The Sorption of Radionuclides on Clay Minerals—the Components of Engineering Safety Barriers

Moscow University Chemistry Bulletin - The sorption properties of various clay minerals and materials based on them in relation to Cs(I), Sr(II), U(VI), Eu(III), and Pu(IV,V,VI) are compared. To...     

J-Aggregates of Astaxanthin and Its Monoesters and Diesters

Moscow University Chemistry Bulletin - The conditions for the preparation of astaxanthin ester aggregates are optimized, and their physicochemical characteristics (size and absorption spectra) are...     

Functionalization of pyridines. 2. Synthesis of acylpyridines, pyridinecarboxylic acids, and their derivatives. Review

Advances in the synthesis of acylpyridines, pyridinecarboxylic acids, and their derivatives involving direct functionalization of the pyridine ring and substituent modification over the past 15 years are reviewed.Dedicated to Prof. A. Katritzky on the occasion of his seventieth birthday.For Communication 1, see [1].M. V. Lomonosov Moscow State University, 1119899 Moscow, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1013–1046, August, 1998.     

Synthesis of trifluoromethyl derivatives of pyrazolidine- and 2-pyrazoline-1-carboxamides and pyrazolidine- and 1-pyrazoline-carbothioamides

The reactions of enones containing trifluoromethyl groups with semicarbazide in basic media proceed unequivocally to give pyrazolidine-1-carboxamides. The direction of the reactions of these enones with thiosemicarbazide depends on their structure; the reaction products are pyrazolidine- and 2-pyrazoline-1-carbothioamides. An enone containing a CF₃ group and an ethoxy group capable of replacement reacts with semicarbazide to give 2-pyrazoline-1-carboxamide and with thiosemicarbazide to give the double addition product, 5-(1-thiosemicarbazido)-2-pyrazoline-1-carbothiamide.M. V. Lomonosov Moscow State University, 119899 Moscow, Russia, N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–644, May, 1998.     

Comparison of Yield,Chemical Composition and Antimicrobial Activity of Distichochlamys citrea Rhizome Essential Oils Obtained by Different Extraction Methods

Moscow University Chemistry Bulletin - Hydrodistillation (HD), steam distillation (SD) and microwave-assisted hydrodistillation (MAHD) extraction methods were assessed for their effects on yield,...     

Synthesis and isomerization recyclization of pyrazino[1,2-α]indoles

A method for synthesis of pyrazinol[1,2-a]indoles with alkyl substituents in position 1 was developed based on indole and isomerization recyclization of their quaternary salts into 9-aminopyrido[1,2-a]indole derivatives was conducted.M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 331–335. March, 1995. Original article submitted February 1, 1995.     

Cation and anion exchange on clay modified electrodes

Carbon paste electrodes modified with clay minerals were used for the study of ion-exchange properties of these clay minerals. Cation exchange of Cu(II) was studied by the dependence on the pH, ionic strength and the form of the minerals. The highest anionic exchange of Hg(II) acetates and chlorides was found on montmorillonites. Anionic exchange of Au(III) chloro complexes was found on montmorillonite, but their sorption is strongly influenced by other anions such as chlorides and thiocyanates. The results found are important with regard to the study of the anion-exchange properties of clay minerals. Received: 2 December 1999 / Accepted: 2 March 2000     

2,3,4,5-Tetrahydropyridine 1-oxides. Synthesis and properties (review)

Published data on the synthesis and transformations of 2,3,4,5-tetrahydropyridine 1-oxides are summarized for the first time, classified, and analyzed.A. N. Kosygin Moscow State Textile Academy, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 435–481, April, 1998.     

常见稀土氧化物矿物中氧同位素分馏研究

通过加和增量模式，对主要稀土氧化物矿物的氧同位素分馏方程进行了计算，并对矿物中稀土成份的变化，Ｔｉ＾４＋、Ｎｂ＾５＋、Ｔａ＾５＋、Ｔｈ＾４＋等类质同象替换，蜚 晶质化作用对矿物氧同位素分馏的影响进行了讨论。由于稀土氧化物矿物的氧同位素分馏曲纡变化较大，不宜用作地质温度计。     

Characterization of some boron minerals against neutron shielding and 12 year performance of neutron permeability

In this study, the nuclear radiation permeability properties of various boron minerals are evaluated because of their high neutron absorption and lowest transmission properties. Because of these properties boron minerals can be used at the area of neutron shielding. X-ray diffraction (XRD) analyses are done for the identification of the minerals, and then their B₂O₃ contents are determined experimentally. In addition, X-ray florescence (XRF) analyses are made for quantitative determination of calcium, iron, zinc and arsenic contents. The methods of Differential Thermal Analysis, Thermal Gravimetry (TG/DTA) and Differential Scanning Calorimeter (DSC) are used for obtaining the enthalpy and weight changes with temperature. Additionally, neutron permeability experiments are conducted. From the experimental results, the highest boron oxide content was found in clay containing colemanite. Iron, zinc and arsenic contents were not affecting the neutron shielding. The lowest permeability is provided by the kurnakovite mineral. Also it is observed that all of the minerals show an increase in their permeability in 12 years. It can be stated that boron minerals, specifically kurnakovite, is determined to yield the lowest neutron permeability value and therefore, the use of these materials for neutron shielding would be suitable.     

Luminescence database I--minerals and materials.

A luminescence database for minerals and materials has been complied from the literature, the aim being to create a resource that will aid in the analysis of luminescence spectral of ionic species in minerals and materials. The database is based on a range of excitation techniques and records both major and minor lines, and their activators. The luminescence techniques included in the database are cathodoluminescence, ion luminescence, and photoluminescence. When combined with other traditional X-ray measurements collected on the same region, use of the luminescence database will give additional insight into the chemistry of minerals and materials.     

The Detection of Floretin and Floridzin in Eastern Apple Tree Fruits (Malus orientalis Uglitzk. ex Juz.) and Assessment of the Quantitative Content of Phenolic Compounds

Moscow University Chemistry Bulletin - The following dihydrochalcones are attracting a great deal of attention as biologically active substances of apple fruits due to their possible antidiabetic...     

Structure of silica

Summary 1) Preliminary data have been obtained, indicating the existence of structures of two types in silicathree-dimensional framework and double-chain. 2) A model has been proposed for the structure of silica, which resembles the structure of layer clay minerals. 3) The absorption bands in the range of the OH and (Si–(OH) stretching vibrations have been interpreted. 4) The adsorption centers on silica for proton-donor molecules are the oxygen atoms of OH^– ions and SiOH groups; the adsorption centers for electron-donor molecules are the hydrogen atoms of the accessible SiOH groups. 5) It has been shown that the solid-state lattice vibrations are changed under the influence of adsorption.All-Union Scientific-Research Institute for Petroleum Refining, Moscow. Translated from Zhurnal Strukturnoi Khimii, Vol. 18, No. 1, pp. 97–106, January-February, 1977.     

Influence of Z,E-isomerism on the chiral-optical properties of amides

The study of the chiral-optical properties of N-acyl-(–)-1-methyl-1,2,3,4-tetrahydroisoquinolines and their acyclic analogs, the n-acyl-(–)-1-phenylethylamines, with the known ratio of Z- and E-isomers showed that the Z-isomers are characterized by the negative Cotton effect in the region of the absorption band of the amide chromophore. The observed Cotton effects of amides of phenylethylamine, which are higher by comparison with those of amides of tetrahydroisoquinoline, are explained by the interaction of the amide and aromatic chromophores, which are in proximity in certain conformation, possible for acyclic conformationally free phenylethylamides.Chemical Faculty, M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 944–949, July, 1996. Original article submitted May 23, 1996.     

Derivatives of 4-halocrotonic acids, convenient reactants in the synthesis of heterocycles. (Review)

Literature data are reviewed for the first time on the use of 4-halocrotonic acid derivatives in the synthesis of five-and six-membered heterocycles containing one or several heteroatoms in the ring, and their annelated analogs.N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences (RAN), Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 435–470, April, 2000.     

An investigation and identification of polysaccharides isolated from archeological specimens

Summary Polymeric compounds have been isolated from archeological specimens (fragments of Central Asian paintings of the 2nd-19th centuries). A comparison of their IR spectra with the spectra of plant gums has shown that they are polysaccharides which have remained undestroyed for up to 1800 yr. In some cases it has been possible from the IR spectra and composition of the extracted polysaccharides to provisionally identify sourcherry or apricot gum, of which these polysaccharides were components.All-Union Central Scientific-Research Laboratory for Conservation and Restoration, Moscow. M. M. Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 15–19, January–February, 1976.     

Study of the extraction of strontium(II) and lead(II) by crown and dithiacrown ethers

A study was carried out on the extraction of strontium(II) and lead(II) picrates by chloroform solutions of crown and dithiacrown ethers. The benzene ring substituents in benzodithia-18-crown-6 only slightly affect the extraction of strontium and lead cations and their separation. The introduction of an adamantyl group onto the benzene ring markedly increases the extraction of lead and the separation selectivity of these cations. The use of dithia derivatives of benzo-18-crown-6 is less efficient for the extraction of both strontium and lead, though the selectivity of their separation is almost the same as in the extraction with benzo-18-crown-6.M. V. Lomonosov Moscow State University, 119899 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1129, August, 1997.     

Investigation by1H NMR of dienediamines as starting materials for the synthesis of indoles and benzofurans by the nenitzescu reaction

Investigations using¹H NMR have been carried out on dienediamines which are starting materials for the synthesis of indoles and benzofurans by the Nenitzescu reaction. Protonation of dienediamines and special features of their configuration and conformation were studied.Center for Drug Chemistry, All-Russian Chemical and Pharmaceutical Research Institute (VNIKhFI), Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 336–342, March, 1997.     

Synthesis of some alkaloids using the allyl derivatives of boron (review)

Data on the application of the allylic derivatives of boron for the synthesis of piperidine, indolizine, pyrrolizidine, and indole alkaloids are reviewed.A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow. N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1015–1027, August, 1999.     

Effect of electrolyte on surface free energy components of feldspar minerals using thin-layer wicking method

Application of the thin-layer wicking (TLW) technique on powdered minerals is useful for characterizing their surfaces. Albite (Na-feldspar) and orthoclase (K-feldspar) are feldspar minerals which are frequently found in the same matrix. Despite similarities in their physicochemical properties, separation of these minerals from each other by flotation is generally possible in the presence of monovalent salts such as NaCl. Both albite and orthoclase exhibit the same microflotation properties and rather close electrokinetic profiles in the absence of salt. In this study, contact angles of albite and orthoclase determined by the TLW technique yielded close values in the absence and presence of amine collector. While the calculated surface energies and their components determined using contact angle data reveal that the energy terms remain farther apart in the absence of the collector, the differences narrow down at collector concentrations where full flotation recoveries are obtained. However, the effect of addition of NaCl on contact angles and surface free energy components at constant amine concentration indicates that albite is significantly affected by salt addition, whereas orthoclase remains marginally affected. This interesting finding is explained on the basis of ion-exchange properties, the stability of the interface, flotation data, and zeta potential data in the presence of NaCl.