Adsorption of Hydrocarbons from Gas-Air Mixture on Polypropylene Stereoisomers

Kinetics of absorption of a mixture of aliphatic, aromatic, and unsaturated hydrocarbons from the gas phase onto polypropylene containing 5, 18, and 40% atactic polymer in its molecular lattice was studied. The kinetic parameters, equilibrium constant, and Gibbs energy of adsorption-desorption of the hydrocarbons were determined by zero-, first-, and second-order optimization of the solution of the multiparameter equation. These parameters were correlated with the adsorbent composition and the number of sorption-desorption cycles.     

Kinetics of the acidic hydrolysis of vinyl derivatives of benzimidazole-2-thione and benzoxazol-2-one and -2-thione

The kinetics of the acidic hydrolysis of seven vinyl derivatives of benzimidazole-2-thione and benzoxazol-2-one and -2-thione were studied by means of polarography. The rate constants and energies of activation of the reaction were determined. The hydrolytic stabilities of the compounds depend on the nature of the heteroring and the site to which the vinyl group is attached.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1532–1535, November, 1982.     

Synthesis of nitro and amino derivatives of benzothiacrown ethers

The condensation reaction of 1,2-bis(2-haloethoxy)-4-nitrobenzenes with acyclic α,ω-(oxa)alkanedithiols in the presence of alkali metal carbonates produced a series of nitrobenzodithiacrown ethers with macrocycles of different size. The structures of three ethers were established by X-ray diffraction. A new method was developed for the synthesis of nitrobenzomonothia-15-crown-5 ether. Nitro derivatives of benzodithiacrown ethers were tested as reagents for extraction of palladium(II), platinum(IV), and rhodium(III) from hydrochloric acid solutions. Extraction of Pd^II salts was found to be highly selective compared to that of Pt^IV and Rh^III salts. Benzodithia-15-crown-5 ether is the most efficient extractant for palladium(II). Reduction of nitrobenzothiacrown ethers with hydrazine hydrate in the presence of a platinum catalyst afforded their amino derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 958–966, May, 2007.     

Stereoisomerism of N-(1-Propenyl)thiobenzamide

A prototropic rearrangement of N-prop-2-enylbenzocarbothioamide afforded two stereoisomeric N-prop-1-enylbenzocarbothioamides (IIa, b) isolated as individual compounds. The stereoisomerism is due to hindered rotation around thioamide bond C(S)-N and also to -diastereoisomerism. The configuration of the isolated isomers was investigated by IR spectroscopy, AM1 and PM3 methods. In the molecules occurs the p,-conjugation with participation of nitrogen atom and multiple bonds resulting in formation of a united delocalized MO in the planar fragment C(S)-NC = C.     

Vinyl Ethers Containing an Epoxy Group: XXI. Synthesis and Acid-Catalyzed Cyclization of 1-[ω-(Vinyloxy)alkoxy]-3-(2-propynyloxy)-2-propanols- A Simple Route to 2-Propynyloxymethyl-Substituted Cyclic Polyethers

Base-catalyzed reaction of 2-[-(vinyloxy)alkoxy]methyloxiranes with 2-propynyl alcohol (3 wt % of t-BuOK, 60-85°C, 3-12 h) afforded first reperesentatives of the 1-[-(vinyloxy)alkoxy]-3-(2-propynyloxy)-2-propanol series in up to 99% yield. Treatment of 1-[2-(vinyloxy)ethoxy]- and 1-[2-(vinyloxy)ethoxyethoxy]-3-(2-propynyloxy)-2-propanols with trifluoroacetic acid (0.5 wt. %) in dry diethyl ether resulted in cyclization with formation of up to 96% of (2-methyl-1,3,6-trioxocan-4-yl)methyl- and (2-methyl-1,3,6,9-tetraoxacycloundecan-4-yl)methyl 2-propynyl ethers.     

Adsorption of Gaseous Hydrocarbons on the Surface of Modified Petroleum-Polymeric Resins

The kinetics of adsorption of model hydrocarbons (benzene, toluene, ethyl benzene, isopropyl benzene, cyclohexane) from the gas phase on the surface of ozonized and maleized petroleum-polymeric resins was studied. The dependences of the dynamic equilibrium capacity of the petroleum-polymeric resins and of the adsorption kinetic parameters on the composition of the adsorbent-adsorbate system were elucidated.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 245–248.Original Russian Text Copyright © 2005 by Bondaletov, Troyan, Chernov, Bannikova, Dmitrieva.     

NMR spectral study of two crystalline modifications of lithium metaborate,LiBO2

⁷Li and¹¹B NMR spectral parameters were obtained for the two structural modifications of lithium metaborate. We first studied the high-temperature -form of LiBO₂, _iso(¹¹ B) 0, e²qQ/h(¹¹B)=42.5±2.0 kHz, e²qQ/h(⁷Li)=155±5 kHz. The following values were obtained for monoclinic -LiBO₂ with tricoordination of the boron atom: _iso(¹¹ B) = 16±2, e²qQ/h(⁷Li)=32±10 kHz. The electric field gradient on the⁷Li and¹¹B nuclei in the different crystal positions was discussed.Institute of Silicate Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 70–73, September–October, 1989.     

Effects of Hydrogen Peroxide on In Vitro Cultures of Tea (Camellia sinensis L.) Grown in the Dark and in the Light: Morphology,Content of Malondialdehyde,and Accumulation of Various Polyphenols

Tea plants (Camellia sinensis L.) are phenol-accumulating crops that are widely used for public health. The healing effect of tea leaf products is due to the biosynthesis of such phenolic compounds (PCs) as flavans, which have P-vitamin capillary-strengthening activity. Due to their limited habitat and the value of their specialized metabolites of a phenolic nature, a promising approach is to establish in vitro cultures from them that retain the ability to form PCs, which is characteristic of ex vivo tea plants. The aim of this study was to investigate the effect of exogenic H₂O₂ (0.01 mM; 0.1 mM; 1 mM) on the growth, morphology, degree of stress response, and accumulation of various phenolic compounds in tea plant callus cultures of different ages (24 or 36 days) grown under different cultivation conditions (darkness or light). According to the results obtained, the H₂O₂ effect on tea callus cultures of different ages did not cause changes in their morphophysiological characteristics, both after 2 h of exposure (rapid response of callus culture, RRCC) and after 48 h (delayed response of callus culture, DRCC). The determination of the malondialdehyde (MDA) content, which serves as an indicator of changes in the level of lipid peroxidation (LPO) and the presence of stress responses in plant cells, indicated either its maintenance at the control level, a decrease, or an increase. All these effects depended on the growth conditions of the tea callus cultures (darkness or light), their age, the duration of exposure (rapid or delayed response), and the H₂O₂ concentration. Similar trends were noted for the total content of PCs as well as the amount of flavans, proanthocyanidins (soluble and insoluble forms), and lignin. The plant cell responses reflected changes in its adaptation programs, when specialized metabolites act as a target for the action of H₂O₂, thereby contributing to an increase in their resistance.