Chun-Chiang Ting

Synthesis and solid-state NMR characterization of cubic mesoporous silica SBA-1 functionalized with sulfonic acid groups

Well-ordered cubic mesoporous silicas SBA-1 functionalized with sulfonic acid groups have been synthesized through in situ oxidation of mercaptopropyl groups with H(2)O(2) via co-condensation of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) templated by cetyltriethylammonium bromide (CTEABr) under strong acidic conditions. Various synthesis parameters such as the amounts of H(2)O(2) and MPTMS on the structural ordering of the resultant materials were systematically investigated. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), multinuclear solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, (29)Si{(1)H} 2D HETCOR (heteronuclear correlation) NMR spectroscopy, thermogravimetric analysis (TGA), and nitrogen sorption measurements. By using (13)C CPMAS NMR technique, the status of the incorporated thiol groups and their transformation to sulfonic acid groups can be monitored and, as an extension, to define the optimum conditions to be used for the oxidation reaction to be quantitative. In particular, (29)Si{(1)H} 2D HETCOR NMR revealed that the protons in sulfonic acid groups are in close proximity to the silanol Q(3) species, but not close enough to form a hydrogen bond.

Rapid sonochemical synthesis of MCM-41 type benzene-bridged periodic mesoporous organosilicas

Benzene-bridged periodic mesoporous organosilicas (PMOs) with the MCM-41 were synthesized by a rapid sonochemical process via co-condensation of tetraethoxysilane (TEOS) and 1,4-bis(triethoxysilyl) benzene (BTEB) under basic conditions within a few minutes using cetyltrimethylammoniumbromide (CTMABr) as a structure-directing agent. The molar ratio of the silicon precursors and the synthesis time were varied in order to investigate their influence on the structural ordering of the materials. The characteristics of the materials were evaluated by X-ray diffraction (XRD), N2-sorption, transmission electron microscopy (TEM) and solid-state NMR spectroscopy. The resultant materials exhibited well-ordered hexagonal mesostructures with surface areas in the range of 602-1237 m(2)/g, pore volumes of 0.37-0.68 cm(3)/g, and pore diameters in the range of 2.5-3.5 nm. Two dimensional (29)Si{(1)H} heteronuclear correlation (HETCOR) NMR spectra confirmed the formation of a single mesophase with various Q (from TEOS) and T (from BTEB) silicon species located randomly within the pore walls due to the co-condensation of BTEB and TEOS, which excluded the possibility of formation of island or two separate phases within such a short synthesis time. The prime advantage of the present synthesis route is that it can effectively reduce the total synthesis time from days to a few minutes, much shorter than the conventional benzene-bridged PMOs synthesis methods.

A one-pot organic–inorganic co-assembling route to ordered mesoporous carbons with cubic and bimodal pore structures

Highly ordered cubic mesoporous carbons with the cubic I4132 mesostructure have been synthesized via organic–inorganic self-assembly of tetraethoxysilane (TEOS), triblock copolymer Pluronic P123, and sucrose under acidic conditions.