Andréa Luzia F. de Souza

A simple approach for the synthesis of gold nanoparticles mediated by layered double hydroxide

The present work introduces a new procedure to obtain gold nanoparticles (AuNPs). AuNPs (77-213 nm) were obtained in the absence of any classical reducing agents in a medium containing Mg2+/Al3+ layered double hydroxide (LDH) and N, N- dimethylformamide. XRD analysis showed the presence of crystalline phases of gold in the Au/LDH composite. The 2θ values of peaks corresponding to the LDH interlayer distance indicated that metallic NPs were deposited on the surface of the material. Furthermore, atomic force microscopy (AFM) analysis showed that AuNPs tend to agglomerate in a nonclassical halter-like shape.

A Ternary Catalytic System for the Room Temperature Suzuki-Miyaura Reaction in Water

The formation of Pd(0) in the absence of any classical reducing agent in a medium containing Mg2+/Al3+ layered double hydroxide (LDH) and N,N-dimethylformamide was evidenced. XRD analysis showed the presence of crystalline phases of palladium in the Pd/LDH composite. Suzuki-Miyaura reactions in aqueous medium were carried out at room temperature, and good yields were obtained with bromoarenes and iodoarenes using the ternary system LDH-Pd-CD (cyclodextrin) as catalyst.

CHARACTERIZATION AND CATALYTIC ACTIVITY OF K2CO3/Al2O3 IN THE TRANSESTERIFICATION OF SUNFLOWER OIL IN CONVENTIONAL AND MICROWAVE HEATING

Commercial and synthetic mesoporous aluminas impregnated with potassium carbonate were characterized by X-ray diffraction (XRD), nitrogen physisorption, infrared spectroscopy and 27Al MAS NMR. The activities in the transesterification reaction of sunflower oil with methanol for biodiesel production were evaluated. 27Al MAS NMR spectra evidenced the presence of AlIV and AlVI in the samples, and also of AlV sites in the mesoporous synthesized alumina, which disappeared after impregnation with potassium salt followed by calcination. All aluminas containing potassium were active for biodiesel production from sunflower seed oil, with high conversions by both conventional heating and microwave irradiation.

Synthesis, structural and spectroscopic studies of BNSalanH2 and BPSalanH2

Abstract The synthesis and characterization of gauche-N,N′-bis-[(2-cyanoethyl)-(2-hydroxyphenylmethyl)]ethane diamine, BNSalanH2 and anti-N,N′-bis-[(methylpropanoate)-(2-hydroxyphenylmethyl)]ethane diamine, BPSalanH2 are reported. These BNSalanH2, O2N4, and BPSalanH2, O4N2, molecules have both acidic and basic groups. The BNSalanH2 and BPSalanH2 molecules adopt a gauche and anti conformation, respectively, and Z stereochemistries. The conformations are governed by intramolecular interactions of both classical and non classical hydrogen bond types. In addition, a 3D self-arrangement in BNSalanH2 is created by C-HNnitrile hydrogen bonds linking molecules along [100] and [010]. The X-ray data for BNSalanH2 are: tetragonal, P41212, a = 7.7030(11) Å, b = 7.7030(11) Å, c = 34.907(7) Å, V = 2071.2(6) Å3, Z = 4, R1 = 0.0483; for BPSalanH2 are: monoclinic, P21/c, a = 12.2572(5) Å, b = 7.9993(4), c = 13.4437(5) Å, β = 108.202(2)° V = 1252.18(9) Å3, Z = 2, R1 = 0.0614.