S- and N-alkylation of 2,2′-(alkane-α,ω-diyldisulfanediyl)-bis(1,3-benzothiazoles) with 1-iodopropan-2-one in the presence of iodine

Russian Journal of Organic Chemistry - The alkylation of 2,2′-(methylenedisulfanediyl)- and 2,2′-(ethane-1,2-diyldisulfanediyl)bis-(1,3-benzothiazoles) with 1-iodopropan-2-one involves...     

Unusual reaction of triazole derivatives with 1-iodomethyl-1,1,3,3,3-pentamethyldisiloxane

The solvent-free reaction of 1-iodomethyl-1,1,3,3,3-pentamethyldisiloxane with 1,2,4-triazole derivatives and 1,2,3-benzotriazole afforded organylcyclosiloxane iodides and triiodides. The reactions involved alkylation of pyridine and pyrrole nitrogens and cleavage of the siloxane bonds mediated by hydrogen iodide generated upon the reaction.

     

Pyrolysis of corrugated cardboard in inert and oxidative environments

The thermal decomposition of corrugated cardboard has been studied in inert and oxidative (non-flaming) atmospheres under a range of radiant heat fluxes relevant to fire conditions in warehouse storage applications. Experiments were performed in a Fire Propagation Apparatus (FPA) on double-wall corrugated cardboard at heat flux levels of 20, 60, and 100 kW/m². Pyrolysis data comprised of gasification rates and surface temperatures were collected for tests carried out in ambient atmospheres consisting of 100% N₂ as well as 2%, 6%, 8%, 10%, and 14% (mol) O₂ in balance nitrogen. It is shown that the presence of oxygen has an appreciable effect at all heat flux levels; however, it is most prevalent at low heat fluxes. Analyses are presented in an effort to gain further understanding of char oxidation processes. Results show that the maximum heat evolved in oxidative environments is relatively constant and similar for all conditions tested. Furthermore this heat release rate is found to be comparatively small relative to the high radiant fluxes tested; this explains the experimentally observed behavior. This study provides a comprehensive dataset that may be used in conjunction with approaches recently adopted in the fire community in which optimization procedures are employed to generate material properties for pyrolysis models used in CFD fire simulations.     

Changes in electrical and optical properties of polyimide films under the action of accelerated electrons

Changes in the structure and optical and electrical properties of Apical brand polyimide films under the action in air of accelerated electrons with an energy of 0.5 MeV and absorbed dose varied in the range 1–300 MGy were studied.     

Alkylation of 1,2,3-benzotriazole with iodomethyl ketones

Solvent-free reactions of 1,2,3-benzotriazole with 1-iodopropan-2-one and 1,3-diiodopropan-2-one in the absence of a catalyst involved alkylation of the heteroring at the N¹ atom and subsequent quaternization at the N³ atom with formation of 1,3-bis(2-oxopropyl)-1H-1,2,3-benzotriazolium triiodide which is a new conducting ionic liquid. The reaction of 1,2,3-benzotriazole with 1,3-diiodopropan-2-one was accompanied by reductive deiodination of the iodomethyl groups in the initial ketone with hydrogen iodide liberated by N¹-alkylation. Triiodide ion readily exchanges for nitrate ion by the action of AgNO₃ to produce 1,3-bis(2-oxopropyl)-1H-1,2,3-benzotriazolium nitrate. The reaction of 1,2,3-benzotriazole with 2-iodo-1-phenylethan-1-one in melt resulted in the formation of 1,3-bis(2-oxo-2-phenylethyl)-1H-1,2,3-benzotriazolium triiodide.     

Production and properties of high purity TeO2− WO3−(La2O3, Bi2O3) and TeO2− ZnO−Na2O−Bi2O3 glasses

TeO₂–WO₃ (TW), TeO₂–WO₃–La₂O₃ (TWL), TeO₂–WO₃–La₂O₃–Bi₂O₃ (TWLB) and TeO₂–ZnO–Na₂O–Bi₂O₃ (TZNB) glasses were produced by high-purity oxide mixtures melting in platinum or gold crucible at 800 °C in the atmosphere of purified oxygen. The total content of Cu, Mn, Fe, Co and Ni impurities was not more than 0.1–0.5 ppm wt in the initial oxides and glasses. The stability of TZNB glasses to crystallization, characterized by (T_x ? T_g) value more than 150 °C, was demonstrated by DSC measurements at heating rate 10 K/min. In the case of La₂O₃-containing glasses the thermal effects of both crystallization and fusion of the crystallized phases were not observed. The hydroxyl groups absorption coefficients of pure tellurite glasses at the maximum of the absorption band (λ ~ 3 μm) were in the region of 0.012–0.001 cm^?1. The optical absorption losses, measured by the laser calorimetry method at λ = 1.56 and 1.97 μm, did not exceed 100 dB/km.     

Synthesis of Polyiodides of N- and S-S-Acetonyl Derivatives of 2,2′-(Disulfanediyl)- and 2,2′-[Alkanediylbis(sulfanyl)]-bisbenzimidazolium

Russian Journal of Organic Chemistry - 2,2′-(Disulfanediyl)- and 2,2′-[alkanediylbis(sulfanyl)]-bisbenzimidazoles react with aliphatic, aromatic, and heterocyclic α-iodoketones in...