,一种15 nm的大介孔,另一种3.97 nm的小介孔;SEM和X射线能谱仪(EDX)分析说明催化剂处于纳米级别,并且锆的含量很高;在高酸价油脂制备生物柴油酯化反应中,纳米磁性催化剂催化酯化转化率达到83.5%,回收率为92.5%,酯化催化活性降低率为10%/次。

The structural change during the preparation of solid acid catalyst with magnetic group as core and catalytic group as shell,as well as its esterification activity were studied.Under the conditions of molar ratio of ZrOCl2/FeCl2 10∶1,acid concentration 1 mol/L,impregation time 2 h,roasting time of 400 ℃ 1 h,the nanometric magnetic catalyst ZrO2/SiO2-Fe3O4 of excellent activity was obtained.The structure and properties of the catalyst were characterized by IR,scanning electron microscopy（SEM）and pore size distribution.IR spectra indicate that the catalyst possesses an acid center,and was extremely easy to absorb water;BET explains that the catalyst is a mesoporous material,and has two kinds of mesopores,one is 15 nm,the other is 3.97 nm;SEM and the X-ray energy dispersion spectrum（EDX） analyses show that the catalyst is in a nano rank,and the content of zirconium is high;In the esterification reaction of oil with high acid value using nanomagnetic solid acid catalyst,the catalytic esterification rate was 83.5 %,the recycled recovery was 92.5 %,and its catalytic activity of esterification was reduced 10 % per time.