Search results for "cyanate"

Photocatalytic oxidation of cyanide in aqueous TiO2 suspensions irradiated by sunlight in mild and strong oxidant conditions

1999

Abstract The photocatalytic oxidation of free cyanide ions was carried out in aqueous aerated suspensions containing polycrystalline TiO2 (anatase) irradiated by sunlight. The influence of the presence of an organic compound (phenol) or of a strong oxidant (H2O2) on the photoprocess was also studied. The dependence of cyanide photo-oxidation rate on the following parameters: (1) cyanide concentration; (2) catalyst amount; and (3) phenol concentration was investigated. At the used experimental conditions, the kinetics of cyanide photo-oxidation is independent of the initial cyanide concentration and of the catalyst amount while it is affected by the phenol concentration and by the presence o…

Complexes of organometallic compounds.XXIII. Aryllead(IV)—thiocyanate complex systems

1969

Fraktionierte Fällung von Lösungen von p-Kresol-Formaldehyd-Harzen

1951

Die Moglichkeit der Fraktionierung von p-Kresol-Formaldehyd-Harzen in organischen Losungsmitteln durch Zugabe von organischen Fallungsmitteln wird durch die mittlere Schmelztemperatur der Harz-Fraktionen, deren Elementaranalyse und durch ihr Viskositatsverhalten belegt. Die /c-Funktionen zeigen Minima, die bei Polyacrylsaure und desaminierten Eiweisen schon beobachtet wurden, aber unseres Wissens bei Phenolharzen noch unbekannt sind. Es werden ferner Angaben gemacht uber die Acetylierung, den Umsatz mit Phenylisocyanat zu Urethanen und die Methylierung mit Diazomethan. Auch die Untersuchung der Acetylderivate und Urethane zeigi. das die Fraktionierung aus organischen Losungsmitteln gelingt.…

1967

Enamines derived from cyclic ketones behave as difunctional intermediates when treated with phenyl isocyanate to produce dicarboxanilides. Reaction of bis(4-isocyanatophenyl)-methane with 1-N-morpholino-1-cyclopentene in DMSO leads to poly[iminocarbonyl(2-morpholino-1-cyclopenten-1.3-ylene)carbonylimino-p-phenylenemethylene-p-phenylene], a polyamide. The effects of various cyclic enamines and diisocyanates on the polymerization are surveyed. Morpholine and piperidine are more effective than pyrrolidine or dimethylamine when incorporated into cyclopentanone enamines. The molecular weight of the polymer decreases when the ring size of the ketone component is increased. The efficiency of the d…

Topochemische reaktionen von monomeren mit konjugierten dreifachbindungen. II. Mitt.: Eine topochemische farb- und vernetzungsreaktion bei polymeren …

1970

Es wurden kristallisationsfahige Polymere mit zwei konjugierten CC-Dreifachbindungen im Grundbaustein hergestellt und ihre Reaktionsfahigkeit im kristallinen Zustand untersucht. Die Polyurethane aus 2.4-Hexadiin-1.6-diol (I) bzw. 3.6.13.16-Tetraoxa-octadeca-8.10-diin-1.18-diol (II) und Hexamethylendiisocyanat sowie der Polyester aus I und Adipoylchlorid farben sich beim Belichten mit UV-Licht oder beim Tempern unterhalb ihres Schmelzpunktes tief rot und werden dabei unloslich. Die Reaktion kann durch Radikaldonatoren katalysiert und durch Radikalfanger inhibiert werden. Die gelosten Polymeren zeigen keine Reaktivitat in dieser Hinsicht. Die Verfarbung und Vernetzungsreaktion kann in Analogi…

A Facile Synthesis of New 3-Substituted-2,3- dihydropyrido[3,2-d]pyrimidine-2,4-diones

2004

Abstract Pyrido[3,2-d]pyrimidine-2,4-diones derivatives have been synthesized in good yields by two efficient synthetic routes, the first one through an hetero-cyclization on the ureas derivatives 3a–e under alkaline conditions, the second one by condensation of the isocyanate 2 with various arylalkylamines in pyridine.

Halogen bond preferences of thiocyanate ligand coordinated to Ru(II) via sulphur atom

2017

Halogen bonding between [Ru(bpy)(CO)2(S-SCN)2] (bpy = 2,2’-bipyridine), I2 was studied by co-crystallising the metal compound and diiodine from dichloromethane. The only observed crystalline product was found to be [Ru(bpy)(CO)2(S-SCN)2]⋅I2 with only one NCS⋅⋅⋅I2 halogen bond between I2 and the metal coordinated S atom of one of the thiocyanate ligand. The dangling nitrogen atoms were not involved in halogen bonding. However, computational analysis suggests that there are no major energetic differences between the NCS⋅⋅⋅I2 and SCN⋅⋅⋅I2 bonding modes. The reason for the observed NCS⋅⋅⋅I2 mode lies most probably in the more favourable packing effects rather than energetic preferences between …

Selective Cobalt over Nickel separation using neat and confined ionic liquids

2020

International audience; Task Specific Ionic Liquids (TSILs) generated by association between tetraalkylammonium cations and coordinating anions such as dicyanamide (Dca-) and thiocyanate (SCN-) were used for the selective separation of Ni(II) over Co(II). SCN-based TSIL presents higher extraction efficiency than the Dca-based one towards Co(II) (E = 85.4 % vs 54.6 %) and Ni (II) (E = 22 % vs 0.5%) but lower separation factors (βCo/Ni = 21 vs 239). Interestingly, extraction of Co(II) and Ni(II) in Dca-based TSIL can be enhanced using salts with chaotropic anions such as NaNO3 (E > 90 % for Co(II) and E = 85% for Ni(II)). The use of NaCl allows, moreover, the efficient separation of both ions…

Iron (II) isothiocyanate complexes with substituted pyrazines: Experimental and theoretical views on their electronic structure

2015

Abstract Synthesis, structural, magnetic, Mossbauer and thermal studies of isothiocyanate iron (II) complexes with substituted pyrazines (iodo-, bromo- and amino-derivatives) are discussed here. Complexes with iodo- and bromo-derivatives were found to have the composition [Fe(Ipz)2(SCN)2(H2O)2]·2Ipz (1) and [Fe(Brpz)2(SCN)2(H2O)2]·2Brpz (2), whereas in the case of amino-functionalized pyrazine the formation of [Fe(NH2pz)4(SCN)2] (3) was observed. 3D organization of the molecular complexes is stabilized within different hydrogen, halogen and lone pair–π interactions. Spin state of iron (II) ions in 1–3 was determined as high spin by Mossbauer and magnetic measurements. DFT calculations for t…

Crystal structure of N,N,N′,N′,N′′,N′′-hexamethylguanidinium cyanate 1.5-hydrate

2015

The title hydrated salt, C7H18N3+·OCN−.1.5H2O, was synthesized starting fromN,N,N′,N′,N′′,N′′-hexamethylguanidinium chloride by a twofold anion-exchange reaction. The asymmetric unit contains two cations, two cyanate anions and three water molecules. One cation shows orientational disorder and two sets of N-atom positions were found related by a 60° rotation, with an occupancy ratio of 0.852 (6):0.148 (6). The C—N bond lengths in both guanidinium ions range from 1.329 (2) to 1.358 (10) Å, indicating double-bond character, pointing towards charge delocalization within the NCN planes. Strong O—H...N hydrogen bonds between the crystal water molecules and the cyanate ions and strong O—H...O hyd…