Modification of the interlayer surface of kaolinite with methoxy groups
Modification of the interlayer surface of kaolinite with methoxy groups
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DOI：
10.1021/la991453o
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发表时间：
2000-06-13
期刊：
影响因子：
3.9
通讯作者：
Kuroda, K
中科院分区：
文献类型：
--
作者：
Komori, Y;Enoto, H;Kuroda, K
无机层状材料的插层反应是制备无机-有机多层纳米复合材料的一种方法，近年来引起了人们的广泛关注。1 r3高岭石是一种层状粘土矿物（Al 2Si 2 O 5（OH）4），是一种独特的超分子杂化体系的主体材料，因为其层间区域夹在一侧的AlO 2（OH）4片层的羟基和另一侧的SiO 4片层的氧化物排列之间。客体分子如二甲基亚砜（DMSO）插层并在高岭石层之间沿一个方向排列。4，5尽管由于层间固有的氢键，高岭石层间表面插层反应性非常低，但客体置换法使客体种类多样化。6，7我们最近报道了高岭土甲醇插层化合物在室温下形成7，并且它是与各种有机物质如烷基胺、8聚（乙烯基吡咯烷酮）、9对硝基苯胺、10和β-己内酰胺进行置换反应的优良中间体。因此，对中间产物甲醇处理高岭石结构的阐明，对于理解高岭石的层间表面反应具有重要意义。Tunney和Detellier已经报道了通过使用高岭土-DMSO或N-甲基甲酰胺（NMF）插层化合物作为中间体，在高于200 ℃的温度范围内的苛刻条件下由高岭土和甲醇形成甲氧基化高岭土。12然而，还没有关于在室温下形成的高岭石-甲醇插层化合物的性质的报道。本文提供了在室温下用甲醇处理的高岭石中用甲氧基改性层间表面的证据。虽然已经通过使用高岭石NMF插层化合物作为中间体的客体置换反应实现了甲醇的插层，7但产物的结构尚未阐明。由于固态2 H NMR和13 C CP/MAS NMR对于甲氧基改性的固体表面的研究非常强大，因此13在室温下高岭石与甲醇（CH 3OH，CD 3-OD）之间的反应产物通过NMR测量进行表征。这种类型的化合物的DTA分析是不合适的，因为有机含量低，峰重叠，由于脱羟基高岭石。高岭石层间表面羟基的有机改性改变了高岭石层间环境的性质。除甲醇外，还研究了用乙二醇、14、15氨基醇、16和苯基膦酸17等分子进行的12种修饰。因此，本论文为高岭石层间表面的有机改性提供了更确切的数据。
Intercalation reaction of inorganic layered materials has been well-known as a method for preparing inorganicr organic multilayer nanocomposites, which have drawn increasing attention in recent years. 1r3 Kaolinite, a layered clay mineral (Al2Si2O5 (OH) 4), is a unique host material for organizing supramolecular hybrid systems because the interlayer region is sandwiched between hydroxyl groups of the AlO2 (OH) 4 sheets in one side and the oxide arrangements of the SiO4 sheets in the other. Guest molecules such as dimethyl sulfoxide (DMSO) are intercalated and aligned in one direction between the layers of kaolinite. 4, 5 Although the interlayer surface reactivity of kaolinite for intercalation is very low owing to its inherent hydrogen bondings between the layers, a guest displacement method has diversified the kind of guest species. 6, 7 We have recently reported that a kaoliniter methanol intercalation compound forms at room temperature 7 and that it is an excellent intermediate for displacement reactions with various kinds of organic species such as alkylamines, 8 poly (vinylpyrrolidone), 9 p-nitroaniline, 10 and ϵ-caprolactam. 11 Therefore, the elucidation of the structure of the intermediate, methanoltreated kaolinite, is significant for the understanding of the interlayer surface reactions of kaolinite. Tunney and Detellier have already reported that methoxylated kaolinite forms from kaolinite and methanol under severe conditions in the temperature range above 200 C by using a kaoliniterDMSO orN-methylformamide (NMF) intercalation compound as an intermediate. 12 However, there have been no reports on the nature of a kaolinitermethanol intercalation compound formed at room temperature.The present paper provides evidence for the modification of the interlayer surface with methoxy groups in kaolinite treated with methanol at room temperature. Although the intercalation of methanol has been achieved by a guest displacement reaction using a kaoliniterNMF intercalation compound as an intermediate, 7 the structure of the product has not yet been elucidated. Because solid-state 2H NMR and 13C CP/MAS NMR are quite powerful for the study of methoxy-modified solid surfaces, 13 the reaction products between kaolinite and methanol (CH3OH, CD3-OD) at room temperature were characterized by NMR measurements. DTA analysis of this type of compound is not appropriate because of low organic content and a peak overlap with that due to dehydroxylation of kaolinite. Organic modification of the hydroxyl groups in the interlayer surface of kaolinite varies the properties of the interlayer environments of kaolinite. In addition to methanol, 12 modifications with molecules such as ethylene glycol, 14, 15 amino alcohol, 16 and phenylphosphonic acid 17 have been investigated. Therefore, the present paper further contributes to this field with more definitive data on organic modification of the interlayer surface of kaolinite.