Reactions of N-(Β-aminoethyl)piperazine and its derivatives

The alkylation, cyanoethylation, and heterocyclization reactoins of N-(-amonoethyl)piperazine and its derivatives, dicarboxylic acid imides, have been investigated. A new method has been proposed for the synthesis of 1,4-diazobicyclo[2.2.2]octane via pyrolytic cleavage of N,N-bis[piperazinoethyl]ethylenediamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 381–385, March, 1991.     

Chemiluminescence and auto-oscillations in the (S?Cr2O72+?UO22+) system

Quasi-harmonic oscillations of chemiluminescence intensity at certain concentrations of the components for the (S–Cr₂O ₇ ^2– –UO ₂ ²⁺ ) system in concentrated sulfuric acid and chemiluminescence and dark stages with the participation of intermediates Cr(V), U(IV) and sulfur peroxide radicals (HS₂O₆ ^.) have been discovered. Chemiluminescence is attributed to the interaction of HS₂O₆ ^. compounds. The processes of deactivation of the excited states of uranyl involve the participation of Cr(V). A scheme for the oscillation chemiluminescence reactions is suggested.

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(S–Cr₂O ₇ ^2– –UO ₂ ²⁺ ) H₂SO₄ , . Cr(V), U(IV) (HS₂O₆ ^.) HS₂O₆ ^. Cr(V) . .

     

Kinetics of energy deactivation in the O2(1Δ)-I medium

The kinetics of energy-exchange and quenching processes in the O₂(¹Δ)-I medium plays an important role in the operation of the chemical oxygen-iodine laser. However, up to now, many of the key processes in this medium are not fully understood. In this work, the flow tube technique is used to determine the rate of excitation energy deactivation in the O₂(¹Δ)-I medium in the presence of small concentrations of water and carbon dioxide. The concentrations of electronically excited species are measured with spectrometers calibrated in absolute spectral responsivity. The effective rate constant for the deactivation of O₂(¹Δ) molecules in processes involving iodine atoms is determined. The results are compared to those obtained in previous works.     

Cycloadducts of 1‐Alkyl‐1,2‐diphospholes with N‐Phenylmaleimide: Synthesis,Structure, Oxidation,and Thionation Reactions

The [4+2] cycloaddition reaction of 1‐alkyl‐1,2‐diphospholes ( 1 ) with N‐phenylmaleimide proceeds at 25°С in toluene to give 1,7‐diphosphanorbornenes ( 2 ) as anti‐endo isomer only. Oxidation of 2 with air at room temperature or thionation with excess of sulfur at 80°С results in the formation of mixed valent P^III, P^V 7‐oxo(thia)‐1,7‐diphosphanorbornenes ( 3 , 4 ) in high yield. The polycyclic compounds 3 and 4 are air stable and have small sums of valence angles at the phosphorus atoms.     

The temperature dependence of the spectral width of singlet oxygen dimole emission

In the temperature range of T = 150–400 K, the dependence of spectral widths (cm⁻¹) on temperature, 182 + 0.38(±0.01)T and 217 + 0.48(±0.01)T, respectively, has been obtained for dimole emission of O₂(a, 0) + O₂(a, 0) → O₂(X, 1) + O₂(X, 0) + hν (λ = 703 nm) and O₂(a, 0) + O₂(a, 0) → O₂(X, 0) + O₂(X, 0) + hν (λ = 634 nm). It was shown that the ratio of dimole emission rate constants does not depend on temperature in the range of 150–400 K and is 1.06 ± 0.01.     

Reactivation of a solid carbon-containing adsorbent, Graton, in a microwave electromagnetic field

Results of experimental studies of reactivation of a graphite packing, Graton, in a microwave electromagnetic field are presented.     

Collision-induced emission of singlet oxygen in the visible spectral region at temperatures of 90–315 K

Collision-induced emission of singlet oxygen molecules is studied using spectrometers calibrated for absolute spectral sensitivity. The collision-induced emission-rate constants at wavelengths of 479, 514, 577, 634, and 703 nm are determined within the temperature range 90–315 K. It is found that the intensities of the emission bands increase with decreasing temperature below 100 K. The interrelation between the collision-induced emission-rate constants and the intensities of the collision-induced absorption bands is discussed. The Einstein coefficients for spontaneous emission of excited free O₂: O₂ complexes are estimated.     

Reactions of 1-ethyl-1,2-diphosphole with acetylenes

Russian Chemical Bulletin - The cycloaddition of 1-ethyl-3,4,5-triphenyl-1,2-diphosphacyclopenta-2,4-diene to acetylenes R1C≡CR2 (R1 = R2 = CO2Me; R1 = Ph, R2 = H) gives phosphinine along...     

Abstracts of articles deposited at VINITI

Journal of Applied Spectroscopy -     

Lasing performance of a chemical oxygen iodine laser (COIL) with advanced ejector-nozzle banks

Experimental results have demonstrated that the use of ejector-nozzle concepts can allow to achieve simultaneously high chemical efficiency and high pressure recovery in a chemical oxygen iodine laser. The estimated small-signal gain of the gain medium generated by these nozzle banks was from 0.5 to 0.8 %/cm. In laser experiments with all nozzle banks (NB-1–NB-5), Pitot pressures of the order of 80 Torr and Mach numbers of ∼2 in the cavity-mixing chamber have been achieved. The geometry of a given ejector-nozzle bank and gas-flow conditions affect the power extraction and chemical efficiency. The main factors for high efficiency and high power are small mixing scale, high area for the oxygen flow, dilution of chlorine by helium, and the arrangement of nozzles. A chemical efficiency of 25% at a power level of ∼900 W was obtained for NB-1 having the smallest mixing scale, parallel injection of all flows, and dilution of oxygen by helium. The highest power of ∼1.2 kW with a chemical efficiency of 19.5% and 160 W/cm² of specific output power was achieved with NB-5 having the largest area for the oxygen flow and dilution of oxygen by helium. Received: 7 October 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003 RID="*" ID="*"Corresponding author. Fax: +7-8462/355-600, E-mail: nikolaev@fian.smr.ru