Thermal decomposition sonolysis

Some of the reports are as follows. Mizukoshi et al. [31] reported ultrasound assisted reduction processes of Pt(IV) ions in the presence of anionic, cationic and non-ionic surfactant. They found that radicals formed from the reaction of the surfactants with primary radicals sonolysis of water and direct thermal decomposition of surfactants during collapsing of cavities contribute to reduction of metal ions. Fujimoto et al. [32] reported metal and alloy nanoparticles of Au, Pd and ft, and Mn02 prepared by reduction method in presence of surfactant and sonication environment. They found that surfactant shows stabilization of metal particles and has impact on narrow particle size distribution during sonication process. Abbas et al. [33] carried out the effects of different operational parameters in sodium chloride sonocrystallisation, namely temperature, ultrasonic power and concentration sodium. They found that the sonocrystallization is effective method for preparation of small NaCl crystals for pharmaceutical aerosol preparation. The crystal growth then occurs in supersaturated solution. Mersmann et al. (2001) [21] and Guo et al. [34] reported that the relative supersaturation in reactive crystallization is decisive for the crystal size and depends on the following factors. 

These results provide further evidence that an important pathway for S(-II) sonolysis at pH < 8.5 is thermal decomposition of H2S within the... 

In conclusion, the sonolysis of S(-II) in the pH range where that species is primarily in the form of HS" and is not expected to undergo thermal decomposition can be modeled with an aqueous free-radical chemical mecha-... 

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

The sonolysis of pure water produced a linear increase of [H+] as a function of time with an apparent zero-order rate constant of 8.3 x 10-9 (M/min). On the other hand, in sonicated PNP solutions the increase of [H+] appeared to be first order with apparent first-order rate constant of = 3 x 104/s. PNP decayed exponentially with time at all pH values. The apparent first-order rate constant decreased from = 3.67 x l(T4/s at pH, = 5 to k = 2.0 x 104/ s at pH = 8. At pH > 10, the apparent first-order rate constant increased slightly because of the slow thermal reaction between PNP and the products of the base-catalyzed decomposition of H202. Sonication of air-saturated solutions not exposed to air produces the same results as those obtained with air-equilibrated solutions. 

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