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Quantitative investigation of the shape selectivity for the competitive intercalation reaction of isomeric mixtures in the interlayer of LDH was achieved by analyzing the solid phases synthesized by the reaction of [LiAl2(OH)6]Cl·yH2O with various compositional mixtures of (E,E)- and (Z,Z)-muconates. The apparent partition constant K′ for the anion-exchange reaction between (E,E)- and (Z,Z)-muconates was quite dependent on the mole fraction of muconates in solution. The only single phase saturated with [LiAl2(OH)6]2[(E,E)-C6H4O4]·zH2O could be obtained in the range of the initial mole fraction of (E,E)-muconate larger than 0.6 in the starting solution, while mixed phases intercalated with (E,E)- and (Z,Z)-muconates could be obtained at lower mole fractions of (E,E)-muconate. The shape selectivity for the competitive reaction of two muconates on the [LiAl2(OH)6]+ lattice could be ascribed to thermodynamic processes, and the conditions under which that pure (E,E)-muconate was efficiently separated from isomeric mixtures of two muconates were successfully evaluated. [Copyright &y& Elsevier]

Abstract This paper reports the preparation of Ti microparticles that are angular and spherical in shape through the combustion of a TiO 2 + αCa (where α is moles of Ca) exothermic mixture in an inert atmosphere. The relationship between the combustion parameters and the properties of the resultant Ti particles is discussed with consideration of the effect of Ca concentration. Using excess amounts of Ca in the experiment was effective in modifying the shape of the particles from angular to spherical. The Ti powder was found to be well-dispersed and the diameter of individual particles ranged from 5 µm to 50 µm. Based on the combustion parameters, the activation energy for the redox reaction was calculated as ∼ 138 kJ/mol. This paper discusses the chemistry of the reduction process and highlights the effects of combustion temperature and the amount of liquid calcium on the characteristics of the Ti particles. Graphical abstract The combustion process in TiO 2 + Ca mixture developed a maximum temperature of about 1820 °C and resulted in Ti spherical particles. fx1 [ABSTRACT FROM AUTHOR]

We have investigated a thermally induced combustion route for preparing 2D hexagonal BN nanoplates from B 2 O 3 +(3+0.5 k )Mg+ k NH 4 Cl solid system, for k =1–4 interval. Temperature–time profiles recorded by thermocouples indicated the existence of two sequential exothermic processes in the combustion wave leading to the BN nanoplates formation. The resulting BN nanoplates were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy, PL spectrometry, and Brunauer–Emmett–Teller surface area analysis. It was found that B 2 O 3 was converted into BN completely (by XRD) at 1450–1930 °C within tens of seconds in a single-step synthesis process. The BN prepared at a k =1–4 interval comprised well-shaped nanoplates with an average edge length ranging from 50 nm to several micrometer and thickness from 5 to 100 nm. The specific surface area of BN nanoplates was 13.7 g/m 2 for k =2 and 28.4 m 2 /g for k =4. [ABSTRACT FROM AUTHOR]