Ultrasonic behaviour of the system water + acetonitrile

Abstract

The effect of acetonitrile on the temperature of the adiabatic compressibility minimum (t.a.c.m.) and temperature of the sound velocity maximum (t.s.v.m.) of water has been studied. The structural contribution to the shift in t.a.c.m. and t.s.v.m., (ΔT_β,str.)_exp. and (ΔT_{u, str.})_exp., has been found to be positive at low concentrations, becoming maximum around X₂≃0.018 and thereafter decreasing to become negative around X₂≃0.045. This behaviour is explained in terms of the effects of added acetonitrile on the structure of water.