No abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Urea derivatives Urea derivatives P 0490Chemistry of Urea Nitro Derivatives. Part 3. Reactions of N,N'-Dinitrourea with Bases. -Salt formation and complexation of title dinitrourea (I) with several monoand divalent metal ions is studied. Additionally, reaction with amines, ammonia, hydrazine and hydroxylamine proceeds with substitution of one nitro group to afford the corresponding N-nitro-N'-alkyl(amino, hydroxy)urea derivatives (III), (IV) or (V), resp., in moderate to good yields. N-Nitrocarbamates like (VII) are formed under mild conditions on dissolution of dinitrourea in alcohols. -(IL'YASOV, S. G.; LOBANOVA, A. A.; POPOV, N. I.; SATAEV, R. R.; Russ.

ZnS ATR elements were coated with well-defined b-oriented ZSM-5 films by in situ growth. Both adsorption isotherms, as well as molecular orientation of p-xylene adsorbed in the films, were measured at 323 and 373 K by FTIR/ATR spectroscopy. The observed isotherms for the b-oriented ZSM-5 films in the present work were very similar to previously reported isotherms of supported MFI films, albeit the crystals in the latter films were aluminum free (silicalite-1) and orientated differently relative to the support surface than the crystals in the films studied in the present work. The novel technique facilitated, for the first time, the examination of how the tilt angle varies with loading and temperature. The data obtained in the present work showed that the p-xylene molecules were mainly oriented with their long axis parallel to the b-direction of the MFI crystals in concert with previously reported results based on FTIR microscopy, Monte Carlo simulations, NMR, and XRD data. At high concentrations, the tilt angle was in good agreement with observations by FTIR microscopy. It was also found that the orientation of the molecules changed with loading, this might be due to different adsorption geometries in the channel intersection as reported previously. The observed tilt angles may also be influenced from competitive adsorption on silanol groups, as was also indicated in the spectra. The results also indicate that the adsorption properties of zeolite films and powders may differ. Hence, adsorption parameters determined for zeolite powders may not necessarily be applicable to films.

No abstract