A process for producing superabsorbents, comprising the steps of i) classifying the superabsorbent particles by means of one or more sieves and ii) removing metallic impurities by means of one or more magnetic separators, wherein classification is accomplished using sieves made of a wire mesh, the wires of the wire mesh consist of a steel composed of at least 70% by weight of iron, at least 10% by weight of chromium and less than 2.5% by weight of nickel, and the throughput of superabsorbent particles in the magnetic separator is in the range from 2.0 to 6.5 g/s per cm.sup.2 of free cross-sectional area.

Provided is a method for producing a polymer for an electronic material having a low content of metal ion impurities and a polymer for an electronic material obtained by such method. The method for producing a polymer for an electronic material according to the present invention comprises a polymerization step of obtaining a polymer by polymerizing a monomer(s) and a purification step of adding a strong acid having 0 or less pKa to the polymer solution and subsequently performing an ion exchange treatment to reduce the concentration of the metal ion impurities.

Provided is a method for producing a polymer for an electronic material having a low content of metal ion impurities and a polymer for an electronic material obtained by such method. The method for producing a polymer for an electronic material according to the present invention comprises a polymerization step of obtaining a polymer by polymerizing a monomer(s) and a purification step of adding a strong acid having 0 or less pKa to the polymer solution and subsequently performing an ion exchange treatment to reduce the concentration of the metal ion impurities.

A polyvinyl alcohol is produced in a method comprising: a polymerization step comprising polymerizing vinyl ester monomers by controlled radical polymerization in the presence of a radical initiator and an organic cobalt complex to obtain a polymer solution containing a polyvinyl ester; an extraction step comprising extracting a cobalt complex from the polymer solution by contacting an aqueous solution containing a water-soluble ligand with the polymer solution; and a saponification step comprising saponifying the polyvinyl ester after the extraction step to obtain a polyvinyl alcohol. A method for producing a polyvinyl alcohol is thus provided that has a narrow molecular weight distribution and a high number-average molecular weight with good hue and further good solubility in water.

A polyvinyl alcohol is produced in a method comprising: a polymerization step comprising polymerizing vinyl ester monomers by controlled radical polymerization in the presence of a radical initiator and an organic cobalt complex to obtain a polymer solution containing a polyvinyl ester; an extraction step comprising extracting a cobalt complex from the polymer solution by contacting an aqueous solution containing a water-soluble ligand with the polymer solution; and a saponification step comprising saponifying the polyvinyl ester after the extraction step to obtain a polyvinyl alcohol. A method for producing a polyvinyl alcohol is thus provided that has a narrow molecular weight distribution and a high number-average molecular weight with good hue and further good solubility in water.

Provided herein are methods and systems for at least partially deactivating at least one component of a reactor effluent from gas phase polyolefin polymerization processes utilizing at least one glycol.

Provided herein are methods and systems for at least partially deactivating at least one component of a reactor effluent from gas phase polyolefin polymerization processes utilizing at least one glycol.

Provided herein are methods and systems for at least partially deactivating at least one component of a reactor effluent from gas phase polyolefin polymerization processes utilizing at least one glycol.

The present invention provides an organometal catalyst having a cationic transition metal complex and a borate-based bulky anion, a method for preparing the same, and a method for preparing an oligomer using the same.

The present invention provides an organometal catalyst having a cationic transition metal complex and a borate-based bulky anion, a method for preparing the same, and a method for preparing an oligomer using the same.