β-Eucryptite by a Sol-Gel Route

-Eucryptite solid solution (LAS) Li2O : Al 2O3 : 3SiO2(113) was prepared via a sol-gel route. Complex solutions of lithium or aluminum salts in ethanol/water mixtures were catalysed by inorganic acids (catalyst/alkoxide ratio 0.1). Different ratios of H2SO4 catalyst were also used.TGA showed that the maximum % yield of LAS 113 occurred using H2SO4 catalyst. Above 400°C exothermic peaks occurred in DSC followed by the glass transition. XRD and IR showed a high crystallinity of -eucryptite solid solution using all acids at the 0.1 ratio with the highest crystallinity for the 0.05 H2SO4 ratio. SEM revealed similar grain sizes in spite of higher acid concentrations. XRD data indicated a change to a tetragonal modification with higher catalyst ratio.     

The ion kinetic energy spectra of isomeric chlorobenzenes and polychlorinated biphenyls (PCB'S)

The ion kinetic energy (IKE) spectra of the isomeric di-and trichlorobenzenes have been examined and the data for the latter compounds suggested that there was incomplete chlorine randomization in their molecular ions in the first field-free region of the mass spectrometer. Previous studies on the mass spectra and [metastable ion]/[daughter ion] ratios of the di-, tetra- and hexachlorobiphenyls (PCB's) indicated chlorine randomization in the molecular ions of those isomers containing less than two chlorine groups ortho to the Ph-Ph ring junction. In contrast the IKE spectra of the isomers are different and the results indicate incomplete chlorine randomization in the first field-free region of the mass spectrometer. These spectral differences may be of some use in PCB analysis.     

ON ALGEBRAIC VOLUME DENSITY PROPERTY

A smooth affine algebraic variety X equipped with an algebraic volume form ω has the algebraic volume density property (AVDP) if the Lie algebra generated by complete algebraic vector fields of ω-divergence zero coincides with the space of all algebraic vector fields of ω-divergence zero. We develop an effective criterion of verifying whether a given X has AVDP. As an application of this method we establish AVDP for any homogeneous space X = G/R that admits a G-invariant algebraic volume form where G is a linear algebraic group and R is a closed reductive subgroup of G.     

A green and simple method for the synthesis of 2,4,5-trisubstituted-1H-imidazole derivatives using acidic ionic liquid as an effective and recyclable catalyst under ultrasound

Research on Chemical Intermediates - In the current work, an acidic ionic liquid ([{(IMC)-4-OMBH}BIM][HSO4]3) has been utilized as an effective and recyclable catalyst for the synthesis of...     

Reaction of Dimethyl Acetylene-Dicarobxylate With Triazinone

Abstract

The addition of dimethyl acetylenedicarboxylate (DMAD) to 6-menthy-1, 2,4-triazlne-3(2H)thione-5(4H)-one afforded 2-methoxylcarboxy-7-methyl-1,3-thiazino[3,2-b][1,2,4]triazine-4,8-dione.     

Model reduction and optimization of a reactive dividing wall batch distillation column inspired by response surface methodology and differential evolution

Carrying out reaction and separation simultaneously in a reactive dividing wall batch distillation column batch RDWC in the case of ethyl acetate synthesis provides the possibility of separating both products and increasing the equilibrium reaction conversion. Overcoming the known azeotrope conditions, high purity for ethyl acetate and decreasing the batch time compared to simple reactive batch distillation are the advantages of this configuration. The corresponding dynamic simulation is carried out by simultaneously solving the model-associated system of differential and algebraic equations. In this study, the optimal values of the vapour and liquid split ratios are considered as the decision variables in order to maximize the amount of ethyl acetate accumulated during batch time. The optimization strategy is implemented inspired by response surface methodology in which an optimal surface is fitted to the collected data set using differential evolution (DE). The optimal surface relevant algebraic equation is then considered as the reduced form of the complex model and the optimal values are obtained using the DE method.     

The Metabolism of the Systemic Fungicide Carboxin (Vitavax) by Rhizopus japonicus

Cultures of Rhizopus japonicus in synthetic glucose medium convert Carboxin into Carboxin sulfoxide and Carboxin sulfone. In steep dedium, under partially anaerobic conditions, Carboxin sulfoxide and another metabolite, which is formed by the addition of the elements of water, are the main products.     

Influence of anionic substitutions on hyperfine interactions and ionic ordering in ferrites

Hyperfine Interactions -     

The ion kinetic energy spectra of some chlorinated insecticides

The ion kinetic energy (IKE) spectra of the p,p′ and o,p′ DDT, DDD and DDE isomers have been examined. The results indicated that the decomposing [M-CCl₃] ions (b) (m/e 235) for the p,p′ and o,p′ DDT isomers were not energetically similar, suggesting retention of the positional identity of the aromatic chlorine substituents. Similar results were obtained for the [M – CHCl₂] ions (b) for the p,p′ and o,p′ DDD isomers. The IKE spectra of p,p′ and o,p′ DDE were indistinguishable, indicating loss of substituent identity of the aromatic chlorine group. The mechanistic and analytical consequences of these data are discussed. The IKE spectra of the four hexachlorocyclohexane isomers (V to VIII) are different and these spectra are obviously useful in the analysis and characterization of these structurally similar compounds. The differences in their reactivity must in some part be due to their different stereochemical orientations of the chlorine substituents.