Thermal degradation of organic matter in the interlayer clay-organic complex: A TG-FTIR study on a montmorillonite/12-aminolauric acid system
Thermal degradation of organic matter in the interlayer clay-organic complex: A TG-FTIR study on a montmorillonite/12-aminolauric acid system
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层间粘土-有机复合物中有机物的热降解：蒙脱土/12-氨基月桂酸体系的热重-傅立叶变换红外研究
DOI：
10.1016/j.clay.2013.07.005
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发表时间：
2013-08-01
影响因子：
5.6
通讯作者：
He, Hongping
中科院分区：
文献类型：
--
作者：
Liu, Hongmei;Yuan, Peng;He, Hongping
天然有机质在层状硅酸盐层间的储存是沉积物中粘土有机质组合的一种重要类型。然而，粘土矿物的层间空间在有机物热降解和烃类生成中的作用还没有得到很好的理解。以蒙脱石和12-氨基月桂酸为原料，合成了层间粘土-有机复合物。还制备了其中简单混合Mt和ALA的Mt-ALA复合物用于比较。采用热重-傅里叶变换红外光谱（TG-FTIR）联用技术研究了Mt-ALA复合物热降解过程中的热事件及相应产物。在没有Mt。ALA在467 ℃下通过C-C键的断裂分解，产生脂肪族烃、含N化合物和羧酸。混合Mt-ALA复合物和层间Mt-ALA复合物中有机质的分解温度分别降低到402和342 ℃。层间Mt-ALA复合物的主要特征产物为NH3和饱和烃。Mt层间空间中的布朗斯台德酸中心由解离的层间水产生，通过霍夫曼消除途径引发ALA的脱氨作用，并通过碳酸化机制显着促进烃类的裂解。刘易斯酸中心对ALA的热降解影响不大。研究表明，粘土矿物的层间空间为有机质提供了储存空间。此外，层间空间内的活性位强烈促进有机物的热降解。(C)2013爱思唯尔有限公司版权所有。
The storage of natural organic matter within the interlayer space of layered silicate is an important type of clayorganic association in sediment. However, the role of the interlayer space of clay minerals in the thermal degradation of organics and the generation of hydrocarbons has not been well understood. In this study, an interlayer clay-organic complex was synthesized using montmorillonite (Mt) and 12-aminolauric acid (ALA). An Mt-ALA complex in which Mt and ALA were simply mixed was also prepared for comparison. Thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) was applied to monitor the thermal events and the corresponding products during the thermal degradation of the Mt-ALA complexes. In the absence of Mt. ALA decomposed at 467 degrees C via the cleavage of C- C bonds, producing aliphatic hydrocarbon, N-containing compounds, and carboxylic acid. The decomposition temperatures of organic matter in the mixed Mt-ALA complex and the interlayer Mt-ALA complex decreased to 402 and 342 C, respectively. The most characteristic products of the interlayer Mt-ALA complex were NH3 and saturated hydrocarbons. The Bronsted acid sites in the interlayer space of Mt, arising from the dissociated interlayer water, initiated the deamination of ALA via the Hoffmann elimination pathway and significantly promoted the cracking of hydrocarbons via a carbonation mechanism. Lewis acid sites had little effect on the thermal degradation of ALA. This work indicated that the interlayer space of clay minerals provided the storage space for organic matter. Moreover, the active sites within the interlayer space strongly promoted the thermal degradation of organics.(C) 2013 Elsevier B.V. All rights reserved.