Cyanate, absorption

PECH did not react with potassium cyanate but reacted with equimolar potassium thiocyanate in DMF (90°Ci.16 h) to give the thiocyanated polymer (2g, IR, 2180 cm 1) in 53% of DS. Comparing the IR spectrum with those of model compounds, Me2CHCH2SCljl (2180 cm-1) and Me2CHCH2NCS (2200., 2125 cm-1), the isothiocyanate moieties are scarcely existed in the polymer 0. Since the -SCN is a protecting form of thiol likewise the -SCI, the polymer 20 are insolubilized with aqueous alkali presumably due to the S-S crosslinking (23.). Further, absorption at 2180 cm in 20 was completely disappeared treating it with two equivalents of triethyl phosphite at 90°C for 16 h in DMF probably due to the formation of phosphonate structure ( ,). ... 

The two systems analyzed were compared and contrasted on many accoimts. The infrared spectra of Figures 5 6 showed the unreacted materials on top and the reacted species below. The strong absorption band at 2200 cm-1 was attributed to the cyanate group and disappeared after reaction. The new absorption bands at 1370 cm-1 and 1570 cm-1 were due to the triazine ring. The percent conversion was monitored easily in this way. In both cases it was very high, almost 100J5 for I. Other important information extracted from the spectra was that no significant cross-reaction occurred. It was required that only physical interaction between the separate species should occiir if a true SIPN was to be obtained. 

Molar absorptivity of the reactive cyanate groups i cm = 137 ml pMol cm ... 

Table IX. Cyanation of trans-Chloro(aryl)bis(triphenylphosphine)-nickel(II) Complexes, IR Absorptions...

Sodium cyanide solution dissolves certain metals (I) with absorption of oxygen, e.g.. gold, silver, mercury, lead, and (2) with evolution of hydrogen, e.g.. copper, nickel, iron. zinc, aluminum, magnesium and solid sodium cyanide, when heated with certain oxides, e.g.. lead monoxide PhO. stannic oxide SnO.. yields the metal of the oxide, e.g.. lead. tin. respectively. and sodium cyanate NaCNO. Two classes of esters arc known, cyanides or nitriles, and isocyanides, isonitriles or carbylatnincs. the latter being very poisonous and of marked nauseating odor... 

It can be assumed that two separate networks with no covalent bonds between the UPR and the cyanate-based triazine network are formed. The possible addition of terminal hydroxyls from the unsaturated polyester to the —C = N bonds in BPA/DC is rather improbable as the addition of alcohols to cyanates, leading to iminocarbonate derivatives (Scheme 8), only occurs in the presence of strong alkali catalysts [134], The cyanate cyclotrimerization has been evidenced from disappearance of the 2230 and 2270 cm-1 and the appearance of 1370 and 1560 cm-1 absorption bands in the infrared spectra of the crosslinked IPN. 

Cyanatc, thiocyanate, and selenocyanate groups can be linked to tellurium via the chalcogen atom or via the nitrogen atom. The v(C—X) infrared absorption bands have been used to distinguish between these two bonding modes. The iso (N-bonded) organic cyanates, R-NCX, have v(C-X) at higher wave numbers than the normal (X-bonded) compounds, R-XCN. 

Fig. 13. Response of the active site copper complex to chemical and physical perturbations. (A) Absorption spectra for the lAGO Cu(II) complex in the absence (—L) and presence (+L) of a coordinating anion, cyanate (OCN ). (B) Absorption spectra for lAGO Cu(II) complex at ambient (300 K, RT) and cryogenic temperatures (200 K, LT).

New Cyanate Ester and Poly(p-phenylene) Resins with Low-Moisture Absorption and Improved Thermal Stability... 

Anhydrous tetraphenylarsonium cyanate is a white solid which is hygroscopic and must be stored in a dry inert atmosphere. It is soluble in ethanol, methanol, and acetonitrile. The compound melts, with decomposition, at ca. 224°. The infrared spectrum, taken as a Nujol mull, exhibits the following bands due to the cyanate fundamental absorptions (incm-i) v(As) at 2140 (s) and d at 622 (s). This spectrum agrees well with a recent spectral study of this compound. Again, as with tetraethylammonium cyanate, Fermi resonance is exhibited in the spectrum of this compound at 1280 (m) and 1192 (m) cm-i. 

Ammonium cyanate is a white solid, which rearranges to urea upon prolonged storage or heating. It is extremely soluble in water, slightly soluble in acetonitrile, ethanol, and chloroform, and insoluble in benzene and diethyl ether. The infrared spectrum and x-ray diffraction powder pattern are most useful for determining the absence of urea in the final product. Nujol mulls of pure ammonium cyanate exhibit absorptions at 3160 (s), 2190 (s), 1334 (m), 1243 (m), and 640 (m) cm-i and are free of any infrared-active bands in the regions characteristic of urea, that is, 3456 and 1683 cm-i. 

In the course of cycloadditions of diazo compounds to cyanates the IR spectra of different substituted 4-aryloxy-l,2,3-triazoles (51) have been measured. The absorptions between 957 and 990 cm" have been attributed to the triazole nucleus while the y(CH) vibration of the triazole-H (R = H) is found in the range 1030-1045 cm" and what is presumably an N=N valence band occurs at 1720 cm" (66CB317). 

To facilitate the program it was decided to study the cobalt(II)-thio-cyanate complex system which was as accessible to direct assay in the exchanger phase as it was in the solution phase by absorption spectrophotometry in the visible region. Both Co(II) and Co(SCN) exhibit sizably different spectral absorption properties in the visible region. Assuming that the presence of higher complexes than one to one in the cation... 

The use of ozone os on oxidant for industrial wastes containing cyanides and other reducible toxic substances appears worthy of careful investigation. The oxidation of simple cyanides by ozone is rapid and complete. Mass transfer controls the absorption. The use of packed towers or sieve plate towers is indicated, and the maintenance of a pH of at least 9.0 is recommended. The destruction of cyanates and cyanide complexes is slower than the cyanide oxidation. These substances are destroyed if sufficient contact time and proper pH control are maintained so that these slower reactions can take place. The use of redox potential to control the degree of oxidation appears promising. Proper interpretation of the redox potential of the treated waste will give an excellent indication of the effectiveness of the treatment and the degree of removal of cyanide and cyanate. 

Derivatives of Group V Elements.—Cyanogen, Cyanides, Cyanates, and Related Species. The number of papers published during the period of this Report which describe the chemistry of these species is markedly lower than that for previous Reports. Theoretical calculations of the electronic structures of HCN,225 HNCS,226 and the CN radical227 228 have been successfully completed. The electronic structure of HNCS has been compared with that of HNCO226 and it is concluded that (i) the 77-system in HNCS involves a nitrogen lone pair stabilized by a C—S 77-bond, whereas the 77-system in HNCO consists of a C—O 77-bond stabilized by the nitrogen lone pair, and (ii) the d -orbitals of sulphur accept electron density in a <7- rather than a 77-fashion. The electronic structure of the NCS ion has also been determined experimentally from the X-ray Kp fluorescence and K absorption spectra of the S atom in KSCN.229... 

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