Abstract: The present invention relates to a process for the production of an aromatic polycarbonate by a polycondensation reaction or a solid phase polymerization reaction under a flow of an inert gas, wherein an alcohol or a phenol, which is produced as a by-product, is separated from the inert gas using a scrubber. In accordance with the present invention, since the by-product can be separated efficiently, an aromatic polycarbonate can be produced under a flow of an inert gas by an efficient and simplified process.

Abstract: A method for crystallizing a low molecular weight aromatic polycarbonate effectively and a method for preparing a polycarbonate resin having a desired intrinsic viscosity by using the polycarbonate crystallized with the above method of crystallization. A low molecular weight aromatic polycarbonate (preferably, the one produced by melt polycondensation) is crystallized by bringing it into contact with an aromatic monohydroxy compound or a mixture of said compound and water. Or, a low molecular weight aromatic polycarbonate is melt mixed with at least one or more kinds of compounds selected from the group consisting of aromatic monohydroxy compounds, carbonic acid diester compounds and aromatic dihydroxy compounds to crystallize the low molecular weight aromatic polycarbonate. The crystallized product is heated at a temperature lower than its melting point under reduced pressure or in an inert gas flow to convert it into a high polymerized state.

Abstract: A process for producing a hydrogenation product of a ring-containing unsaturated hydrocarbon polymer, which product is low in the content of the heterogeneous catalyst used.