US Patent 7601794 Monomer solution for producing polycarbonate

A non-reactive monomer mixture is formed from a dihydroxy component having one or more dihydroxy compounds dissolved in a melted diaryl carbonate. The dihydroxy component has less than 600 ppb alkali metal, an acid stabilizer, or both less than 600 ppb alkali metal and an acid stabilizer. The dihydroxy compounds of the dihydroxy component and the diaryl carbonate are present in a mole ratio of from 0.9 to 1.1. The monomer mixture is at a temperature between the saturation point of the monomer mixture and the highest melting temperature of the individual dihydroxy compounds. The non-reactive monomer mixture can be stored and transported and then polymerized to form polycarbonate upon addition of a catalyst.