Synthesis of macroheterocycles — Analogs of dibenzo-crown compounds. 18-Membered dioxadiaza-crown compounds

Macrocyclic diamides were synthesized by condensation of bridged 1,7-bis(2-aminophenyl)-1,7-dioxaheptanes that contain an additional donor oxygen or nitrogen atom in the bridge with glutaric, diglycolic, and N-tosyliminodiacetic acid dichlorides under high-dilution conditions. Subsequent reduction with boron hydride leads to 18-membered dibenzodiaza-crown-4-6 compounds. The structural assigments were made using the IR, ¹H and ¹³C NMR, and mass spectra.See[1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1128–1135, August, 1988.     

Pulse studies of cyclohexane oxidative ammonolysis to adiponitrile over Ti?Sb?O catalysts

The catalytic activities in ammoxidation of cyclohexane to adiponitrile (ADN) was compared with the phase compositions of Ti–Sb–O catalysts. It was shown that the reaction is limited by the step of ADN desorption from the catalyst.

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Ti–Sb–O (). , .

     

Donor-acceptor concept of covalent interaction of substrate with catalysts

In terms of a unitary approach, the ability of complexes, clusters and metals of transition and nontransition elements for covalent interaction with reagents has been analyzed. the requirements for the catalysts to be efficient in the covalent activation of substrates have been formulated.

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Development of fluctuations in propagation of coherent light in a gas. II

The effects of multiquantum resonance processes and light scattering on the development of fluctuations in propagation of coherent light in a gas are analyzed.     

A weight-function approach for determining watershed initial conditions for combustion waves

In many generic combustion models, one finds that a combustionwave will develop with a specific wave speed. However, thereare possible initial temperature profiles which do not evolveinto such waves, but rather die out to the ambient temperature.There can exist, in some models, a clear distinction betweenthose initial conditions that do evolve into combustion wavesand those that do not; this is sometimes referred to as thewatershed initial condition. When fuel consumption is consideredto be negligible, analytical methods can be used to obtain theexact watershed. In this paper, we consider the problem of determiningpseudo-watersheds and ascertaining the relationship betweenthese pseudo-watersheds and the exact watersheds. In the processa novel weight-function approach for infinite spatial domainsis developed.     

钨离子团簇与N2分子的反应性

利用激光蒸发团簇源产生Wn团簇束,团簇束通过一个充有N2气体分 子的低压反应池,利用飞行时间质谱探测反应产物,在类单次碰撞条件下研究了W+10 -W+50和N2分子的反应性,在室温条件下测量了N2分子与W+n团簇反应的 反应几率。团簇尺寸在10～26原子的团簇与N2分子的反应几率与团簇尺寸有很强的相关性 ,对n=16,22,23的团簇具有比较高的反应性。W+n与N2分子的反应性与Wn与N 2分子的反应性显示出相似的规律性。     

Influence of solid-phase ferritization method on phase composition of lithium-zinc ferrites with various concentration of zinc

Methods of X-ray phase analysis (XRPA) and differential thermogravimetry in a magnetic field (DTG(M)) are used to investigate the phase composition of Li_0.5(1?x)Fe_2.5?0.5x Zn _x O₄ (x _Zn?=?0.2, 0.4, and 0.6) ferrite spinels synthesized at a temperature of 700?°C during 120?min by thermal annealing of a reagent mixture in a furnace and heating of the mixture using high-power beam of accelerated electrons with energy of 2.4?MeV. Thermal ferritization of all compositions leads to the formation of phases whose composition is close to simple monoferrites. Lithium?Czinc ferrite phases are formed during annealing under electron irradiation. It is concluded that the rate of controllable diffusion interaction of monoferrite phases significantly increases under conditions of high-power electron irradiation.