Method and apparatus to make high molecular weight melt polycarbonate

A method for preparing polycarbonate comprising:

• (a) melting monomers comprising a dihydroxy aromatic compound and bis(methyl salicyl) carbonate and mixing with at least one transesterification catalyst to generate a pre-polymerization reaction mix;
• (b) treating the mix to generate a fine mist comprising droplets of the reaction mixture of predetermined droplet size;
• (c) exposing the mist to a high temperature environment at reduced pressure under conditions such that said monomers polymerize and at least a portion of at least one volatile reaction byproduct separates from said droplets;
• (d) removing at least a portion of the at least one volatile byproduct from the droplets;
• and
• (e) collecting polymerized polycarbonate product.

An apparatus for the generation of high molecular weight polycarbonate comprising:

• (a) a means to melt monomers comprising at least one ester-substituted diaryl carbonate and at least one dihydroxy aromatic compound and mix the monomers with at least one melt polymerization catalyst to generate a pre-polymerization reaction mix;
• (b) a device to generate a fine mist of predetermined droplet size from the pre-polymerization reaction mix;
• (c) a reaction vessel for exposing the mist to a high temperature environment under reduced pressure such that said monomers polymerize and at least a portion of at least one volatile reaction byproduct separates from said droplets;
• (d) a vent to remove at least a portion of said volatile byproducts from the droplets;
• and
• (e) a device to collect the polymerized polycarbonate product from the reaction vessel.