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The study of haemin-catalysed oxidation reactions was extended to substituted aromatic rings. Both electron-donating and electron-withdrawing substituents on aromatic rings act as para- and meta-directing agents in the presence of tetrakis(2,6-dichlorophenyl)porphyrin iron(III) chloride as catalyst and m-chloroperbenzoic acid as oxidant. A new kinetic method for measuring relative rates of epoxidation of alkenes and related compounds has been developed; while steric hindrance results in decreasing the rate of hydroxylation, electron-rich and electron-withdrawing substituents were found to increase the rate of hydroxylation. A linear relationship between the logarithm of the relative rate of hydroxylation and σ Hammet is obtained, although electron-donating and electron-withdrawing substituents fit separate lines. Addition of pyridine to haemin was shown to increase the yield of epoxidation but decrease the yield of aromatic hydroxylation.

In this paper we have tried to develop a semi-empirical formula for estimation of starting time of reactions during mechanical alloying process according to self-propagating high temperature synthesis (SHS) mechanism. For this purpose, three SHS systems containing Ti–C, Mo–Si and Si–C were selected and their behaviors were observed. Aforementioned systems were milled in a planetary ball mill equipped with temperature sensor detector of cups. Samplings were done at different times of discontinuously milling. To change mills' energy, stainless steel and tungsten carbide balls were used. In order to detect the phases and characterizations of milled powder, XRD instrument was utilized. Results showed that all productions were synthesized after sudden increase in temperature. Maximum measured temperature and critical time had up and downtrends for production of TiC, MoSi₂ and SiC, respectively. Crystalline size of milled powder had nano-meter scale. By using experimental data along with theoretical equations, a semi-empirical formula between critical time for transformation of raw materials to productions, type of milled system and ball mill parameter can be presented with high accuracy. According to calculated formula, critical time was related to ball mill energy and Gibbs free energy of milled system with direct and inverse proportionality, respectively.

Wastewater discharge from textile industries contribute much to water pollution and threaten the aqua ecosystem balance. Synthesis of agriculture waste based adsorbent is a smart move toward overcoming the critical environmental issues as well as a good waste management process implied. This research work describes the adsorption of methylene blue dye from aqueous solution on nickel oxide attached magnetic biochar derived from mangosteen peel. A series of characterization methods was employed such as FTIR, FESEM analysis and BET surface area analyzer to understand the adsorbent behavior produced at a heating temperature of 800${}^{\circ }$C for 20min duration. The adsorbate pH value was varied to investigate the adsorption kinetic trend and the isotherm models were developed by determining the equilibrium adsorption capacity at varied adsorbate initial concentration. Equilibrium adsorption isotherm models were measured for single component system and the calculated data were analyzed by using Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich isotherm equations. The Langmuir, Freundlich and Tempkin isotherm model exhibit a promising R²-correlation value of more than 0.95 for all three isotherm models. The Langmuir isotherm model reflectsan equilibrium adsorption capacity of 22.883mg$\cdot$g${}^{-1}$.

The selective oxidation of sulfides with hydrogen peroxide to give sulfoxides was carried out in aqueous solution by water-soluble manganese porphyrin as mimics of cytochrome P450-like catalyst. Different factors that influencing the selective oxidation of sulfides, for example, catalyst, amount of catalyst, solvent and reaction temperature were investigated. MnTE4PyP (meso-tetrakis(N-ethylpyridinium-4-yl) manganese porphyrin) was efficient and selective catalyst for oxidation of various sulfides. The reaction showed first-order dependence in both [sulfide] and [H₂O₂], and a fractional order respect to catalyst. Oxygen atom transfer mechanism involves high-valence intermediate was proposed, which was supported by kinetic orders and spectrophotometric evidences.

Si₃N₄–SiC composites were fabricated by spark plasma sintering at 1700${}^{\circ }$C for 480 S with MgSiN₂ and Y₂O₃ as additives. The morphology and phase characterization of the composites were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The values of $n$ parameter indicate that the grain boundary reaction is the rate controller at 1500${}^{\circ }$C and diffusion becomes the controlling step at 1550${}^{\circ }$C. The nanohardness and Young’s modulus attained the maximum value of 18.5 and 316GPa, respectively.