The present invention provides for a system comprising a static reactor vessel which requires no moving parts, and adapted for precise control of reaction processing parameters including temperature, pressure, and flow rate; a mechanism for settling of the product phase from the salt ammonia phase and removing a significant portion of the ammonium chloride waste material; a method for recovering essentially all of the process ammonia and a method for maintaining a reaction environment which is suitably ionic/acidic.

The present invention relates to a method for preparing a polyetherester copolymer having excellent economical efficiency by recycling unreacted diol and excellent physical properties. Accordingly, the preparation method may prepare a polyetherester copolymer of high purity having excellent economical efficiency by purifying a byproduct to separate a recycle stream including unreacted diol therefrom, and reusing the recycle stream.

The present invention relates to a method for preparing a polyetherester copolymer having excellent economical efficiency by recycling unreacted diol and excellent physical properties. Accordingly, the preparation method may prepare a polyetherester copolymer of high purity having excellent economical efficiency by purifying a byproduct to separate a recycle stream including unreacted diol therefrom, and reusing the recycle stream.

Provided is a process for obtaining a film or film-forming article. The process includes a) providing a solvent system comprising at least one molecule bearing a sulfoxide function, where the solvent system has a water content of less than 1000 ppm by weight and having a pH of greater than or equal to 6. The process also includes b) preparing a polymer solution, either by dissolving the polymers in the solvent system or by synthesizing the polymers in the solvent system. The process also includes c) removing the solvent system to obtain the film or the film-forming article.

Provided is a process for obtaining a film or film-forming article. The process includes a) providing a solvent system comprising at least one molecule bearing a sulfoxide function, where the solvent system has a water content of less than 1000 ppm by weight and having a pH of greater than or equal to 6. The process also includes b) preparing a polymer solution, either by dissolving the polymers in the solvent system or by synthesizing the polymers in the solvent system. The process also includes c) removing the solvent system to obtain the film or the film-forming article.

The present invention relates to a method for recovering ethylene and a vinyl-comonomer that is capable of improving the rate of recovery of unreacted monomers remaining after polymerization of ethylene and a vinyl-based comonomer and increasing process efficiency through the reduction of costs.

Specifically, the method for recovering ethylene and a vinyl-comonomer includes: a step of polymerizing ethylene and a vinyl-based comonomer at a pressure of 1500 bar or more; a step of depressurizing the product obtained in the polymerization step including an ethylene-vinyl-based comonomer polymer, ethylene, and a vinyl-based comonomer to 0.1 bar to 5 bar; a step of adding ethylene to the product obtained in the polymerization step under the pressure of 0.1 bar to 5 bar; and a step of separating ethylene and a vinyl-based comonomer from the product obtained in the polymerization step to which the ethylene is added.

Provided is a wastewater purification method, the method including: supplying a first mixed stream, in which an acid component and wastewater including water, a nitrile-based monomer, and ammonia are mixed, to a first column; recovering the nitrile-based monomer from an upper discharge stream from the first column; supplying a second mixed stream, in which a lower discharge stream from the first column and a base component are mixed, to a second column; and recovering the ammonia from an upper discharge stream from the second column and separating purified wastewater.

The present invention relates to a process for obtaining a dialkyl phthalate and a reusable target PVC plastic from a PVC feedstock containing at least one phthalate, including: a) solid-liquid extraction of PVC feedstock in the form of particles by placing the particles in contact with a solvent to produce a liquid phase enriched in the phthalate and a solid phase including PVC plastic depleted in the phthalate; b) transformation of the phthalate of the liquid phase into dialkyl phthalate by transesterification using the solvent; c) a solid-liquid separation between the solid phase and the liquid phase to produce at least one solid stream including the PVC plastic depleted in the phthalate so as to obtain the target PVC plastic; d) a liquid-liquid separation of the liquid phase, to produce at least a first liquid effluent including the dialkyl phthalate and a second liquid effluent comprising said solvent.

The present invention relates to a process for obtaining a dialkyl phthalate and a reusable target PVC plastic from a PVC feedstock containing at least one phthalate, including: a) solid-liquid extraction of PVC feedstock in the form of particles by placing the particles in contact with a solvent to produce a liquid phase enriched in the phthalate and a solid phase including PVC plastic depleted in the phthalate; b) transformation of the phthalate of the liquid phase into dialkyl phthalate by transesterification using the solvent; c) a solid-liquid separation between the solid phase and the liquid phase to produce at least one solid stream including the PVC plastic depleted in the phthalate so as to obtain the target PVC plastic; d) a liquid-liquid separation of the liquid phase, to produce at least a first liquid effluent including the dialkyl phthalate and a second liquid effluent comprising said solvent.

The present invention relates to a process for obtaining a dialkyl phthalate and a reusable target PVC plastic from a PVC feedstock containing at least one phthalate, including: a) a solid-liquid extraction of said PVC feedstock in the form of particles by placing said particles of the PVC feedstock in contact with a solvent including at least one alcohol C.sub.nH.sub.2n+1OH with n<4 or n>8, to produce a liquid phase enriched in said phthalate and a solid phase including PVC plastic depleted in said phthalate; b) transformation of said phthalate of said liquid phase into dialkyl phthalate of formula C.sub.6H.sub.4(COOC.sub.nH.sub.2n+1).sub.2 by transesterification using said alcohol; c) a solid-liquid separation between the solid phase and the liquid phase to produce at least one solid stream including the PVC plastic depleted in said phthalate so as to obtain said target PVC plastic; d) a liquid-liquid separation of the liquid phase, to produce at least a first liquid effluent including said dialkyl phthalate and a second liquid effluent comprising said solvent.