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The Friedlander reaction is the most commonly used method to synthesis substituted quinolines, the essential intermediates in the medicine industry. A facile one-pot approach for synthesizing substituted quinolines by the reaction of isoxazoles, ammonium formate-Pd/C, concentrated sulfuric acid, methanol and ketones using Friedlander reaction conditions is reported. Procedures for the synthesis of quinoline derivatives were optimized, and the yield was up to 90.4%. The yield of aromatic ketones bearing electron-withdrawing groups was better than the ones with electron-donating substituents. The structures of eight substituted quinolines were characterized by MS, IR, H-NMR and 13CNMR, which were in agreement with the expected structures. The mechanism for the conversion was proposed, which involved the Pd/C catalytic hydrogen transfer reduction of unsaturated five-membered ring of isoxazole to produce ortho-amino aromatic ketones. Then the nucleophilic addition of with carbonyl of the ketones generated Schiff base in situ, which underwent an intermolecular aldol reaction followed by the elimination of H2O to give production of substituted quinolines. This new strategy can be readily applied for the construction of quinolines utilizing a diverse range of ketones and avoids the post-reaction separation of the o-amino aromatic ketone compounds. The conventionally used o-amino aromatic ketone compounds in Friedlander reaction to prepare substituted quinoline are laborious to synthesize and are apt to self-polymerize. While oxazole adopted in this work can be prepared at ease by the condensation of benzoacetonitrile and nitrobenzene derivatives under the catalysis of a strong base. Moreover, the key features of this protocol are readily available starting materials, excellent functional group tolerance, mild reaction conditions, operational simplicity, and feasibility for scaling up.

An environmentally friendly wet chemistry approach is used to synthesize silver nanotrees with a single step. The silver nanotrees with single crystalline (111) faces were synthesized without any external reducing or stabilizing agents in water media, involving a galvanic-cell mechanism between the silver nanostructure and biomass-derived monolithic activated carbon (MAC). By varying the concentration of [Ag(NH3)2]NO3, silver nanoflowers, nanowires and nanorods can also be selectively obtained. The silver morphology can also be tuned by some anions such as PO43−, Cl− and OH− in MAC, which afford a more flexible morphological control in this galvanic-cell mechanism than those reported previously. Importantly, the obtained silver dendrites are found to yield excellent catalytic activity for the reduction of 4-nitroaniline by borohydride.

Silver is one of the most important materials in plasmonics. Tuning the size of various silver nanostructures has been actively pursued in the last decade. However, silver nanobelt, a typical one-dimensional silver nanostructure, has not been systematically studied as to tuning its size for controllable plasmonic response. Here we show that silver nanobelts, with mean width ranging from 45 to 105 nm and thickness at ca. 13 nm, can grow abundantly on monolithic activated carbon (MAC) through a galvanic-cell reaction mechanism. The widths of silver nanobelts are positively correlated to the growth temperatures. The width/thickness ratio of the silver nanobelts can be adjusted so that their transversal plasmonic absorption peaks can nearly span the whole visible light band, which endows them with different colours. This work demonstrates the great versatility of a simple, green and conceptually novel approach in controlled synthesis of noble metal nanostructures.

It is also well known that naked SiO2 is not an efficient photocatalyst due to its relatively large band gap, which could only absorb short-wave ultraviolet light. In this report, SiO2/carbon quantum dot (SiO2/CQD, about 4 nm) nanocomposites were successfully prepared by one-step thermal method using tetraethylorthosilicate (TEOS) as the source of both silicon and carbon. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). These nanocomposites exhibit higher photocatalytic activity for rhodamine B (RhB) degradation than C-doped SiO2 and pure SiO2 nanoparticles under near-UV light irradiation at room temperature in air. In the present catalyst system, CQD play two important roles for the enhanced photocatalytic activity of SiO2/CQD nanocomposites. It is expected that these novel, environmentally friendly and highly photoactive SiO2/CQD nanocomposites may promote practical applications of photocatalysts and provide an effective approach to high-efficiency complex catalyst design.

CeO2 triangular microplates were obtained via thermal treatment of triangular precursor, which were synthesised through a convenient precipitation route using Ce(NO3)3·6H2O as the cerium source and NH4NO3 as the mineralising agent. The field emission scanning electron microscopy (FESEM) images show the obtained uniform trigon-like particles with edge lengths ranging from 2 to 5 um. The optical absorption spectrum indicates that the CeO2 trigons have a direct band gap of 3.65 eV. The electrochemical characteristics of the trigon-like CeO2 structures were studied by investigation of cyclic voltammetry (CV). It was found that the CeO2 trigons can greatly improve the electron transfer ability.