Abstract: An aromatic polycarbonate and an active-hydrogen compound are subjected to the transesterification reaction in the presence of a transesterification catalyst under a reduced pressure condition followed by reaction with a salicylic acid ester derivative expressed by the following chemical formula (1), {wherein X is methyl or ethyl, and Y is a carbonyl group or a divalent functional group expressed by the following formula (2), (where Z is an alkylene group having a carbon number of 1 to 30, an arylene group having a carbon number of 6 to 30 or an aralkylene group having a carbon number of 7 to 30)}. An aromatic polycarbonate having a high molecular weight can be produced by this process.

Abstract: A polycarbonate composition contains 100 parts by weight of a linear aromatic polycarbonate and 0.001 to 100 parts by weight of a cyclic aromatic carbonate. The cyclic aromatic carbonate is useful as a flowability-improving agent and a shape-transferability-improving agent for the linear aromatic polycarbonate.

Abstract: A polycarbonate copolymer which consists essentially of 5 to 95 mol % of recurring units containing a specific spiroglycol unit and 95 to 5 mol % of recurring units containing a specific biphenol unit, and has a reduced viscosity (.eta..sub.sp /c), measured at 20.degree. C. in a solution containing methylene chloride as a solvent and having a concentration of 0.5 g/dl, of at least 0.3 dl/g, a photoelasticity coefficient of 70.times.10.sup.-13 cm.sup.2 /dyne or less, and a glass transition temperature of at least 95.degree. C.; and a process for the production thereof. This polycarbonate copolymer is useful as a material for an information transmission medium or an information recording medium.

Abstract: A process for the production of a terminal-blocked aromatic polycarbonate by melt-polycondensing an aromatic dihydroxy compound and diphenylcarbonate, the process comprising adding a specific carbonate or carboxylic ester after a polycarbonate formed has an intrinsic viscosity of at least 0.3 dl/g, to form a terminal-blocked polycarbonate having an intrinsic viscosity which is greater than, or smaller than, the intrinsic viscosity of the polycarbonate formed before the addition by 0.1 dl/g at the most; and a process for the production of a polycarbonate having an increased intrinsic viscosity by melt-polycondensing an aromatic dihydroxy compound and diphenylcarbonate, the process comprising adding a specific diaryl carbonate or dicarboxylic diaryl ester after a polycarbonate formed has an intrinsic viscosity of at least 0.3 dl/g, to form a polycarbonate having an intrinsic viscosity greater than the intrinsic viscosity of the polycarbonate formed before the addition by more than 0.1 dl/g.

Abstract: A process for the production of a stabilized polycarbonate which comprises melt-polycondensing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a polycondensation catalyst and then, after the reaction mixture shows an intrinsic viscosity of at least 0.1, adding at least one stabilizer selected from the group consisting of specific compounds having a sulfonates group sulfonic acid anhydride group or a sulfate group in an amount of 0.01 to 500 ppm of a polycarbonate to be formed, to form a polycarbonate having a desired intrinsic viscosity.

Abstract: A process for the production of an aromatic polycarbonate, which comprises polycondensing an aromatic dihydroxy compound and a diaryl carbonate in the presence, as a polycondensation catalyst, of at least one alkali metal salt selected from the group consisting of alkali metal salts of ate-complexes of a metal element, which is silicon, germanium, stannum or plumbum, and alkali metal salts of oxoacids of said metal elements. The above aromatic polycarbonate is almost free from being colored, is also almost free from a decrease in polymerization degree when molded, and is further almost free from forming branches and insolubles.

Abstract: A process for the production of a stabilized polycarbonate which comprises melt-polycondensing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a polycondensation catalyst and then, after the reaction mixture shows an intrinsic viscosity of at least 0.1, adding at least one stabilizer selected from the group consisting of specific compounds having a sulfanate group and a sulfonic acid anhydride group in an amount of 0.01 to 500 ppm of a polycarbonate to be formed, to form a polycarbonate having a desired intrinsic viscosity.

Abstract: A process for the production of a stabilized polycarbonate which comprises melt-polycondensing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a polycondensation catalyst and then, after the reaction mixture shows an intrinsic viscosity of at least 0.1, adding at least one stabilizer selected from the group consisting of specific compounds having either a sulfonate group, a sulfonic acid anhydride group or a sulfate group in an amount of 0.01 to 500 ppm of a polycarbonate to be formed, to form a polycarbonate having a desired intrinsic viscosity.

Abstract: A fiber- or film-forming wholly aromatic polyester having melt anisotropy, said polyester consisting essentially of(1) units (a) derived from an aromatic dicarboxylic acid at least 90 mole % of which consists of a p-oriented aromatic dicarboxylic acid and units (b) derived from an aromatic dihydroxy compound at least about 90 mole % of which consists of a mono-substituted hydroquinone ring-substituted by an alkyl group having at least 5 carbon atoms or an aralkyl group having at least 7 carbon atoms or a mixture of said mono-substituted hydroquinone and unsubstituted hydroquinone or a substituted hydroquinone other than said mono-substituted hydroquinone, the proportion of said mono-substituted hydroquinone being at least 80 mole %; or(2) said units (a) and (b), and units (c) derived from a p-oriented aromatic hydroxycarboxylic acid at least about 70 mole % of which consists of p-hydroxybenzoic acid and/or a mono-substituted p-hydroxybenzoic acid, the proportion of the units derived from the p-oriented aromat

Abstract: Hollow water-absorbing polyester filaments, each having fine pores evenly distributed throughout the filament and extending approximately in parallel to the filament axis, are produced by melt-spinning a blend of a polyester and a pore-forming agent consisting of at least one sulfonate compound of the formula:R'SO.sub.3 M'wherein R' is an alkyl radical having 3 to 30 carbon atoms or an aryl or alkylaryl radical having 7 to 40 carbon atoms and M' is an alkali or alkaline earth metal, and by removing at least a portion of the sulfonate compound from the hollow filaments by using an alkali aqueous solution so as to cause a number of fine pores to be formed in the hollow filaments and to cause each hollow to be connected to the outside of the filament through the fine pores.

Abstract: A process for preparing diesters of carboxylic acids by oxidative carbonylation of C.sub.2 -C.sub.20 olefins, C.sub.1 -C.sub.20 monohydric aliphatic alcohols and carbon monoxide in an atmosphere containing molecular oxygen at a temperature of from room temperature to about 350.degree. C. in the presence of a carrier-supported catalyst containing a platinum group metal, wherein said catalyst comprises, supported on a carrier, a post-reduced compound of a platinum group metal and a post-reduced compound of a metal having an atomic number of not less than 22 selected from the group consisting of metals of Groups Ib, IIb, III, IV, V, VI and VIIb of the periodic table.