E. N. Oborina

New organosilicon derivatives of some analytical reagents: sorbents and metallochromic agents

A synthesis of organosilicon monomeric and polymeric derivatives of 1,4-phenylenediamine, 4-aminoantipyrine, and aniline, which are analytical agents possessing sorption properties, was accomplished. The synthesized organosilicon polymers were studied as sorbents of heavy metals FeIII, HgII and noble metals AgI, AuIII, RhIII, PdII, PtIV. Poly[(3-N-silsesquioxanylpropyl-4aminoantipyrine)] exhibited high sorption activity with respect to platinum group metals in comparison with poly[N,N´-bis(3-silsesquioxanylpropyl)-1,4-phenylenediamine]. The reaction of poly[(3-N-silsesquioxanylpropyl-4-aminoantipyrine)] practically with all the elements under study was accompanied by coloring. The starting monomer exhibited similar metallochromic properties.

Organosilicon derivatives of thiuram disulfide showing sorptive and metallochromic properties

190 Our systematic study in the area of carbofunctional organosilicon monomers and ion exchange and com plexing sorbents derived from them [1, 2] revealed compounds showing metallochromic properties. Such compounds are organosilicon derivatives of dithiocar bamic acid, biguanidine, and iminoguanidine [3], which are not only new organosilicon ionites and complexones but also of interest as test systems of new generation. Test methods developed on the basis of the test systems assume ever greater importance from year to year as express methods demanding no complex instrumentation for detection of elements and their semiquantitative and sometimes quantitative determi nation [4]. The general approach of all chemical test methods consists most frequently in the use of analyt ical reactions and reagents that ensure a visual effect (coloration of different intensity). In continuation of our studies, thiuram disulfide derivatives already used as chromogenic reagents attracted our attention. In particular, tetraethylthi uram disulfide is not only an efficient anti alcohol medicine (Antabuse) but is also used in analytical practice due to formation of colored complexes with a number of elements [5, 6]. For example, it forms with Cu(II) a yellow brown chelate complex known as Mercupral and used as a reagent for determination of silver and mercury [7].

New carbofunctional organosilicon monomers and polymers possessing sorption and metal chromatic properties

Monomeric and polymeric β-naphthylamine and dithizone organosilicon derivatives were synthesized. The organosilicon polymers were studied as sorbents of heavy (FeIII, HgII) and noble (AgI, AuIII, RhIII, PdII, PtIV) metal ions, as well as of CeIII and TbIII. They were found to possess high sorption activity toward platinum group metals and iron. The monomers and polymers obtained exhibit metal chromatic properties. Their reactions virtually with all the elements studied, except cerium and terbium, are accompanied by coloration.

Organosilicon compounds containing carbofunctional biguanidine group

The reaction of triethoxysilylpropylamine (AGM-9) with dicyanodiamide was studied. The condensation of AGM-9 with dicyanodiamide occurs in the presence of a catalytic amount of CuCl2 at 125–145°C within 5–24 h; it involves both the amino group of AGM-9 and ethoxy substituents at the Si atoms, with an unusual exchange of a Si-O bond for a Si-N bond. The final reaction product is 1-N-(3-triethoxysilylpropyl)-2-N-[3-aminopropylsilyl(diethoxy)]biguanidine. Its hydrolytic polycondensation yields an organosilicon polymer, a polycondensate of AGM-9 with 1-N-(3-triethoxysilylpropyl)biguanidine, which is a highly efficient sorbent for Ag(I) (static sorption capacity 544 mg g−1).

Reaction of Dioxides Derived from Organosilicon Thiocarbamides with Ammonia and Methylamine

Reactions of organosilicon thiocarbamide dioxides {[R3Si(CH2)3NH]2CSO2, R = Et (I), O1.5 (II)} with methylamine and ammonia were studied. The reaction of compound I with ammonia involves, along with the substitution of the NHC(SO2)NH fragment by a guanidine residue, Si-C bond cleavage to form an oligomer comprising [O(Et)Si(CH2)3NH]2C=NH and [O1.5Si(CH2)3NH]2C=NH elementary units. The reactions of compound II with methylamine and ammonia resulted in the synthesis of organosilicon polymers containing guanidine groups. These polymers exhibit a high sorption capacity toward Ag(I).

New Sorption Materials Based on Organosilicon Derivatives of Thiosemicarbazides

The synthesis of organosilicon derivative monomers and polymers characterized with sorption properties has been performed. The synthesized organosilicon polymers have been investigated as sorbents for heavy (Hg(II)) and noble (Ag(I), Au(III), Rh(II), Pd(II), and Pt(IV)) metals. The coefficients of the interphase metal distribution have been estimated.

The Interaction of New Types of Polyorganyl Silsesquioxanes with Cerium and Terbium

Sorption of new types of carbofunctional organosilicon polymers, poly[N,N′-bis-(3-silsesquioxanyl propyl)thiuram disulfide], poly-[N-(3-silsesquioxanyl propyl)-α-naphthylamine], and poly-(3-silsesquioxanyl propyl ammonium dithizonate), is studied with respect to cerium and terbium.

Increase in selectivity of the metallochromic effect of potential test systems based on 3-(triethoxysilyl)propylammonium dithizonate

New organosilicon derivatives of dithizone with high sorption activity and nonselective metallochromic properties were synthesized. When they are modified, the possibility of increasing the selectivity of their metallochromic effect and prospects for using them as test systems are shown.

Adsorption of platinum(IV) onto composites based on silicon dioxide and vinyl acetate/1-vinylimidazole and vinyl acetate/4-vinylpyridine copolymers

Composite materials are synthesized using the sol–gel method involving tetraethoxysilane and vinyl acetate/1-vinylimidazole and vinyl acetate/4-vinylpyridine copolymers, and their sorption capacity with respect to platinum(IV) ions is studied. The composites exhibit the highest sorption activity at 338 K in 1 M HCl solution (sorption capacity with respect to Pt(IV) varies from 180 to 249 mg g–1). The interaction between platinum(IV) and the surface of the sorption material is a result of the chemisorption process. The Langmuir, Freundlich, and Dubinin–Radushkevich models are used to describe the nature of adsorption.