The intramolecular Pd­(II)-catalyzed alkenylation of aryl homoallyl ethers constitutes a mild, versatile, and efficient procedure for the synthesis of highly and diversely substituted chromanes and 2H-chromenes. The use of p-TsOH as an additive allows more efficient reactions that could be carried out a room temperature in most cases. The procedure has a wide scope, allowing the synthesis of alkylidenechromanes and 2H-chromenes substituted at C-2 or C-3 of the chromene moiety, thus accessing relevant flavenes and isoflavenes, and even coumarins, in high yields (59 to 91%, 32 examples).

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Amines with two carbon atoms in the organic chain [ethylamine (EA), diethylamine (DEA), triethylamine (TEA)] have been used as precipitant agents to obtain a hydrotalcite-like compound with Zn (II) and Al (III) as layered cations and with nitrate anions in the interlayered region to balance the charge. This Layered Double Hydroxide was prepared following the coprecipitation method, and the effect on the crystal and particle sizes was studied. Also, the effect of submitting the obtained solids to hydrothermal post-synthesis treatment by conventional heating and microwave assisted heating were studied. The obtained solids were exhaustively characterized using several instrumental techniques, such as X-ray diffraction, Thermal Analysis (DTA and TG), Chemical Analysis, Infrared Spectroscopy (FT-IR), determination of Particle Size Distribution and BET-Surface area. Well crystallized solids were obtained showing two possible LDH phases, depending on the orientation of the interlayer anion with respect to the brucite-like layers. The results indicated that there is a certain influence of the amine, when used as a precipitating agent, and as a consequence of the degree of substitution, on the crystallinity and particle size of the final solid obtained. The LDHs obtained using TEA exhibited higher crystallinity, which was improved after a long hydrothermal treatment by conventional heating. Regarding the shape of the particles, the formation of aggregates in the former solid was detected, which could be easily disintegrated using ultrasound treatments, producing solid powder with high crystallinity and small particle size, with homogeneous size distribution.

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A simple, easily applicable method is proposed to quantify the amount of ZnO segregated during synthesis and post-synthesis treatments of Zn-Al layered double hydroxides with the hydrotalcite structure. The method provides a feasible, easy, fast, and reliable way to get values for ZnO content, and the method can be extended to other compounds.

In this work, a valorization procedure is developed for the wastes generated during aluminum recycling, namely, for saline slag. The procedure is divided into two steps: 1) recovery of aluminum from various slag fractions, and b) the use of recovered aluminum in the synthesis of two zeolites, namely, analcime (NaAlSi2O6•H2O) and pollucite (CsAlSi2O6•nH2O). Saline slag was ground, sieved (1 mm), washed and separated into two fractions of different sizes, larger or lower than 0.4 mm. The fraction < 0.4 mm was treated under reflux conditions with NaOH or CsOH solutions of different concentrations. The extraction liquor contained aluminum and alkali metal cations and allowed to obtain the zeolitic materials by hydrothermal synthesis at 200 °C for 24 hours after adding the necessary amount of Si. These solids were fully characterized. The results of the first step showed that a high percentage of Al (~44 wt.%) in the fraction < 0.4 mm, can be recovered.The results of the second step indicated that crystalline analcime and pollucite zeolites can be hydrothermally synthesized from extraction liquors and a source of Si, the zeolites being the only phases detected by powder X-ray diffraction.