Organosilicon ion‐exchange and complexing adsorbents

Long and systematic investigations of the present authors in the creation of organosilicon adsorbents, ion‐exchange and complexing agents are summarized. A wide series of such adsorption materials were synthesized by hydrolytic polycondensation and oxidizing hydrolytic polycondensation of organosilicon monomers of general formula X3SiQY and X3SiQZQSiX3, where X = Cl, AlkO; Q = alkylene C1–C3, phenylene; Y and Z = carbofunctional ionic and complexing groups. In this way, it was possible to obtain polyorganylsilsesquioxanes with carbofunctional groups such as Y = SH, SO3H, S(CH2)2NH2, SCH2COOH, NHC(O)CH3, NHC(S)CH3, NHC(NH)NH2, NHC(NH)NHC(NH)NH2, Z=S, SS, S(CH2)2S, NHC(O)NH, NHC(S)NH, NHSSNH, NHS(O)NH, NHS(O2)NH, NHC(SO2)NH, NHC(NH)NH, NHC(S)S− · NH3+, etc., which turned out to be very effective ion‐exchange and complexing adsorbents. These adsorbents have a crosslinked silsesquioxane structure. The three‐dimensional structure of the polyorganylsilsesquioxane skeleton of these adsorbents provides for their high thermal and chemical stability. They are stable up to 230–270°C and do not lose their adsorption activity in 10–18 mol/l H2SO4 at 100°C and in boiling concentrated HCl. The ion‐exchange and complexing properties of organosilicon adsorbents were studied on 50 elements of the Periodical system. Effective adsorbents toward noble metals, rare, rare‐earth and toxic elements have been found. The practical application of organosilicon adsorbents is described.