Polycarbonate polyols are made by copolymerizing carbon dioxide and an alkylene oxide in the presence of a starter compound and a carbonate catalyst. The process is operated in semi-batch mode by combining starter, catalyst and a small amount of alkylene oxide in a reaction vessel, pressurizing the vessel with carbon dioxide, initiating polymerization, and then feeding both carbon dioxide and alkylene oxide to the vessel under polymerization conditions without removal of product until the feeds are completed.

A method for preparing a polycarbonate ester includes feeding a monomer mixture containing (i) at least one compound selected from the group consisting of compounds of the following Formulae 1 and 3; (ii) a compound of the following Formula 2; and (iii) a 1,4:3,6-dianhydrohexitol to a polycondensation reactor and allowing the monomers and the 1,4:3,6-dianhydrohexitol to react to prepare the polycarbontate ester. The prepared polycarbonate ester has improved mechanical properties including tensile strength and impact strength: ##STR00001##

The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relates to an apparatus and a process for preparing these polycarbonates with the aid of a devolatilizing extruder with at least three devolatilizing zones, and zones for introducing entraining agent into dispersion are present upstream of at least three devolatilizing zones.

The present invention is to provide a process for producing a high molecular-weight aromatic polycarbonate resin, the process includes mixing a dialcohol compound represented by the following Formula (1) with a first catalyst to obtain a catalyst composition; mixing the obtained catalyst composition with an aromatic polycarbonate prepolymer to obtain a prepolymer mixture; and obtaining a high molecular-weight aromatic polycarbonate by subjecting the obtained prepolymer mixture to heating treatment under reduced pressure condition. In the Formula (1), R.sup.1 to R.sup.4 each independently represent a hydrogen atom, an alkyl group and the like. Q represents a divalent group or a single bond. ##STR00001##

A process for preparing polycarbonate by the phase interface process in the presence of at least one catalyst, wherein immediately after the optionally first addition of the at least one catalyst, from 0.01 to 20 J/kg of mixing energy is introduced into the system comprising the at least one catalyst within a time of from 2 to 1200 s. A mixture, an organic phase, and a process for distributing at least one catalyst in a system comprising an organic phase and an aqueous phase are also disclosed herein.

Techniques regarding the synthesis of one or more polymers through one or more ring-opening polymerizations conducted within a flow reactor and facilitated by one or more anionic catalysts are provided. For example, one or more embodiments can comprise a method, which can comprise polymerizing, via a ring-opening polymerization within a flow reactor, a cyclic monomer in the presence of one or more anionic organocatalysts.

The invention relates to a method for operating a production plant for producing a chemical product (1) by reacting a H-functional reactant (2) with phosgene (3) during an interruption in production when taking at least one plant part of the production plant out of operation, wherein low-oxygen and oxygen-rich phosgene-containing exhaust gas flows are directed separately from one another in different phosgene decomposition directions and separately from one another—at spatially different points—into a combustion device, wherein plant parts that have not been taken out of operation are operated in a closed-circuit operating mode. The invention also relates to a production plant for producing a chemical product by reacting H-functional reactants with phosgene, which is suitable for being operated with the method according to the invention.

A method of manufacturing a poly(ether-carbonate) polyol comprises a polymerization stage that includes polymerizing carbon dioxide and at least one alkylene oxide, with a starter, in the presence of a double metal cyanide polymerization catalyst and a catalyst promoter that is devoid of halide anions and cyanide. The catalyst promoter is separate from the double metal cyanide polymerization catalyst.

The present invention relates to an aromatic polycarbonate obtained via the melt transesterification of a diaryl carbonate, a bisphenol and an endcapping agent selected from paracumyl phenol, dicumyl phenol, p-tert-butyl phenol and mixtures of at least two of said endcapping agents, said polycarbonate having a melt volume rate of at least 20 cm.sup.3/10 min (ISO 1133, 300° C., 1.2 kg), a terminal hydroxyl group content of at most 800 ppm by weight, a Fries branching content of at most 1300 ppm by weight and a content of bulky end groups of at least 20 mol % defined as the sum of the mol % of end-groups based on said bisphenol and the mol % of end-groups based on said endcapping agent.

Techniques regarding the synthesis of one or more polymers through one or more ring-opening polymerizations conducted within a flow reactor and facilitated by one or more anionic catalysts are provided. For example, one or more embodiments can comprise a method, which can comprise polymerizing, via a ring-opening polymerization within a flow reactor, a cyclic monomer in the presence of one or more anionic organocatalysts.