Abstract: Disclosed is a method for continuously producing a dialkyl carbonate and a diol, comprising: (1) feeding a cyclic carbonate and an aliphatic monohydric alcohol to a continuous multi-stage distillation column, and effecting a transesterification in the presence of a catalyst in the multi-stage distillation column and/or at least one transesterification reactor which communicates fluid-tightly with the distillation column, while continuously withdrawing a low boiling point gaseous mixture containing the produced dialkyl carbonate from a upper portion of the distillation column and a high boiling point liquid mixture from a lower portion of the distillation column; and (2) continuously feeding water and the high boiling point mixture to a hydrolysis reactor, to thereby effect a continuous hydrolysis of the unreacted cyclic carbonate contained therein and produce a diol and carbon dioxide.

Abstract: Disclosed is a method for producing an aromatic polycarbonate which comprises subjecting to a transesterification reaction in a polymerizer at least one polymerizable material selected from a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, and a molten prepolymer obtained from the monomer mixture, wherein a liquid mass of polymerizable material being transesterified in the polymerizer has an exposed surface, and wherein the transesterification reaction of the liquid mass of polymerizable material is performed under reaction conditions such that the following formula (1) is satisfied:log (S/V).gtoreq.2.times.10.sup.-5 .times.Mn+0.8 (1)wherein S represents an evaporation surface area (m.sup.2) which is defined as the area (m.sup.2) of the exposed surface of the liquid mass of polymerizable material; V represents the volume (m.sup.

Abstract: Disclosed is a method for producing an aromatic polycarbonate, which comprises: reacting a feedstock dialkyl carbonate with a feedstock phenol in the presence of a catalyst to produce diphenyl carbonate, wherein a phenol mixture comprising component phenols which are different in supply source is used as the feedstock phenol, and polymerizing the produced diphenyl carbonate with an aromatic dihydroxy compound to produce an aromatic polycarbonate while producing phenol as a by-product, wherein the by-product phenol obtained in the production of the aromatic polycarbonate is used as a component phenol of the feedstock phenol mixture for producing diphenyl carbonate, and wherein the content of the by-product phenol in the feedstock phenol mixture is controlled to a level in the range of from 70 to 99% by weight. According to the method of the present invention, an aromatic polycarbonate having excellent melt stability at high temperatures can be stably produced.

Abstract: A porous, crystallized, aromatic polycarbonate prepolymer is disclosed, which comprises recurring aromatic carbonate units and terminal hydroxyl and aryl carbonate groups, wherein these terminal groups are in a specific molar ratio and has specific number average molecular weight, surface area and crystallinity. The prepolymer can readily be converted by solid-state condensation polymerization to a porous, crystallized, aromatic polycarbonate having excellent properties. The porous, crystallized, aromatic polycarbonate of the present invention can readily be molded to obtain a shaped, porous, crystallized polycarbonate. The porous, crystallized, aromatic polycarbonate and the shaped, porous, crystallized polycarbonate of the present invention have excellent heat resistance and solvent resistance and exhibit advantageously low water absorption so that these are suited for use as a filter material, an adsorbent or the like.

Abstract: Disclosed is a process for producing an aromatic carbonate or aromatic carbonate mixture by a transesterification reaction between a starting material selected from a dialkyl carbonate, an alkyl aryl carbonate and a mixture thereof and a reactant selected from an aromatic hydroxy compound, an alkyl aryl carbonate and a mixture thereof, wherein the starting material and the reactant are continuously fed to a continuous multi-stage distillation column to effect a transesterification reaction therebetween in the presence of a catalyst in the distillation column, while continuously withdrawing the produced aromatic carbonate or aromatic carbonate mixture as a high boiling point product in a liquid form from a lower portion of the distillation column and continuously withdrawing the by-product as a low boiling point product in a gaseous form from an upper portion of the distillation column by distillation, thereby enabling the aromatic carbonate or aromatic carbonate mixture to be produced continuously.

Abstract: A porous, crystallized, aromatic polycarbonate prepolymer is disclosed, which comprises recurring aromatic carbonate units and terminal hydroxyl and aryl carbonate groups, wherein these terminal groups are in a specific molar ratio, and has specific number average molecular weight, surface area and crystallinity. The prepolymer can readily be converted by solid-state condensation polymerization to a porous, crystallized, aromatic polycarbonate having excellent properties. The porous, crystallized, aromatic polycarbonate of the present invention can readily be molded to obtain a shaped, porous, crystallized polycarbonate. The porous, crystallized, aromatic polycarbonate and the shaped, porous, crystallized polycarbonate of the present invention have excellent heat resistance and solvent resistance and exhibit advantageously low water absorption so that these are suited for use as a filter material, an adsorbent or the like.

Abstract: A process for producing a diaryl carbonate in high yield and with high selectivity which comprises disproportionating an alkylaryl carbonate in the presence of a lead catalyst to produce a diaryl carbonate and a dialkyl carbonate and recovering the diaryl carbonate from the reaction products. Use of the lead catalyst is effective in avoiding corrosion problems normally caused by other catalyst systems.

Abstract: A crystallized aromatic polycarbonate having a weight average molecular weight of from 6,000 to 200,000 and having a terminal hydroxyl group content of not greater than 0.03% by weight based on the weight of the polycarbonate is effectively produced by first heating a mixture of a dihydroxydiaryl compound comprising at least 85 mole % of a dihydroxydiaryl alkane with a diaryl carbonate to prepare a prepolymer having a weight average molecular weight of from 2,000 to 20,000 and having terminal aryl carbonate groups in an amount of greater than 50 mole %, based on the total number of moles of all the terminal groups of the prepolymer, secondly crystallizing the prepolymer and finally subjecting the crystallized prepolymer to solid-state polymerization. The crystallized aromatic polycarbonate does not contain impurities, is colorless and has excellent properties such as resistance to heat and to boiling water. Therefore, the polycarbonate is advantageously used as engineering plastics.

Abstract: A method for producing aliphatic O-arylurethanes by the reaction of an aliphatic primary amine with an aromatic hydroxyl compound and urea. Ammonia produced as a by-product in the reaction is removed during the reaction so that the ammonia concentration of the reaction solution is maintained at 2 wt % or less.

Abstract: An aromatic polyether ketone comprising 5 to 100 mole % of units having the formula: ##STR1## and 0 to 95 mole % of units having the formula: ##STR2## and having a reduced viscosity of about 0.1 to about 4.0 (30.degree. C.), is novel and excellent in the properties such as heat resistance, chemical resistance and relatively easily melt processable. When at least one terminal group of the polymer is capped with an inert aromatic group, the properties are further improved.

Abstract: A process for producing a urethane compound which comprises reacting at least one compound selected from the group consisting of a primary amine, a secondary amine and a urea compound with carbon monoxide and an organic hydroxyl compound in the presence of a catalyst system comprising:(a) at least one member selected from the group consisting of platinum group metals and compounds containing at least one platinum group element; and(b) at least one halogen-containing compound selected from the group consisting of alkali or alkaline earth metal halides, onium halides, compounds capable of forming onium halides in the reaction, oxo acids of halogen atoms and their salts, complex compounds containing halogen ions, organic halides and halogen molecules,in the presence of molecular oxygen and/or an organic nitro compound as an oxidizing agent at a temperature of from about 80.degree. C. to about 300.degree. C. under a pressure of from about 1 Kg/cm.sup.2 to about 500 Kg/cm.sup.2.

Abstract: A process for producing an aliphatic isocyanate from an aliphatic primary amine comprising a carbonylation step in which an aliphatic primary amine is allowed to react with carbon monoxide at a temperature of about 100.degree.-250.degree. C. in the presence of an aromatic hydroxyl compound having a pKa value of not more than about 11, molecular oxygen and a catalyst system comprising at least one member selected from palladium and rhodium metals and components thereof and at least one member selected from iodine and bromine and compounds thereof and a combined separation and recovery step comprising a pyrolysis-distillation reaction in which the mixture of carbonylated products is heated to a temperature of from about 100.degree. to 300.degree. C.

Abstract: A process for producing a diphenylmethane dicarbamate by reacting an N-phenylcarbamate with a methylenating agent is disclosed. The process is carried out by condensing N-phenylcarbamate in two steps using a combination of two different types of acid catalysts. The catalysts exhibit a strong catalyzing effect and yet can be readily separated from the reaction mixture. The process produces dineuclear diphenylmethane dicarbamates in high selectivity. The acid catalysts can be easily recovered from the reaction mixtures and put to another use.

Abstract: Manufacture of a diphenylmethane diisocyanate for an N-phenylcarbamate is economically accomplished in high yield with high selectivity by a method which comprises (A) a process of methylenation for the formation of a condensation product containing at lest 80 mol % of a dinuclear diphenylmethane dicarbamate by the steps of (1) causing a methylenating agent to react upon at least 2 moles of an N-phenylcarbamate, based on 1 mole of the methylene group of said methylenating agent, in a liquid phase in the presence of an aqueous inorganic acid solution, (2) separating the resultant reaction mixture into the aqueous inorganic acid solution and an organic phase reaction mixture containing substantially none of said inorganic acid, and (3) subsequently treating said organic phase reaction mixture in the presence of an N-phenylcarbamate and a carboxylic acid having a pKa of not more than 4 in an aqueous solution at a temperature of 25.degree. C.