Physico-chemical of organo-functionalized magnesium phyllosilicate prepared by microwave heating

Abstract

In this work, organo-functionalized magnesium phyllosilicates were prepared via hydrothermal synthesis with four sources of silicon: 3-aminopropyltriethoxysilane (AMPTS), N-[3-(trimethoxysilyl)propyl]-ethylenediamine (TMSPEDA), N-[3-(trimethoxysilyl)propyl]-diethylenetriamine (TMSPETA) and tetraethoxyorthosilane (TEOS). Microwave radiation (MW) was employed as heating source and the results were compared with the analogous materials synthesized by conventional heating in an oven (CE). The materials obtained were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), solid state 29Si and 13C nuclear magnetic resonance (NMR), thermogravimetry (TG) and elemental analysis of carbon, nitrogen and hydrogen (CHN). The 2:1 type of trioctahedral phyllosilicate was confirmed by the presence of the 060/330 reflection, at 59.5° 2θ. The presence of the organic modifier was proven by the bands at 2930, 2850, and 1490cm−1 and the typical features of the phyllosilicate were found at 3700cm−1 (Mg–OH) and 1014cm−1 (Si–O–Si). 13C-NMR showed that the organic chains were intact in the interlayer space (5–64ppm). Thermogravimetry indicated that these pending groups were stable in this support until 200°C when they begin to decompose. Silicon-29 NMR confirmed that the pending groups were bound directly to the silicon atoms by the resonance of Si–C bond at 48 and 55ppm. The results showed the success of the procedure for all the proportions of the silicon sources used, with a reduction of reaction time in the range from 91% to 96% using microwave radiation in relation to the conventional heating oven.