Functionalized olive wood shell stone as a new revalorized agri-food waste active in organocatalysis

Abstract

Olive wood shell stone has been used as an effective matrix for silanization and further anchoring of an organic probe such as 3-(5-chloro-anthraquinonylamino)propanoic acid (1). Covalent fixation of the anthraquinoid molecule was achieved by a “grafting to” silanization process with 3-aminopropyltrimethoxysilane (APTMS) followed by an amidation procedure. Ligand 1 was routinely characterized by multinuclear magnetic resonance (1H, 13C and 15N) and X-ray diffraction crystallography, while the new agri-food revalorized organocatalyst material was characterized by a number of analytical techniques such as granulometry, elemental analysis, thermogravimetry, differential scanning calorimetry, X-ray photoelectron spectroscopy, FTIR (ATR and DRIFT), moisture content, Karl-Fisher, ζ-potential and optical and fluorescence microscopy. The new revalorized material was assayed in the heterogeneous organocatalytic cyanosilylation of carbonyls compounds under very mild conditions with excellent yields and high recyclability under both presence and absence of solvent. Kinetic studies were also performed in order to understand the water uptake implications of this new organocatalyst.