This disclosure describes polymerization processes and processes for quenching polymerization reactions using reactive particulates, such as amorphous silica, as quenching agents, typically in solution or bulk polymerization processes.

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.

The present invention relates to a polymerization process, comprising: a) supplying a feed containing ethylene and at least one alpha-olefin having 3 to 12 carbon atoms in a hydrocarbon solvent to a polymerization reactor, b) contacting the feed of step a) in the reactor with a catalyst to form a reaction mixture containing an ethylene-alpha-olefin co-polymer, c) withdrawing the reaction mixture from the polymerization reactor as a reactor outlet stream which comprises the ethylene-alpha-olefin co-polymer, unreacted monomer and comonomer, catalyst, and hydrocarbon solvent, d) heating the reactor outlet stream to a temperature which is at least 5° C. higher than the temperature of the reaction mixture at the outlet of the reactor for a time period of between 1 and 250 seconds in order to de-activate the polymerization catalyst, and e) separating hydrocarbon solvent, monomer and comonomer from the reactor outlet stream and recycling it back to the polymerization reactor without further purification steps.

The present invention relates to a polymerization process, comprising: a) supplying a feed containing ethylene and at least one alpha-olefin having 3 to 12 carbon atoms in a hydrocarbon solvent to a polymerization reactor, b) contacting the feed of step a) in the reactor with a catalyst to form a reaction mixture containing an ethylene-alpha-olefin co-polymer, c) withdrawing the reaction mixture from the polymerization reactor as a reactor outlet stream which comprises the ethylene-alpha-olefin co-polymer, unreacted monomer and comonomer, catalyst, and hydrocarbon solvent, d) heating the reactor outlet stream to a temperature which is at least 5° C. higher than the temperature of the reaction mixture at the outlet of the reactor for a time period of between 1 and 250 seconds in order to de-activate the polymerization catalyst, and e) separating hydrocarbon solvent, monomer and comonomer from the reactor outlet stream and recycling it back to the polymerization reactor without further purification steps.

Quaternary ammonium tribromides and quaternary phosphonium tribromides are recovered from an organic solvent by washing with an aqueous hydrazine solution. The hydrazine reacts to form nitrogen, hydrobromic acid and a quaternary ammonium or quaternary phosphonium monobromide. The hydrobromic acid and quaternary ammonium or quaternary phosphonium migrate to the aqueous phase, thereby effecting the removal of the tribromides from the organic solvent. The hydrobromic acid can be neutralized with a quaternary ammonium or quaternary phosphonium hydroxide to produce a quaternary ammonium or quaternary phosphonium monobromide. The monobromides produced can be reacted with elemental bromine to regenerate a tribromide brominating agent.

Quaternary ammonium tribromides and quaternary phosphonium tribromides are recovered from an organic solvent by washing with an aqueous hydrazine solution. The hydrazine reacts to form nitrogen, hydrobromic acid and a quaternary ammonium or quaternary phosphonium monobromide. The hydrobromic acid and quaternary ammonium or quaternary phosphonium migrate to the aqueous phase, thereby effecting the removal of the tribromides from the organic solvent. The hydrobromic acid can be neutralized with a quaternary ammonium or quaternary phosphonium hydroxide to produce a quaternary ammonium or quaternary phosphonium monobromide. The monobromides produced can be reacted with elemental bromine to regenerate a tribromide brominating agent.

Process for the production of anionic water-soluble polymer obtained by the polymerization of acrylic acid and acrylamide obtained by biocatalysed reaction, said process comprising the steps of preparing a diluted solution of acrylic acid by mixing acrylic acid and water wherein the mass ratio between acrylic acid and water is comprised between 95:5 and 70:30, preparing a diluted solution of bioacrylamide and water wherein the mass ratio between bioacrylamide and water is comprised between 60:40 and 10:90, mixing said diluted solution of acrylic acid with said diluted solution of bioacrylamide, neutralizing partially or totally the acid function of acrylic acid and polymerizing the resulting mixture.

Process for the production of anionic water-soluble polymer obtained by the polymerization of acrylic acid and acrylamide obtained by biocatalysed reaction, said process comprising the steps of preparing a diluted solution of acrylic acid by mixing acrylic acid and water wherein the mass ratio between acrylic acid and water is comprised between 95:5 and 70:30, preparing a diluted solution of bioacrylamide and water wherein the mass ratio between bioacrylamide and water is comprised between 60:40 and 10:90, mixing said diluted solution of acrylic acid with said diluted solution of bioacrylamide, neutralizing partially or totally the acid function of acrylic acid and polymerizing the resulting mixture.

A method can be used for manufacturing an ethylene-propylene-diene terpolymer for a fuel cell. A polymerization step includes subjecting an organic chelate compound forming a coordinate bond, a vanadium-based Ziegler-Natta catalyst, an organoaluminum compound, and ethylene, propylene, and diene monomers, together with a solvent, to polymerization in a reactor. A separation step includes recovering residual catalysts and unreacted monomers from the stream discharged from the reactor. An acquisition step includes recovering the solvent from the stream deprived of the residual catalysts and unreacted monomers to acquire the ethylene-propylene-diene terpolymer.

A method can be used for manufacturing an ethylene-propylene-diene terpolymer for a fuel cell. A polymerization step includes subjecting an organic chelate compound forming a coordinate bond, a vanadium-based Ziegler-Natta catalyst, an organoaluminum compound, and ethylene, propylene, and diene monomers, together with a solvent, to polymerization in a reactor. A separation step includes recovering residual catalysts and unreacted monomers from the stream discharged from the reactor. An acquisition step includes recovering the solvent from the stream deprived of the residual catalysts and unreacted monomers to acquire the ethylene-propylene-diene terpolymer.