Solid-phase reaction of organometallic derivatives of nitrophenols,P-nitrothiophenol,andP-nitroaniline with bromides,according to the molecular spectroscopy data

The effect of the visualization of the reaction of bromide anion with PhHg- and PPh₃Auderivatives of phthalein has been extended to the organometallic derivatives (M=Hg, Au, Sn, Pb, Sb) of other classes of indicators: nitrophenols, nitrothiophenol, and 4-nitrobenzenesulfonylanilide. On the basis of the analysis of the electronic reflection spectra and the IR spectra it has been found that the changes occurring upon the reaction of these compounds with bromides are determined by the formation of complexes and/or anions and are more pronounced in the latter case. The character of the interaction depends on the dissociation ability of the M-X bonds (which was determined earlier while studying the reaction with DMSO), the ability to form complexes, and on the steric hindrance which has proved to be considerable in the solid-phase reaction (with Br^–).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1974–1977, November, 1993.     

Nonuniform isothermal curing of cylindrical products made of polymeric composites

Conclusion By increasing the curing temperature and reducing the winding rate, it is possible to obtain compressive radial stresses in a cylindrical product during the entire curing stage — which should prevent loss of integrity during the curing operation. When the duration of the curing process is limited, the magnitude of the compressive stresses will depend in an extreme manner on curing temperature. Meanwhile, in the general case, ensuring minimal residual stresses will not ensure the absence of tensile radial stresses during curing.Translated from Mekhanika Kompozitnykh Materialov, No. 5, pp. 873–877, September–October, 1988.     

Thermal decomposition of transition metal carboxylates

Thermal decomposition of anhydrous Cu(HCOO)₂ (1) affords H₂, CO, CO₂, H₂O, HCuOOH, CuHCOO, Cu, and the polymeric product, which contains -CH₂O,-C(O)OH-, and -RCH-0- groups. Dccomposition of1 proceeds in stages with formation of copper(I) formate as an intermediate. Possible pathways of decomposition ofI, including isomeric forms of the HCO₂ radical as intermediates, were analyzed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1406–1412, June, 1996.     

Kinetic laws of the thermal degradation of epoxide-resin-based composites

Conclusions In our study we establish, using polyepoxides and polyepoxide composites as examples, that the kinetic laws governing the thermal degradation of polymer matrices as a component of composites may differ significantly from those for block polymers, and provide an explanation of this effect.Translated from Mekhanika Kompozitnykh Materialov, No. 3, pp. 391–397, May–June, 1990.     

Pressure-Induced Spin-Crossover in EuFeO3

Hyperfine Interactions - EuFeO3 perovskite has been studied by using 57Fe Mössbauer effect and X-ray diffraction under pressures up to 90 GPa and in the temperature range of 4.2–300 K. A...     

Structures of bromo-substituted pyrone-4-carboxylic acids obtained by direct bromination

Ethyl esters of mono- and dibromocomanic acid were obtained by direct bromination, and the corresponding acids were obtained from the esters by acid hydrolysis. The structures of the compounds obtained and of the previously synthesized bromo-substituted comanic acid were established, and it was proved that the attack of bromine is directed to the 5-C and 3-C atoms; attack takes place first at the more nucleophilic 5-C center, after which the 3-C atom undergoes attack.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 901–903, July, 1978.     

A note on DOL length sets

Length sets of polynomially bounded DOL systems are considered by analyzing sets K ∩ {n : n ? q} where K is a DOL length set. It turns out that DOL and PDOL systems behave in different ways with respect to these sets. Especially, it follows that all DOL length sets— contrary to PDOL length sets—are not generated unambiguously, i.e. without repetitions, by DOL systems. Moreover it is proved that the number of axioms used determines an infinite hierarchy of length set families both in DOL and PDOL case.