Abstract: Phosphoric acid triesters of the formula ##STR1## are produced in two or more stages by reacting phosphorus oxyhalides, phosphorus pentahalides, phosphoric acid monoester dihalides or phosphoric acid diester halides corresponding to the following general formula:ZO PO Hal.sub.2 (ZO).sub.2 PO Halwherein Z is defined as above and Hal represents Cl and/or Br with at least one hydroxyaryl compound of the formula ##STR2## in a two-phase mixture of an organic solvent an aqueous alkaline earth metal and/or alkali metal hydroxide solution.

Abstract: The present invention is concerned with a process for the production of high molecular weight thermoplastic ppolycarbonates having improved flame resistance and in conjunction with glass fibres, improved mechanical properties and the polycarbonates so produced. A solution polycarbonate is reacted with an alkali metal salt soluble in the melt of the polycarbonate until the Staudinger Index has increased by about 3 to 30 cm.sup.3 /g. This usually requires about 0.0001 to 0.1 wt. % of the salt, based on the weight of polycarbonate and a temperature of about 250.degree. to 400.degree. C for between about 1 and 30 minutes. In a preferred embodiment the reaction is conducted in a self-cleaning twin screw extruder.

Abstract: A process for the preparation of a symmetric diarylcarbonate by reacting phosgene with a phenol wherein said reactions is carried out by the phase interface process in a diphastic mixture of an aqueous alkali metal hydroxide solution and a liquid diaryl carbonate in the presence of from 0.001 to 0.1 mol of a tertiary amine or a quaternary ammonium compound per mol of phenol.