Preparation and characterization of bonded silica hydride intermediate from triethoxysilane and dimethylmethoxysilane using supercritical carbon dioxide and dioxane as reaction medium

Synthesis, characterisation and chromatographic evaluation of pentafluorophenyl and phenyl bonded silica phases prepared using supercritical carbon dioxide as a reaction solvent

“…Ashu-Arrah et al [2] and Cao et al [6] have both demonstrated that supercritical CO 2 is a good solvent for silylation reactions, comparable or better than organic solvents. This is because the solvating power (density) and mass transfer kinetics of sc-CO 2 (lower viscosity and higher diffusivity), facilitate easy penetration of CO 2 and ligands to silica pores and silanols that are not accessible with organic solvent.…”

“…Wide ranges of temperature and pressure programming conditions, coupled with short reaction time and easily recycled reaction medium makes sc-CO 2 a viable green chemistry alternative to conventional organic solvent based methods of preparation [1,2]. Cao et al demonstrated that sc-CO 2 will adsorb water from silica surface while performing silanisation thus acting as a desiccant [6], a feature which distinguishes sc-CO 2 from organic solvents.…”

“…Myers et al reported the derivatisation of silica with a polyaminosilane in sc-CO 2 at 150 • C and low pressure [9]. Ashu-Arrah et al synthesised mercaptopropyl bonded silica (MPS) and silica hydride (Si H) intermediates at temperature not far exceeding ambient conditions over shorter reaction time [1,2]. Holmes et al designed a procedure for the synthesis and swelling of large pore diameter mesoporous silica sphere using sc-CO 2 as a reaction solvent [10].…”

“…Using a green chemistry approach which exploits the properties of supercritical carbon dioxide (sc-CO 2 ), such as lower toxicity, programmable solvating power and high diffusivity, organosilanes can be reacted with surface silanol groups for a clean, organic solvent free synthesis of silica bonded phases for liquid chromatography [1][2][3][4][5].…”

Immobilization of Antibodies and Enzymes on 3-Aminopropyltriethoxysilane-Functionalized Bioanalytical Platforms for Biosensors and Diagnostics

“…FTIR and solid-state NMR spectroscopy are useful for probing bonding methodology, surface coverage, and silanol conversion efficiencies with supercritical-CO 2 as reaction solvent. 103 …”