A clean and effective supercritical carbon dioxide method for the host–guest synthesis and encapsulation of photoactive molecules in nanoporous matrices

Abstract

The present work is concerned with host-guest processes in the micro-and mesoporous restricted spaces provided by silica aerogels and aluminosilicates. A supercritical carbon dioxide ship-in-a-bottle approach was used for the synthesis of photoactive molecules (triphenylpyrylium and dimethoxyltrityl cations) inside these nanoporous matrices. The resulting hybrid nanocomposites can act as stable and recoverable heterogeneous photocatalysts, having obvious advantages with respect to the more easily degraded organic cations frequently used in homogeneous catalysis. Two aspects of green chemistry are combined in this study to produce nanoporous materials loaded with cationic photosensitizers: (i) the use of supercritical carbon dioxide as a reaction medium in one-pot and as a zero waste technology, and (ii) the use of transparent high surface area nanoporous supports that are expected to be more effective for the target photoactive applications than traditional opaque microporous matrices.

Bacterial cellulose films: influence of bacterial strain and drying route on film properties

“…Evacuation of solvents in supercritical conditions is commonly used to produce aerogels which is a term given to open pore materials presenting low density and large specific surface area. The most known aerogels are silica, (Murillo-Cremaes et al 2010;Moner-Girona et al 2003;Martin et al 2008;Budunoglu et al 2011) carbon, (Wu et al 2013;Mecklenburg et al 2012) organic-inorganic aerogels (Hendel et al 2013;Ennajih et al 2012) and more recently thick pieces of BC aerogels have also been reported (Hendel et al 2013;Liebner et al 2010;Cai et al 2008;Russler et al 2012).…”

An equation of state for pore‐confined fluids

“…Application areas include, among others: (1) the use of supercritical fluids to modify porous materials, [1][2][3][4] (2) physical adsorption of trace components from gaseous effluents, 5 (3) gas storage using microporous materials, 6 and (4) chemical separations using inorganic membranes. Application areas include, among others: (1) the use of supercritical fluids to modify porous materials, [1][2][3][4] (2) physical adsorption of trace components from gaseous effluents, 5 (3) gas storage using microporous materials, 6 and (4) chemical separations using inorganic membranes.…”

“…The prediction of properties in porous materials is of continuing interest in the fields of chemical and materials engineering. Application areas include, among others: (1) the use of supercritical fluids to modify porous materials, [1][2][3][4] (2) physical adsorption of trace components from gaseous effluents, 5 (3) gas storage using microporous materials, 6 and (4) chemical separations using inorganic membranes. 7 The confinement of a fluid in a porous matrix changes its properties relative to its bulk state and this may be important in engineering applications.…”

Hybrid aerogel preparations as drug delivery matrices for low water-solubility drugs

“…First, the null surface tension of a supercritical fluid allows the 80 drying of alcogels preserving their porosity to form aerogels (Wagh et al, 1999;Yoda and Ohshima, 1999). Second, due to the low viscosity and high 81 diffusivity of fluids under supercritical conditions, scCO2 solutions have the ability to penetrate and efficiently impregnate porous matrices with organic 82 solutes, in this work selected model drugs, again without damaging the porous structure (Domingo et al, 1998;Murillo-Cremaes et al, 2010). 83…”