Effects of primary C1–C6 linear alcohol addition and sonochemically decomposed products on multi-bubble sonoluminescence

Multi-bubble sonoluminescence (MBSL) was measured in Ar-saturated water containing 2 mmol dm −3 of a series of alcohols under sonication at a frequency of 410 kHz. The sonoluminescence intensity was weakened in the presence of the alcohols. The effect was emphasized further when an alcohol with a longer alkyl chain was added. The spectral and temporal changes are presumed to be attributable to gaseous products generated by sonochemical decomposition of alcohols. Gas generation, originating from alcohol decomposition, was observed even in the short 2 min sonication. When compared with the case of ethanol addition, larger amounts of gaseous products were generated when long chain 1-hexanol was added. The increase in gaseous product yield indicates that the alcohol decomposition proceeds with the progress of the sonication. The present study evaluated the dependency of MBSL on the hydrophobicity of added alcohol and characteristics of the decomposed gas products, such as solubility to water and specific heat ratio.