Monomer recovery system and process for obtaining a purified branched vinyl ester stream

Abstract

The present invention relates to a recovery system and process for obtaining purified branched vinyl ester stream. The purification system is made of a vapor-liquid phase separator of one or multiple stages (S1) for separating an overhead stream (S1') and a bottom stream (S1°') from a feed stream; a distillation column (C3) for separating an overhead stream (C3') and a bottom stream (C3") from (S177) stream; and a distillation column (C4) for separating an overhead stream (C4') with the purified branched vinyl ester stream and a bottom stream (C4") from (C3") stream. The process has the steps of injecting a feed stream to a vapor-liquid phase separator of one or multiple stages (S1) and recovering an overhead stream (S1') and a bottom stream (S177); injecting (S 1 ") stream to a distillation column (C3) and recovering an overhead stream (C3') and a bottom stream (C3 "); and injecting (C3") stream to a distillation column (C4) and recovering an overhead stream (C4') and a bottom stream (C4"). The process discloses as well using a column with a side stream to purify the bottom stream (C3").

Description

MONOMER RECOVERY SYSTEM AND PROCESS FOR OBTAININGA PURIFIED BRANCHED VINYL ESTER STREAMCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 705,412, filed October 9, 2024.TECHNICAL FIELD

[0002] The present invention relates to a monomer recovery system and process for obtaining a purified branched vinyl ester stream from a recovery system feed stream (which is a recycle stream from a high-pressure polymerization reactor) comprising more than 50 wt.% of a branched vinyl ester. Particularly, the feed stream comprises branched vinyl ester, light vinyl ester, C5-C16 hydrocarbon solvent, contaminants such as oxygenated impurities and moisture, and heavies.

[0003] More particularly, the monomer recovery system feed stream may be derived from a high-pressure ethylene polymerization process. Hence, the present invention generally relates to a process for optimizing the recovery of unreacted (co)monomers from a polymerization process.BACKGROUND

[0004] In polymerization processes, the reaction conversion is never close to 100%, especially at high-pressure polymerizations, wherein the conversion usually reaches rates no greater than 60 %. Consequently, recycling (co)monomers is economically desirable for the feasibility of the process.

[0005] However, in a polymerization process comprising ethylene, branched vinyl esters and light vinyl esters as comonomers, there is a technical difficulty in separating branched vinyl esters and light vinyl esters from moisture, oxygenate impurities and light fractions of C5-C16 hydrocarbons due to the high non-ideality of the mixture. Separating such fractions is not a simple task, since many equilibrium stages are required.

[0006] Hence, the present invention surprisingly developed an optimized system and process for obtaining a branched vinyl ester stream with high purity and recovery levels.SUMMARY

[0007] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subj ect matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0008] In one aspect, embodiments disclosed herein relate to a recovery system for obtaining a purified branched vinyl ester stream, the system comprising:- a vapor-liquid phase separator of one or multiple stages (SI), (Cl) for separating an overhead stream (ST), (CT) comprising a light vinyl ester-rich fraction, and a bottom stream (SI”), (Cl”) comprising a branched vinyl ester-rich fraction from a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) or a flash vessel SI;- a distillation column (C3) for separating an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction from (SI”), (Cl”) stream; and- a distillation column (C4) for separating an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising contaminants and heavies from (C3”) stream.

[0009] In another aspect, embodiments disclosed herein relate to a recovery system for obtaining a purified branched vinyl ester stream, the system comprising:- a distillation column (Cl) for separating an overhead stream (CT) comprising a light vinyl ester-rich fraction, a vent stream (ET) comprising non-condensable gases and light vinyl ester-rich fractions, and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction from a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; and- a distillation column (C6) for separating an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising contaminants and heavies and a side stream C6s comprising the purified branched vinyl ester stream from (Cl”) stream.

[0010] In further aspects, embodiments disclosed herein relate to a monomer recovery process for obtaining a purified branched vinyl ester stream, the process comprising:- injecting a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies to a vapor-liquid phase separator of one or multiple stages (SI), (Cl) and recovering an overhead stream (ST), (CT) comprising a light vinyl ester -rich fraction and a bottom stream (SI”), (Cl”) comprising a branched vinyl ester-rich fraction, wherein the vapor-liquid phase separator of one or multiple stages (SI) is a distillation column (Cl) or a flash vessel;- injecting (SI”) or (Cl”) stream to a distillation column (C3) and recovering an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction;- injecting (C3”) stream to a distillation column (C4) and recovering an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising contaminants and heavies.

[0011] In another aspect, embodiments disclosed herein relate to a recovery process for obtaining a purified branched vinyl ester stream, the process comprising:- injecting a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies to a distillation column (Cl) and recovering an overhead stream (CT) comprising a light vinyl ester -rich fraction, and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction;- injecting (Cl”) stream to a distillation column (C6) and recovering an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising contaminants and heavies and a side stream C6s comprising the purified branched vinyl ester stream;

[0012] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 and FIG. 2 show a basic configuration of a monomer recovery system for obtaining a purified branched vinyl ester stream comprising a vapor-liquid phase separator of one or multiple stages ((SI) or (Cl), respectively), and two distillation columns (C3) and (C4).

[0014] FIG. 3 and FIG. 4 show a configuration of a monomer recovery system for obtaining a branched vinyl ester stream and a purified light vinyl ester stream comprising a vapor-liquid phase separator of one or multiple stages ((SI) or (Cl), respectively), and four distillation columns (C2), (C3), (C4) and (C5).

[0015] FIG. 5 and FIG. 6 show a configuration of a monomer recovery system for obtaining a branched vinyl ester stream and a purified light vinyl ester stream comprising a vapor-liquid phase separator of one or multiple stages ((SI) or (Cl), respectively) and four distillation columns (C2), (C3), (C4) and (C5), also having a return of total or partial (C5”) bottom stream to distillation column (C3).

[0016] FIG. 7 shows a configuration of a monomer recovery unit for obtaining a branched vinyl ester stream and a purified light vinyl ester stream comprising three distillation columns (Cl), (C6) and (C7), wherein (C6) and (C7) have a further side stream withdrawal.

[0017] FIG. 8 shows a configuration of a monomer recovery unit for obtaining a branched vinyl ester stream and a purified light vinyl ester stream comprising distillation column (Cl) and three more columns (C2), (C5) and (C6), wherein (C6) has a further side stream withdrawal.

[0018] FIG. 9 represents the high-pressure polymerization process from which the feed streams (DI’) and (D2’) are derived. In FIG. 9, the numbers represent: 1. Ethylene feed; 2. Chain transfer agent injection points; 3. Primary compressor; 4. Secondary compressor; 5. Comonomer 1 (Fresh and Recovered) injection pump; 6. Comonomer 2 (Fresh and Recovered) injection pump; 7. Reactor feed (single or multiple); 8. Reactor(s); 9. Initiator Injection Pump(s); 10. Reactor pressure control valve; 11. Product Cooler; 12. High Pressure Separator (HPS); 13. High Pressure Recycle (HPR); 14. Low Pressure Separator (LPS); 15.Low Pressure Recycle (LPR); 16. Extrusion System; 17. Product Silos; 18. Product; 19. Liquids drained from the process ((DL) - VN rich stream and (D2’) - VA rich stream); 20. Process gas purge; 21. Low Pressure Recycle Cooler

[0019] FIG. 10 represents Second Distillation of Drained VN: composition of feed and top (A) / bottom (B) of column (LD = 500 ppm)DETAILED DESCRIPTION

[0020] Embodiments disclosed herein relate to a monomer recovery system for obtaining a purified branched vinyl ester stream, the system comprising:- a vapor-liquid phase separator of one or multiple stages (SI) or (Cl) for separating an overhead stream (S L) or (C 1 ’)) comprising a light vinyl ester-rich fraction and a bottom stream (SI”) or (Cl”) comprising a branched vinyl ester-rich fraction from a feed stream (DL) comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; wherein the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI) or a distillation column (Cl);- a first distillation column (C3) for separating an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, a vent stream (E3’) comprising non-condensable gases and light vinyl ester-rich fraction, and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction from (SI”) or (Cl”) stream; and- a distillation column (C4) for separating an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising heavies from (C3”) stream .

[0021] The recovery unit according to the present invention provides high purity levels and high recovery ratios of the branched vinyl ester which is intended to be recovered from the feed stream. The outlet stream (C4’), which is the overhead stream from (C4) distillation column, has a branched vinyl ester purity level of more than 80, 85, 90, 95 or up to 99,9 wt.%, based on the total weight of the purified branched vinyl ester stream (C4’), and a branched vinyl ester recovery ratio of more than 70, 75, 80, 85, 90 and up to 99 wt.%, based on the total weight of branched vinyl ester contained in the feed stream (DL).

[0022] Figures 1 and 2 represent a basic configuration of one of the embodiments of the present invention, comprising the vapor-liquid phase separator of one or multiple stages (SI) or (Cl), respectively), and their respective overhead (ST), (CT), vent (EF), and bottom (SI”), (Cl”) streams; distillation column (C3), and its respective overhead (C3’), vent (E3’), where applicable, and bottom (C3”) streams; and distillation column (C4), and its respective overhead (C4’) and bottom (C4”) streams.Feed stream

[0023] The feed stream (DF) comprises branched vinyl esters, light vinyl esters, solvents comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies. Particularly, this feed stream comprises more than 40 wt.%, more than 45 wt.%, more than 75 wt.%, or more than 80 wt.%, of a branched vinyl ester, and no more than 30 wt.%, no more than 20 wt.%, no more than 10 wt.%, or no more than 5 wt.% of a light vinyl ester, based on the total weight of the feed stream. More particularly, the feed stream (DF) is rich in branched vinyl ester, and comprises more than 50 wt.% of a branched vinyl ester.

[0024] Alternatively, the system according to the present invention may additionally comprise a second feed stream (D2’) that comprises light vinyl esters, branched vinyl esters, solvents comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies. Particularly, this feed stream comprises more than 80 wt.%, more than 85 wt.%, more than 90 wt.%, more than 95 wt.%, or more than 98 wt.% of a light vinyl ester and an amount ranging from 0.5 to 5 wt.% of a branched vinyl ester, based on the total weight of the feed stream. More particularly, the feed stream (D2’) is rich in light vinyl ester and comprises more than 95 wt.% of a light vinyl ester.

[0025] In one or more embodiments, the feed streams are derived from a high-pressure polymerization process and comprises branched vinyl ester and light vinyl ester as unreacted comonomer(s). Alternatively, they can also comprise ethylene as an unreacted monomer. In one or more embodiments, the high-pressure polymerization process from which feed streams (DF) and (D2’) are derived is described in FIG. 9, and it comprises:- a primary compressor suctioning an ethylene monomer stream at a pressure ranging from 20 to 50 kgf / cm2and compressing the ethylene monomer stream to a discharge pressure up to 300 kgf / cm2;- feeding the compressed ethylene monomer stream discharged from primary compressor, a stream comprising at least one branched vinyl ester and, optionally, a light vinylester monomer stream in a secondary compressor and compressing the monomers stream, wherein the secondary compressor has a suction pressure ranging from 150 to 300 kgf / cm2and a discharge pressure up to 3600 kgf / cm2;- feeding the compressed monomers stream discharged from the secondary compressor and free-radical initiator stream(s) into a reaction system through at least one injection point;- reacting the compressed ethylene, the at least one branched vinyl ester and, optionally, the light vinyl ester with the free-radical initiator within the reaction system to produce an ethylene-branched vinyl ester polymer;- separating the produced ethylene-branched vinyl ester polymer from unreacted monomers in a separation system comprising at least one high-pressure separation vessel and a low-pressure separation vessel;- returning at least part of the unreacted monomers to the suction of the primary compressor and / or to the suction of the secondary compressor;- cooling and condensing a heavy liquids stream comprising recycled unreacted comonomers such as the at least one branched vinyl ester and optionally the light vinyl ester, solvent used as vehicle for free-radical polymerization initiators and compressor oils, which are separated from the ethylene-rich gas stream in separation vessels;- directing the feed streams (DT) and (D2’) resulting from the condensation of the low- pressure recycle stream, occurring respectively at the suction separator and at the interstage separators of the primary compressor to the monomer recovery system of the present disclosure; and- recovering a purified branched vinyl ester and alternatively a light vinyl ester monomer streams from the monomer recovery system and feeding back to the polymerization process, mixed with fresh monomers.Branched Vinyl Ester

[0026] In one or more embodiments, branched vinyl ester aimed to be purified through the system and process of the present invention may include branched vinyl esters generated from isomeric mixtures of branched alkyl acids. Branched vinyl esters in accordance with the present disclosure may have the general chemical formula (I):

[0027] where R1, R2, and R3have a combined carbon number in the range of 3 to 20. In some embodiments, R1, R2, and R3may all be alkyl chains having varying degrees of branching in some embodiments, or a subset of R1, R2, and R3may be independently selected from a group consisting of hydrogen, alkyl, or aryl in some embodiments.

[0028] In one or more embodiments, the branched vinyl ester monomers may include branched vinyl esters having the general chemical formula (II):

[0029]

[0030] wherein R4and R5have a combined carbon number of 6 or 7.

[0031] Examples of branched vinyl esters may include monomers having the following chemical structures, including derivatives thereof:

[0032] In one or more embodiments, the branched vinyl ester may be virgin, or it may be derived from a polymerization process, preferably being an unreacted (co)monomer.

[0033] In one or more embodiments, branched vinyl esters may include vinyl esters of neononanoic acid, neodecanoic acid, and the like. In other embodiments, branched vinyl esters may include Versatic™ acid series tertiary carboxylic acids, including Versatic™ acid EH, Versatic™ acid 9 and Versatic™ acid 10 prepared by Koch synthesis, VeoVa 9™, VeoVa 10™, VeoVa EH™ commercially available from Hexion™ chemicals.

[0034] According to the present invention, the branched vinyl ester may be present in the feed stream (DT) in an amount of more than 40 wt.%, more than 45 wt.%, more than 75 wt.%, or more than 80 wt.%„ based on the total weight of the feed stream. In a preferred embodiment, the branched vinyl ester is present in the feed stream (DT) in an amount of more than 50 wt.%, based on the total weight of the (DT) feed stream.

[0035] According to another embodiment of the present invention, the branched vinyl ester may be present in the feed stream (D2’) in an amount of up to 5 wt.%, up to 4 wt.%, up to 3 wt.%, up to 2 wt.%, up to 1 wt.%, or up to 0.5 wt.% based on the total weight of the feed stream. In a preferred embodiment, the branched vinyl ester is present in the feed stream (D2’) in an amount of up to 5 wt.%, based on the total weight of the (D2’) feed stream.Light Vinyl Ester

[0036] In one or more embodiments, the light vinyl ester aimed to be separated from the branched vinyl ester may be selected from vinyl acetate, acrylic acids and alkyl acrylate. In one preferred embodiment, the light vinyl ester is vinyl acetate.

[0037] According to the present invention, the light vinyl ester may present in the feed stream (DT) in an amount of no more than 30 wt.%, no more than 20 wt.%, no more than 10 wt.%, or no more than 5 wt.%, based on the total weight of the (DT) feed stream.

[0038] According to another embodiment of the present invention, the light vinyl ester may present in the feed stream (D2’) in an amount of more than 80 wt.%, more than 85 wt.%, more than 90 wt.%, more than 95 wt.%, or more than 98 wt.%, based on the total weight of the (D2’) feed stream. Preferably, the (D2’) feed stream is rich in light vinyl ester and comprises more than 95 wt.% of a light vinyl ester.Solvent

[0039] The solvent present in the feed stream comprises a mixture of hydrocarbons with 5 to 16 carbon atoms, particularly, it is an alkane with 5 to 16 carbon atoms. In one or more embodiments, the solvent may comprise, for example, one or more from the group comprising n-octane, iso-octane (2,2, 4-trimethylpentane), n-dodecane, iso-dodecane (2,2,4,6,6-pentamethylheptane), and any other isoparaffinic solvents.

[0040] In one preferred embodiment, the solvent comprises a mixture of isoparaffinic hydrocarbons with 8 to 16 carbon atoms. Exemplary solvents comprising a mixture of isoparaffinic hydrocarbons, for example, are commercially available under the tradename of Braskem Sensitis ™ 17 / 21, which is a mixture of isoparaffinic hydrocarbons with 10 to 14 carbon atoms, or Braskem Sensitis ™ 22 / 25, which is a mixture of isoparaffinic hydrocarbons with 10 to 13 carbon atoms.

[0041] According to the present invention, the solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms may be present in the feed stream in amounts ranging from 0.1 to 20 wt.%, particularly in amounts ranging from 0.1 to 10 wt.%, based on the total weight of the feed stream (DE) or (D2’).Heavies

[0042] In one or more embodiments, the feed stream comprises heavies in amounts up to 15 wt.%, preferably from 1 to 10 wt.%, based on the total weight of the feed stream. In the context of the present invention, heavies may include lubricants with an atmospheric distillation range from 320 °C to 700 °C, viscosities ranging from 30 to 70 cSt at 40 °C and from 5 to 9 cSt at 100 °C, and a viscosity index between 105 and 115; and polyisobutylene with an atmospheric distillation range from 190 °C to 735 °C, viscosities ranging from 450 to 500 cSt at 37.8 °C and from 20 to 30 cSt at 100 °C, and a viscosity index also between 107 and 113. Non-limiting examples of lubricants may be selected from mineral oils and polymeric waxes, generally used as compressor oils and / or seal fluids in the high pressure polymerization process.Contaminants

[0043] In one or more embodiments, the feed stream also comprises traces of contaminants in its composition, such as, but not limited to, water and oxygenate compounds, such as carboxylic acids derived from the production / decomposition of the branched vinyl ester and / or of the light vinyl ester, esters, ketones, aldehydes and / or alcohols with 3 to 8 carbon atoms. In the context of the present invention, the expression “traces of’ may be understood as comprising up to 5 wt.% of said compound in the stream composition.

[0044] In one particular embodiment, the feed stream (DF) and / or (D2’) may comprise up to 2 wt.% of oxygenate compounds, including organic acids derived from the branched vinyl ester and / or of the light vinyl ester, an alcohol with 3 to 8 carbon atoms, such as tert-butanol and an aldehyde such as acetaldehyde, and up to 0.5 wt.% of water.Dissolved non-condensable compounds or gases

[0045] Alternatively, the feed stream (DF) and / or (D2’) may comprise traces of non- condensable compounds or gases dissolved in the feed stream. Non limiting examples of non- condensable compounds or gases are ethylene, propylene or propane. Particularly, the feed stream may comprise up to about 3000 ppm of dissolved ethylene.Polymerization inhibitor

[0046] The high reactivity of the monomers to be recovered in the recovery system of the present disclosure may impose specific requirements on process design, including the injection of polymerization inhibitors. During the monomer recovery process, polymerization inhibitors from the substituted phenol group, known as radical scavengers, may be employed.

[0047] The inhibitor selection is dependent on the maximum allowable loss of unsaturation required by the high-pressure polymerization process, considering the ratio between fresh monomer and recovered monomer. In one embodiment of the invention, the maximum allowable loss of unsaturation required by the high-pressure polymerization process is 20%, preferably 10%. Additionally, the inhibitor must meet the chemical and operational requirements of the high-pressure polymerization technology to which the monomer, recovered by the present system, is returned. Accordingly, for each type of monomer recovered, a different type of inhibitor may be selected. Particularly, different inhibitors may be selected to be fed in each step of the recovery process, such as a specific inhibitor for the recovery of the light vinyl ester and another specific inhibitor for the recovery of branched vinyl ester.

[0048] Polymerization inhibitors for the recovery of light vinyl esters according to the present disclosure may include, but are not restricted to, hydroquinones, methoxyphenol.(MeHQ), and mixtures thereof. According to one embodiment of the invention, the polymerization inhibitor is added to the feed stream (D2’) upstream of column (C2). The dosage amount depends on the type of inhibitor used. When hydroquinone is applied, thedosage is adjusted to maintain a concentration between 20 and 300 ppm w / w at the bottom of column (C2), preferably between 50 and 250 ppm w / w and, even more preferably, between 150and 210 ppm w / w.

[0049] Polymerization inhibitors for the recovery of branched vinyl esters according to the present disclosure may include, but are not limited to, methoxyphenol (MeHQ), BHT (butylated hydroxytoluene), TBHQ (tert-butylhydroquinone), and mixtures thereof. According to one embodiment of the invention, the polymerization inhibitor is added to the feed stream (DE) upstream of the first column (Cl) or flash vessel (SI). The dosage amount depends on the type of inhibitor used. When MEHQ (4-Methoxyphenol) is applied, the dosage is adjusted to maintain a concentration between 20 and 150 ppm w / w in the feed to vessel (SI) or of 20 to 300 ppm at the bottom of column (Cl). Preferably, when MEHQ (4-Methoxyphenol) is applied, the dosage is adjusted to maintain a concentration between 25 and 50 ppm w / w in the feed to vessel (SI) or at the bottom of column (Cl).

[0050] In a preferred embodiment, the dosing of the polymerization inhibitor is carried out in the feed stream of unit (SI) or (Cl) and upstream of the condenser or reflux stream of columns (Cl), (C3), and (C4).

[0051] In another embodiment, the dosing of the polymerization inhibitor is carried out in the feed stream of unit (Cl) and upstream of the condenser or reflux stream of columns (Cl) and (C6).

[0052] Preferably, the amount of inhibitor at the top section of the distillation columns (Cl), (C2), (C3), (C4) and (C5) may vary and is less than the concentration of the inhibitor in the fresh monomer (light and / or branched vinyl esters) or less than or equal to the maximum allowable concentration of polymerization inhibitor permitted by the high-pressure polymerization process to which the monomer recovered by the present system is returned.

[0053] Preferably, the concentration of the polymerization inhibitor in feed (DE) or (D2’) is adjusted so that the bottom of columns (Cl) and (C2) is up to 300 ppm, up to 200 ppm, up to 150 ppm, up to 100 ppm, up to 50 ppm or up to 20 ppm. Preferably, the concentration of the polymerization inhibitor in the bottom of (Cl) is up to 50 ppm and in the bottom of (C2) is up to 200 ppm.

[0054] Alternatively, the inhibitor dosage at the feed stream of (SI) is optimized to minimize fouling and thermal degradation in the bottom region of the columns. For example, the concentration of the polymerization inhibitor may be up to 150 ppm, up to 100 ppm, up to50 ppm or up to 20 ppm. Preferably, the concentration of the polymerization inhibitor is up to 50 ppm.Vapor-liquid phase separator of one or multiple stages (SI) or Cl

[0055] The vapor-liquid phase separator of one or multiple stages (SI) or (Cl) aims to separate the feed stream (DF) into an overhead stream (ST) or (CT), and a bottom stream (SI ”) or (Cl”). It is also envisioned that a vent stream EF may be separated from the feed stream (DF).

[0056] In one or more embodiments, the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl). In such embodiments, the bottom temperature and pressure of distillation column (Cl) ranges from 150 to 170 °C and from 250 to 350 mbar, respectively, while the overhead temperature and pressure of distillation column (Cl) ranges from 25 to 35 °C and from 200 to 300 mbar (abs), respectively.

[0057] In one or more embodiments, the feed stream may be fed to distillation column (Cl) at a position ranging from 50 to 95% (up to top) of the tray section or of the packing. In a preferred embodiment, the recycle stream (DF) is fed to the vapor-liquid phase separator of one or multiple stages (Cl) at a position from 80 to 90% (up to top) of tray section or of the packing. In an even more preferred embodiment, the recycle stream (DF) is fed to the vaporliquid phase separator of one or multiple stages (Cl) at a position of 89% (up to top) of tray section or of the packing.

[0058] In an alternative embodiment, the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI), and it operates at a temperature ranging from 130 to 145 °C and under atmospheric pressure.

[0059] The overhead stream (SF) or (CF) comprises a light vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of a light vinyl ester, based on the total weight of (DF) stream. Particularly, the overhead stream (SF) or (CF) comprises more than 60 wt.% and up to 99 wt.% of a light vinyl ester, and it may comprise traces of contaminants, such as water, alcohol and carboxylic acids derived from the light vinyl ester, as well as traces of a light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms. In a preferred embodiment, the overhead stream (CF) comprises more than 80 wt.% and up to 99 wt.% of alight vinyl ester and / or the overhead stream (SF) comprises more than 60% and up to 70% of a light vinyl ester.

[0060] The vent stream (EF) comprises up to 99.9 wt.% of the non-condensable gases which are presented in the feed stream (DE). The vent stream also comprises light components such as more than 50 wt.% and up to 95 wt.% of light vinyl ester, 0.1 wt.% and up to 10.0 wt.% of oxygenates and 0.1 wt.% and up to 0.5 wt.% of water.

[0061] In one or more embodiments, when the light vinyl ester is a vinyl acetate and non-condensable compound is ethylene, (EF) stream may also comprise up to 30.0 wt.% of the vinyl acetate that is present in the feed stream (DF).

[0062] The bottom stream (SI”) or (Cl”) comprises a branched vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester which is intended to be purified in the system and method of the present invention. Particularly, the bottom stream (SI”) or (Cl”) comprises more than 70 wt.% and up to 95 wt.% of the branched vinyl ester, up to 10 wt.% of the light vinyl ester, up to 10 wt.% of a heavy solvent fraction comprising a mixture of hydrocarbons with 10 to 16 carbon atoms, up to 5 wt.% of heavies, and less than 1 wt.% of contaminants, such as carboxylic acids. In a preferred embodiment, the bottom stream (Cl”) has up to 100 ppm w / w of the light vinyl ester, and the bottom stream (SI”) has up to 10 wt.% of the light vinyl ester.

[0063] Polymerization inhibitor is added upstream of the condenser or into the reflux stream. The dosage depends on the type of inhibitor used to minimize light vinyl ester degradation. For example, when the light vinyl ester is vinyl acetate and hydroquinone is used as polymerization inhibitor, the dosage is adjusted to maintain a concentration of hydroquinone in the vinyl acetate between 5 and 15 ppm w / w in the top product stream or reflux stream. This concentration may be modified depending on the inhibitor and on the restrictions imposed by the high-pressure polymerization process to which the purified monomer is returned.Distillation column C3

[0064] The distillation column (C3) aims to separate the (SI”) or (Cl”) stream, i.e., the bottom stream of the vapor-liquid phase separator of one or multiple stages (SI) or (Cl), respectively, into an overhead stream (C3 ’), a bottom stream (C3 ’ ’) and, when the vapor-liquid phase separator is a flash vessel (SI), an additional vent stream (E3’).

[0065] The (Cl”) stream may be fed to distillation column (C3) at a position ranging from 30 to 50% (up to top) of the tray section or of the packing. In a preferred embodiment, the (Cl”) stream is fed to distillation column (C3) at a position from 30 to 40% (up to top) of the tray section or of the packing. In an even more preferred embodiment, the (Cl”) stream is fed to distillation column (C3) at a position of 38% (up to top) of the tray section or of the packing.

[0066] When the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl), the overhead stream (C3’) comprises more than 50 wt.% of a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms. Particularly, it may comprise more than 70 wt.%, or even more than 80 wt.%, and up to 90 wt.% of the light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms, in addition to up to 10 wt.% of the light vinyl ester, up to 10 wt.% of carboxylic acids derived from the light vinyl ester and up to 10 wt.% of heavies.

[0067] When the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI), the overhead stream (C3’) comprises more than 40 wt.% of light vinyl ester and more than 30 wt.% of a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms. Particularly, it may comprise to up to 50 wt.% of the light vinyl ester, more than 40 wt.%, or even more than 60 wt.%, and up to 80 wt.% of the light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms, in addition, up to 10 wt.% of carboxylic acids derived from the light vinyl ester, up to 1.1 wt.% of oxygenates and up to 10 wt.% of heavies.

[0068] In this case, the vent stream (E3’) comprises more than 80.0 wt.% of light vinyl ester, up to 5.0 wt.% of the non-condensable gases, 5 wt.% of carboxylic acids derived from the light vinyl ester, up to 5.0 wt.% of light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, 1.0 wt.% of oxygenates, and up to 0.5 wt.% of water.

[0069] The bottom stream (C3”) comprises a further branched vinyl ester-rich fraction. Particularly, it may comprise more than 80 wt.%, or more than 98 wt.%, of the branched vinyl ester, in addition to up to 10 wt.% of heavies and traces amounts of a heavy solvent fraction comprising a mixture of hydrocarbons selected from the group of C12-C16 and contaminants.

[0070] In one or more of these embodiments, the bottom temperature of distillation column (C3) ranges from 150 to 180 °C and the bottom pressure ranges from 300 to 400 mbar (abs); and the overhead pressure ranges from 140 to 155 mbar (abs).

[0071] When the vapor-liquid phase separator one is a distillation column (Cl), the overhead temperature of distillation column (C3) ranges from 40 to 50 °C.

[0072] Alternatively, when the vapor-liquid phase separator is a flash vessel (SI), the overhead temperature of distillation column (C3) ranges from 20 to 30 °C.

[0073] Polymerization inhibitor is added upstream of the condenser or into the reflux stream. The dosage depends on the type of inhibitor used to minimize the branched vinyl ester degradation. For example, when the branched vinyl ester is vinyl neodecanoate (VN) and MEHQ is used as a polymerization inhibitor, the dosage is adjusted to maintain a concentration of MEHQ in the VN between 2 to 5 ppm w / w in the top product stream or the reflux stream. This concentration may be modified depending on the restrictions imposed by the high- pressure polymerization process.Distillation column C4

[0074] The distillation column (C4) aims to separate the (C3”) stream, an overhead stream (C4’) and a bottom stream (C4”) from (C3”) stream, i.e., the bottom stream of the distillation column (C3).

[0075] The (C3”) stream may be fed to the distillation column (C4) at a position ranging from 30 to 70% (up to top) of the tray section or of the packing. In a preferred embodiment, the (C3”) stream may be fed to the distillation column (C4) at a position ranging from 45 to 70% (up to top) of the tray section or of the packing. In an even more preferred embodiment, the (C3”) stream may be fed to the distillation column (C4) at a position of 57% (up to top) of tray section or of the packing.

[0076] The overhead stream (C4’) comprises the purified branched vinyl ester stream, which is the product intended to be recovered in the present invention. Particularly, the purified branched vinyl ester stream may comprise more than 95 wt.%, or more than 98 wt.%, or more than 99 wt.% of the branched vinyl ester. (C4’) stream may also have traces of carboxylic acids derived from the branched vinyl ester, heavies and a heavy solvent fraction comprising a mixture of hydrocarbons selected from the group comprising C12-C16.

[0077] The bottom stream (C4”) comprises heavies and contaminants in amounts of more than 70 wt.%, based on total weight of the components of (C4”) stream. Contaminants in (C4’ ’) stream is mainly composed by carboxylic acids derived from the branched vinyl ester.Particularly, the amounts of heavies in (C4”) stream may be more than 60 wt.% or more than 70 wt.% and the amounts of carboxylic acids may be up to 15 wt.%, based on the total weight of (C4”) stream. In some embodiments, (C4”) stream may also contain up to 15 wt.% of branched vinyl ester loss.

[0078] In one or more embodiments, the overhead temperature of distillation column (C4) ranges from 100 to 140 °C and the overhead pressure ranges from 50 to 200 mbar (abs); and wherein the bottom temperature of distillation column (C4) ranges from 160 to 190 °C and the bottom pressure ranges from 100 to 250 mbar (abs).

[0079] Polymerization inhibitor is added upstream of the condenser or into the reflux stream. The dosage depends on the type of inhibitor used to minimize branched vinyl ester degradation. For example, when the branched vinyl ester is vinyl neodecanoate (VN) and MEHQ is used as a polymerization inhibitor, the dosage is adjusted to maintain a concentration of MEHQ in the VN between 2 to 5 ppm w / w in the top product stream or reflux stream. This concentration may be modified depending on the restrictions imposed by the high-pressure polymerization process.

[0080] In order to increase recovery efficiency, a partial or total condenser may be provided at the overhead portion of one or more of each distillation column (Cl), (C3) and (C4) for cooling and condensing the vapor leaving column and a reboiler is provided at the bottom portion to supply a heat source required for distillation. Any conventional condenser and reboiler may be used, especially using water / steam to provide this heat exchange.

[0081] According to an alternative embodiment, distillation column (Cl) comprises an electric reboiler at its bottom, instead of having a conventional one. In such embodiments, the bottom conditions of distillation column (Cl) range from 180 to 200 °C and from 600 to 700 mbar (abs); while the overhead conditions of distillation column (Cl) range from 40 to 48 °C and 450 to 600 mbar (abs).

[0082] In one of more embodiments, particularly when the vapor-liquid phase separator is a distillation column (Cl), there is a gaseous loss and a partial condensation at its overhead due to the presence of non-condensable gases in the feed stream.

[0083] When the vapor-liquid phase separator is a flash vessel (SI), there is a gaseous loss and a partial condensation at (C3) overhead. In such embodiments, there is also a demister at top of the flash vessel to enhance the removal of liquid droplets entrained in vapor stream. It may be a mesh-type coalescer, vane pack, cyclone, or any other conventional structureintended to aggregate the mist into droplets that are heavy enough to separate from the vapor stream.

[0084] According to the present invention, the distillation columns (Cl), (C3) and (C4) are independently selected from tray columns and packing columns. In one or more embodiments, (Cl), (C3) and (C4) have, respectively, lower than 15, lower than 30 and lower than 20 of theoretical stages. Preferably, (Cl) has a number of theoretical stages ranging from 6 to 10, (C3) has a number of theoretical stages ranging from 15 to 25 and (C4) has a number of theoretical stages ranging from 10 to 14.

[0085] In one or more embodiments, the feed stream may be fed to distillation column (Cl) at a position ranging from 60 to 95% (up to top) of the tray section or of the packing; (Cl”) stream may be fed to distillation column (C3) at a position ranging from 35 to 50% of the tray section or of the packing; while (C3”) stream may be fed to distillation column (C4) at a position ranging from 45 to 70% (up to top) of the tray section or of the packing.

[0086] In another embodiment of the present invention, the recovery system according to the present invention further comprises both a distillation column (C2) and a distillation column (C5), which aim to obtain a purified light vinyl ester stream. Hence, in such embodiments, the recovery system according to the present invention further comprises:

[0087] a distillation column (C2) for separating an overhead stream (C2’) comprising a wet light vinyl ester fraction, a vent stream (E2’) and a bottom stream (C2”) comprising a light vinyl ester-rich fraction from a (C2i) stream; and

[0088] a distillation column (C5) for separating an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction from (C2”) stream.Distillation column C2

[0089] The distillation column (C2) aims at separating an overhead stream (C2’), a vent stream (E2’) and a bottom stream (C2”) from a (C2i) stream, i.e., the stream that enters the distillation column (C2). According to the present invention, the (C2i) stream comprises the (ST) or (Cl’) stream, i.e., the overhead stream of the vapor-liquid phase separator of one or multiple stages (SI) or (Cl) that comprises a light vinyl ester-rich fraction. In one or more embodiments, (C2i) stream consists of (ST) or (CT) stream.

[0090] In an alternative embodiment, (C2i) stream comprises a mixture of (ST) or (Cl’) stream and an additional stream (D2’), which is also rich in light vinyl ester. In such embodiments, (D2’) stream contains light drained liquids derived from a high-pressure polymerization process.

[0091] In one particular embodiment, (D2’) stream comprises more than 90 wt.% of light vinyl ester and may also comprise traces of a light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms and contaminants, such as water and oxygenate compounds, as well as traces of branched vinyl ester, heavies and dissolved non-condensable compound, such as ethylene. In said embodiments, (C2i) stream is composed by (CT) or (ST) stream and (D2’) stream in any proportion.

[0092] In one embodiment of the invention, the (C2i) stream is fed to the distillation column (C2) at a position ranging from 40, 50, 60, 70, 80 or 90% (up to top) of the tray section or of the packing. In a preferred embodiment, the (C2i) stream is fed to the distillation column (C2) at a position ranging from 60 to 80% (up to top) of tray section or of the packing. In an even more preferred embodiment, the (C2i) stream is fed to the distillation column (C2) at a position of 73% (up to top) of tray section or of the packing.

[0093] More particularly, the aim of distillation column (C2) is to separate water (moisture) from the light vinyl ester, since water forms an azeotrope with the light vinyl ester, i.e., a mixture in which a gas composition and a liquid composition are the same and the components therein may not be separated through simple distillation.

[0094] The overhead stream (C2’) comprises a wet light vinyl ester fraction, which comprises more than 50 wt.%, or more than 75 wt.%, or even more than 90 wt.% of the water contained in the feed streams (DT) and (D2’). Particularly, (C2’) stream comprises from 1 to 10 wt.% of water and from 80 to 99 wt.% of the light vinyl ester, based on the total weight of (C2’) stream. (C2’) stream may also comprise up to 10 wt.% of contaminants, such as acetaldehyde and C3-(C4) alcohols.

[0095] The vent stream (E2’) comprises up to 60 wt.% of non-condensable gases, up to 80 wt.% of light vinyl ester, up to 10.0 wt.% of oxygenates and up to 5 wt.% of water.

[0096] The bottom stream (C2”) comprises a light vinyl ester-rich fraction, which is substantially free from water. The expression “substantially free” means that water may be present in amounts lower than 500 ppm w / w, or lower than 300 ppm w / w, or lower than200 ppm w / w. Particularly, (C2”) stream may comprise more than 80 wt.%, or more than 90 wt.%, or more than 98 wt.% of the light vinyl ester and it may further comprise traces of other contaminants, such as oxygenate compounds.

[0097] In one or more embodiments, the bottom temperature of distillation column (C2) ranges from 75 to 95 °C and the bottom pressure ranges from 1.1 to 1.9 bar (abs); and wherein the overhead temperature of distillation column (C2) ranges from 35 to 50 °C and the overhead pressure ranges 1.0 to 1.8 bar (abs).Distillation column C5

[0098] The distillation column (C5) aims at separating an overhead stream (C5’) and a bottom stream (C5”) from (C2”) stream, i.e., the bottom stream of the distillation column (C2).

[0099] In one embodiment of the invention, the (C2”) stream is fed to the distillation column (C5) at a position ranging from 40, 50, 60, 70, 80 or 90% (up to top) of the tray section or of the packing. In a preferred embodiment, the (C2”) stream is fed to the distillation column (C5) at a position ranging from 50 to 70% (up to top) of tray section or of the packing. In an even more preferred embodiment, the (C2”) stream is fed to the distillation column (C5) at a position of 60% (up to top) of tray section or of the packing.

[0100] The overhead stream (C5’) comprises the purified light vinyl ester stream which is intended to be recovered in one or more embodiments of the present invention. Particularly, (C5’) stream comprises the purified light vinyl ester in amounts more than 95 wt.%, or more than 98 wt.%, or more than 99 wt.%, based on the total weight of the components of (C5’) stream. (C5’) stream may also have traces of contaminants, such as C3-C4 alcohols, water and carboxylic acids derived from the light vinyl ester.

[0101] The bottom stream (C5”) comprises a branched vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester. Particularly, it comprises up to 70 wt.% of the branched vinyl ester and it may further comprise from 10 to 40 wt.% of the light vinyl ester, from 5 to 20 wt.% of a heavy solvent fraction comprising a mixture of hydrocarbons with 12 to 16 carbon atoms, 5 to 10 wt.% of carboxylic acids derived from the light vinyl ester and traces of polymeric waxes, such as polyisobutylene.

[0102] In one or more embodiments, the bottom temperature of distillation column (C5) ranges from 100 to 130 °C and the bottom pressure ranges from 1.1 to 1.9 bar (abs); and wherein the overhead temperature of distillation column (C5) ranges from 35 to 50 °C and the overhead pressure ranges from 1.0 to 1.8 bar (abs).

[0103] According to the present invention, distillation columns (C2) and (C5) are independently selected from tray columns and packing columns. The distillation column (C2) may have a number of theoretical stages lower than 20 and distillation column (C5) may have a number of theoretical stages lower than 15. Preferably, distillation columns (C2) and (C5) have a number of theoretical stages ranging from 11 to 17 and 8 to 12, respectively.

[0104] In one or more embodiments, the feed points of both distillation columns (C2) and (C5) may be at a position ranging from 40 to 85% (up to top) of the tray section or of the packing.

[0105] In one or more embodiments, the recovery system according to the present invention provides high purity levels and high recovery ratios of the light vinyl ester. The outlet stream (C5’), which is the overhead of distillation column (C5), has a purity level (light vinyl ester content) ranging from 95 to 99,99 wt.%, based on the total weight of the purified light vinyl ester stream (C5’), and a light vinyl ester recovery ratio of 80 to 99 wt.%, based on the total weight of light vinyl ester contained in the feed streams (DF) and (D2’).

[0106] Figure 3 represents one or more embodiments of the present invention comprising the recovery unit comprising a flash vessel (SI) and distillation columns (C2), (C3), (C4) and (C5), and their respective overhead and bottom streams (ST), (SI”), (C2’), (C2”), (C3’), (C3”), (C4’) and (C4”), (C5’) and (C5”). In Figure 3, (EF), (E2’) and (E3’) comprise the vent stream of columns (SI), (C2) and (C3), respectively.

[0107] Figure 4 represents one or more embodiments of the present invention comprising the recovery unit comprising distillation columns (Cl), (C2), (C3), (C4) and (C5), and their respective overhead and bottom streams (CT), (Cl”), (C2’), (C2”), (C3’), (C3”), (C4’) and (C4”), (C5’) and (C5”). In Figure 4, (EF) and (E2’) comprise the vent stream of columns (Cl) and (C2), respectively

[0108] In Figures 3 and 4, (C2i) comprises both (SF) and (D2’) streams or (CF) and (D2’) streams respectively.

[0109] In another embodiment, as shown in Figures 5 and 6, the system may comprise further recycled streams. In some embodiments, the bottom stream (C5”) of column (C5) may be combined with the bottom stream (Cl”) of column (Cl), forming a (C3i) stream, that is fed to column (C3), aiming for a further recovery of branched vinyl ester from (C5) bottom stream. In another embodiment, a portion of the bottom stream (C5”) of column (C5), stream (C5i), may be combined with the bottom stream (SI”) of the flash vessel (SI), forming a (C3i) stream, that is fed to column (C3), aiming for a further recovery of branched vinyl ester from (C5) bottom stream. Alternatively, these streams (C5”) and / or (C5i) may be fed to distillation column (C3) at a different feed point, above the (SI”) or (CT ’) stream feeding point, but inside the range of 55 to 80% (up to top) of the tray section or of the packing of (C3) column. In Figure 5, the recycle of bottom stream (C5”) of column (C5) is partial, forming a separated (C5i) stream that is fed to the column (C3). In Figure 6, the recycle of bottom stream (C5”) of column (C5) is total, wherein the (C5”) stream is fully directed to the (C3) column.

[0110] It is also envisioned that the system may comprise a further recycle, aiming for a further recovery of light vinyl ester from the (C3) column overhead (C3’) stream to the column (C2). Such (C3 ’) stream may be mixed with the (C2) feed stream (C2i) prior to entering into the (C2) distillation column or alternatively be fed at a point below the feeding point of (C2i) stream, but up to 10% (up to top) of the tray section or of the packing of (C2).

[0111] A further embodiment of the present invention relates to a recovery system for obtaining a purified branched vinyl ester stream, the system comprising:- a distillation column (Cl) for separating an overhead stream (CT) comprising a light vinyl ester -rich fraction and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction from a feed stream (DF) comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; and- a distillation column (C6) for separating an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising heavies and a side stream C6s comprising the purified branched vinyl ester stream from (Cl”) stream.Distillation Column Cl 1

[0112] The distillation column (Cl) aims to separate an overhead stream (CT) and a bottom stream (Cl”) from the feed stream. It is also envisioned that a vent stream (EC) may be separated in (Cl).

[0113] The overhead stream (CT) comprises a light vinyl ester-rich fraction, i.e., it comprises more than 70 wt.% of a light vinyl ester, based on the total weight of (DE) feed stream. Particularly, the overhead stream (CT) comprises more than 80 wt.% and up to 99 wt.% of a light vinyl ester, and it may comprise traces of contaminants, such as water, alcohol and carboxylic acids derived from the light vinyl ester, as well as traces of a light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms. In a preferred embodiment, the overhead stream (CT) comprises more than 90 wt.% and up to 99 wt.% of a light vinyl ester.

[0114] The vent stream El’ comprises up to 99.9 wt.% of the non-condensable gases which are presented in the feed stream (DE). The vent stream compromises also light components as more than 50 wt.% and up to 95 wt.% of light vinyl ester, 0.1 wt.% and up to 10.0 wt.% of oxygenates and 0.1 wt.% and up to 0.5 wt.% of water.

[0115] The bottom stream (Cl”) comprises a branched vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester which is intended to be purified. Particularly, the bottom stream (Cl”) comprises more than 70 wt.% and up to 95 wt.% of the branched vinyl ester, up to 10 wt.% of a heavy solvent fraction comprising a mixture of hydrocarbons with 12 to 16 carbon atoms, up to 5 wt.% of heavies, and traces of contaminants such as carboxylic acids, as well as traces of the light vinyl ester.

[0116] The bottom conditions of distillation of column (Cl) may range from 150 to 170 °C and from 250 to 350 mbar (abs), while the overhead conditions of distillation of column (Cl) ranges from 25 to 35 °C and from 200 to 300 mbar (abs).Distillation Column C6

[0117] The distillation column (C6) aims to separate an overhead stream (C6’), a bottom stream (C6”) and a side stream C6s from (Cl ”) stream, i.e., the bottom stream of distillation column (Cl).

[0118] The overhead stream (C6’) comprises more than 50 wt.% of a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11carbon atoms. Particularly, it may comprise more than 70 wt.%, or more than 80 wt.%, and up to 90 wt.% of the light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms, in addition to up to 15 wt.% of carboxylic acids derived from the branched vinyl ester and up to 15 wt.% of heavies. (C6’) stream may also contain up 15 to wt.% of the branched vinyl ester.

[0119] The bottom stream (C6”) comprises heavies and contaminants in amounts of more than 50 wt.%, based on total weight of the components of (C6”) stream. Contaminants in (C6”) stream are mainly composed by carboxylic acids derived from the branched vinyl ester. Particularly, the amounts of heavies in (C6”) stream may be more than 50 wt.% to 80 wt.%, and the amount of carboxylic acid may be more than 5 wt.%. to 10 wt.%, based on the total weight of the components in (C6”) stream. In one or more embodiments, (C6”) stream also comprises more than 10 wt.% to 20 wt.% of a heavy solvent fraction comprising a mixture of hydrocarbons with 12 to 16 carbon atoms, based on the total weight of the components in (C6”) stream.

[0120] Side stream C6s comprises the purified branched vinyl ester stream, which is the product intended to be recovered. Particularly, the purified branched vinyl ester stream may comprise more than 95 wt.%, or more than 98 wt.%, or more than 99 wt.% of the branched vinyl ester. The side stream may also have traces of a heavy solvent fraction comprising a mixture of hydrocarbons selected from the group comprising Cn-Cie and contaminants, such as carboxylic acids derived from the branched vinyl ester.

[0121] In one or more embodiments, the bottom conditions of distillation column (C6) ranges from 160 to 180 °C and from 100 to 500 mbar (abs); and the overhead conditions of distillation column (C6) ranges from 65 to 72 °C and from 25 to 35 mbar (abs).

[0122] According to such embodiments, (Cl) and (C6) may be independently selected from tray or packing columns, and the feed stream may be fed to distillation column (Cl) at a position ranging from 60 to 95% (up to top) of the tray section or of the packing; while (Cl”) stream may be fed to distillation column (C6) at a position ranging from 20 to 40% (up to top) of the tray section or of the packing. Besides, the withdrawal of side stream C6s may be at a position ranging from 60 to 80% (up to top), preferably from 65 to 75% (up to top), of the tray section or of the packing.

[0123] In one or more embodiments, (Cl) and (C6) have, respectively, lower than 15 and lower than 48 of theoretical stages. Preferably, (Cl) has a number of theoretical stages ranging from 6 to 10 and (C6) has a number of theoretical stages ranging from 26 to 38.

[0124] In addition, in embodiments wherein the recovery system comprises distillation columns (Cl) and (C6), the recovery unit may alternatively also comprise a distillation column (C7), which aims at obtaining a purified light vinyl ester stream. Hence, in such embodiments, the recovery system according to the present invention further comprises:

[0125] a distillation column (C7) for separating an overhead stream (C7’) comprising a wet light vinyl ester fraction, a vent stream (E7’) comprising a light vinyl ester fraction and non-condensable, and a bottom stream (C7”) comprising a branched vinyl ester-rich fraction and a side stream (C7s) comprising a purified light vinyl ester stream from (C7i) stream, wherein (C7i) stream comprises (CT) stream.Distillation Column C7

[0126] The distillation column (C7) aims at separating an overhead stream (C7’), a vent stream (E7’), a bottom stream (C7”) and a side stream C7s from (C7i) stream, i.e., the stream that enters the distillation column (C7) and it comprises (CT) stream (the overhead stream of the distillation column (Cl) comprising a light vinyl ester-rich fraction). In one or more embodiments, (C7i) stream consists of (CT) stream.

[0127] In alternative embodiments, (C7i) stream comprises a mixture of (CT) stream and an additional stream (D2’), which is also rich in light vinyl ester. In such embodiments, (D2’) stream contains light drained liquids derived from a high-pressure polymerization process.

[0128] In one particular embodiment, (D2’) stream comprises more than 90 wt.% of light vinyl ester and may also comprise traces of a light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbon atoms and contaminants, such as water and oxygenate compounds, as well as traces of branched vinyl ester, heavies and dissolved ethylene. In said embodiments, (C7i) stream is composed of (CT) stream and (D2’) stream in any proportion.

[0129] More particularly, the aim of distillation column (C7) is to separate i) water (moisture) from the light vinyl ester at its overhead, since water forms an azeotropic mixturewith the light vinyl ester, ii) heavies at its bottom and iii) a purified light vinyl ester stream by a side stream.

[0130] The overhead stream (C7’) comprises a wet light vinyl ester fraction, which comprises less than 5.0 wt.%, or less than 3.0 wt.%, or even less than 2.0 wt.% of the water contained in the feed stream. Particularly, (C7’) stream comprises from 1 to 10 wt.% of water and from 99 to 80 wt.% of the light vinyl ester, based on the total weight of (C7’) stream. (C7’) stream may also comprise up to 10 wt.% of contaminants, such as acetaldehyde and Cs-(C4) alcohols.

[0131] The vent stream E7’ comprises up to 60 wt.% of non-condensable gases, up to 80 wt.% of light vinyl ester, up to 10.0 wt.% of oxygenates and up to 5 wt.% of water.

[0132] The bottom stream (C7”) comprises a branched vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester. Particularly, it comprises less than 70 wt.% of the branched vinyl ester and it may further comprise from 10 to 40 wt.% of the light vinyl ester, from 5 to 20 wt.% of a heavy solvent fraction comprising a mixture of hydrocarbons with 12 to 16 carbon atoms, 5 to 10 wt.% of carboxylic acids derived from the light vinyl ester and traces of polymeric waxes, such as polyisobutylene.

[0133] The side stream C7s comprises the purified light vinyl ester stream, which is intended to be recovered in one or more embodiments of the present invention. Particularly, (C7s) stream comprises the purified light vinyl ester in amounts more than 95 wt.%, or more than 98 wt.%, or more than 99 wt.%, based on the total weight of the components of the side stream. The side stream may also have traces of contaminants, such as C3-C4 alcohols, water and carboxylic acids derived from the light vinyl ester.

[0134] In one or more embodiments, the bottom conditions of distillation column (C7) ranges from 150 to 165 °C and from 1.2 to 2.0 bar (abs); and the overhead conditions ranges from 45 to 55 °C and from 1.1 to 1.8 bar (abs).

[0135] According to such embodiments, (C7) may be either a tray or packing column, and it may be fed at a position ranging from 30% to 50% (up to top) of the tray section or of the packing. The withdrawal of the side stream (C7s) may be at a position ranging from 65% to 90% (up to top), preferably from 70% to 85% (up to top), of the tray section or of the packing.

[0136] In one or more embodiments, (C7) has lower than 36 of theoretical stages. Preferably, (C7) has a number of theoretical stages ranging from 19 to 29.

[0137] The present invention further relates to a monomer recovery process for obtaining a purified branched vinyl ester stream. The process comprises:

[0138] - injecting a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies to a vapor-liquid phase separator of one or multiple stages (SI) or (Cl) and recovering an overhead stream (ST) or (CT) comprising a light vinyl ester -rich fraction and a bottom stream (SI”) or (Cl”) comprising a branched vinyl ester-rich fraction, wherein the vaporliquid phase separator of one or multiple stages is a distillation column (Cl) or a flash vessel (Si);

[0139] - injecting (SI”) or (Cl”) stream to a distillation column (C3) and recovering an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons with 5 to 11 carbon atoms and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction;

[0140] - injecting (C3”) stream to a distillation column (C4) and recovering an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising contaminants and heavies.

[0141] The process according to the present invention provides high purity levels and high recovery ratios of the branched vinyl ester intended to be recovered from the feed stream. The outlet stream (C4’), which is the overhead stream from (C4) distillation column, has a branched vinyl ester purity level ranging from 90 to 99,9 wt.%, based on the total weight of the purified branched vinyl ester stream, and a branched vinyl ester recovery ratio of 80 to 99 wt.%, based on the total weight of branched vinyl ester contained in the (DT) feed stream.

[0142] In one or more embodiments, the purification process also comprises the following steps aiming at further obtaining a purified light vinyl ester stream:

[0143] - injecting a (C2i) stream to a distillation column (C2) and recovering an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and

[0144] - injecting (C2”) stream to a distillation column (C5) and recovering an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction,

[0145] wherein (C2i) stream consists of (ST) or (CT) stream or it comprises a mixture of (ST) or (Cl’) stream and an additional stream (D2’) derived from a high-pressure polymerization process, wherein (D2’) stream comprises more than 90 wt.% of light vinyl ester, based on the total weight of (D2’) stream.

[0146] In such embodiments, the process according to the present invention further provides high purity levels and high recovery ratios of the light vinyl ester. The outlet stream (C5’), which is the overhead of distillation column (C5), has a purity level (light vinyl ester content) ranging from 95 to 99,99 wt.%, based on the total weight of the purified light vinyl ester stream, and a light vinyl ester recovery ratio of 80 to 99 wt.%, based on the total weight of light vinyl ester contained in the feed stream.

[0147] In one or more embodiments, the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl).

[0148] In one or more embodiments, the bottom and overhead conditions of distillation columns (Cl), (C3), (C4), also (C2) and (C5), if present, are as already described above, and they can be independently selected from tray or packing columns. In one or more embodiments, (Cl) has a number of theoretical stages lower than 15, preferably ranging from 6 to 10; (C3) has a number of theoretical stages lower than 30, preferably ranging from 15 to 25; (C4) has a number of theoretical stages lower than 20, preferably ranging from 10 to 14, (C2) has a number of theoretical stages lower than 20, preferably ranging from 11 to 17; and (C5) has a number of theoretical stages lower than 15, preferably ranging from 8 to 12.

[0149] In one or more embodiments, the (DF) feed stream may be injected to distillation column (Cl) at a position ranging from 60 to 95% (up to top) of the tray section or of the packing; (Cl”) stream may be injected to distillation column (C3) at a position ranging from 35 to 50% (up to top) of the tray section or of the packing; while (C3”) stream may be injected to distillation column (C4) at a position ranging from 45 to 70% (up to top) of the tray section or of the packing.

[0150] In the embodiments wherein the process of the present invention comprises distillation columns (C2) and (C5), the feed points of both (C2) and (C5) may be at a position ranging from 40 to 85% (up to top) of the tray section or of the packing.

[0151] In order to increase recovery efficiency, a partial or total condenser is provided at the overhead portion of each distillation column for cooling and condensing the vaporleaving column and a reboiler is provided at the bottom portion to supply a heat source required for distillation. Any conventional condenser and reboiler may be used, especially using water / steam to provide this heat exchange.

[0152] According to an alternative embodiment, distillation column (Cl) comprises an electric reboiler at its bottom, instead of having a conventional one. In such embodiments, the process of the present invention further comprises providing heat to the bottom of distillation column (Cl) through an electric reboiler, wherein the bottom conditions of distillation column (Cl) range from 180 to 200 °C and from 600 to 700 mbar (abs); while the overhead conditions of distillation column (Cl) range from 40 to 48 °C and 450 to 600 mbar (abs).

[0153] In one of more embodiments, particularly when the vapor-liquid phase separator is a distillation column (Cl), there is a gaseous loss and a partial condensation at its overhead due to the presence of non-condensable gases in the feed stream.

[0154] In an alternative embodiment, the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI), and it operates at a temperature ranging from 130 to 145 °C and under atmospheric pressure.

[0155] In such embodiments, when the vapor-liquid separator is a flash vessel, there is a gaseous loss and a partial condensation at the overhead of distillation column (C3), which comprises a partial condenser operating with a refrigerant system configured for maintaining the overhead stream in a temperature range from 20 to 30 °C. In these embodiments, any conventional refrigerant fluid more efficient than water may be used, such as, but not limited to, ethylene glycol, propylene glycol, butane and glycol / water mixtures.

[0156] Besides, a demister may also be installed at top of the flash vessel to enhance the removal of liquid droplets entrained in vapor stream. It may be a mesh-type coalescer, vane pack, cyclone, or any other conventional structure intended to aggregate the mist into droplets that are heavy enough to separate from the vapor stream.

[0157] In one or more embodiments, the purification process according to the present invention further comprises a step of returning (C5”) stream, which is the bottom stream of distillation column (C5), to distillation column (C3). This return aims at enhancing the recovery of the branched vinyl ester, since (C5”) stream comprises a branched vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester.

[0158] In such embodiments, (C5”) stream may i) be mixed to (SI”) or (Cl”) stream before entering distillation column (C3) or ii) be fed to distillation column (C3) at a different feed point above (SI”) or (Cl”) stream feeding point, but inside the range of 60 to 90% (up to top) of the tray section or of the packing.

[0159] Figure 5 and Figure 6 represent one or more embodiments when there is a step of returning (C5”) bottom stream to distillation column (C3), wherein both (C5”) and (SI”) or (Cl”) streams are mixed before entering column (C3).

[0160] It is also envisioned that the purification process according to the present invention may comprise a step of returning (C3’) stream, which is the overhead stream of distillation column (C3), to distillation column (C2). This return aims at enhancing the recovery of the light vinyl ester, since (C3’) stream comprises a light vinyl ester-rich fraction, i.e., it comprises more than 50 wt.% of the branched vinyl ester.

[0161] In such embodiments, (C3’) stream may i) be mixed to (C2i) stream before entering distillation column (C2) or ii) be fed to distillation column (C2) at a different feed point below (C2i) stream feeding point, but up to 10% (up to top) of the tray section or of the packing of (C2).

[0162] Figure 5 represents one or more embodiments when there is a step of returning (C3’) overhead stream to distillation column (C3), wherein (C3’) is fed to a different feeding point from the (C2i) stream feed in (C2) column.Alternative Embodiment

[0163] An alternative embodiment of the present invention, which can be seen in Figure7, relates to a purification process for obtaining a purified branched vinyl ester stream, the process comprising:- injecting a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies to a distillation column (Cl) and recovering an overhead stream (CT) comprising a light vinyl ester-rich fraction and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction; and- injecting (Cl”) stream to a distillation column (C6) and recovering an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprisesa mixture of hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising contaminants and heavies and a side stream (C6s) comprising the purified branched vinyl ester stream.

[0164] In addition, in embodiments wherein the purification process of the present invention comprises distillation columns (Cl) and (C6), the process may also comprise a further step for also obtaining a purified light vinyl ester stream through a distillation column (C7). Such step comprises:- injecting (C7i) stream to a distillation column (C7) and recovering an overhead stream (C7’) comprising a wet light vinyl ester fraction, a bottom stream (C7”) comprising a branched vinyl ester-rich fraction and a side stream (C7s) comprising a purified light vinyl ester stream, wherein (C7i) stream comprises (Cl’) stream.

[0165] In alternative embodiments, (C7i) stream comprises a mixture of (CT) stream and an additional stream (D2’), which is also rich in light vinyl ester. In such embodiments, (D2’) stream contains light drained liquids derived from a high-pressure polymerization process.

[0166] In one particular embodiment, (D2’) stream comprises more than 90 wt.% of light vinyl ester and may also comprise traces of a light solvent fraction comprising a mixture of hydrocarbons with 5 to 11 carbom atoms and contaminants, such as water and oxygenate compounds, as well as traces of branched vinyl ester, heavies and dissolved ethylene. In said embodiments, (C7i) stream is composed of (CT) stream and (D2’) stream in any proportion.

[0167] In one or more embodiments, the bottom and overhead conditions of distillation columns (Cl), (C6), and (C7), if present, as well as its corresponding incoming and outgoing streams are as already described above.

[0168] Examples

[0169] Analytical methodologies

[0170] Different analytical methods were employed to measurement and characterization of a number of properties used in the following Examples, including the laboratory tests conducted for the proof of concept of vinyl neodecanoate (VN) recovery and the thermal stability of this monomer (Examples 3 and 4 below), such as color determination, unsaturation index, acidity, density, viscosity, refractive index, and chemical composition.

[0171] Color was measured according to ASTM D1209 using the LoviBond PFXI 880 equipment with matched optical cells (typically 50 mm path length). The instrument was calibrated against platinum-cobalt standard solutions. Fresh monomers were considered as colorless (white), serving as a reference for evaluating discoloration in recovered fractions.

[0172] Unsaturation index was determined via potentiometric titration in accordance with ASTM DI 159, using a Metrohm Titrino Plus 848. Samples were titrated with a bromidebromate solution in a non-chlorinated solvent system, with endpoint detection via double platinum electrode. Bromine number was calculated based on titrant volume and sample mass, enabling precise quantification of vinyl unsaturation.

[0173] Acid value was determined following ASTM DI 639, which involves titration of acidic constituents in the sample with a standardized alcoholic potassium hydroxide (KOH) solution. The endpoint was detected using phenolphthalein as an indicator. Results were expressed in mg KOH per gram of sample, indicating the total acidity present.

[0174] Density was measured in accordance with ASTM D4052 using an Anton Paar SVM 2000 Viscometer-Densimeter. The instrument performs automated measurement of density and viscosity via oscillating U-tube technology, with temperature control set to 20 °C.

[0175] Boiling point distribution was determined according to ASTM D2887 using a PerkinElmer Clarus 590 gas chromatograph (GC) equipped with a flame ionization detector (FID) and a non-polar capillary column. The method simulates distillation by GC, providing a detailed boiling range profile of Isoparaffin, VN, Versatic Acid, Polyisobutylene (PIB) and Lubricants.

[0176] Dynamic viscosity and density were measured simultaneously in accordance with ASTM D7042 using the Anton Paar SVM 2000. The instrument utilizes viscometry and oscillating U-tube technology to provide high-accuracy measurements.

[0177] Refractive index was determined in accordance with ASTM D1218 using an Anton Paar Abbemat 350 refractometer. The instrument provides automatic measurement with temperature-controlled sample handling.

[0178] Chemical composition, purity and recovery rates of branched-vinyl ester (VN) matrix was analyzed using gas chromatography-mass spectrometry (GC-MS). The instrumentation consisted of an Agilent 7890 gas chromatograph coupled to a 5977B mass selective detector operating in electron ionization (El) mode. Chromatographic separation wasachieved using a capillary column (HP-1) with a stationary phase of 100% poly dimethylsiloxane, measuring 100 meters in length, 250 micrometers in internal diameter, and 0.5 micrometers in film thickness. The carrier gas was helium, delivered at a constant flow rate of 1.5 mL / min. Identification and quantification of chemical constituents were performed by comparing retention times and mass spectral data to reference spectral libraries. The following chromatography parameters were used:Injection Parameters:Injector type: Split / Splitless (SSL)Injection mode: Split ratio of 25: 1Injector temperature: 250 °CCarrier gas pressure: 30 psiSample injection volume: 1 pLOven Temperature Program:Initial temperature: 40 °C (held for 0 minutes)Ramp rate: 8 °C / min to 240 °CHold at 240 °C for 25 minutesMass Spectrometer Parameters:Mass range: 30 to 400 atomic mass units (amu)Acquisition mode: Total Ion Chromatogram (TIC) and Scan

[0179] Quantitative analysis of VN + PIB (polyisobutylene) + Isoparaffin + Versatic Acid, purity and recovery rates of light vinyl ester (vinyl acetate) were conducted using gas chromatography with flame ionization detection (GC-FID). The instrumentation consisted of an Agilent 7890 gas chromatograph equipped with a flame ionization detector (FID). Chromatographic separation was performed using a medium polarity capillary column (RTX- 1301), measuring 60 meters in length, 250 micrometers in internal diameter, and 1 micrometer in film thickness. The following chromatography parameters were used:Injection Parameters:Injector type: Split / Splitless (SSL)Injection mode: Split ratio of 100: 1Injector temperature: 250 °CCarrier gas pressure: 29 psiSample injection volume: 0.5 pLChromatographic Conditions:Carrier gas flow rate: 1.5 mL / min (constant flow mode)Oven temperature program:Initial temperature: 40 °C (held for 0 minutes)Ramp rate: 5 °C / min to 120 °C Hold at 120 °C for 2 minutes Ramp rate: 10 °C / min to 245 °C Final hold at 245 °C for 15 minutes.Example 1 - Process Simulation of the Recovery System

[0180] The design of the inventive recovery systems were conducted using a commercial process simulator - ASPEN Plus V12.1. Vinyl neodecanoate (VN) and vinyl acetate were selected as the branched vinyl ester and light vinyl ester, respectively. The thermodynamic modeling strategy employed in the recovery process of vinyl neodecanoate (VN) and its associated contaminants was established based on an extensive literature review and experimental data, including true boiling point (TBP) measurements, thermogravimetric analyses, and calorimetric evaluations of each of the monomer, contaminants and their thermodynamic interactions. This data enabled accurate characterization of the mixture and informed the selection of appropriate thermodynamic models. The non-ideality of the liquid phase was represented using the Non-Random Two-Liquid (NRTL) model, while the vapor phase non-ideality was described using the Hayden-O'Connell (HOC) equation of state. Parameter adjustment was performed using both experimental results and literature data, ensuring reliable simulation of the recovery process, particularly in systems exhibiting minimal differences in boiling points among components.

[0181] Eight different process and system configurations were tested and their data is summarized in Table 1 below, which shows monomer recovery, purity, and specific thermal energy consumption in the condenser and reboiler for each of these 8 process configurations, using a drained VN feed (DE) (74.03% VN, 16.74% VA) and a drained VA feed (D2’) (97.93% VA, 1.29% VN) representative of an industrial high pressure polymerization process of ethylene, VN and VA as monomers.Table 1 - Recovery, purity, and specific thermal energy consumption in the condenser and reboiler for varied VN and VA recovery processes configurationsExample 2- Industrial Scale Monomer Recovery System Simulation

[0182] For this example industrial scale inventive monomer recovery system was simulated according to the process shown in FIG. 6 and with each stream detailed in Table 2. The design of the inventive recovery system was conducted using the commercial process simulator ASPEN Plus as described in Example 1.

[0183] For each ton of ethylene-vinyl acetate-vinyl neodecanoate terpolymer produced in a high-pressure polymerization process, approximately 210 kg of two monomer-rich streams - vinyl acetate (light vinyl ester- 53.7%) and vinyl neodecanoate (branched vinyl ester - 46.3%) - must be purified. Each stream is processed in a specific section. Any light monomer carried into the heavy stream is redirected to the light vinyl ester recovery section, and vice versa. This cross-recycling ensures efficient monomer recovery.

[0184] The lighter feed stream (D2’) contains in this example approximately 97.9% (w / w) vinyl acetate (VA), 1.29% (w / w) vinyl neodecanoate (VN) and 0.14% (w / w) ethylene.It also includes by-products from the polymerization process, such as 0.10% (w / w) acetic acid and 0.17% (w / w) of oxygenated compounds (acetaldehyde and tert-butanol) and contaminants, 0.29% (w / w) isoparaffins (used in the peroxide solution), around 577 ppm of moisture and trace of heavy products (325 ppm (w / w) lubricating oil and PIB10 (a polyisobutene-based emollient commercially available by Braskem S. A.).

[0185] The vinyl acetate (VA) recovery process from drainage streams involves two distillation columns, (C2) and (C5), operating at a pressure of 1.6 bar(a). Column (C2), with 12 theoretical stages and a partial condenser, removes moisture, light components, and part of the oxygenates from the feed. The VA-rich stream, introduced at the fourth stage of (C2) after receiving the overhead product from column (Cl) (VN recovery section), is processed with a reflux ratio of 5 and a top product withdrawal rate (C2’) of 2% of the feed. Moisture removal in (C2) ensures that the recovered VA at the top of column (C5) contains approximately 148 ppm (w / w) of water at (C5’) stream. Around 1.14% (w / w) of the VA is lost through the column vent ((E2’) stream).

[0186] Hydroquinone (as polymerization inhibitor) is introduced into the feed stream (C2i) and upstream of the condenser of column (C2), so as to maintain target concentrations of approximately 15 ppm in the reflux drum and 200 ppm at the (C2) column bottom, respectively.

[0187] The bottom product of column (C2) (stream (C2”)) feeds column (C5), which has 8 theoretical stages and operates with a reflux ratio of 1.1. Additionally, hydroquinone is also introduced upstream of the condenser of column (C5) to maintain a polymerization inhibitor concentration of approximately 15 ppm in the reflux drum. This column removes acetic acid, maintaining its concentration in the recovered VA at approximately 50 ppm (w / w). The bottom withdrawal rate (C5”) is 2.3% of the feed C2”). The VA recovered at the top of (C5) has a purity of 99.86%, with 0.12% tert-butanol due to incomplete oxygenate removal in (C2). The estimated loss of VA in the bottom product of (C5) ((C5”) stream) is 0.6% of its initial amount in the (C5) collum feed. The bottom stream from column (C5) is routed to the drained VN recovery section, aiming to increase the recovery of VN present in the drainage streams.

[0188] The heavier feed stream (DI’) (branched vinyl ester rich stream) contains 74.03% (w / w) vinyl neodecanoate (VN) and 19.74% vinyl acetate (VA). It also includes byproducts from the polymerization process, such as 0.63% organic acids (52.38% acetic acidand 47.62% versatic acid) and 512 ppm of oxygenated compounds (acetaldehyde and tertbutanol) and contaminants, 3.53% heavy products (lubricating oil and PIB), 4.72% isoparaffins (used in the peroxide solution), and around 307 ppm of moisture.

[0189] The purification of the vinyl neodecanoate (VN)-rich stream is carried out through fractional distillation in three vacuum-operated columns: (Cl), (C3), and (C4), operating at approximately 250 mbar, 150 mbar, and 75 mbar, respectively.

[0190] Column (Cl), with six theoretical stages and a partial condenser cooled to around 20 °C, receives the drained VN stream at about 40 °C, fed at the second stage. The overhead stream ((CT) stream), representing 14.3% of the feed and composed mainly of vinyl acetate (99.86% w / w), is routed to the light vinyl ester recovery section and mixed with the feed to column (C2), together with the recycled stream (D2’) (light vinyl ester rich feed stream), recycled from the high pressure polymerization process. Approximately 1.42% (w / w) of the VA in the feed is lost through the column vent (EC stream), which typically contains 40.7% non-condensable compounds, 51.3% VA, 3.3% moisture, and 4.8% oxygenates.

[0191] The bottom product of (Cl) ((Cl”) stream), free of VA and moisture, is sent to column (C3) after being mixed with the bottom stream from column (C5) ((C5”) stream). Column (C3), with 16 theoretical stages and a reflux ratio of approximately 20, selectively removes isoparaffins and acetic acid. The overhead stream ((C3’) stream), representing about 8.5% of the feed, contains all the acetic acid, 97.1% of the isoparaffins, and approximately 10% of the lower molecular weight PIB in the (C3) feed stream ((C3i) stream).

[0192] The bottom product of (C3) ((C3”) stream) feeds column (C4), which has 10 theoretical stages and operates with a reflux ratio of 0.6. The recovered VN is withdrawn from the top of column (C4) ((C4’) stream) and has a concentration of VN of 99.72%, with 0.27% of heavy isoparaffin and light PIB fractions, and 84 ppm of versatic acid. The bottom withdrawal rate (C4”) is 8.4% of the (C4) feed ((C3”) bottom stream), and the VN loss in this stream is estimated at 4.1%.

[0193] Polymerization inhibitor MEHQ (monomethyl ether of hydroquinone) is injected, as VN polymerization inhibitor, into the feed stream of column (Cl) ((DE) stream) to maintain a concentration of approximately 50 ppm at the (Cl) column bottom. Polymerization inhibitors are also injected upstream of the condensers of columns (Cl), (C3), and (C4). Specifically, Hydroquinone (VA polymerization inhibitor) is added at the top of column (Cl) to maintain a concentration of approximately 15 ppm in its reflux drum, andMEHQ (VN polymerization inhibitor) is added at the top of columns (C3) and (C4) to maintain a concentration of approximately 5 ppm in their respective reflux drums.

[0194] The combined operation of the drained VA and VN recovery sections enables the recovery of 95.5% (w / w) of vinyl acetate and 95% (w / w) of vinyl neodecanoate.Table 2 - Flowrate and Weight PercentExample 3 - A proof of concept to evaluate the purification of drained VN stream

[0195] In order to evaluate the mathematical representation of the simulation model to simulate the purification and recovery results for the industrial process, a proof of concept test was conducted using the same model of Example 1 to simulate a laboratory scale distillation system and compare with actual distillation data obtained by the laboratory distillation. The aim of the test was to evaluate the purification of a drained VN stream and confirm the distillation recovery and capability predicted by the Aspen model of the industrial scale recovery process described in Example 1.

[0196] A continuous glass distillation column was used to perform a two-step separation of the drained products. The column includes rectifying and stripping sections, with 550 mm height and 50 mm of internal diameter, packed with EX structured stainless steel packing. A synthetic feed reproducing the (Cl”) stream was distilled in two stages: first to remove components lighter than VN, then to separate heavier fractions. The thermodynamic model used for the industrial unit design (Examples 1 and 2) was applied to simulate the lab column and validate the results against experimental data.

[0197] The feed stream can be preheated prior to entering the column. The condenser cooling fluid temperature is adjustable to maintain a low degree of subcooling in the condensed overhead product. Both packed sections are equipped with heating jackets to minimize energy losses in these regions.

[0198] A mixture containing 93.12% vinyl neodecanoate (VN), 3.41% isoparaffin 17 / 21, 1.62% PIB10, 1.136% lubricating oil, 0.633% versatic acid, and 791 ppm of acetic acid was distilled under a pressure of 112 torr. The distillation was carried out using a continuous glass column with a distillate withdrawal interval of 1.5 seconds and total reflux for 10 seconds. The established distillate withdrawal interval ensured that the distillate flow rate remained above the minimum operating flow of the overhead pump. The feed rate was set at 30.57 g / min, with a bottom product withdrawal rate of 27.1 g / min. The feed temperature was maintained at 100 °C.

[0199] The heating jacket of the rectifying section was controlled to maintain an external wall temperature 5 °C above the column’s top temperature, while the jacket of the stripping section was set to 5 °C below the column’ s bottom temperature. Heating was provided by an electric resistance element, and the reboiler power was adjusted to maintain a column pressure drop in the range of approximately 50-60 mmWC, ensuring stable operation and consistent vapor-liquid equilibrium conditions throughout the column.

[0200] The distillation of the mixture under the described conditions resulted in a bottom product free of acetic acid and isoparaffin. Chromatographic analysis of the bottom product indicated acetic acid and isoparaffin levels below the detection limit, 50 ppm e 500 ppm, respectively. The removal of isoparaffin through the column top, as estimated by simulation, was underestimated, corresponding to 94% of the amount present in the feed. The loss of VN through the column top was 7% (w / w), lower than the 9% predicted by thedistillation simulation. The top and bottom temperatures were 133.5 °C and 146.1 °C, respectively, 3.2% and 1.1% lower than the simulated values.

[0201] The mixture resulting from the first distillation contained approximately 97.04% VN, 0.49% versatic acid, 1.17% PIB, and 1.29% lubricant, with no detectable acetic acid or isoparaffins. This mixture was distilled at a pressure of 89.58 torr, with a distillate withdrawal time of 2.6 seconds alternated with 2 seconds of total reflux, a feed rate of 18.3 g / min, and a distillate-to-feed ratio of 74%.

[0202] The distillate from the second distillation showed a VN concentration of 99.97%, 300 ppm of versatic acid, and isoparaffin and PIB levels below the detection limit (<500 ppm)- (Error! Reference source not found.O). The bromine number of the recovered VN was 67.3 g / 100 g, corresponding to 92% of the bromine number of fresh VN. The simulation estimated a composition of 99.94% VN, 230 ppm versatic acid, and 410 ppm PIB. The bottom product did not reach steady-state, but showed a trend of decreasing VN content (93.7%) and increasing versatic acid (2.56% w / w) and heavy components (3.79% w / w, including PIB and lubricant) - (Error! Reference source not found.O). The simulation predicted a bottom composition of 93.4% VN, 1.93% versatic acid, and 4.64% heavy components. VN recovery through the column top was 74.4% (w / w) of the amount in the feed, slightly lower than the 76.2% predicted by the distillation simulation. The top and bottom temperatures were 138.0 °C and 146.2 °C, respectively, approximately 0.3% lower and 1.8% higher than the simulated values.Example 4 - Simulation of a Recovery Unit with a Flash Vessel

[0203] This example refers to simulation of a distillation unit (FIG. 1 and Table 3) used for purifying a recycle stream originating from a high-pressure ethylene copolymerization process with branched vinyl esters (DF). The amount of the stream to be purified corresponds to 97 kg per ton of ethylene-vinyl acetate-vinyl neodecanoate terpolymer produced. This stream ((DF) stream) contains approximately 75 wt.% vinyl neodecanoate. A polymerization inhibitor MEHQ (hydroquinone monomethyl ether) is added to the feed stream ((DF) stream) in a concentration of 40-50 ppm (wt / wt).

[0204] The design of the inventive recovery system was conducted using the process simulator as previously described in Example 1.

[0205] Initially, the stream is heated via heat exchangers until it reaches a temperature of 140 °C, allowing partial vaporization of the mixture. The heated stream is then sent to a flash vessel (SI) operating at atmospheric pressure. At this stage, approximately 25% of the total stream is vaporized inside the flash vessel, promoting partial separation of the more volatile components.

[0206] The liquid fraction from the bottom of the flash vessel, now with a lower content of volatile compounds ((SI”) stream), is directed to a distillation column (C3), where separation of isoparaffin present in the mixture occurs. Column (C3) operates at a pressure of 150 mbar abs, with a reflux ratio of 15 and a distillate-to-feed ratio of 12% (w / w). Column (C3) has 18 theoretical equilibrium stages, a partial condenser, and a forced circulation reboiler. A light-rich stream (vinyl acetate) is vented (EF stream), corresponding to approximately 0.5% of the feed flow rate. Isoparaffin is withdrawn from the top of the column (C3) ((C3’) stream) to ensure the specification of the recovered vinyl neodecanoate at the final stage of the recovery process.

[0207] The bottom stream from column (C3) ((C3”) stream) is then sent to a second distillation column (C4), where final recovery of the vinyl neodecanoate takes place. Column (C4) operates at a pressure of 50 mbar abs, with a reflux ratio of 1.2 and a distillate-to-feed ratio of 94% (w / w). The column (C4) has 10 theoretical equilibrium stages, a total condenser, and a forced circulation reboiler. The recovered stream, with a purity of 99.5 wt.% of vinyl neodecanoato, is obtained at the top of column (C4) ((C4’) stream) and sent back to the polymeration process.Table 3 - Flowrate and Weigh PercentExample 5 - Distillation for VN recovery for evaluation of inhibitor concentration

[0208] In the laboratory, distillation for the recovery of VN (vinyl neodecanoate), two tests were carried out using a bench-scale distiller equipped with a 50 mm diameter column. The column included rectification and stripping sections, packed with 550 mm of structured packing of the EX type from Sulzer. One test aimed at the removal of isoparaffin + PIB, and the other at the removal of versatic acid from the VN. Initially, the fresh VN was dosed with 100 ppm (w / w) of hydroquinone; however, the polymerization inhibitor did not dissolve in the monomer. It was observed that even with heating, solubility was not achieved. Due to the insolubility of hydroquinone in VN, it was not feasible to use the same polymerization inhibitor employed in the polymerization process. As an alternative, MEHQ, already present in fresh VN and also a recognized inhibitor in the polymerization technology, was selected. Thermal stability tests of the VN were conducted for different concentrations, 5 ppm (as fresh VN), 25 ppm, 50 ppm and 100 ppm. The new inhibitor showed solubility at various concentrations. The stability tests did not indicate fouling formation, but a reduction in the monomer's unsaturation index (ASTM DI 159) and yellowing of the mixture were observed. A concentration of 25 to 50 ppm of MEHQ demonstrated the lower instauration reduction after heating (Table 4). The use of 25-50 ppm of MEHQ minimizes unsaturation loss at the highest temperature points of the distillation, particularly at the bottom of the distillation columns.Table 4 - Result of the Stability Test by Bromine Number and Color Analysis

[0209] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

Claims

CLAIMSWhat is claimed:

1. A monomer recovery system, for a high-pressure polymerization process, for obtaining a purified branched vinyl ester stream, the system comprising: a vapor-liquid phase separator of one or multiple stages (SI), (Cl) for separating a recycle stream (D 1’) into at least an overhead stream (S 1’), (C 1’) comprising a light vinyl ester- rich fraction and a bottom stream (SI”), (Cl”) comprising a branched vinyl ester-rich fraction, the feed stream (DI ’) comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons selected from hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) or a flash vessel (SI); a distillation column (C3) for separating an incoming stream (SI”), (Cl”) into at least an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons selected from hydrocarbons with 5 to 11 carbon atoms, and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction; and a distillation column (C4) for separating an incoming stream (C3”) into an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising contaminants and heavies.

2. The recovery system according to claim 1, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl).

3. The recovery system according to claim 1, wherein the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI).

4. The recovery system according to claim 1, wherein the purified branched vinyl ester stream has a branched vinyl ester purity level of more than 80, 85, 90, 95 or up to 99,9 wt.% by GC-MS, based on the total weight of the purified branched vinyl ester stream (C4”), and the purified branched vinyl ester stream has a branched vinyl ester recovery ratio of more than 70, 75, 80, 85, 90 and up to 99 wt.%, based on the total weight of branched vinyl ester contained in the feed stream (DC).

5. The recovery system according to claim 2, wherein the bottom temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 150 to 170 °C and the bottom pressure ranges from 250 to 350 mbar (abs); the overhead temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 25 to 35 °C and the overhead pressure ranges 200 to 300 mbar (abs); and / or the overhead temperature of the first distillation column (C3) ranges from 40 to 50 °C.

6. The recovery system according to claim 3, wherein the vapor-liquid phase separator of one or multiple stages (SI) operates at a temperature ranging from 130 to 145 °C and under atmospheric pressure; and / or the overhead temperature of distillation column (C3) ranges from 20 to 30 °C.

7. The recovery system according to claim 1, wherein the bottom temperature of the distillation column (C3) ranges from 150 to 180 °C and the bottom pressure ranges from 200 to 400 mbar (abs); the overhead pressure of the distillation column (C3) ranges 140 to 155 mbar (abs); the overhead temperature of the distillation column (C4) ranges from 100 to 140 °C and the overhead pressure ranges 50 to 200 mbar (abs); and / or the bottom temperature of the distillation column (C4) ranges from 160 to 190 °C and the bottom pressure ranges from 100 to 250 mbar (abs).

8. The recovery system according to claim 1, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) selected from tray column or packing column; and / or distillation columns (C3), (C4) are independently selected from tray columns and packing columns.

9. The recovery system according to claim 1, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) and has a number of theoretical stages lower than 15, preferably ranging from 6 to 10; distillation column (C3) has a number of theoretical stages lower than 30, preferably ranging from 15 to 25; anddistillation column (C4) has a number of theoretical stages lower than 20, preferably ranging from 10 to 14.

10. The recovery system according to claim 2, wherein the feed stream (DE) is fed to the vapor-liquid phase separator of one or multiple stages (Cl) at a position ranging from 50 to 95% (up to top) of the tray section or of the packing, preferably from 80 to 90% (up to top) of the tray section or of the packing, and more preferably at a position of 89% (up to top) of the tray section or of the packing; the (Cl”) stream is fed to the distillation column (C3) at a position ranging from 30 to 50% (up to top) of the tray section or of the packing; preferably from 30 to 40% (up to top) of the tray section or of the packing; and more preferably at a position of 38% (up to top) of the tray section or of the packing; and / or the (C3”) stream is fed to the distillation column (C4) at a position ranging from 30 to 70% (up to top) of the tray section or of the packing, preferably from 45 to 70% (up to top) of the tray section or of the packing, and more preferably at a position of 57% (up to top) of the tray section or of the packing.

11. The recovery system according to claim 1, further comprising a vent stream El’ comprising non-condensable gases, light components such as light vinyl ester, oxygenates and water which are present in the feed stream (DE).

12. The recovery system according to claim 1, further comprising: a distillation column (C2) for separating a (C2i) stream into at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or a distillation column (C5) for separating a (C2”) stream into an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction.

13. The recovery system according to claim 12, wherein the bottom temperature of the distillation column (C2) ranges from 75 to 95 °C and the bottom pressure ranges from 1.2 to 1.9 bar (abs); the overhead temperature of the distillation column (C2) ranges from 35 to 50 °C and the overhead pressure ranges 1.1 to 1.8 bar (abs);the bottom temperature of the distillation column (C5) ranges from 100 to 130 °C and the bottom pressure ranges from 1.2 to 1.9 bar (abs); and / or wherein the overhead temperature of the distillation column (C5) ranges from 35to 50 °C and the overhead pressure ranges 1.1 to 1.8 bar (abs).

14. The recovery system according to claim 12, wherein distillation columns (C2) and (C5) are independently selected from tray columns and packing columns.

15. The recovery system according to claim 14, wherein distillation column (C2) has a number of theoretical stages lower than 20, preferably ranging from 11 to 17; and distillation column (C5) has a number of theoretical stages lower than 15, preferably ranging from 8 to 12.

16. The recovery system according to claim 12, wherein the (C2i) stream is fed to the distillation column (C2) at a position ranging from 40 to 90% (up to top) of the tray section or of the packing, preferably from 60 to 80% (up to top) of tray section or of the packing, and even more preferably of 73% (up to top) of tray section or of the packing; the (C2”) stream is fed to the distillation column (C5) at a position ranging from 40 to 90% (up to top) of the tray section or of the packing; preferably from 50 to 70% (up to top) of tray section or of the packing, and even more preferably of 60% (up to top) of tray section or of the packing.

17. The recovery system according to claim 12, further comprising a vent stream (E2’) comprising non-condensable gases, light vinyl ester, oxygenates and water.

18. The recovery system according to claim 12, wherein the purified light vinyl ester stream has a light vinyl ester purity level ranging from 95 to 99,99 wt.% by GC-MS, based on the total weight of the purified light vinyl ester stream, and the purified light vinyl ester stream has a light vinyl ester recovery ratio of 80 to 99 wt.%, based on the total weight of light vinyl ester contained in the feed stream (C2i).

19. The recovery system according to claim 2, further comprising:a distillation column (C2) for separating a (C2i) stream into at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or a distillation column (C5) for separating a (C2”) stream into an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction wherein the (C2i) stream consists of or comprises a mixture of (CT) stream and an additional stream (D2’) that is recycled from a high-pressure polymerization reactor, wherein (D2’) stream may preferably comprise more than 90 wt.% of light vinyl ester, based on the total weight of (D2’) stream.

20. The recovery system according to claim 19, wherein the system further comprises a reflux wherein: the bottom stream (C5”) of column (C5) may be combined with the bottom stream (Cl”) of column (Cl), forming a (C3i) stream, that is fed to column C3; and / or the bottom stream (C5”) of column (C5) may be fed to distillation column (C3) at a different feed point above (Cl”) stream, but inside the range of 55 to 80% (up to top) of the tray section or of the packing.

21. The recovery system according to claim 3, further comprising: a distillation column (C2) for separating a (C2i) stream into at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or a distillation column (C5) for separating a (C2”) stream into an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction wherein the (C2i) stream consists of or comprises a mixture of (ST) stream and an additional stream (D2’) that is recycled from a high-pressure polymerization reactor, wherein (D2’) stream may preferably comprise more than 90 wt.% of light vinyl ester, based on the total weight of (D2’) stream.

22. The recovery system according to claim 21, wherein the system further comprises a reflux wherein:the bottom stream (C5”) of column (C5) may be partially combined with the bottom stream (SI”) of flash vessel (SI), forming a (C3i) stream, that is fed to column C3; the bottom stream (C5”) of column (C5) may be partially fed to distillation column (C3) at a different feed point above (SI”) stream, but inside the range of 55 to 80% (up to top) of the tray section or of the packing; the top stream (C3’) of column (C3) may be combined with the (C2i) stream, that is fed to column C2; and / or the top stream (C3’) of column (C3) may be fed to distillation column (C2) at a different feed point below the feeding point of (C2i) stream, but up to 10% (up to top) of the tray section or of the packing of (C2).

23. The recovery system according to claim 21, further comprising a vent stream E3’ comprising light vinyl ester, non-condensable gases, carboxylic acids derived from the light vinyl ester, light solvent fraction that comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, oxygenates, and of water.

24. The recovery system according to claim 2, further comprising an electric reboiler at the bottom of the vapor-liquid phase separator of one or multiple stages (Cl), and wherein the bottom temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 180 to 200 °C and the bottom pressure ranges from 600 to 700 mbar (abs); and the overhead temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 40 to 48 °C and the overhead pressure ranges 450 to 600 mbar (abs).

25. The recovery system according to claim 3, wherein the flash vessel (SI) further comprises a demister at its top.

26. The recovery system according to claim 3, wherein the distillation column (C3) has a partial condenser at its overhead operating with a refrigerant system configured for maintaining the overhead stream in a temperature range from 20 to 30 °C.

27. A monomer recovery system for a high-pressure polymerization process for obtaining a purified branched vinyl ester stream, the system comprising:a distillation column (Cl) for separating a recycle stream (DF) into an overhead stream (CF) comprising a light vinyl ester -rich fraction and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction from a feed stream comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons selected from hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies; and a distillation column (C6) for separating a (Cl”) stream into an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons selected from hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising heavies and a side stream C6s comprising the purified branched vinyl ester stream.

28. The recovery system according to claim 27, wherein the bottom temperature of distillation column (Cl) ranges from 150 to 170 °C and the bottom pressure ranges from 0.1 to 0.22 bar (abs); the overhead temperature of distillation column (Cl) ranges from 25 to 35 °C and the overhead pressure ranges 200 to 300 mbar (abs); the bottom temperature of distillation column (C6) ranges from 160 tol80 °C and the bottom pressure ranges from 100 to 500 mbar (abs); and / or the overhead temperature of distillation column (C6) ranges from 65 to72 °C and the overhead pressure ranges 25 to 35 mbar (abs).

29. The recovery system according to claim 27, further comprising a distillation column (C7) for separating a (C7i) stream into an overhead stream (C7’) comprising a wet light vinyl ester mixture fraction, a bottom stream (C7”) comprising a branched vinyl ester-rich fraction and a side stream C7s comprising a purified light vinyl ester stream, wherein the (C7i) stream comprises the (CF) stream.

30. The recovery unit according to claim 29, wherein the (C7i) stream consists of the (CF) stream, or the (C7i) stream comprises a mixture of the (C 1 ’) stream and an additional (D2’) stream recycled from a high-pressure polymerization reactor, wherein the (D2’) stream comprises more than 90 wt.% of light vinyl ester by GC-FID, based on the total weight of the (D2’) stream.

31. The recovery unit according to claim 29, whereinthe bottom temperature of distillation column (C7) ranges from 150 to 165 °C; the bottom pressure of distillation column (C7) ranges from 1.2 to 2.0 bar (abs); the overhead temperature of distillation column (C7) ranges from 45 to 55 °C; and / or the overhead pressure of distillation column (C7) ranges 1.1 to 1.8 bar (abs).

32. The recovery system according to claim 29, further comprising a vent stream (E7’) comprising non-condensable gases, light vinyl ester, oxygenates and water.

33. The recovery system according to claim 27, further comprising a distillation column (C2) for separating a (C2i) stream into an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; wherein the (C2i) stream comprises the (CT) and / or a distillation column (C5) for separating a (C2”) stream into an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction.

34. The recovery system according to claim 33, wherein the (C2i) stream consists of the (CT) stream, or the (C2i) stream comprises a mixture of the (C 1 ’) stream and an additional (D2’) stream recycled from a high-pressure polymerization reactor, wherein the (D2’) stream comprises more than 90 wt.% of light vinyl ester by GC-FID, based on the total weight of the (D2’) stream.

35. The recovery system according to claim 33, further comprising a vent stream (E2’) comprising non-condensable gases, light vinyl ester, oxygenates and water.

36. A monomer recovery process for obtaining a purified branched vinyl ester stream for a high pressure polymerization process, the recovery process comprising:- injecting a recycled stream (DF) comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies into a vapor-liquid phase separator of one or multiple stages (SI), (Cl) and recovering an overhead stream (S 1’), (C 1 ’) comprising a light vinyl ester-rich fraction and a bottom stream (SI”), (Cl”) comprising a branched vinyl ester-rich fraction, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) or a flash vessel (SI);- injecting the stream (SI”), (Cl”) to a distillation column (C3) and recovering an overhead stream (C3’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons selected from hydrocarbons with 5 to 11 carbon atoms and a bottom stream (C3”) comprising a branched vinyl ester-rich fraction;- injecting the (C3”) stream into a distillation column (C4) and recovering an overhead stream (C4’) comprising the purified branched vinyl ester stream and a bottom stream (C4”) comprising contaminants and heavies.

37. The recovery process according to claim 36, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl).

38. The recovery process according to claim 36, wherein the vapor-liquid phase separator of one or multiple stages is a flash vessel (SI).

39. The recovery process according to claim 36, wherein the purified branched vinyl ester stream has a branched vinyl ester purity level of more than 80, 85, 90, 95 or up to 99,9 wt.% by GC-MS, based on the total weight of the purified branched vinyl ester stream (C4”), and the purified branched vinyl ester stream has a branched vinyl ester recovery ratio of more than 70, 75, 80, 85, 90 and up to 99 wt.%, based on the total weight of branched vinyl ester contained in the feed stream (DF).

40. The recovery process according to claim 37, wherein the bottom temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 150 to 170 °C and the bottom pressure ranges from 250 to 350 mbar (abs); the overhead temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 25 to 35 °C and the overhead pressure ranges 200 to 300 mbar (abs); and / or the overhead temperature of the first distillation column (C3) ranges from 40 to 50 °C.

41. The recovery process according to claim 38, wherein the vapor-liquid phase separator of one or multiple stages (SI) operates at a temperature ranging from 130 to 145 °C and under atmospheric pressure; and / or the overhead temperature of distillation column (C3) ranges from 20 to 30 °C.

42. The recovery process according to claim 36, wherein the bottom temperature of the distillation column (C3) ranges from 150 to 180 °C and the bottom pressure ranges from 200 to 400 mbar (abs); the overhead pressure of the distillation column (C3) ranges 140 to 155 mbar (abs); the overhead temperature of the distillation column (C4) ranges from 100 to 140 °C and the overhead pressure ranges 50 to 200 mbar (abs); and / or the bottom temperature of the distillation column (C4) ranges from 160 to 190 °C and the bottom pressure ranges from 100 to 250 mbar (abs).

43. The recovery process according to claim 36, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) selected from tray column or packing column; and / or the distillation columns (C3), (C4) are independently selected from tray columns and packing columns.

44. The recovery process according to claim 36, wherein the vapor-liquid phase separator of one or multiple stages is a distillation column (Cl) and has a number of theoretical stages lower than 15, preferably ranging from 6 to 10; the distillation column (C3) has a number of theoretical stages lower than 30, preferably ranging from 15 to 25; and the distillation column (C4) has a number of theoretical stages lower than 20, preferably ranging from 10 to 14.

45. The recovery process according to claim 37, wherein the feed stream (DC) is fed to the vapor-liquid phase separator of one or multiple stages (Cl) at a position ranging from 50 to 95% (up to top) of the tray section or of the packing, preferably from 80 to 90% (up to top) of the tray section or of the packing, and more preferably at a position of 89% (up to top) of the tray section or of the packing; the (Cl”) stream is fed to the distillation column (C3) at a position ranging from 30 to 50% (up to top) of the tray section or of the packing; preferably from 30 to 40% (up to top) of the tray section or of the packing; and more preferably at a position of 38% (up to top) of the tray section or of the packing; and / or the (C3”) stream is fed to the distillation column (C4) at a position ranging from 30 to 70% (up to top) of the tray section or of the packing, preferably from 45 to 70% (up to top) ofthe tray section or of the packing, and more preferably at a position of 57% (up to top) of the tray section or of the packing.

46. The recovery process according to claim 36, further comprising removing noncondensable gases which are presented in the feed stream (DE), and light components such as light vinyl ester, oxygenates and water through a vent stream (ET).

47. The recovery process according to claim 36, further comprising: injecting a (C2i) stream to a distillation column (C2) and recovering at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or injecting the (C2”) stream to a distillation column (C5) and recovering at least an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction.

48. The recovery process according to claim 47, wherein the bottom temperature of the distillation column (C2) ranges from 75 to 95 °C and the bottom pressure ranges from 1.2 to 1.9 bar (abs); the overhead temperature of the distillation column (C2) ranges from 35 to 50 °C and the overhead pressure ranges 1.1 to 1.8 bar (abs); the bottom temperature of the distillation column (C5) ranges from 100 to 130 °C and the bottom pressure ranges from 1.2 to 1.9 bar (abs); and / or the overhead temperature of the distillation column (C5) ranges from 35to 50 °C and the overhead pressure ranges 1.1 to 1.8 bar (abs).

49. The recovery process according to claim 47, wherein distillation columns (C2) and (C5) are independently selected from tray columns and packing columns.

50. The recovery process according to claim 49, wherein the distillation column (C2) has a number of theoretical stages lower than 20, preferably ranging from 11 to 17; and the distillation column (C5) has a number of theoretical stages lower than 15, preferably ranging from 8 to 12.

51. The recovery process according to claim 47, whereinthe (C2i) stream is fed to the distillation column (C2) at a position ranging from 40 to 90% (up to top) of the tray section or of the packing, preferably from 60 to 80% (up to top) of tray section or of the packing, and even more preferably of 73% (up to top) of tray section or of the packing; the (C2”) stream is fed to the distillation column (C5) at a position ranging from 40 to 90% (up to top) of the tray section or of the packing; preferably from 50 to 70% (up to top) of tray section or of the packing, and even more preferably of 60% (up to top) of tray section or of the packing.

52. The recovery process according to claim 47, further comprising removing noncondensable gases, light vinyl ester, oxygenates and water through a vent stream (E2’).

53. The recovery process according to claim 47, wherein the purified light vinyl ester stream has a light vinyl ester purity level ranging from 95 to 99,99 wt.% by GC-MS, based on the total weight of the purified light vinyl ester stream, and the purified light vinyl ester stream has a light vinyl ester recovery ratio of 80 to 99 wt.%, based on the total weight of light vinyl ester contained in the feed stream (C2i).

54. The recovery process according to claim 37, further comprising: injecting a (C2i) stream into a distillation column (C2) and recovering at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or injecting a (C2”) stream into a distillation column (C5) and recovering at least an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction; wherein the (C2i) stream consists of or comprises a mixture of (CT) stream and an additional stream (D2’) that is recycled from a high-pressure polymerization reactor, wherein (D2’) stream may preferably comprise more than 90 wt.% of light vinyl ester, based on the total weight of (D2’) stream.

55. The recovery process according to claim 54, further comprising a reflux stream wherein: the bottom stream (C5”) of column (C5) is combined with the bottom stream (Cl”) of column (Cl), forming a (C3i) stream, that is fed to column C3; and / orthe bottom stream (C5”) of column (C5) is fed to distillation column (C3) at a different feed point above (Cl”) stream, but inside the range of 55 to 80% (up to top) of the tray section or of the packing.

56. The recovery process according to claim 38, further comprising: injecting a (C2i) stream into a distillation column (C2) and recovering at least an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; and / or injecting a (C2”) stream into a distillation column (C5) and recovering an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction wherein the (C2i) stream consists of or comprises a mixture of (ST) stream and an additional stream (D2’) that is recycled from a high-pressure polymerization reactor, wherein (D2’) stream may preferably comprise more than 90 wt.% of light vinyl ester, based on the total weight of (D2’) stream.

57. The recovery process according to claim 56, wherein the system further comprises a reflux wherein: the bottom stream (C5”) of column (C5) is partially combined with the bottom stream (SI”) of flash vessel (SI), forming a (C3i) stream, that is fed to column C3; the bottom stream (C5”) of column (C5) is partially fed to distillation column (C3) at a different feed point above (SI”) stream, but inside the range of 55 to 80% (up to top) of the tray section or of the packing; the top stream (C3’) of column (C3) is combined with the (C2i) stream, that is fed to column C2; and / or the top stream (C3’) of column (C3) is fed to distillation column (C2) at a different feed point below the feeding point of (C2i) stream, but up to 10% (up to top) of the tray section or of the packing of (C2).

58. The recovery process according to claim 56, further comprising removing light vinyl ester, non-condensable gases, carboxylic acids derived from the light vinyl ester, light solvent fraction that comprises a mixture of hydrocarbons with 5 to 11 carbon atoms, oxygenates, and water through a vent stream (E3’).

59. The recovery process according to claim 37, further comprising an electric reboiler at the bottom of the vapor-liquid phase separator of one or multiple stages (Cl), and wherein the bottom temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 180 to 200 °C and the bottom pressure ranges from 600 to 700 mbar (abs); and the overhead temperature of the vapor-liquid phase separator of one or multiple stages (Cl) ranges from 40 to 48 °C and the overhead pressure ranges 450 to 600 mbar (abs).

60. The recovery process according to claim 38, wherein the flash vessel (SI) further comprises a demister at its top.

61. The recovery process according to claim 38, wherein the distillation column (C3) has a partial condenser at its overhead operating with a refrigerant system configured for maintaining the overhead stream in a temperature range from 20 to 30 °C.

62. A monomer recovery system for a high-pressure polymerization process for obtaining a purified branched vinyl ester stream, the system comprising: injecting a recycle stream (DI’) comprising branched vinyl ester, light vinyl ester, a solvent comprising a mixture of hydrocarbons selected from hydrocarbons with 5 to 16 carbon atoms, contaminants and heavies into a distillation column (Cl) for separating an overhead stream (CT) comprising a light vinyl ester -rich fraction and a bottom stream (Cl”) comprising a branched vinyl ester-rich fraction; and injecting a (Cl”) stream into a distillation column (C6) for separating an overhead stream (C6’) comprising a light solvent fraction, wherein the light solvent fraction comprises a mixture of hydrocarbons selected from hydrocarbons with 5 to 11 carbon atoms, a bottom stream (C6”) comprising heavies and a side stream (C6s) comprising the purified branched vinyl ester stream.

63. The recovery process according to claim 62, wherein the bottom temperature of distillation column (Cl) ranges from 150 to 170 °C and the bottom pressure ranges from 0.1 to 0.22 bar (abs); the overhead temperature of distillation column (Cl) ranges from 25 to 35 °C and the overhead pressure ranges 200 to 300 mbar (abs);the bottom temperature of distillation column (C6) ranges from 160 tol80 °C and the bottom pressure ranges from 100 to 500 mbar (abs); and / or the overhead temperature of distillation column (C6) ranges from 65 to72 °C and the overhead pressure ranges 25 to 35 mbar (abs).

64. The recovery process according to claim 62, further comprising injecting a (C7i) stream into a distillation column (C7) for separating an overhead stream (C7’) comprising a wet light vinyl ester mixture fraction, a bottom stream (C7”) comprising a branched vinyl ester-rich fraction and a side stream (C7s) comprising a purified light vinyl ester stream, wherein the (C7i) stream comprises the (CT) stream.

65. The recovery process according to claim 64, wherein the (C7i) stream consists of the (CT) stream, or the (C7i) stream comprises a mixture of the (C 1 ’) stream and an additional (D2’) stream recycled from a high-pressure polymerization reactor, wherein the (D2’) stream comprises more than 90 wt.% of light vinyl ester by GC-FID, based on the total weight of the (D2’) stream.

66. The recovery process according to claim 64, wherein the bottom temperature of distillation column (C7) ranges from 150 to 165 °C; the bottom pressure of distillation column (C7) ranges from 1.2 to 2.0 bar (abs); the overhead temperature of distillation column (C7) ranges from 45 to 55 °C; and / or the overhead pressure of distillation column (C7) ranges 1.1 to 1.8 bar (abs).

67. The recovery process according to claim 64, further comprising removing noncondensable gases, light vinyl ester, oxygenates and water through a vent stream E7’.

68. The recovery process according to claim 62, further comprising injecting a (C2i) stream into a distillation column (C2) for separating an overhead stream (C2’) comprising a wet light vinyl ester fraction and a bottom stream (C2”) comprising a light vinyl ester-rich fraction; wherein the (C2i) stream comprises the (CT) and / or injecting a (C2”) stream into a distillation column (C5) for separating an overhead stream (C5’) comprising a purified light vinyl ester stream and a bottom stream (C5”) comprising a branched vinyl ester-rich fraction.

69. The recovery process according to claim 68, wherein the (C2i) stream consists of the (CT) stream, or the (C2i) stream comprises a mixture of the (C 1 ’) stream and an additional (D2’) stream recycled from a high-pressure polymerization reactor, wherein the (D2’) stream comprises more than 90 wt.% of light vinyl ester by GC-FID, based on the total weight of the (D2’) stream.

70. The recovery process according to claim 69, further comprising a vent stream (E2’) comprising non-condensable gases, light vinyl ester, oxygenates and water.

71. The recovery system according to claim 1, wherein the recycle stream (DF) further comprises an added polymerization inhibitor.

72. The recovery system according to claim 19, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

73. The recovery system according to claim 21, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

74. The recovery system according to claim 37, wherein the recycle stream (DF) further comprises an added polymerization inhibitor.

75. The recovery system according to claim 30, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

76. The recovery system according to claim 34, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

77. The recovery process according to claim 36, wherein the recycle stream (DF) further comprises an added polymerization inhibitor.

78. The recovery process according to claim 54, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

79. The recovery process according to claim 56, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

80. The recovery process according to claim 62, wherein the recycle stream (DT) further comprises an added polymerization inhibitor.

81. The recovery process according to claim 65, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

82. The recovery process according to claim 69, wherein the recycle stream (D2’) further comprises an added polymerization inhibitor.

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