The methanol-trimethoxyborane azeotrope is an ea.sily prepa.
red solvent of strong H-bond donor and weak H-bond acceptor
properties. It has a low viscosity and low boiling point, and is
completely transparent in the visible and uv at wave lengths above
220 nm. It has a dieLectric constant of 9 and ion pair formation
constants between 103 and 104 for simple electrolytes. The glass
electrode pH-meter can be used in this solvent, with the ordinary
calomel reference electrode. Indicator acidity measurements are
somewhat complicated by the forma•tion of H-bonded ion pairs.
The solvent is useful for measuning the relative acidity of
strong acids; CH3S020H and CF3S020H are readily differentiated.
It should be useful for other physico-chemical measurements and
also in preparative chemistry