NOPR Collection:

Photocatalytic reduction of dinitrogen to ammonia

Sat, 01 Jun 1996 00:00:00 GMT

Title: Photocatalytic reduction of dinitrogen to ammonia Authors: Ranjit, K T; Viswanathan, B Abstract: The fixation of dinitrogen to ammonia via Haber's process is an energy intensive process and hence it is attractive to search for alternate pathways for the fixation of dinitrogen molecule under milder conditions. The photocatalytic reduction of dinitrogen to ammonia represents one such proposition. The discovery of this reaction by Schrauzer and Guth in 1977 prompted many workers to study this intriguing reaction and several studies have been reported in literature demonstrating the feasibility of this process. However, the low yields of ammonia obtained thus far, makes this process an uneconomical proposition. This article discusses the problems associated with the photoreduction of dinitrogen and gives an appraisal of the aspects concerning the photofixation of dinitrogen molecule on semiconductor systems. Page(s): 443-453

Benzenoid isomers with extremal values of the Kekulé structure count

Sat, 01 Jun 1996 00:00:00 GMT

Title: Benzenoid isomers with extremal values of the Kekulé structure count Authors: Gutman, Ivan; Morikawa, Tetsuo; Cyvin, Sven J Abstract: In families of benzenoid isomers, the molecules with maximum (minimum) Kekulé structure counts should possess maximum (minimum) stability and other distinguished properties. Identifying these extremal isomers turns out to be a difficult task. In this paper we solve such a problem for the class of isomers B(m,n), obtained from a benzenoid molecule B by attaching to its two fixed sites linear polyacene fragments of length m and n; m + n = constant. Page(s): 454-457

Linear-free energy relationships in solid-state reactions-Part V Solid-solid reactions of copper(II) chloride with substituted anilines

Sat, 01 Jun 1996 00:00:00 GMT

Title: Linear-free energy relationships in solid-state reactions-Part V Solid-solid reactions of copper(II) chloride with substituted anilines Authors: Bassi, P S; Chopra, G S; Singh, Rajinder Abstract: Solid-solid reactions of copper(II) chloride dihydrate with substituted anilines (XC₆H₄NH₂, where X = 4-CI, 4-Br,4-I, 4-CH₃, and 4-OCH₃) have been studied. The reaction products CuCl₂-[XC₆H₄NH₂)₂ ha been characterized. The kinetics have been studied by measuring the increase in thickness of the colored boundary of the product. The energies of activation are 55.7, 58.3, 81.1, 48.0 and 36.0 kJ mol^-1 for X=4-CI, 4- Br, 4-I, 4-CH₃ and 4-OCH₃ respectively. There is no correlation of rate data or activation energy with either of the Hammett's constants. Page(s): 458-462

Solvation of octahedral Co(III) complexes in water + DMSO mixtures

Sat, 01 Jun 1996 00:00:00 GMT

Title: Solvation of octahedral Co(III) complexes in water + DMSO mixtures Authors: Dash, Upendra N; Pasupalak, Narendra N; Mahanta, Sanjeet Abstract: Studies of ultrasonic velocity have been made in solutions of carbonatopentaamine Co(III) nitrate, aquopentaamine Co(lll) nitrate, oxalatopentaamine Co(lll) nitrate, malonatopentaamine Co(lll) nitrate and succinatopentaamine Co(lll) nitrate in water + DMSO (X_DMSO=0.1, 0.05 and 0.025) to evaluate various acoustic parameters at 30°C. Apparent molar volume studies have also been made for the solutions of these complexes in these solvents at 25, 30 and 35°C. The solvation numbers of the octahedral Co(lll) nitrates have been determined. The results are discussed in the light of ion-ion and ion-solvent interactions, and of structural effects on the solvent in solution. Page(s): 463-470