Synthesis of nanostructured materials using supercritical CO2: Part II. Chemical transformations

A new sustainable route in supercritical CO2 to functionalize silica SBA-15 with 3-aminopropyltrimethoxysilane as material for carbon capture

“…Moreover, this approach generates significant amounts of organic solvent waste. As an alternative to traditional organic solvents, supercritical carbon dioxide (scCO 2 ) has recently received significant attention as an attractive medium to functionalize the surface of inorganic materials in a more sustainable way [13]. scCO 2 is considered a green solvent because it is non-toxic, non-flammable, inexpensive, naturally abundant and relatively inert.…”

“…These researchers demonstrated that the HDMS reaction proceeds releasing NH 3 on the silica surface leading to the formation of ammonium carbamate in the CO 2 properties of expanded fluids including their low viscosity [29,30], high diffusivity [31] and extremely low surface tension allow the transport of the silane agent to the internal surface of nanopores and can highly improve the dispersion of the amine groups in the mesopores. The density of the expanded fluid can be modified from gas-like to liquid-like with small changes in temperature and/or pressure thus allowing a control of the surface coverage which is not always possible in liquid-phase processes [13]. Futhermore, CO 2 and ethanol can easily be separated from the material by CO 2 extraction and this is a great advantage in comparison to the liquid methods.…”

Preparation of mesoporous silica supported cobalt catalysts using supercritical fluids for Fischer–Tropsch synthesis

“…Carbon dioxide can be one of the most suitable supercritical fluids for the above purpose because it is non-toxic, non-reactive, and non-flammable, and is capable of dissolving some metal precursors with an addition of entertainer. The supercritical impregnation is pointed out to consist of (a) the dissolution of a metallic precursor in supercritical CO 2 , and (b) transfer the precursor to the substrate for adsorption (Erkey, 2009 successfully prepared using supercritical impregnation method (Bozbag et al, 2012). Recently, we also reported that supercritical CO 2 could allow cobalt precursors penetrating into mesopores, leading to good dispersion of penetrated particles compared with the liquid solvents (Shimizu et al, 2012).…”

Formation of poly(methyl methacrylate)-ZnO nanoparticle quantum dot composites by dispersion polymerization in supercritical CO2

“…However, the surface modification process typically required large amounts of organic solvents that are harmful to the environment. To solve this problem, many researchers have attempted to synthesize polymer-nanoparticle composites by using supercritical fluid (SCF)-based technology [28][29][30][31][32]. Supercritical CO 2 (i.e.…”