Study of the influence of alkali element compounds on the activity of aluminopalladium catalysts for oxidation of carbon monoxide

A discussion is presented of a discovery that the anionic part of sodium salts introduced into the catalyst by impregnation of -Al₂O₃ after deposition of palladium salts and their reduction in that catalyst affects the activity and dynamic properties of the catalysts in the oxidation reaction of CO into CO₂ at stoichiometric ratios of CO/O₂ = 2.Scientific-Production Association Gos. In-t Prikl. Khim., Leningrad. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 5, pp. 591–595, September–October, 1991. Original article submitted July 17, 1991.     

Investigations in the imidazole series

Purinyl(theophyllinyl)-8-mercapto aldehydes and their acetals were synthesized by the reaction of 8-thio derivatives of purine and theophylline with -halo aldehydes and their acetals. The IR spectra demonstrated that the indicated aldehydes exist in the solid state as tautomeric forms — 3-hydroxy derivatives of thiazolino[2,3-f]purines(xanthines). Dehydration of the latter gave thiazolo[2,3-f]purine, 6,8-dimethylthiazolo[2,3-f]xanthine, and their 2-alkyl-substituted derivatives. The structures of the three-ring compounds were established by reductive desulfuration to 7-alkyl-substituted purines and theophyllines.See [1] for communication LXXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 996–999, July, 1972.     

Early Stage of Structural Changes and Molecular Dynamics of Cytochrome C in an Aqueous Solution Caused by the Addition of Methanol

Crystallography Reports - Molecular dynamics simulations of horse heart cytochrome C were performed in an aqueous solution and in a 50 : 50 water–methanol mixture. Three independent 100-ns...     

New Approaches to Synthesizing Electroactive Polymers

The chemical oxidative polymerization of aniline in a heterophase system is studied. In the presence of a solid substrate, the aniline polymerization involves two kinetically and chemically independent processes, namely, the polymerization in the bulk solution and at the substrate surface. The growth of the polyaniline coating at the substrate surface includes three successive processes: interfacial polymerization, adsorptive polymerization, and destruction of the polymer chain. The interfacial oxidative polymerization of diphenylamine and phenothiazine is examined. The yield and chemical structure of polymers is shown to depend on the polymerization conditions.     

Dynamic response of the spherical pendulum subjected to horizontal Lissajous excitation

Nonlinear Dynamics - This paper examines the oscillations of a spherical pendulum with horizontal Lissajous excitation. The pendulum has two degrees of freedom: a rotational angle defined in the...     

A review of analytical techniques for determination of Sudan I–IV dyes in food matrixes

Sudan dyes are a family of lipophilic azo dyes, extensively used in industrial and scientific applications but banned for use as food colorants due to their carcinogenicity. Due to the continuing illicit use of Sudan dyes as food colorants their determination in different food matrices – especially in different chilli and tomato sauces and related products – has during the recent years received increasing attention all over the world. This paper critically reviews the published determination methods of Sudan I–IV dyes. LC–UV–vis and LC–MS are the dominating methods for analysis of Sudan I–IV dyes. Sudan dyes are usually found in food at mg kg⁻¹ levels at which it may be necessary to use a preconcentration step in order to attain the desired detection limits. Liquid–solid extraction is the dominating sample preparation procedure. In recent years it has been supplemented by ultrasonic-assisted extraction and pressurized liquid extraction. Various solid phase extraction types have been used for sample cleanup. The large majority of works use conventional C18 columns and conventional LC eluents. Traditionally the UV–vis absorbance detection has been the most frequently used. In the recent years MS detection is applied more and more often as it offers more reliable identification possibilities.     

Mass spectra of acid and trisubstituted 1- and 2-adamantyl phosphites

The decomposition of acid and trisubstituted phosphites containing 1- and 2-adamantyl, cyclohexyl, and ethyl groups in various combinations was studied under electron impact. The major directions for the fragmentation of the compounds studied are related to cleavage of the C-O bond, which is accompanied by migration of one or two hydrogen atoms to the phosphorus-containing fragment. Mono-, di-, and triadamantyl phosphites feature the loss of phosphorous acid (in the case of acid phosphites) or alkylphosphorous acid (n the case of trisubstituted phosphites) from the molecular ion, which leads to the generation of a diadamantyl or alkyladamantyl species. In this case, the charge is localized predominantly on the hydrocarbon fragment.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1676–1678, July, 1990.     

Synthesis of polysiloxane xerogels with fluorine-containing groups in the surface layer and their sorption properties

Hydrolysis and polycondensation reactions of tetraethoxysilane (TEOS) with 3,3,3-trifluoropropyl-trimethoxysilane (TFMS) or 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFES) were used to synthesize xerogels functionalized with fluorine-containing groups. According to transmission electron microscopy, the skeletons of synthesized polysiloxane xerogels have globular structures and consist of agglomerates of particles with fluorinated groups on their surfaces. FTIR spectroscopy showed that primary xerogel particles possess spatial polysiloxane networks, with fluorinated groups along with silanol groups and water in the surface layer. According to thermal analyses, the water content was 3–8 wt.%, and it decreased with increasing length of the fluorinated chain. Thermal destruction of the surface layer starts above 300 °C. The sorbents that were obtained were predominantly mesoporous materials with well-developed porous structures (S_BET = 400–960 m² g⁻¹, V_s = 0.66–0.93 cm³ g⁻¹). The influence of the TEOS/functional silane ratio and the natures of the functional groups on the structural and adsorptive properties were shown. The samples synthesized are organophilic. The affinity for n-hexane increases with increasing length of the fluorine-containing chain (PFES) and the content of fluorinated groups in the surface layer. The hybrid organic–inorganic materials that were obtained can be used for adsorption of hydrocarbons, including oil, from water.