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1. WO2020163400 - PROCÉDÉ DE RECUPÉRATION DE MONOMÈRES

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

WHAT IS CLAIMED IS:

1. A process for recovering monomers and solvent present in a waste stream comprising the steps of:

(a) providing a waste feed stream containing monomers, solvent and impurities;

(b) subjecting the waste feed stream of step (a) to a separation process under conditions for separating the monomers and solvent from the impurities of the waste stream;

(c) recovering the monomers and solvent in one or more streams; and

(d) passing the one or more of the monomers and solvent streams from step (c) to further processing.

2. The process of claim 1, wherein the separation process of step (b) includes a distillation process; wherein a mixed stream of monomers and solvent is separated from the waste feed stream in the distillation process; and wherein the separated mixed stream of monomers and solvent separated in the distillation process is recovered in step (c).

3. The process of claim 2, wherein the mixed stream of monomers and solvents contains 50 weight percent to 65 weight percent solvent; 20 weight percent to 30 weight percent styrene; 15 weight percent to 20 weight percent acrylonitrile; and less than 1 weight percent of combined water, ethylbenzene and heavies.

4. The process of claim 1, wherein the separation process of step (b) includes a first distillation process and a second distillation process in series with the first distillation process; wherein a side stream of solvent is separated from the waste feed stream in the first distillation process; wherein the separated solvent side stream separated in the first distillation process is recovered in step (c); wherein a mixed stream of monomer and impurities is separated from the waste feed stream in the first distillation process; wherein the mixed stream of monomer and impurities separated in the first distillation process is recovered in step (c); wherein the recovered mixed stream of monomer and impurities is fed to the second separation distillation process; wherein a side stream of monomer is separated from the mixed stream fed into the second separation distillation process; and wherein the separated side stream of monomer separated in the second separation distillation process is recovered in step (c). 5. The process of claim 4, wherein the waste feed stream contains (ai) an initial content of solvent of 20 weight percent to 60 weight percent; (aii) an initial content of styrene monomer of 10 weight percent to 50 weight percent; (aiii) an initial content of acrylonitrile monomer of

5 weight percent to 35 weight percent; (aiv) an initial content of ethylbenzene of 0 weight percent to 5 weight percent; (av) an initial content of water of 0 weight percent to 5 weight percent; and (avi) an initial content of undesired heavies of 0 weight percent to 5 weight percent; and wherein, after separating at least a portion of the solvent, styrene monomer and acrylonitrile monomer from the waste feed stream in step (b), the separated waste stream from step (b) contains (bi) a reduced content of solvent of 0 weight percent to 30 weight percent; (bii)a reduced content of styrene monomer of 0 weight percent to 25 weight percent; (biii) a reduced content of acrylonitrile monomer of 0 weight percent to 20 weight percent; (biv) a reduced content of ethylbenzene of 0 weight percent to 3 weight percent; (bv) a reduced content of water of 0 weight percent to 3 weight percent; and (bvi) a reduced content of undesired heavies in the range of 0 weight percent to 3 weight percent.

6. The process of claim 1, wherein the separation process of step (b) includes a first distillation process and a second distillation process in series with the first distillation process; wherein a side stream of a first monomer is separated from the waste feed stream in the first distillation process; wherein the first monomer side stream separated in the first distillation process is recovered in step (c); wherein a mixed stream of a second monomer, water and solvent is separated from the waste feed stream in the first distillation process; wherein the mixed stream of second monomer, water and solvent separated in the first distillation process is recovered in step (c); wherein the recovered mixed stream of second monomer, water and solvent is fed to the second separation distillation process; wherein a mixed stream of second monomer and water is separated from the mixed stream fed into the second separation distillation process; wherein the mixed stream of second monomer and water is recovered in step (c); wherein a stream of solvent is separated from the mixed stream fed into the second distillation process; and wherein the solvent stream is recovered in step (c).

7. The process of claim 1, wherein the separation process of step (b) includes a first extractive distillation process and a second separation distillation process in series with the first extractive distillation process; wherein a stream of an azeotrope of monomer and water and a stream of extraction solvent is fed to the first extractive distillation process; wherein a stream of monomer is separated in the first extractive distillation process; wherein the monomer separated in the first extractive distillation is recovered in step (c); wherein a mixed stream of extraction solvent and water is separated in the first extractive distillation process; wherein the mixed stream of extraction solvent and water is recovered in step (c); wherein the mixed stream of recovered extraction solvent and water is fed to the second separation distillation process; wherein a stream of extraction solvent and a stream of water are separated in the second separation distillation process; and wherein the stream of extraction solvent and the stream of water are recovered in step (c).

8. A copolymer polyol made with at least a portion of the monomers stream and at least a portion of the solvent stream recovered in step (c) of the process of claim 1.

9. A process for producing a copolymer polyol comprising the steps of:

(I) providing a reaction mixture of monomers in the presence of a solvent, wherein at least a portion of the monomers and at least a portion of the solvent in the reaction mixture are the recovered monomers and recovered solvent recovered by the process of claim 1 ; and

(II) subjecting the reaction mixture of step (I) to reaction conditions to form a copolymer polyol product.

10. A process for separating acrylonitrile from water comprising the steps of:

(A) feeding an azeotrope composition of acrylonitrile and water to an extractive distillation column; and

(B) distilling the acrylonitrile from water by extractive distillation in the extractive distillation column using an extraction solvent.