RESUMO
The sulfide oxygenation activities of both heptamolybdate ([Mo7O24]6-, [1]6-) and its peroxo adduct [Mo7O22(O2)2]6- ([2]6-) were examined in this contribution. [Mo7O22(O2)2]6- was prepared in a yield of 65% from (NH4)6[Mo7O24] (1a) upon treatment of 10 equiv. of H2O2 and structurally identified through single crystal X-ray diffraction study. (nBu4N)6[Mo7O22(O2)2] (2b) is an efficient catalyst for the sequential oxygenation of methyl phenyl sulfide (MPS) by H2O2 to the corresponding sulfoxide and subsequently sulfone with a 100% utility of H2O2. Surprisingly, (nBu4N)6[Mo7O24] (1b) is a significantly faster catalyst than 2b for MPS oxygenation under identical conditions. The pseudo-first order kcat constants from initial rate kinetics are 54 M-1 s-1 and 19 M-1 s-1 for 1b and 2b, respectively. Electrospray ionization mass spectrometry (ESI-MS) investigation of 1b under the catalytic reaction conditions revealed that [Mo2O11]2- is likely the main active species in sulfide oxygenation by H2O2.
RESUMO
The development and prove-out of yellow-light-emitting pyrotechnic illuminants based on recover, recycle, and reuse (R3 ) technology is described. Magnesium used in this investigation was recovered from four different illuminating pyrotechnic munitions by means of an environmentally friendly demilitarization process. Despite significant differences in the particle size and purity between the four lots of recovered magnesium, the performance of each lot-on evaluation in the M127A1 US Army yellow-light-emitting illuminant configuration-exceeded the military requirement and performance of the virgin magnesium-containing control. All formulations were found to have low sensitivities to various ignition stimuli and possessed high thermal onset temperatures. In addition to the military significance, this demonstrated "green" pyrotechnics technology of using recycled magnesium in illuminating pyrotechnics may also be of interest to the civilian fireworks community.
