Synthesis of basic cancrinite in a butanediol-water system
Synthesis of basic cancrinite in a butanediol-water system
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DOI：
10.1021/cm001136z
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发表时间：
2001-06
影响因子：
8.6
通讯作者：
M. Fechtelkord;Britta Posnatzki;J. Buhl
中科院分区：
文献类型：
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作者：
M. Fechtelkord;Britta Posnatzki;J. Buhl
在1，3-或1，4-丁二醇/水混合物中，在353-493 K温度和24-168 h反应时间下合成了钙霞石。两个主要系列已经完成。在第一系列中，在合成中将二氧化硅源（四乙氧基硅烷、Aerosil和沉淀二氧化硅）与氧化铝源（仲丁醇铝和异丙醇铝）直接组合。在第二系列中，将由四乙氧基硅烷和仲丁醇铝/异丙醇铝形成的有机凝胶以及由四乙氧基硅烷与硝酸钠和硝酸铝水溶液水解或由偏硅酸钠与铝酸钠的组合形成的无机凝胶干燥并用于合成。产物通过X射线粉末衍射以及29 Si和27 Al MAS NMR光谱进行表征。结果表明，对合成温度、持续时间和碱度的敏感性主要取决于合成中使用的二氧化硅/氧化铝源的反应性潜力和溶解度。虽然直接应用的反应物显示出对合成温度等的最高敏感性，但凝胶显示出甚至最好的合成结果，并且钙霞石在宽范围的合成参数（温度、持续时间和氢氧化钠浓度）中形成。在这里使用的温和反应条件下，钙霞石的接种动力学，结晶动力学和热力学性质之间的强烈关系似乎是负责的行为。如果氧化铝和二氧化硅源以相同比例缓慢且稳定地溶解，则钙霞石形成作为动力学控制的过程是优选的。
Cancrinite has been synthesized in a 1,3- or 1,4-butanediol/water mixture at temperatures of 353-493 K and reaction times of 24-168 h. Two main series have been performed. In the first series the silica sources (tetraethoxysilane, Aerosil, and precipitated silica) were combined directly with the alumina sources (aluminum sec-butoxide and aluminum isopropoxide) in the synthesis. In the second series organic gels formed from tetraethoxysilane and aluminum sec-butoxide/aluminum isopropoxide as well as inorganic gels formed from hydrolyzation of tetraethoxysilane with aqueous sodium and aluminum nitrate solution or from combination of sodium metasilicate with sodium aluminate were dried and used for synthesis. The products were characterized by X-ray powder diffraction as well as 29 Si and 27 Al MAS NMR spectroscopy. The results show that the sensitivity to the synthesis temperature, duration, and alkalinity depends mainly on the reactivity potential and solubility of the silica/alumina source used in the synthesis. While the directly applied reactants show the highest sensitivity to synthesis temperature and so forth, the gels show even the best synthesis results and cancrinite is formed in a wide range of synthesis parameters (temperature, duration, and sodium hydroxide concentration). A strong relationship between seeding kinetics, crystallization kinetics, and thermodynamic properties of cancrinite seems to be responsible for that behavior under the mild reaction conditions used here. Cancrinite formation as a kinetically controlled process is preferred if both the alumina and silica source dissolve slowly and steadily in the same proportions.