A greener continuous flow procedure for the synthesis and purification of methyl oximino acetoacetate, a key intermediate for the generation of several heterocyclic scaffolds, has been established. The synthesis is based on the continuous flow generation of nitrous acid to effect the oximation reaction. Neat reactants and a nearly saturated aqueous NaNO 2 solution have provided a methodology with a very low solvent consumption. The extraction of the oxime from the reaction mixture, a challenging process due to the presence of acetic acid in the solution, has been achieved by liquid−liquid extraction in a microreactor and a continuous multistage phase separation platform. Fine-tuning of the output pH by inline monitoring using a flow cell has enabled optimal extraction performance as well as the minimization of the acetic acid residue in the organic phase and the use of very low amounts of extraction solvents. An excellent value for the process mass intensity of 11.1 has been achieved. Moreover, the lack of acetic acid in the product avoids an additional and energy-consuming distillation step.
Thin films were sputter deposited from a Fresnoite (Ba2Si2TiO8) ceramic target at substrate temperatures lower than 175°C. The as-deposited thin films were near amorphous with a void network morphology. In spite of the fact that the film compositions were shifted from stoichiometry, x-ray diffraction studies showed that the films crystallized to form randomly oriented Fresnoite grains. The crystallization kinetics were quite sluggish and the resultant activation energy for the crystallization process was 370 ± 30 kJ/mol. Even after annealing for 10 h at 750°C an appreciable amount of amorphous material remained in the thin films. The short-range order in this amorphous material was changed from that of the as-deposited thin films. The overall devitrification kinetics of amorphous Fresnoite thin films at a fixed temperature were represented theoretically by an equation of Tool's type.
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