Infrared study of co adsorbed species on ru/silicalite catalyst

Carbon monoxide adsorbed species on Ru/silicalite and their reactivity towards oxygen have been studied using in situ diffuse reflectance infrared spectroscopy (DRIFT). Four species were detected: a bridge bonded CO on metallic Ru (1980 cm ^-1), a linearly adsorbed CO on metallic Ru (2040 cm^-1), a linearly adsorbed CO on partially oxidized Ru (2081 cm^-1), and a multicarbonyl on oxidized Ru (2081 and 2133 cm^-1). Among the four CO species the most strongly held species was the bridge bonded CO on metallic Ru while the multicarbonyl was the most weakly held species. These four species have different reactivities towards oxygen. Only the linearly adsorbed CO on metallic Ru can be oxidized at room temperature.     

Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance

Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame.     

Crystal structures and Mössbauer spectroscopic studies of oxo-centered trinuclear chloroacetate complexes

The crystal structures of oxo-centered trineclear cobalt-iron chloroacetate complex [Co^IIFe ₂ ^III O(CH₂ClCO₂)₆(H₂O)₃]·3H₂O (1) was compared with that of previously reported trinuclear iron complex [Fe^IIFe ₂ ^III O(CH₂ClCO₂)₆(H₂O)₃]·3H₂O (2) which has an isomorphous structure to 1. Compound 1 crystallizes in space group P2₁/n with Z=4 in a unit cell of a=14.826 (4) Å, b=4.536 (8) Å, c=14.000 (4) Å, =100.32 (2)⁰ and V=2968 (11) ų. The structure was refined to R=0.75 and R_w=0.82. The coordination geometries of the three iron atoms are observed equivalent in 1 indicating a static disorder of the position among cobalt and iron atoms. Two distinct Fe^III doublets observed in Mössbauer spectra of 1 become an indistinguishable broad doublet by dehydration of crystal water. On the other hand, no significant line-broadening is observed after the dehydration in complex 2. The results indicate that the dehydration in 2 induces a local environmental change reordering of an electronic configuration around iron atoms, whereas the remaining disordering is reflected in Mössbauer spectrum after the dehydration in 1.     

Polyamide Layer Chromatography. VIII. Preparation of Polyamide Layer on Poly(ethylene terephthalate) Film and its Application to Aromatic Nitro Compounds

Poly(ethylene terephthalate) film was used as supporter for preparation of polyamide layer. The most convenient method of preparation was described. This layer can be cut into any size and its sensitivity is higher than the glass plate supported layer. Twenty aromatic nitro compounds were used to show the behavior of polyester film based polyamide layer.     

Solute absorption into molten polystyrene

The equilibrium volatilities at near infinite dilution of various solutes absorbed in molten polystyrene have been determined by a gas chromatographic technique. This method is much more rapid, although, with the present apparatus, probably less accurate than conventional static techniques. The primary parameters obtained from measurements of retention volumes are the Henry's law constants, from which are derived the weight and volume fraction activity coefficients, the Flory-Huggins interaction parameters, and the heats of dilution and solution. Of the solutes investigated, 2-butanone (MEK) was the least, and benzene the most compatible (highest and lowest volume fraction activity coefficients, respectively) with molten polystyrene. A small, but definite, variation of the activity coefficients with polystyrene molecular weight was observed.     

Reaction of gaseous hydrogen fluoride with aluminium and its compounds

The reaction of metallic aluminium surfaces, aluminium oxides, hydrated oxides and sulphate with gaseous anhydrous hydrogen fluoride was studied at 470°C and pressures between 10 and 100 torr. The complementary analytical techniques of X-ray induced photoelectron spectra, X-ray and electron diffraction, and electron microscopy were used for identifying the (frequently unexpected) products.