A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

We report a green and convenient protocol to prepare 4,7,12,15-tetrachloro[2.2]paracyclophane, the precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way.

Instant Microwave Synthesis of Titania Nanoflowers for Application in DSSCs

Nanoflowers are desirable in light driven applications like Dye Sensitized Solar Cells (DSSCs) due to their large surface area and greater light absorption capabilities. An instant, simple, cheap and environment friendly method of preparing titanium dioxide nanoflowers is presented. The nanoflowers are produced in a time as short as 5 minutes in aqueous conditions without the use of hazardous hydrofluoric acid or organic surfactants at 1 atm. pressure and low temperature of 100°C. Titanium dioxide commercial nanopowders are treated with microwaves in an aqueous sodium hydroxide solution for small durations. The resulting powders are annealed at 450°C in air and characterization is performed using XRD, SEM and Raman spectroscopy.