Inhibition of iron corrosion in 0.5 M sulphuric acid by metal cations

Corrosion inhibitors are widely used in acid solutions during pickling and descaling. Mostly organic compounds containing N, O, and S groups are employed as inhibitors. In this study, the inhibition performance of metal cations such as Zn²⁺, Mn²⁺ and Ce⁴⁺ ions in the concentration range 1-10 × 10⁻³ M has been found out. The corrosion behaviour of iron in 0.5 M H₂SO₄ in the presence of metal cations is studied using polarization and impedance methods. It is found that the addition of these metal cations inhibits the corrosion markedly. The inhibition effect is in the following order Ce⁴⁺ ? Mn²⁺ > Zn²⁺.     

A convenient preparation of 2-thioxo-4(3H)-quinazolinones

A simple method is described for the preparation of 3-aryl-2-thioxo-4(3H)-quinazolinones (4) by the reaction of anthranilic acids and ammonium or triethylammonium N-aryl-dithiocarbamates in ethanol. The method is also applicable to the preparation of 3-ethyl-2-thioxo-4(3H)-quinazolinone.     

Evaluation of ammonium terminated PMMA as compatibilizers for monomer casting polyamide6/clay nanocomposites

The compatibilization effects provided by ammonium terminated PMMA(PMMA‐t‐NH₃⁺) on monomer casting polyamide6 (MCPA6)/clay(pristine sodium montmorillonite) nanocomposites were studied in this article. PMMA‐t‐NH₃⁺ used in this study was prepared by radical polymerization using 2‐aminoethanethiol hydrochloride as chain transfer agent. MCPA6/clay/PMMA‐t‐NH₃⁺ nanocomposites were prepared by in situ anionic ring‐opening polymerization of ε‐caprolactam. X‐ray diffraction and transmission electron microscopy plus rheological measurement were used to characterize those nanocomposites. The results indicated that PMMA‐t‐NH₃⁺ would be a good compatibilizer for this system. With PMMA‐t‐NH₃⁺ content increasing, a better dispersion of clay was successfully achieved in the MCPA6 matrix. Furthermore, analysis using differential scanning calorimetry indicated that well dispersed clay layers limited the mobility of the MCPA6 molecule chains to crystallize, reduce the crystalline degree, and favor the formation of the γ‐crystalline form of the MCPA6 matrix. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1802–1810, 2008     

Efficient construction of a chiral all-carbon quaternary center by asymmetric 1,4-addition and its application to total synthesis of (+)-bakuchiol

The conjugate addition of lithium divinylcuprate to (4S,2′E)-3-(6′-TBDPS-3′-methylhex-2′-enoyl)-4-phenyloxazolidin-2-one proceeded efficiently to create a chiral all-carbon quaternary center with a high diastereoselectivity (R:S = 95:5). The absolute configuration of the newly generated chiral center was confirmed by applying this methodology to the total synthesis of (+)-bakuchiol.     

笼形聚偕胺肟树脂的研究──(NH_4)_2IrCl_6在酸处理树脂上的吸附及还原过程

研究了酸处理树脂对（NH4）2IrCl6的吸附行为。吸附动力学数据表明（NH4）2IrC6在酸处理树脂上通过物理吸附生成1：1配合物，并被还原为Ir（0）。     

Reindarstellung von Lanthan- und Praseodym-Ammoniumdoppelnitraten durch fraktionierte Kristallisation in großem Maßstab

Summary Lanthanum ammonium nitrate of purity 97%, containing 34.1 kgRE ₂O₃, was crystallized fractionally and yielded 32.5 kg oxide of purity better than 99.9% (the larger part was 99.99% pure). Out of mixtures with 66% Pr there resulted praseodymium ammonium nitrate containing 13.45 kg oxide of purity better than 99.5%. The effective separation factors are discussed, showing a better efficiency of the ammonium than of the magnesium double nitrates for the separation of praseodymium and lanthanum.

     

catena‐Phosphorus Cations

Recent advances towards a systematic development of catena‐phosphorus cations are reviewed. The cations represented in this new and developing chapter in fundamental phosphorus chemistry complement the series of neutral and anionic polyphosphorus compounds.     

Triple Brackets and Lax Morphism Categories

Various aspects of the traditional homotopy theory of topological spaces may be developed in an arbitrary 2-category C with zeros. In particular certain secondary composition operations called box brackets recently have been defined for C; these are similar to, but extend, the familiar Toda brackets in the topological case. In this paper we introduce further the notion of a suspension functor in C and explore the ramifications of relativizing the theory in terms of the associated lax morphism category of C, denoted mC. Four operations associated to a 3-box diagram are introduced and relations among them are clarified. The results and insights obtained, while by nature somewhat technical, yield effective and efficient techniques for computing many operations of Toda bracket type. We illustrate by recording some computations from the homotopy groups of spheres. Also the properties of a new operation, the 2-sided matrix Toda bracket, are explored.     

Study of the Dependence on Temperature and Composition of the Volumic Properties of Ethane-1,2-diol + 2-Methoxyethanol + 1,2-Dimethoxyethane + Water Solvent System and Graphical Representation in the Quaternary Domain

In this paper, the temperature and composition dependencies of the volumetric behavior are studied for the ethane-1,2-diol + 2-methoxyethanol + 1,2-dimethoxyethane + water quaternary system. Density data were collected at different temperatures ranging from −10 to 80 ^∘C and at atmospheric pressure over the whole composition range, 0≤ x_i(i = 1, 2, 3, 4)≤ 1. Moreover, we also made use of the results on the six binary (ij) and four ternary (kij) subsystems studied previously. The excess molar volume (V^E) data have been fitted to an equation derived from the well-known Redlich–Kister equation and some interesting correlations were found. Furthermore, in order to represent in an effective way the behavior of the V^E = V^E(x_i) function (and of the derived partial molar quantities) in the quaternary domain, a new algorithm has been developed, which gives 3D plots where the dependent function is depicted by means of “colored slices” of the tetrahedron corresponding to the investigated composition quaternary domain.