Molecular dynamics of cis‐1‐(2‐hydroxy‐5‐ methylphenyl)ethanone oxime and N‐(2‐hydroxy‐4‐methylphenyl)acetamide in solution studied by NMR spectroscopy

The formation of hydrogen bonds and molecular dynamics for the molecules cis‐1‐(2‐hydroxy‐5‐methylphenyl)ethanone oxime ( I ) and N‐(2‐hydroxy‐4‐methylphenyl)acetamide ( II ) have been investigated in solution using NMR. The results confirm the formation of O? H···O, O? H···N and O···H? N type inter‐ and intramolecular hydrogen bonds. Spin‐lattice relaxation times (T₁), activation energy of molecular dynamics and energy of intramolecular hydrogen bonds have been determined. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of polychlorinated 2,5-dihydro-2-furanones from maleic anhydride

The reaction of maleic anhydride with phosphorus pentachloride, which leads to polychlorinated 2,5-dihydro-2-furanones, was studied. The structures of the compounds obtained were proved by means of spectral methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 600–601, May, 1991.     

Catalytic effect of supramolecular system based on cationic surfactant and monopodands in nucleophilic substitution of phosphorus esters

The data are presented on the synthesis of podands with terminal quinoxaline fragments of rings and their influence on both the micellization properties of cetyltrimethylammonium bromide in a water—DMF solution and kinetics of basic hydrolysis of O-p-nitrophenyl O-ethyl chloromethylphosphonate and O-p-nitrophenyl O-hexyl chloromethylphosphonate in the absence and presence of surfactants. The mechanism of the podand effect on the reaction rate depends on the structures of phosphonate and podand. 1,8-Bis(3-ethyl-1,2-dihydro-2-oxoquinoxalin-1-yl)-3,6-dioxaoctane inhibits the basic hydrolysis of the substrates to 3—4 times. In a micellar solution of the surfactant, an approximately 20-fold acceleration of the reaction rate constant is observed. The observed rate constant decreases when podand is added to a micellar solution. The catalytic effect of the polycomponent system is due to concentrating of the reactants. The micellar microenvironment can exert both positive and negative effects on the reactivity of phosphonates.     

Evaluation on multicenter integrals for the hartree-fock-roothaan equations in molecular coordinate systems

Bakinskii State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 5, pp. 135–139, September–October, 1991.     

Evaluation of Incomplete Gamma Functions Using Downward Recursion and Analytical Relations

New downward recursion and analytical approaches are presented for the calculation of incomplete gamma functions (,x) and (,x). The efficiency of calculation with an adequate interval of these expressions is compared with those of other methods and great numerical stability and good rate of convergence is obtained for wide range of integral parameters. It is shown that the downward recursive relations are stable for all values of and x of (,x).     

Some peculiarities in regeneration of zeolite-containing cracking catalysts by carbon dioxide

Catalytic properties of Mn and La oxides that are acceptors of CO₂ in regeneration of zeolite-containing cracking catalysts in the presence of carbon dioxide have been studied. Regeneration rate of coked catalysts by carbon dioxide in the presence of Mn and La significantly increases. During regeneration, coke oxidation to Co and redistribution of hydrogen in carbonaceous fragments take place to produce methane and hydrogen. Activation energy of methane and hydrogen formation equals 46 kcal/mol. Variation of activation energy with temperature is typical for Co formation.

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, Mn La . CO . 46 /. CO .