초록 ▼

An improvement to the interfacial boundary process for producing carbonic acid diaryl esters is disclosed. In the two-stage process that entails phosgene and monophenols reaction in an inert solvent, in the presence of alkali and in the presence of a nitrogen base catalyst, the improvement comprisin

An improvement to the interfacial boundary process for producing carbonic acid diaryl esters is disclosed. In the two-stage process that entails phosgene and monophenols reaction in an inert solvent, in the presence of alkali and in the presence of a nitrogen base catalyst, the improvement comprising maintaining a temperature below 50° C. in the first and second stages.

대표청구항 ▼

1. In the interfacial boundary process for producing carbonic acid diaryl esters from phosgene and monophenols in an inert organic solvent, in the presence of an alkaline solution and a nitrogen base catalyst, the process including: (i) a first stage wherein phosgene, said inert organic solvent a

1. In the interfacial boundary process for producing carbonic acid diaryl esters from phosgene and monophenols in an inert organic solvent, in the presence of an alkaline solution and a nitrogen base catalyst, the process including: (i) a first stage wherein phosgene, said inert organic solvent and phenol in solution are combined to form a material system having a pH of 11.0 to 12.0; and (ii) a second stage wherein the reaction to form carbonic acid diaryt ester is completed, the improvement comprising maintaining a temperature below 50° C. in each of said first and second stages, and wherein the carbonic acid diaryl esters have a urethane content of less than 100 ppm. 2. The process of claim 1 wherein the temperature in each of said first and second stages is below 40° C. 3. The process of claim 1 wherein the temperature in each of said first and second stages is below 35° C. 4. The process according to claim 1 further comprising converting the carbonic acid diaryl ester to a polycarbonate through a transesterification reaction. 5. The process of claim 1 wherein said nitrogen base is ethylpiperidine. 6. The process of claim 1 wherein said inert organic solvent is selected from dichloromethane, toluene, chlorobenzene and chlorotoluene.