摘要
以ＮａＯＨ、Ｎａ２ＣＯ３混合液或以ＮＨ４ＯＨ、（ＮＨ４）２ＣＯ３混合液为沉淀剂制备了Ｍｇ／Ａｌ＝３－６．７的Ｍｇ－Ａｌ水滑石。将水滑石在５００－６００℃下焙烧制得了具有与ＭｇＯ相同的晶体结构的Ｍｇ（Ａｌ）Ｏ复合氧化物，它们的比表面积大于或接近γ－Ａｌ２Ｏ３，而且具有良好的热稳定性。ＣＯ２吸附法测定表面碱性和等电点测定结果表明，Ｍｇ（Ａｌ）Ｏ的表面碱量和表面极性与ＭｇＯ比较接近；ＣＯ２－ＴＰＤ测定即表明（Ｍｇ（Ａｌ）Ｏ）具有和ＭｇＯ类似的表面碱性中心分布。另外，根据ＮＨ３－ＴＰＤ测定即发现Ｍｇ（Ａｌ）Ｏ还保留有γ－Ａｌ２Ｏ３的某些酸性性质。因此，可以认为Ｍｇ（Ａｌ）Ｏ具有双重酸碱性质。
Magnesium aluminum hydrotalcites with the molar ratios of MS to Al of 3-6.7 were perpared by coprecipitating an aqueous solution of magnesium and aluminum salts with NaOH-Na2CO3 or NH4OH-(NH4) 2CO3 mix solution.By calcinating the hydrotalcites at 500-600℃ the Mg-Al complex oxides,Mg(Al) O were produced.XRD determination confirmed that Mg(Al) O has the same crystal structure as MgO.The B E T determination showed most of the Mg(Al) O have large surface area(180-235m2/g) and high thermal stability.The basic characters of Mg(Al) O were investigated by CO2 adsorption,CO2-TPD and isoelectric point determinations.It was found that the basic center density and basic center distribution of Mg(Al) O are similar to those of MgO.On the other hand,it was confirmed by NH3-TPD determination that,Mg(Al) O retained some acidity properties like those of γ-Al2O3.
出处
《分子催化》
EI
CAS
CSCD
1996年第2期88-94,共7页
Journal of Molecular Catalysis(China)
基金
中国石油化工总公司顾问委员会基础研究基金
关键词
催化剂
载体材料
镁铝复合氧化物
制备
Hydeotalcite,Mg-Al complex oxide,Preparation method,Physicochemical characterization
