Ionic aggregation in random copolymers containing phosphonium ionic liquid monomers

Copolymers of n‐butyl acrylate and phosphonium ionic liquid monomers possessing various alkyl substituents and counterions were synthesized through a combination of conventional free radical copolymerization and anion exchange. Differential scanning calorimetry and dynamic mechanical analysis provided the thermal and mechanical properties of these phosphonium cation‐containing random copolymers. Factors including alkyl chain length of phosphonium substituents, counterion type, as well as ionic concentration significantly influenced the association of phosphonium cations. Phosphonium ionomers with trialkyl substituents on phosphonium cations did not display the characteristic small‐angle X‐ray scattering peak, suggesting the absence of ionic clusters. However, low q peaks in wide‐angle X‐ray diffraction was indicative of significant concentration fluctuations wherein the ionic monomeric units associated. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Simulation of three‐dimensional flows over moving objects by an improved immersed boundary–lattice Boltzmann method

An improved immersed boundary–lattice Boltzmann method (IB–LBM) developed recently [28] was applied in this work to simulate three‐dimensional (3D) flows over moving objects. By enforcing the non‐slip boundary condition, the method could avoid any flow penetration to the wall. In the developed IB–LBM solver, the flow field is obtained on the non‐uniform mesh by the efficient LBM that is based on the second‐order one‐dimensional interpolation. As a consequence, its coefficients could be computed simply. By simulating flows over a stationary sphere and torus [28] accurately and efficiently, the proposed IB–LBM showed its ability to handle 3D flow problems with curved boundaries. In this paper, we further applied this method to simulate 3D flows around moving boundaries. As a first example, the flow over a rotating sphere was simulated. The obtained results agreed very well with the previous data in the literature. Then, simulation of flow over a rotating torus was conducted. The capability of the improved IB–LBM for solving 3D flows over moving objects with complex geometries was demonstrated via the simulations of fish swimming and dragonfly flight. The numerical results displayed quantitative and qualitative agreement with the date in the literature. Copyright © 2011 John Wiley & Sons, Ltd.     

General Synthetic Route to Monosubstituted Cycloheptadienes from Organometallic Compounds

An examination of the literature reveals that only a limited number of monosubstituted cycloheptadiene compounds have been reported. An obvious synthetic route to 5-substituted -1, 3-cycloheptadiene derivatives would be the reaction of nucleophiles with the cycloheptadienyl cation, but this pathway is generally unsuccessful due to the limited stability of the cation. On the other hand, the iron tricarbonyl complex of this cation shows remarkable stability¹ and an ability to react with nucleophiles². If the -Fe(CO)₃ group could be removed easily, a facile route to this family of organic compounds would be available. This work reports our investigation of the range of nucleophiles that can be utilized and the oxidizing agents that can remove efficiently the -Fe(CO)₃ group.     

Pinacol Coupling of Aromatic Aldehydes and Ketones in Ethyl Acetate Mediated by TiCl4‐Mg

Titanium tetrachloride in ethyl acetate can be reduced by Mg powder to the corresponding low‐valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 38–85% yields within 15–60 min at rt with stirring.     

Synthesis of 2-aminooxazolines from isonitriles and iodine

A novel one-pot protocol for the synthesis of substituted 2-aminooxazoline from isonitriles and 2-aminoethanol was developed and the reactions involved imidoyl diiodide intermediates,which were generated by mixing isonitriles and iodine in CH₂C1₂ at room temperature.     

Application of Graphene as a Sorbent for Simultaneous Preconcentration and Determination of Trace Amounts of Cobalt and Nickel in Environmental Water and Vegetable Samples

A new method using a column packed with graphene as adsorbent was developed for the preconcentration of trace amounts of cobalt (Co) and nickel (Ni) prior to their determinations by flame atomic absorption spectrometry. Several factors influencing the extraction efficiency of Co and Ni and their subsequent determinations, such as pH, amounts of the chelating agent, flow rates of sample and eluent solution, eluent type and its volume, breakthrough volume, and adsorption capacity were established. Under the optimum conditions, the calibration graphs were linear in the range of 4.0‐200.0 μg L^?1 and 5.0‐200.0 μg L^?1 with detection limits of 0.36 μg L^?1 and 0.51 μg L^?1 for Co and Ni, respectively. Good relative standard deviations for ten determinations of 100.0 μg L^?1 of Co and Ni were 3.2 and 3.6%, respectively. The results for determination of Co and Ni in tap water, river water, sea water, vegetable and spiked samples have demonstrated the accuracy and applicability of the proposed method. To validate the proposed method, three certified reference materials of environment water (GSBZ 50030‐94 and GSB 07‐1186‐2000) and tomato leaf (GSBZ 51001‐94) were analyzed, and the determined values were in good agreement with the certified values.     

Fermion Tunnels of Cylindrical Symmetric Black Hole and?the?Corrected Entropy

Using the method proposed by Banerjee and Majhi, we researched fermion tunneling from cylindrical symmetric black hole, and obtained the correctional entropy. In our work, we first prove that the ratios of the wave function’s components are constants near the horizon, so the reasonable action form of the Dirac equation can then be gotten. From the method beyond semiclassical approximation, we finally calculate the Hawking temperature and correctional entropy.