Synthesis of New Hybrid Organic-Inorganic Alumina Gels by the Sol-Gel Method

New hybrid organic-inorganic alumina gels have been prepared by reacting aluminum sec-butoxide and propane-1,2-diol, in CCl₄ as solvent. This reaction occurred without water addition and without the use of any catalyst, leading to the formation of transparent and monolithic gels. IR,²⁷Al and¹³CNMR show that an interchange reaction between OBu ^s alkoxide groups and diol groups occurred, leading to the hybrid gels. Samples heat treated at different temperatures under argon are weakly porous and have a small specific surface area. XRD indicates the presence of pure α-alumina at 1450°C.     

From furans to anilines: toward one-pot two-step amination/diels-alder sequences

Selective metal-free amination and Diels-Alder reactions are described in the furan series, leading to polysubstituted anilines or to stable oxabicyclic adducts in high yield. Interestingly, anilines are conveniently prepared through a novel one-pot, two-step amination/Diels-Alder procedure from commercially available 5-bromo-2-furaldehyde.     

Enhancement of Congo red dye removal efficiency using Mg-Fe-layered double hydroxide

Research on Chemical Intermediates - In this study, Mg-Fe(II)-Al-layered double hydroxide with different molar ratios Fe/Al (Mg0.80-Fe0.14-Al0.06-LDHs and Mg0.80-Fe0.20-Al0.00-LDHs) was prepared...     

Remediation of copper ions from aqueous solution using hybrid magadiite: kinetics,isotherm and mechanism of removal

Research on Chemical Intermediates - This paper deals with the potential use of hybrid magadiite composite as an alternative adsorbent for the removal of copper ions. Na-magadiite was synthesized...     

Synthesis,characterization and study of methyl 3-(2-oxo-2H-1,4-benzoxazin-3-yl) propanoate as new corrosion inhibitor for carbon steel in 1M H2SO4 solution

Research on Chemical Intermediates - A new benzoxazin derivative, namely methyl 3-(2-oxo-2H-1,4-benzoxazin-3-yl) propanoate (1,4-MBXP), was synthesized under mild conditions from 2-aminophenols and...     

Electrochemical determination of Cd<Superscript>2+</Superscript> at a titanium electrode modified with a lead film by square wave anodic stripping voltammetry

The modified titanium electrode with lead film (PbTiE) was used for determination of trace levels of cadmium using square wave anodic stripping voltammetry (SWASV). The measurement of cadmium on the PbTiE has the best reply under the following conditions of PbTiE preparation: 10^–3 mol L^–1 Pb²⁺ in HCl (pH 1.0), deposition potential of–1.40 V vs. Ag/AgCl/KCl_sat and deposition time of 300 s. The PbTiE reveals highly linear behavior in the concentration range 5 × 10^–8 to 10^–6 mol L^–1, with a limit of detection of 2 × 10^–9 mol L^–1. Interference of nine ionic species was evaluated. The measurements were carried out without removing dissolved oxygen from the solution.     

Convergence analysis of truncated incomplete Hessian Newton minimization method and application in biomolecular potential energy minimization

This paper gives a general convergence analysis to the truncated incomplete Hessian Newton method (T-IHN). It shows that T-IHN is globally convergent even with an indefinite incomplete Hessian matrix or an indefinite preconditioner, which may happen in practice. It also proves that when the T-IHN iterates are close enough to a minimum point, T-IHN has a Q-linear rate of convergence, and an admissible line search steplength of one. Moreover, a particular T-IHN algorithm is constructed for minimizing a biomolecular potential energy function, and numerically tested for a protein model problem based on a widely used molecular simulation package, CHARMM. Numerical results confirm the theoretical results, and demonstrate that T-IHN can have a better performance (in terms of computer CPU time) than most CHARMM minimizers.     

Antifungal activities of amino acid ester functional pyrazolyl compounds against Fusarium oxysporum f.sp. albedinis and Saccharomyces cerevisiae yeast

Series of functional multidendate ligands based on pyrazole and amino acid derivatives were prepared in good and excellent yields (75–5%) by condensation of one equivalent of amino acid ester hydrochloride substrates with two equivalents of (3,5-dimethyl-1H–pyrazol-1-yl)methanol. These tridentate functionalized compounds and their starting materials were screened for their antifungal activities against Fusarium oxysporum f.sp. albedinis and the yeast of Saccharomyces cerevisiae. Considerable activities were recorded with respect to the two studied microorganisms.     

Phase behavior of polystyrene acrylonitril copolymer and polymethylmethacrylate blends under shear

Polymer blends undergo external stresses such as pressure and shear in course of processing cycles. The knowledge of their phase behavior at each step of these cycles is crucial for understanding their physical properties and eventually improves their performance in practical applications. The effects of shear on the phase diagram of binary polymer blends are considered. A theoretical formulism is used upon which the free energy is the sum of two terms. The first term is modeled with the Flory–Huggins free energy of mixing and describes the thermodynamic behavior of the system in the quiescent state. The second term represents the excess free energy stored during flow. In the presence of shear flow, the excess free energy is expressed in terms of the viscosity and the shear modulus. Both quantities depend on composition and shear rate. The curvature of the variation of viscosity versus composition has a tremendous impact upon the nature of phase separation. Phase diagrams are described by the spinodal curves and show for the case considered here miscibility enhancement with increasing shear rate. A good correlation is found with experimental data of the literature on blends of polystyrene acrylonitril copolymer and polymethylmethacrylate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011