The effect of frequency on sonochemical reactions III: dissociation of carbon disulfide.
Investigations were made of the effects of frequency, temperature, intensity and gases on the rate of sonochemical dissociation of carbon disulfide. Application of 900 kHz ultrasound did not produce any noticeable change. When carbon disulfide was irradiated with 20 kHz, the liquid formed a heterogeneous mixture of black particles in a yellow solution. The rate of dissociation decreased with increasing temperature, in agreement with most sonochemical reactions. The rate also decreased with decreasing area of the horn tip, keeping total power constant. This dependence on the horn tip area, as well as that on the frequency, is in opposition to the dependence for the formation of iodine from the sonication of aqueous potassium iodide solution [See Part II, Ultrasonics Sonochemistry 3 (1996) 19]. The X-ray spectrum of the black particles and the yellow residue obtained after evaporation showed the presence of amorphous carbon and monoclinic sulfur. The rate of sono-dissociation of carbon disulfide in the presence of different gases is in the order He > H2 > Air > Ar > O2 > CO2.
Ottawa-Carleton Chemistry Institute, Department of Chemistry, Carleton University, Ontario, Canada.
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