Effect of pressure on proton jumps in methanol at 250C

Conductivities of HCl and KCl in methanol containing traces (0.12 to 0.40 mol %) of water have been measured in the concentration range of asymptotically equals 0.4 to asymptotically equals 5 mmol dm-3 at 250C up to 2000 kg cm-2. The limiting equivalent conductance ( lambda 0) for HCl and KCl decreased with increasing pressure. The excess proton conductance due to the proton-jump mechanism has been measured by lambda 0(HCl) - lambda 0(KCl) and found to increase with increasing pressure in nearly and absolutely pure methanol. The acceleration of proton jumps by pressure indicates that the rotation of methanol molecules about the longer molecular axis becomes faster at higher pressure. This anomaly is attributed to distortion with pressure of hydrogen bonds in methanol and to an increase in the repulsive field exerted by the proton on the molecule to rotate. (author)