Modification of solid particles with epoxysilanes and characterization by the Preussmann-test

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• 作者：Petra Sch?nherr ; Andreas Seifert ; Ralf Lungwitz ; Frank Simon ; Norbert Moszner ; Peter Burtscher ; Stefan Spange
• 关键词：Preussmann-test ; 4-(4-Nitrobenzyl)pyridine ; Epoxysilane ; Solid state NMR ; Surface functionalization ; UV/vis
• 刊名：Progress in Organic Coatings
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：75
• 期：4
• 页码：335-343
• 全文大小：1356 K

文摘

The interaction of 4-(4-nitrobenzyl)pyridine (NBP) with electrophile reagents results in an intensive colored product. This process occurs rapidly and serves as an indication reaction for several electrophilic reagents which is known as Preussmann-test (PT). In this study the application of the PT is firstly presented for surface bonded epoxy groups. 3-Glycidoxypropyltrimethoxysilane (Glymo) has been used for surface functionalization of various solids such as alumo silicate, MgO, Ba-glass, Sr-glass, and various silicas such as Aerosil^? 300, OX 50, Sunspheres and silica gel KG 60. The covalent bonding of the epoxy moieties on the particle's surface by the silane function has been demonstrated by solid state NMR spectroscopy. The detection of active epoxy groups was implemented by the use of ¹³C-{¹H}-CP-MAS-NMR and XPS investigations. These both analytical methods require a large demand of time. Advantageously, the PT, which is applied to Glymo functionalized surfaces, enables a fast and certain assignment of the presence of active epoxy groups. The indicator reaction for detection of epoxy groups is the blue coloration of the samples. The reversible switching of the epoxy particles coloration is attributed to residual acid surface groups from the alumo silicates due to the protonation of the alkylated NBP product.