Abstract: The object of the present invention is to provide a high quality polyester resin having high productivity, stability and safety, a catalyst for polyester production with high catalytic activity, a method for producing the polyester resin with the catalyst, a polyester resin obtained with the catalyst, and a hollow molded container having the polyester resin. The polyester resin of the present invention satisfies specific parameters regarding polymerizability, stability, and metal content. The catalyst for polyester production satisfies specific parameters. The catalyst particularly preferably has: (a) a solid titanium-containing compound which has a maximum solubility in ethylene glycol of 1,000 ppm or more in terms of converted titanium amount when dissolved in ethylene glycol with heating at 150° C.

Abstract: The object of the present invention is to provide a high quality polyester resin having high productivity, stability and safety, a catalyst for polyester production with high catalytic activity, a method for producing the polyester resin with the catalyst, a polyester resin obtained with the catalyst, and a hollow molded container comprising the polyester resin. The polyester resin of the present invention satisfies specific parameters regarding polymerizability, stability, and metal content. The catalyst for polyester production satisfies specific parameters. The catalyst particularly preferably comprises: (a) a solid titanium-containing compound which has a maximum solubility in ethylene glycol of 1,000 ppm or more in terms of converted titanium amount when dissolved in ethylene glycol with heating at 150° C.

Abstract: By the present invention, there are provided a catalyst for polyester preparation, which comprises a solid titanium compound containing titanium, oxygen, carbon and hydrogen and having a Ti—O bond and which has a maximum solubility in ethylene glycol, as measured when the catalyst is dissolved in ethylene glycol under heating at 150° C., of not less than 3,000 ppm in terms of a titanium atom, a catalyst for polyester preparation, which comprises a titanium-containing solution wherein a contact product of a hydrolyzate of a titanium halide or a hydrolyzate of a titanium alkoxide with a polyhydric alcohol is dissolved in ethylene glycol in an amount of 3,000 to 100,000 ppm in terms of a titanium atom, a process for preparing a polyester using the catalyst, and a polyester prepared by the process.

Abstract: By the present invention, there are provided a catalyst for polyester preparation, which comprises a solid titanium compound containing titanium, oxygen, carbon and hydrogen and having a Ti—O bond and which has a maximum solubility in ethylene glycol, as measured when the catalyst is dissolved in ethylene glycol under heating at 150° C., of not less than 3,000 ppm in terms of a titanium atom, a catalyst for polyester preparation, which comprises a titanium-containing solution wherein a contact product of a hydrolyzate of a titanium halide or a hydrolyzate of a titanium alkoxide with a polyhydric alcohol is dissolved in ethylene glycol in an amount of 3,000 to 100,000 ppm in terms of a titanium atom, a process for preparing a polyester using the catalyst, and a polyester prepared by the process.

Abstract: The present invention provides a catalyst or polyester production capable of producing a polyester with high catalytic activity and a process For producing a polyester using the catalyst. The catalyst for polyester production comprises a solid titanium compound which is obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. The present invention also provides a method to obtain a polyester having a small increase of the acetaldehyde content during the molding. This method comprises bringing a polyester, which is obtained by the use of a titanium compound catalyst and in which the reaction has been completed, into contact with a phosphoric ester aqueous solution or the like having a concentration of not less than 10 ppm in terms of phosphorus atom.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity and a process for producing a polyester using the catalyst. The catalyst for polyester production comprises a solid titanium compound which is obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. The present invention also provides a method to obtain a polyester having a small increase of the acetaldehyde content during the molding. This method comprises bringing a polyester, which is obtained by the use of a titanium compound catalyst and in which the reaction has been completed, into contact with a phosphoric ester aqueous solution or the like having a concentration of not less than 10 ppm in terms of phosphorus atom.

Abstract: An activated carbon oxidized by air or oxygen at near ambient temperatures having a contact pH between 7.6 and 8.5 for use in water treatment systems to prevent pH excursions during operation of the system.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.