Efficient and Environmentally Friendly Approach to the Synthesis of Ferrocenyl‐Substituted 1,5‐Diketone Compounds Under Solvent‐Free Conditions

Abstract

This article describes a fast, efficient, economical, and environmentally friendly method for the preparation of a series of ferrocenyl‐substituted 1,5‐diketone compounds via Michael addition of ferrocenyl‐substituted chalcones with deoxybenzoin or dibenzyl ketone under solvent‐free conditions, and affords the corresponding Michael adducts with excellent yields of 77–93%.     

Microbial desulfurization of waste latex rubber with Alicyclobacillus sp.

A microbe with desulfurizing capability, Alicyclobacillus sp., was selected to recycle waste latex rubber (WLR). The growth characteristics of the microorganism and the technical conditions in the co-culture desulfurization process were studied. The desulfurization effect of Alicyclobacillus sp. on the WLR was characterized, and the mechanism for the microbial desulfurization of WLR was tentatively explored. The results showed that adding 5% (w/v) WLR into medium had little effect on the growth of Alicyclobacillus sp. The surfactant polysorbate 80 (Tween 80) had a toxic effect on Alicyclobacillus sp., but the growth of the microbe was vigorous if the proper technique was used: the mixing of WLR with Tween 80, followed by the addition of the mixture into the culture media. With the increase of desulfurization time, the swelling value of desulfurizated waste latex rubber (DWLR) increased, but the crosslink density decreased. After co-culture desulfurization for 8–10 days, a DWLR with good desulfurization effect was obtained. The mechanical properties of natural rubber (NR)/DWLR composite improved significantly over those of NR/WLR composite. XPS and FTIR results revealed that Alicyclobacillus sp. could break the crosslinked sulfur bonds and oxidize them to sulfones groups. The increase of O element content on the surface of DWLR was confirmed by water contact angle measurements. The relationship between the crosslink density and sol fraction of DWLR with different desulfurization times agreed with the Horikx equation, an indication that the microorganisms could break the crosslinked sulfur bonds on the surface of WLR, but leaving the main chains intact.     

Dispersion Mechanism of Superfine SiC Particles in the Different Condition Liquid

SiC@A1(OH)₃-Y(OH)₃ core-shell composite particles are synthesized by co-precipitation method for strengthening the antioxidation of SiC at high temperature. To reach better A1(OH)₃-Y(OH)₃ composite shell and higher coating ratio on the SiC particles surfaces, SiC particles must be adequately dispersed in the SiC suspension during the coating process. The dispersion mechanism of SiC particles is investigated by the sedimentation method. Through test and analysis, the optimum conditions of the dispersion of SiC particles in the SiC suspension are sedimentating for 10 minutes, ultrasonic dispersion for 10 minutes, the lower SiC concentration, pH = 9, the dispersant content for the 2% volume of SiC suspension and using the polyelectrolyte dispersant, respectively.     

Lichens as biomonitors for the determination of polycyclic aromatic hydrocarbons (PAHs) in Caracas Valley,Venezuela

Biomonitoring of PAH air pollution using lichens was carried out. Sixteen PAHs were studied in 11 locations along the valley of Caracas (Venezuela). The results of this work indicate that 14 of the 16 analysed PAHs were highly accumulated into the lichen thalli of Pyxine coralligera Malme. PAH levels in the samples revealed that the several volatile PAHs (naphthalene, acenaphtylene, acenaphtene, and fluoranthene) have the highest levels in the majority of the studied locations. The fluoranthene/pyrene and phenantrene/antracene ratios suggested that the major sources of PAHs are anthropogenic, mainly associated with gasoline and diesel combustion (pyrolytic) and unburnt oil derivates (petrogenic). The total PAH concentrations obtained in the present study were in the range of 0.24 to 9.08?µg/g, similar to those reported by other works in European and Asian cities.     

正癸烷与二甲苯在超临界压力下的热裂解

采用连续流动装置对正癸烷和二甲苯在超临界压力下的热裂解对比研究. 用气相色谱和色质联用仪对其气相产物和液相产物进行分析, 计算气相产物产率和裂解转化率, 并运用计算化学方法获得正癸烷和二甲苯不同化学键的键能, 从实验和理论上分析其裂解反应的难易程度和裂解规律. 实验结果表明, 在4 MPa和650、700、750 ℃条件下, 正癸烷比二甲苯更容易裂解, 正癸烷裂解产物以C₁-C₃小分子的烃类和氢气为主, 而二甲苯裂解产物主要为乙苯、甲苯和其它芳香类化合物; 键能计算结果表明, 正癸烷碳链骨架的C－C键能和C－H键能均较小, 裂解反应的诱发步骤应该是C－C键断裂, 而二甲苯苯环上C－C和C－H键能均较大, 裂解诱发步骤应该是侧链甲基脱氢反应. 因此正癸烷裂解反应以C－C键断裂和脱氢反应为主, 二甲苯裂解主要发生侧链甲基C－C键断裂和脱氢反应, 而芳环则比较稳定, 理论计算键能分析与裂解实验结果一致.     

Approximation properties for solutions to non‐Lipschitz stochastic differential equations with Lévy noise

In this paper, we consider the non‐Lipschitz stochastic differential equations and stochastic functional differential equations with delays driven by Lévy noise, and the approximation theorems for the solutions to these two kinds of equations will be proposed respectively. Non‐Lipschitz condition is much weaker condition than the Lipschitz one. The simplified equations will be defined to make its solutions converge to that of the corresponding original equations both in the sense of mean square and probability, which constitute the approximation theorems. Copyright © 2014 John Wiley & Sons, Ltd.     

Standing waves for 4‐superlinear Schrödinger‐Kirchhoff equations

We consider standing waves for 4‐superlinear Schrödinger–Kirchhoff equations in with potential indefinite in sign. The nonlinearity considered in this study satisfies a condition that is much weaker than the classical Ambrosetti–Rabinowitz condition. We obtain a nontrivial solution and, in the case of odd nonlinearity, an unbounded sequence of solutions via the Morse theory and the fountain theorem, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

An inverse coefficient problem for a quasilinear parabolic equation with periodic boundary and integral overdetermination condition

In this paper, the inverse problem of finding the time‐dependent coefficient of heat capacity together with the solution periodic boundary and integral overdetermination conditions is considered. Under some natural regularity and consistency conditions on the input data, the existence, uniqueness, and continuous dependence upon the data of the solution are shown. Some considerations on the numerical solution for this inverse problem are presented with an example. Copyright © 2014 John Wiley & Sons, Ltd.     

The Allen–Cahn equation with dynamic boundary conditions and mass constraints

The Allen–Cahn equation, coupled with dynamic boundary conditions, has recently received a good deal of attention. The new issue of this paper is the setting of a rather general mass constraint, which may involve either the solution inside the domain or its trace on the boundary. The system of nonlinear partial differential equations can be formulated as a variational inequality. The presence of the constraint in the evolution process leads to additional terms in the equation and the boundary condition containing a suitable Lagrange multiplier. A well‐posedness result is proved for the related initial value problem. Copyright © 2014 John Wiley & Sons, Ltd.