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Abstract  

The set of all 51 possible12C/13C isotopomers of a C8 cluster of D2d symmetry has been studied by means of the harmonic vibration analysis based on the force field resulting from the second order Møller-Plesset (MP2) perturbation treatment with the 6-31G* basis set. The isotopomers can undergo 200 isomerizations which can be classified into 5 distinct groups using the properties of sums of the squares of harmonic vibrational frequencies.

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A procedure for labeling of a fullerene derivative 1-[N',N'-bis(2-chloroethyl)-4-aminophenyl]-N-methyl-fullereno-C60-[1,9-c]pyrrolidine (C60-C13H18N2Cl2) with 125I is reported. The compound was first iodinated with a large excess of iodine monochloride and then radiolabeled by isotopic exchange with Na125I in a toluene-water two-phase system. The dependence of the radiolabeling yield on the reaction temperature and exchange time was examined. The radiolabeling yield of the compound was as high as 94% after heating for 2 hours at 130 °C.

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Abstract  

The present work aims chiefly to study the thermal behaviour of complex compounds with general formula: [M(HL) xH2O](A) yH2O (where HL=C13H11N4O2=6-(2-pyridylazo)-3-acetamidophenol (PAAP), M=Cu(II), Zn(II), Cd(II) and Fe(III) x=1, 3; y=2, 5) while A=CH3COO (Ac), Cl2. The second formula is [M(H2L) xH2O]Cl2 yH2O, (where H 2 L=C13H12N4O2 (PAAP), M=Ni(II), Co(II) x=3; y=4, 6). The compounds were identified by elemental analysis, FT-IR spectra and TG/DTG,DTA methods. It was found that during the thermal decomposition of complex compounds water molecules of crystallization are released in the first step. In the next step the pyrolysis of organic ligand takes place. Metal oxide remained as a solid product of the thermal decomposition. Mass spectroscopy has been used for the determination of the thermal decomposition on the intermediate products. It was found that the thermal stability of the studied compounds increases as the ionic radii decreases. The activation energy E, the entropy change S *, the enthalpy H * change and Gibbs free energy change G * were calculated from TG curve.

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Abstract  

Reversed-phase high-performance liquid chromatography with u.v. detection was applied for rapid and sensitive determination of pertechnetate in99Mo/99mTc generator eluates, using a mixture solvent of acetonitrile and 0.04M aqueous acetate buffer (1/1) containing a few volume percentage of 0.5 M tetra-n-butylammonium hydroxide as the mobile phase. Employing a -bondapak C13 column, the TcO 4 species was separated, monitored with absorbance at 254 nm, and observed at the retention time of 3.5 min. The detection limit was found to be 5.2·10–10 g of Tc for each injection. Total Tc contents in the99mTc eluates from clinically-used99Mo/99mTc generator were analyzed by this technique. The99mTc (99Tc) species was separated from the contaminant99Mo. This method was found to be useful for the purification of99mTc (99Tc) as well as the determination of total Tc content.

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Abstract  

We studied the production of nine typical organic analytical reagents labeled with11C,13N and18F by irradiation with charged particles and bremsstrahlung and the purification of labeled compounds with HPLC and sublimation. As a result, we found that six reagents, α-naphthol, β-naphthol, quinoline, α-nitroso-β-naphthol, 8-hydroxyquinoline, and 1,10-phenanthroline H2O could be labeled with11C by bombarding a mixture of each reagent and boron with protons. More than 10% of the11C was successfully exchanged with carbon atoms in the original reagents. We also found that sublimation is useful for purifying 8-hydroxyquinoline labeled with11C. The extraction property of11C-labeled 8-hydroxyquinoline between water and chloroform could be easily monitored by radioactivity measurement.

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Abstract  

In kerosene samples from nuclear fuel reprocessing, iodoalkanes with chain-lengths from C4 to C13 have been identified. The kerosene samples were purified by means of solid-phase extraction. By this method other fission products like125Sb and106Ru were quantitatively removed from the solution. The only remaining radioactive nuclide was thus129I. The iodoorganic compounds in the kerosene from the solvent were enriched from 6000 Bq/L to 100 000 Bq/L129I by vacuum distillation. Chromatographic separation by HPLC, fractionation, and -measurement of the fractions showed that at least one polar and one nonpolar iodoorganic compound were present. Derivatisation of the iodoorganic compounds with, 1,4-diazabicyclo-2,2,2-octane to quatermary ammonium salts and252Cf plasma desorption mass spectrometry of the products revealed that the main iodoorganic constituents in the kerosene were iodobutane as polar and iodododecane as nonpolar compound in approximately equal concentrations.

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Abstract

A new supramolecular compound [Ni3(Hdatrz)6(sca)2(H2O)4]sca·11H2O (Hdatrz = 3,5-diamino-1,2,4-triazole, H2sca = succinic acid) was synthesized and characterized by elemental analysis, single crystal X-ray diffraction and thermogravimetric analysis. X-ray structural analysis reveals that the crystal is triclinic, space group P − 1 with lattice parameters a = 10.192(2) Å, b = 11.671(2) Å, c = 13.600(3) Å, β = 68.086(3)°, Z = 1, D c = 1.689 g/cm−3, F(000) = 728. The enthalpy change of the reaction of formation in water was determined by an RD496–CK2000 microcalorimeter at 25 °C with the value of −23.71 ± 0.023 kJ mol−1. In addition, the thermodynamics of the reaction of formation in water for the compound was investigated by changing the temperature of the reaction and the fundamental parameters k, E, n, , and were obtained.

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Abstract  

C60 fullerene was radiolyzed in toluene solution both in presence of air and in vacuum at four different radiation doses 12, 24, 36, 48 and 96 kGy. Clear evidences of the addition of benzyl radicals to the fullerene cage derive from FT-IR and C13-NMR spectra of the reaction product. In presence of air the interference of oxygen is evident in the FT-IR spectra and from the elemental analysis. A detailed analysis of the kinetics of the multiple addition of benzyl radicals to the fullerene cage was made spectrophotometrically with the determination of the addition rate constants at the each addition step and the average number of benzyl groups added to the fullerene cage as function of the radiation dose.

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Abstract  

Sensitive and selective nuclear reaction methods have been sought for the nuclear microprobe measurement of the spatial distributions of13C and13C/12C ratios. The13C(α, n)16O reaction, with neutron detection, is the most selective for13C, and has a sensitivity of ca. 100 ppm. The reactions13C(d, p)14C and12C(d, p)13C, with proton detection, are the most sensitive for the simultaneous measurement of13C and12C, with detection limits of 30 and 2 ppm respectively. Less sensitive alternative reaction pairs are;13C(3He, p)15N and12C(3He, p)14N;13C(d, nγ)14N and12C(d, pγ)13C;13C(3He, pγ)15N and12C(3He, pγ)14N. The conditions governing their use, particularly light element interferences, are detailed.

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Abstract  

The physicochemical characterization of the solid-state enantiomers and racemate of efaroxan hydrochloride (C13H17N2O+Cl-, M=252.5 g mol-1) was performed by thermoanalytical methods (differential scanning calorimetry, thermogravimetry and thermomicroscopy) and spectral methods (infrared spectrometry and X-ray diffractometry). The efaroxan enantiomers and racemate were shown to be unstable near the melting point. At the beginning of the decomposition, a loss of hydrogen chloride was observed. However when sealed pans were used, the compounds decomposed at higher temperature, allowing a precise evaluation of the melting enthalpies by means of differential scanning calorimetry. The nature of the racemate and its thermal stability were assessed by evaluating its free formation enthalpy. An enantiotropic solid-solid transformation (II→I) was noted for the racemate; the reverse process (I→II) follows zero-order kinetics.

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