磁性纳米固体超强酸的合成、表征及性能

首次制备了SO₄^2-/Co_0.5Fe_2.5O₄-ZrO₂磁性固体超强酸,利用TEM,DTA,XRD和FTIR等手段研究了Co_0.5Fe_2.5O₄磁性基质对ZrO₂的粒子大小、晶化温度与结构的影响.考察了磁性固体超强酸的催化性能及催化剂的寿命、回收率和磁性.结果表明,引入Co_0.5Fe_2.5O₄磁性基质不但赋予催化剂以磁性,而且在固体超强酸形成过程中延迟了ZrO₂由四方晶相向单斜晶相的转变,有助于稳定样品表面的含硫物种,磁性固体超强酸对酯化反应具有较高的催化活性,可活化再生,并保持磁性.

Synthesis, Characterization and Properties of Magnetic Nanometer-sized Solid Superacid

In this paper, magnetic solid acid catalyst of SO 2- 4/Co 0.5 Fe 2.5 O 4 ZrO 2 with different molar ratios has been synthesized, and the influence of magnetic substrates Co 0.5 Fe 2.5 O 4 on particle size, crystallizing temperature, and crystal structure of ZrO 2 was investigated. The catalytic activity of the magnetic solid acid was studied for esterification reaction, and life, recovery and variation of magnetic property of the catalyst were tested. The results show that the addition of the magnetic substrate not only magnetizes but also delay the conversion from ZrO 2(t) to ZrO 2(m) during the formation of solid superacid, which makes acid sites on the surface of sample more stable and promotes its superacidity and catalytic activity. The conversion of esterification catalyzed by SO 2- 4/Co 0.5 Fe 2.5 O 4 ZrO 2 can reach 97 31% and 74 69% conversion can be obtained after it was used for 6 times in the reaction and after it was regenerated, the conversion reaches 96 25%, meaning that the catalytic activity of this catalyst may be recovered.