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Features of vanadium(V) sorption by cross-linked organosilicon polymers-polyorganylsilsesquioxanes containing acetamide, phthalamide, malondiamide, and thiourea dioxide functional substituents, were studied.

Triethoxysilyl)propyl)amino}pyridine is synthesized by condensation of (3-(triethoxysilyl)- propyl)amine with 2-aminopyridine. Its peretherification with triethanolamine leads to 2-((3-silatranylpropyl)- amino)pyridine and hydrolytic copolycondensation with tetraethoxysilane to cross-linked organosilicon copolymer {SiO 2 2(O 1.5 Si(CH 2 ) 3 NHC 6 H 4 N)} n . The latter in the medium of hydrochloric acid behaves as an anionite in respect of anionic chlorocomplexes of gold(III), platinum(IV), palladium(II) and rhodiumIII). Organosilicon compounds containing heterocycl substituents possess a specific biological activity (1, 2). Polyorganylsesquioxanes containing such groups in organic radical are effective complexing agents (3, 4). In continuation of such investigations we per- formed synthesis of a new carbofunctional organo- silicon compound, 2-{(3-(triethoxysilyl)propyl)- amino}pyridine (I). By analogy with the earlier studied by us organosilicon derivatives of thiocarb- amide, carbamide, carboxylic amides and related compounds (5 7), we prepared compound I by con- densation of (3-(triethoxysilyl)propyl)amine ( II) with 2-aminopyridine.

Condensation of (aminomethyl)triethoxysilane with thiocarbamide in the presence of catalytic amounts of ammonium sulfate was used to synthesize N,N-bis(triethoxysilylmethyl)thiocarbamide. The latter was brought into oxidative hydrolytic polycondensation with H2O2 to obtain poly[N,N′-bis(silsesquioxanylmethyl)thiocarbamide S, S-dioxide] whose properties were compared with the properties of poly[N,N′-bis(silsesquioxanylpropyl)thiocarbamide S,S-dioxide]. Both polymers in highly acidic media rather strongly absorb Ag(I), while at pH 7 they reduce most absorbed Ag+ to the metal. Their reaction with potassium permanganate involves reduction of Mn7+ to Mn4+. The first polymer is a less effective sorbent and redox agent than the second.

Organic derivatives of dithiocarbamates are findingextensive practical use. Many of them possess specificbiological activities and are recommended as medicinaldrugs [1, 2]. An important field of practical applicationof organic compounds containing dithiocarbamategroups is their use as reagents to determine heavy metalions [3–5] and to purify wastewaters from toxic con-taminants [6, 7]. Sorbents with dithiocarbamate groupshave been reported [8, 9].While developing the research into carbofunction-ally substituted organosilicon monomers and materialsfor sorption based on them [10, 11], we synthesized andstudied an organosilicon sorbent containing dithiocar-bamate groups.The initial monomer, 3-triethoxysilylpropylammo-nium 3-triethoxysilylpropyldithiocarbamate (

A large number of sorption materials differing in both nature and structure have been proposed for the removal of toxic metal ions from process and natural waters [1‐3]. Due to various limitations (complex production technology, low chemical and mechanical stability, low efficiency, and incompatibility of the concentrated product thus obtained with the subsequent method of analysis), only few of them can be used in practice. The increase in man-caused impact on the environment strongly calls for the design of efficient methods for neutralization of industrial waste water and, what is equally important, highly sensitive and fast methods for determination of toxic metals in natural waters. In this study, we demonstrate that two organosilicon polymers, poly[ N -(3-silsesquioxanylpropyl)thioacetamide] O 1.5 Si ( CH 2 ) 3 NHC (= S ) CH 3 ( I ) and poly[ N -(3-silsesquioxanylpropyl)- N '-acetylthiocarbamide] O 1.5 Si ( CH 2 ) 3 NHC (= S ) NHC (= O ) CH 3 ( II ), can be used as effective sorbents for Hg(II), Cd(II), and Bi(III) ions. Polymers I and II are carbofunctional polyorganylsilsesquioxanes; they possess higher chemical and thermal stability and higher mechanical strength than their organic analogs [4‐6]. The production process for these materials is very simple; it is based on hydrolytic polycondensation of the corresponding γ -carbofunctionally substituted triethoxypropylsilanes [7, 8]. These polymers are yellow or pale brown powders having a developed surface ( S sp = 450‐ 600 m 2 /g) and high porosity ( = 1.8‐2.1 cm 3 /g). The sorption capacity of polymers I and II was stud

The reducing power of organosilicon thiourea S-dioxides, N,N'-bis(3-triethylsilylpropyl)thiourea S-dioxide and poly[N,N'-bis(silsesquioxanylpropyl)thiourea S-dioxide], was studied. The first, monomeric dioxide readily reduces cyclohexanone to cyclohexanol. In its presence, under phase-transfer conditions, dipropyl disulfide reacts with bromobenzene to form propyl phenyl sulfide, and tellurium reacts with ethyl bromide to form diethyl telluride. The reducing power of the polymeric dioxide was demonstrated by the example of reduction of potassium permanganate. Irrespective of the medium (neutral, acidic, or alkaline), this polymer reduces Mn(VII) to Mn(IV).

Sorption of UO22+ on polysilsesquioxanes with thiourea dioxide, acetamide, phthalimide, and malonamide functional groups was studied.

Literature data concerning research organosilicon ion-exchangers and complexing agents have been summarized and systematized. Data on organophilic organosilicon adsorbents and sorption systems for chromatography are not considered here. Copyright © 1999 John Wiley & Sons, Ltd.

Adsorption of n-alkanes (C7H16–C11H24), cyclohexane, benzene, CHCl3, CCl4, and ClCH2CH2Cl by polymethylsilsesquioxane [MeSi(OH)0.4O1.3]n was investigated by inverse gas chromatography in the Henry region. The adsorption isotherms are linear for all adsorbates. The standard changes in the thermodynamic parameters of adsorption were determined. The absence of specific selectivity with respect to aliphatic, cyclic, or aromatic hydrocarbons or chloroalkanes indicates that the adsorbent is chemically homogeneous.

Copolymers of N-vinylpyrazole with vinyl chloride and methyl methacrylate were produced by radical polymerisation. The involvement of the obtained (co) polymers in sol–gel synthesis with the participation of tetraethoxysilane leads to the production of hybrid organic–inorganic composites. Films were obtained from solutions of the (co)polymers and composites by casting, and their proton conductivity was determined (7.8 103 S cm1).

Literature data concerning research organosilicon ion-exchangers and complexing agents have been summarized and systematized. Data on organophilic organosilicon adsorbents and sorption systems for chromatography are not considered here. Copyright © 1999 John Wiley & Sons, Ltd.