Vanadium phosphorus oxide modified by silver doping: A highly effective catalyst for allylic oxidation of cycloolefins
Abstract Allylic oxidation of cycloolefins was carried out over Ag-VPO catalyst using tert-butyl hydroperoxide (TBHP) as oxidant in argon atmosphere, under our reaction conditions, attack of the activated C–H bonds was preferred instead of the epoxidation of C=C bond and corresponding α, β-enones were obtained as the main products. It is a high yielding, safe and eco-friendly method.
A qualitative study on the performance of cylindrical vacuum photodiodes (VPDs) for x-ray detection in plasma focus device has been carried out. Various parameters of VPD such as electrode's diameter, electrode's separation, and its sensitivity are experimentally tested in plasma focus environment. For the first time it is found experimentally that the electrode-separation in the lateral direction of the two coaxial electrodes of cylindrical VPD also plays an important role to increase the efficiency of the detector. The efficiency is found to be highest for the detector with smaller cathode-anode lateral gap (1.5 mm) with smaller photo cathode diameter (10 mm). A comparison between our VPD with PIN (BPX-65) diode as an x-ray detector has also been made.