Kinetic Modeling of the Decomposition of Carbon Tetrachloride in Thermal Plasma

Decomposition of carbon tetrachloride in a RF thermal plasma reactor was investigated in argon atmosphere. The net conversion of CCl₄ and the main products of its decomposition were determined from the mass spectrometric analysis of outlet gases. Flow and temperature profiles in the reactor were calculated and concentration profiles of the species along the axis of the reactor were estimated using a newly developed chemical kinetic mechanism, containing 12 species and 34 reaction steps. The simulations indicated that all carbon tetrachloride decomposed within a few microseconds. However, CCl₄ was partly recombined from its decomposition products. The calculations predicted 70\% net conversion of CCl₄, which was close to the experimentally determined value of 60\%. A thermodynamic equilibrium model also simulated the decomposition. Results of the kinetic and thermodynamic simulations agreed well above 2000 K. However, below 2000 K the thermodynamic equilibrium model gave wrong predictions. Therefore, application of detailed kinetic mechanisms is recommended for modeling CCl₄ decomposition under thermal plasma conditions.     

High performance liquid chromatography of glycoconjugates

Stationary phases were prepared for the analytical and micropreparative high performance affinity chromatography of carbohydrates and glycoproteins by covalent attachment of lectins and certain biogenic amines to the surface of microparticulate, macroporous diol-silica. Columns packed with immobilized concanavalin A or wheat germ agglutinin afforded rapid separation of both glycoproteins and low molecular weight carbohydrates. The combined use of the two lectins in a mixed bed column or in two columns in series by sequential elution with the appropriate haptenic sugars facilitated the separation of mixtures having a broad range of complex carbohydrates. Chromatographic experiments for the study of the interaction of certain biogenic amines with immobilized glycoproteins used as the stationary phase led to the development of siliceous bonded phases with serotonin, tryptamine or phenylpropanolamine ligates. The sorbents thus obtained were mildly hydrophobic and cationic in contact with eluents of pH 8 or less. They were used for the separation of various carbohydrates; in addition they also proved effective for the separation of protein mixtures under conditions similar to those customarily employed in electrostatic or hydrophobic interaction chromatography.     

Renormalisation of out-of-equilibrium quantum fields

We consider the initial value problem and its renormalisation in the framework of the two-particle-irreducible (2PI) effective action. We argue that in the case of appropriately chosen self-consistent initial conditions, the counterterms needed to renormalise the system in equilibrium are also sufficient to renormalise its time evolution. In this way we improve on Gaussian initial conditions which have the disadvantage of generically not showing a continuum limit. For a more detailed discussion see [Sz. Borsányi and U. Reinosa, arXiv:0809.0496].     

Identification of ethyl pyruvate and dihydrocinchonidine adducts by electrospray ionization mass spectrometry

Several ethyl pyruvate and dihydrocinchonidine adducts, formed by non-covalent interactions with alkali cations, have been identified for the first time using electrospray ionization mass and tandem mass spectrometry. This type of adduct may have an important role in asymmetric reactions of pyruvates in the presence of cinchonas.     

Some applications of the condensation of the singularities of families of nonnegative functions

RecentlyPrus-Wi?niowski [14] has proved that the continuous functions of Λ-bounded variation on [0, 1] form a set of the first category in the Banach space C[0, 1] and also in each Banach space CΓBV[0, 1] of continuous functions of Γ-bounded variation on [0, 1] provided that the sequence Γ is adequate. In the present paper these results are extended and completed by using a principle of the condensation of the singularities of a family of nonnegative functions that follows from the theorems given byBreckner [3]. It is shown that Baire category properties similar to those stated in [14] are valid for two very large classes of real-valued functions called functions of bounded λ-variation of orderp and functions of boundedmth variation of orderp, respectively. The benefit of considering these classes is that they comprise several classes of functions of bounded variation type which have occurred so far in Fourier analysis or real analysis; in particular, the functions investigated in [14]. Thus, by specializing the results derived in the present paper, they give at once Baire category information concerning a number of well-known sets of real-valued functions.     

Ultrasonics in heterogeneous metal catalysis: sonochemical chemo- and enantioselective hydrogenations over supported platinum catalysts

Sonochemical chemo- and enantioselective hydrogenations over supported platinum catalysts are described. We disclose our results with respect to a sonochemical modification of the chemoselective hydrogenation of cinnamaldehyde over supported platinum catalysts, and the asymmetric hydrogenation of ethyl pyruvate promoted by various ultrasonic pretreatments. The ultrasonic pretreatment of the supported platinum catalysts was found to be highly beneficial in almost every case, improving both the catalytic activity and selectivity. The effect of additional experimental variables, such as hydrogen pressure, catalyst support, temperature and the ultrasonic insonation time were also studied. The enantioselectivity of the hydrogenation of ethyl pyruvate increased up to 97.1% ee. In the case of cinnamaldehyde hydrogenation, the selective preparation of cinnamyl alcohol became possible. The theoretical aspects of the working mechanisms in comparison with 'silent' reactions will also be provided.     

Polarographisches Verhalten von 1,2,3-Cyclohexantrion-trioxim in sauren Lösungen

The deoximation kinetics of 1,2,3-cyclohexanetrione trioxime was studied polarographically in 0.5 and 1.0M-HClO₄ solutions. From the three vicinal oxime groups, that in position 2 is hydrolysed by protonisation, followed by water uptake and hydroxylamine loss. The probable mechanism of the deoximation was proved by the study of the polarographic behaviour of 1,2,3-cyclohexanetrione-1,3-dioxime and by means of amperometric determination of the unchanged trioxime with Ni(II)-salt.