Silanization of superficially porous silica particles with p-aminophenyltrimethoxysilane
Silanization of superficially porous silica particles with p-aminophenyltrimethoxysilane
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DOI：
10.1016/j.microc.2019.02.013
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发表时间：
2019-06-01
影响因子：
4.8
通讯作者：
Colon, Luis A.
中科院分区：
文献类型：
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作者：
Borges-Munoz, Amaris C.;Miller, Daniel P.;Colon, Luis A.
用于色谱应用的二氧化硅颗粒的表面官能化通常通过硅烷化反应来实现。硅烷分子（例如，氯硅烷或烷氧基硅烷）通过硅氧烷键连接到二氧化硅表面。尽管通过硅烷化的表面改性被广泛使用，但反应参数如何影响表面覆盖度很少讨论，特别是当使用反应性较低的烷氧基硅烷试剂时。研究了对氨基苯基三甲氧基硅烷（p-APTMS）在多孔粒子表面接枝的反应条件。理论计算预测，每nm（2）（类似于5 μ mol/m（2））的p-APTMS的接枝可以容纳在二氧化硅表面上。除非优化反应条件，否则无法达到该值。为了最大限度地提高二氧化硅表面的氨基苯基层的表面覆盖率，我们研究了温度、反应时间和向硅烷化反应中加入水对表面覆盖率的影响。优化后，发现使用升高的温度（130 ℃），每个p-APTMS分子加入3.3当量的水，并在作为溶剂的癸烷中反应24小时，提供了高达4.5 μ mol/m2（2.7个接枝物/nm 2）的表面覆盖率，接近通过理论密度泛函理论计算提出的极限。
The surface functionalization of silica particles for chromatographic applications is typically achieved by means of silanization reactions. A silane molecule (e.g., chlorosilanes or alkoxysilanes) with a functional group of interest is attached to the silica surface through a siloxane bond. Even though the surface modification via silanization is widely used, how the reaction parameters affect the degree of surface coverage is rarely discussed, particularly when using the less reactive alkoxysilanes reagents. We studied reaction conditions to graft p-aminophenyltrimethoxysilane (p-APTMS) on superficially porous particles. Theoretical calculations predicted that 3 grafts of p-APTMS per nm(2) (similar to 5 mu mol/m(2)) can be accommodated on the silica surface. This value is not achieved unless the reaction conditions are optimized. To maximize the surface coverage of the aminophenyl layer at the silica surface, we investigated the influence of temperature, reaction time, and addition of water to the silanization reaction on the surface coverage. After optimization, it was found that using elevated temperatures (130 degrees C), adding 3.3 equivalents of water per p-APTMS molecule, and reacting for 24 h in decane as the solvent provided a surface coverage as high as 4.5 mu mol/m(2) (2.7 grafts/nm(2)), approaching the limit suggested via theoretical density functional theory calculations.