异丙醇铝控制水解制备高纯拟薄水铝石和多孔氧化铝

Synthesis of high-purity pseudoboehmite and porous alumina from aluminum isopropoxide

主要进行异丙醇铝水解制备高纯拟薄水铝石和高纯多孔γ-Al2O3的研究。合成路线以异丙醇铝为原料,改变反应过程中水化液组成、水化温度和水化时间,制备一系列拟薄水铝石及其焙烧产物多孔γ-Al2O3。结果表明,水化液中异丙醇的存在会抑制无定型氢氧化铝的晶化,但也有助于形成大孔径、高比表面和大孔容的氧化铝;纯水体系下,60℃以下水化会出现三水铝石,60℃以上水化的产物则为拟薄水铝石;γ-Al2O3孔结构与前驱体拟薄水铝石的结晶度有关,晶粒越大的拟薄水铝石,焙烧所得氧化铝的孔径和孔容也增大。因此,水化条件的改变可以实现拟薄水铝石结构的控制,进而获得不同结构的多孔氧化铝。为由异丙醇铝水解制备高纯拟薄水铝石和多孔氧化铝的工业化提供相应的研究基础。

A series of pseudoboehmite and porousγ-Al2O3with high-purity were synthesized from aluminum isopropoxid by changing the composition of hydration fluid,hydration temperature and hydration time during hydrolysis-hydration process.The results showed that the presence of isopropanol in the hydration solution cinhibited the crystallization of amorphous aluminum hydroxide,and contributed to the formation of alumina with large pore size,high specific surface and large pore volume.Under pure water system,gibbsite phase appeard bellow 60℃,and the pseudo-boehmite was product above 60℃.The pore structure ofγ-Al2O3 was related to the crystallinity of the pseudoboehmite.Pore size and pore volume of the alumina obtained by calcination increased with the increase of pseudo-boehmite grains.Therefore,the change of hydration conditions can realize the control of pseudo-boehmite structure,and then obtain porous alumina with different structures.This study will provide a new method and theoretical basis for the large-scale synthesis of high-purity pseudoboehmite and porous alumina.