Influence of a Surface Microheterogeneity on the Disjoining Pressure of Adsorbed Lennard–Jones Fluid. Computer Simulation

Computer simulation of the adsorption of Lennard–Jones fluid in slitlike micropores with structured walls was performed by the Monte Carlo and molecular dynamic methods. The influence of pore width, temperature, pressure, and surface structure on the disjoining pressure was considered. Structural and energy characteristics of the surface affect significantly the value of the disjoining pressure. Among the surface structural characteristics, the important role is played by the number and localization of vacancy-type defects.     

(2-Vinyloxyethyl)hydrazines

Reaction of hydrazine hydrate with 2-chloroethyl vinyl ether afforded (2-vinyloxyethyl)hydrazine and 1,1-bis(2-vinyloxyethyl)hydrazine in 20-38% yield.     

Synthesis of 1, 2-diazabicyclo [4.4.0] decane and its derivatives

A new heterocyclic system, 1, 2-diazabicyclo [4.4.0] decane is synthesized, starting from-(piperidyl-2) propionic acid. The latter is converted to-(1-nitrosopiperidyl-2)-propionic acid, and thence, via-(1-aminopiperidyl-2) propionic acid, to 3-keto-1, 2-diazabicyclo [4.4.0] decane. Derivatives of 1, 2-diazabicyclo [4.4.0] decane with a substituent at position 2 are prepared.     

Nitration of pentaerythritol by HNO3-H2SO4-H2O system

Conclusions It was shown experimentally that the nitrating agent in the O-nitration of pentaerythritol by HNO₃-H₂SO₄-H₂O nitrating mixtures is not the nitronium cation but evidently the free unionized nitric acid molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 134–140, January, 1970.     

Some observations on the synthesis and HPLC of tris-(acetylacetonato)technetium(III) and (IV) complexes

[⁹⁹Tc(III) (acac)₃] was synthesized by published procedure, but recovered by extraction into CH₂Cl₂. The product was purified by preparative HPLC over a reversed phase column, RP18, using a mobile phase of 11 CH₃OHH₂O. The cationic complex [⁹⁹Tc(IV) (acac)₃]⁺ prepared by the oxidation of the purified neutral Tc(III) complex was unstable in methanol/methanol-water medium, being reduced back to the Tc(III) complex.     

Use of azolium ylides in the synthesis of con-densed heterocyclic systems from 2-quinox-alylacetonitriles

The reaction of -substituted 2-quinoxalylacetonitriles with 1-alkyl(aryl)imidazoles, -benzimidazoles, -1,2,4-triazoles and 5,6-dihydroimidazo[i,j]quinoline was studied. It was found that during the course of the reaction an unusually easy dealkylation of the azole ring takes place, while the aryl substituent is not split off. A reaction mechanism has been proposed including the formation of an ylide intermediate, followed by subsequent electrophilic attack on the C₍₂₎ position of the azolium ring. The applicability boundaries of the reaction studied and the spectral characteristics of the synthesized compounds were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 224–229, February, 1993.     

Chelation of carbocations by polyethers and polyamines

Chelates formed by carbocations and cyclic polyethers and polyamines are studied with semiempirical and ab initio MO methods.     

Isothermal degradation of poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole

The isothermal degradation of poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole in vacuo has been studied. Measurement of the increase in pressure with time, coupled with infrared analysis, was used to determine the distribution of the degradation products. Processes A and B with different second-order rate laws were determined to be significant in the temperature range of 550–700°C. Process A leads to the formation of equimolar quantities of hydrogen and ammonia and has an activation energy of 68 kcal/mole. Process B leads to the production of HCN, NH₃, and H₂ in the ratio of 1:1:2.5 and has an activation energy of 77 kcal/mole. The activation energies and the rate laws are consistent with a mechanism in which the initial degradation step is the bimolecular reaction of two aromatic rings.     

Interaction of heavy metal ions with ammonium humates

Sorption properties of ammonium humates with respect to Fe(III), Cu(II), Al(III), Ni(II), Pb(II), and Zn(II) are studied. The effect of the metal ion concentration on the ammonium humate consumption is examined and the corresponding dependences are analyzed using regression equations. The IR spectra of brown coal humic acids, ammonium humates, as well as Fe, Cu, Ni, Zn, Pb, and Al humates are presented.