Raising of negative pressure to around -200 bar for some organic liquids in a metal Berthelot tube

Trends in negative pressure achieved over a few thousand cavitation events were observed for ethanol, benzene and xylene in a stainless steel Berthelot tube sealed with a pre-de-gassed Ni plug. When the system was repeatedly heated and then cooled alternately over a temperature range between 60 degrees C and 10 degrees C (temperature cycle), negative pressure increased steeply for earlier cycles and levelled off eventually as in a water-metal tube system. Owing to the cavitation history effect, negative pressures of around -200 bar, the highest ever attained for organic liquids in the Berthelot method, were generated at around 15 degrees C in a useful volume ( approximately 1 cm 3 ). It has become feasible to measure thermodynamic properties of organic liquids under negative pressure, since the pressures were up to half of the homogeneous nucleation limits of cavitation.