In this paper, Au/TiO2 nanocomposite was synthesized and utilized as highly efficient and green photocatalyst for organic reactions. A sheet‐like anatase titanium dioxide material with a highly active (001) crystal plane was prepared via a solvothermal method. Gold nanoparticles were then loaded on the surface of TiO2 by a liquid‐phase reduction method to give an Au/TiO2 material with good photocatalytic activity. The Au/TiO2 nanocomposite was utilized as a photocatalyst to develop a light‐promoted Minisci oxidative coupling reaction of ether and aza aromatics by using oxygen as green oxidant and only catalytic amount of acid as additive. The protocol shows a good functional group tolerance as well as good to excellent yields for various substrates. With mechanistic studies, Au/TiO2 nanocomposite proved to be an efficient photocatalyst to activate C−H bond via a SEO approach of heteroatoms. Moreover, the solid semiconductor photocatalyst shows good recycling performance, could be easily recovered and reused without significant decrease in yield.
The selective functionalisation of arylamine derivatives with hexafluoroisopropanol through copper(II)‐catalysed aerobic oxidative coupling was developed to generate various fluoroalkylated arylamines under mild conditions. This method has a wide substrate scope with excellent functional group tolerance and provides the fluorinated products in good to excellent yields. Furthermore, preliminary studies indicate that this reaction occur via a radical mechanism. This protocol, which uses atmospheric O2 as an oxidant, provides an alternative green route for constructing fluorinated compounds.
The utilization of gold tailings and bentonite as raw materials for prepared foamed ceramic was studied. The effects of boric acid and titanium dioxide content on the properties and microstructures of foamed ceramic were studied from the aspects of bulk density, compressive strength, bending strength, phase composition, and micromorphology. These results show that the synergistic effect of boric acid and titanium dioxide leads to the crystallization of quartz, which enhanced the compressive strength and bending strength and decreased the thermal conductivity of foamed ceramics, while the bulk density increases gradually with the addition of titanium dioxide. Taking into account all of these properties, the optimal results are as follows: bending strength of 1.111 MPa, compressive strength of 1.165 MPa, bulk density of 0.258 g/cm3, the porosity of 81.89%, the thermal conductivity of 0.088 (W/(m⋅K)). This study indicated that gold tailings are a promising candidate for the preparation of foamed ceramics used as external insulation building materials.
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