Gravimetric determination of zirconium with a new azopyrazolone derivative

3-Methyl-5-oxo-1-phenyl-2-pyrazolin-4-ylazo-2'-(6',8'-naphthalenedisulfonic acid) (disodium salt) is proposed as a new reagent for the gravimetric determination of zirconium. The precipitate formed at pH 1–1.5 can be weighed directly and there are few interferences.     

Aerosol formation and reaction pathways of atmospheric oxidation of dimethylsulfide

This paper concerns with three series of experiments about dimethylsulfide gas phase oxidation, carried out at increasing NOx level (< 20 ppb, 1 ppm, 10 ppm) to show the relation between the amounts of nitrogen oxides and the molar yields of sulfur containing products. DMSO, DMSO2, HCHO, HCOOH and SO2 were found as main reaction products. From these experiments and from preceding studies, a sensitive decrease in the quantity of total sulfur products in aerosol phase is underlined. This result derives from the reaction of NOx with CH3S(O)O2 and CH3S(O)OO radicals, which leads to stable intermediates as methylsulphonylperoxynitrate, MSPN, with a characteristic PAN-like structure.     

Temperature dependence of the configurational free energy of a branched polymer

We consider a lattice model of branched polymers in dilute solution in which the polymer is modelled as an animal, weakly embeddable in the (simple cubic) lattice. In order to model the effect on the thermodynamic properties of changing the temperature or the quality of the solvent, we include an energy associated with the number of nearneighbour contacts between pairs of vertices of the animals. We show that the configurational free energy of the animal is a continuous function of the temperature and derive rigorous upper and lower bounds on the temperature dependence of the free energy. Finally, we comment on similarities between these results and corresponding ones for a model in which the energy is associated with the cyclomatic index of the animal.     

Methyltriazolocoumarins: New furocoumarin isosters as potential photochemotherapeutic agents

A number of new methyltriazolocoumarins with a linear psoralen-like structure or an angular angelicin-like structure were synthetized. The syntheses were performed starting from the appropriate methylated 7-aminocoumarins which were nitrated, reduced and successively diazotized with concomitant cyclization to form the condensed triazolo ring. The new methyltriazolocoumarins show promising spectroscopic properties which are potentially predictive of their photochemical and photobiological behaviour.     

Highly polarized enamines. 2. Synthesis and investigation of the further amination of derivatives of α,α-DIAMINO-β-cyano-β-nitroethylene

Highly polarized enediamines of the a, -diamino--cyano--nitroethylene type have been obtained by the hydrolysis of 4-chloro-5-nitropyrimidines. Several chemical conversions of the enamines obtained have been studied, particularly leading to derivatives of 2-(cyanonitromethylene)imidazoline and -hexahydropyrimidine, and also to derivatives of N, N-bisvinylpiperazine and 7 methylene-1, 4-diazabicyclo(2.2. 1 ]heptane.Center for Drug Chemistry, All-Russian Chemical and Pharmaceutical Research Institute, Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 811–820, June, 1996. Original article submitted February 6, 1996.For Part 1, see [1].     

A Possibility of Improving Lead Dioxide Electrode of Lead Battery

The influence exerted by a reinforcing additive, an aqueous suspension of 4D fluoroplastic (Teflon), on the structural, physicochemical, and service characteristics of the positive electrode of the lead battery was studied. A paste with polymer and carbon additives, extending the service life of the lead dioxide electrode, was developed for industrial use.