Patent Description:
Methods of co-producing propylene oxide and styrene monomer ("POSM" processes) include the oxidation of ethyl benzene to form ethyl benzene hydroperoxide, the catalytic reaction of the hydroperoxide with propylene to form propylene oxide and <NUM>-phenyl ethanol, and the dehydration of the <NUM>-phenyl ethanol (also known as α-methyl benzyl alcohol) to produce styrene monomer. An example of a POSM process is described at <CIT>. POSM processes also are described at <CIT> and <CIT>, and <CIT> and <CIT>, which disclose methods for upgrading a low value heavy residue produced during the processes.

In POSM processes there may be multiple purge streams that contain one or more recoverable chemicals, including, but not limited to, mono propylene glycol, α-methyl benzyl alcohol, benzaldehyde, and/or acetophenone. These purge streams may be treated as waste streams, and, in some instances, used as fuel.

There remains a need for methods and systems that are capable of recovering one or more chemicals from one or more streams created by POSM processing, including, but not limited to, one or more chemicals that can be recycled into a POSM process, used as a fuel, purified to obtain a final commercial product and/or a product that may be used in a different process, or a combination thereof.

Provided herein are methods that address one or more of the foregoing needs, including methods that permit the recovery of one or more chemicals from streams, including purge streams, drawn from processes for co-producing propylene oxide and styrene monomers. One or more of the recovered chemicals may be recycled in a process, such as a POSM process. The method provided herein include providing at least one stream from a process for co-producing propylene oxide and styrene monomer;.

wherein the organic extraction liquid is toluene.

In some embodiments, the methods also include contacting the first aqueous extraction stream with an additional amount of the organic extraction liquid to form a second aqueous extraction stream and a second organic extraction stream; wherein the second aqueous extraction stream comprises (i) mono-propylene glycol, and (ii) a third amount of α-methyl benzyl alcohol, a third amount of benzaldehyde, a third amount of acetophenone, or a combination thereof, and the third amount of α-methyl benzyl alcohol, the third amount of benzaldehyde, and the third amount of acetophenone are less than the second amount of α-methyl benzyl alcohol, the second amount of benzaldehyde, and the second amount of acetophenone, respectively.

In some embodiments, the methods also include separating mono-propylene glycol, benzaldehyde, α-methyl benzyl alcohol, acetophenone, or a combination thereof from a first aqueous extraction stream, a first organic extraction stream, or a combination thereof.

Methods are provided for recovering one or more chemicals from one or more streams drawn from a process for co-producing propylene oxide and styrene monomer. The method is described in claim <NUM>.

In some embodiments, one stream from a process for co-producing propylene oxide and styrene monomer is disposed in the settling tank. In some embodiments, two streams from a process for co-producing propylene oxide and styrene monomer are disposed in the settling tank. In some embodiments, three streams from a process for co-producing propylene oxide and styrene monomer are disposed in the settling tank. In some embodiments, more than three streams (e.g., <NUM> to <NUM> streams) from a process for co-producing propylene oxide and styrene monomer are disposed in the settling tank. When more than one stream is disposed in a settling tank, one or more of the streams may be directly disposed in the settling tank, one or more of the streams may be combined prior to being disposed in the settling tank, or a combination thereof. In some embodiments, the at least one stream from the process for preparing propylene oxide and styrene monomer includes a purge stream.

The settling tank may include any known settling tank. The settling tank generally may include a reservoir, at least one inlet, and at least one outlet. In some embodiments, the weight ratio of the organic stream to the aqueous stream in the settling tank is <NUM>-<NUM>:<NUM>-<NUM>. In some embodiments, the weight ratio of the organic stream to the aqueous stream in the settling tank is <NUM>:<NUM>. An additional amount of an aqueous liquid, an organic liquid, or both may be adding to the settling tank before, during, or after the one or more streams drawn from a process for co-producing propylene oxide and styrene monomer are disposed in the settling tank.

The aqueous stream of the settling tank, in some embodiments, includes (i) mono-propylene glycol, and (ii) a first amount of α-methyl benzyl alcohol, a first amount of benzaldehyde, a first amount of acetophenone, or a combination thereof. In some embodiments, the methods described herein include contacting the aqueous stream with an organic extraction liquid in a liquid-liquid extraction unit to form a first aqueous extraction stream and a first organic extraction stream; wherein the first aqueous extraction stream includes (i) mono-propylene glycol, and (ii) a second amount of α-methyl benzyl alcohol, a second amount of benzaldehyde, a second amount of acetophenone, or a combination thereof, and the second amount of α-methyl benzyl alcohol, the second amount of benzaldehyde, and the second amount of acetophenone are less than the first amount of α-methyl benzyl alcohol, the first amount of benzaldehyde, and the first amount of acetophenone, respectively.

In some embodiments, the second amount of α-methyl benzyl alcohol is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the first amount of α-methyl benzyl alcohol. In other words, if the first amount is <NUM> units and the second amount is <NUM> % less than the first amount, then the second amount is <NUM> units.

In some embodiments, the second amount of benzaldehyde is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the first amount of benzaldehyde.

In some embodiments, the second amount of acetophenone is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the first amount of acetophenone, respectively.

In some embodiments, the contacting of the aqueous stream with the organic extraction liquid includes mixing the aqueous stream and the organic extraction liquid. The aqueous stream and the organic extraction liquid may be mixed for <NUM> seconds to <NUM> seconds, <NUM> seconds to <NUM> seconds, or <NUM> seconds. The mixing may be achieved by any known technique, such as stirring, moving (e.g., inverting) the liquid-liquid extraction unit, or a combination thereof. The methods also may include discontinuing mixing for a time sufficient to separate the aqueous stream and the organic extraction liquid. The time sufficient to separate the aqueous stream and the organic extraction liquid may be <NUM> minutes to <NUM> hours, <NUM> minutes to <NUM> hours, or <NUM> hour.

The aqueous stream and the organic extraction liquid may be present at any weight ratio in the liquid-liquid extraction unit. In some embodiments, the aqueous stream and the organic extraction liquid are present in the liquid-liquid extraction unit at a weight ratio of <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM> (aqueous stream:organic extraction liquid).

The liquid-liquid extraction unit may be operated at any temperature and/or pressure that does not undesirably impact the methods described herein. In some embodiments, the pressure in the liquid extraction unit is ambient pressure. A pressure greater than ambient pressure may be used, however, in some embodiments. For example, the pressure in the liquid-liquid extraction unit may be <NUM> bar to <NUM> bar. In some embodiments, the temperature in the liquid-liquid extraction unit is <NUM> to <NUM>. The phrase "the temperature in the liquid-liquid extraction unit" may refer to a temperature in the liquid-liquid extraction unit and/or the temperature of the contents of the liquid-liquid extraction unit. In some embodiments, an increased temperature may be used. For example, the contents of the liquid-liquid extraction unit may be heated before, during, and/or after the contents are disposed in the liquid-liquid extraction unit. For example, the temperature in the liquid-liquid extraction unit may be <NUM> to <NUM>.

The liquid-liquid extraction unit may include known apparatus in which an extraction may be performed. In some embodiments, the liquid-liquid extraction unit includes a mixing-separating vessel, a liquid-liquid extraction column, a mixer-coalescer device, or a combination thereof.

The organic extraction liquid is toluene.

<FIG> is a schematic of a system <NUM> that may be used to perform embodiments of the methods described herein. The system <NUM> includes a settling tank <NUM> and a liquid-liquid extraction unit <NUM>. In the embodiment depicted at <FIG>, three purge streams (<NUM>, <NUM>, <NUM>) from a POSM process are combined and then disposed in the settling tank <NUM>. In the settling tank <NUM>, the three purge streams (<NUM>, <NUM>, <NUM>) separate into an organic stream <NUM> and an aqueous stream <NUM>. The organic stream <NUM>, in some embodiments, is optionally (i) purified, (ii) recycled into the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn, or (iii) purified and recycled into the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn. The aqueous stream <NUM> and an organic extraction liquid <NUM> are disposed in the liquid-liquid extraction unit <NUM>. The contacting and subsequent separation of the aqueous stream <NUM> and the organic extraction liquid <NUM> produces an organic extraction stream <NUM> and an aqueous extraction stream <NUM>. The aqueous extraction stream <NUM> may be subjected to further purification, such as the purification steps described herein, and the organic extraction stream <NUM> may be subjected to further purification, recycled into the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn, or a combination thereof. In some embodiments, the three purge streams (<NUM>, <NUM>, <NUM>) include Stream <NUM>, Stream <NUM>, and Stream <NUM> of Example <NUM>.

In some embodiments, the methods described herein also include contacting the first aqueous extraction stream with an additional amount of the organic extraction liquid to form a second aqueous extraction stream and a second organic extraction stream; wherein the second aqueous extraction stream includes (i) mono-propylene glycol, and (ii) a third amount of α-methyl benzyl alcohol, a third amount of benzaldehyde, a third amount of acetophenone, or a combination thereof, and the third amount of α-methyl benzyl alcohol, the third amount of benzaldehyde, and the third amount of acetophenone are less than the second amount of α-methyl benzyl alcohol, the second amount of benzaldehyde, and the second amount of acetophenone, respectively. The additional amount of the organic extraction liquid may include a new portion of the organic extraction liquid, a recycled portion of the organic extraction liquid, or a combination thereof. As depicted, for example, at <FIG> and <FIG>, the organic extraction liquid may be purified, and then recycled to a liquid-liquid extraction unit.

In some embodiments, the third amount of α-methyl benzyl alcohol is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the second amount of α-methyl benzyl alcohol. In other words, if the second amount is <NUM> units and the third amount is <NUM> % less than the second amount, then the third amount is <NUM> units.

In some embodiments, the third amount of benzaldehyde is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the second amount of benzaldehyde.

In some embodiments, the third amount of acetophenone is <NUM> % to <NUM> %, <NUM> % to <NUM> %, or <NUM> % to <NUM> % less than the second amount of acetophenone, respectively.

In some embodiments, the methods described herein include disposing the first aqueous extraction stream in a coalescer. The coalescer may include any apparatus that is configured to facilitate and/or promote the coalescence of small particles and/or droplets of hydrocarbons into larger particles and/or droplets. The coalescer of the methods described herein may include a mechanical coalescer or an electrostatic coalescer.

In some embodiments, the methods described herein include contacting a first aqueous extraction stream with activated carbon. The activated carbon may be in the form of an activated carbon bed. The activated carbon may remove at least a portion of impurities from the aqueous extraction stream through one or more mechanisms, such as adsorption.

In some embodiments, the methods include disposing the first aqueous extraction stream in an apparatus, such as a drying column, that is configured to isolate mono-propylene glycol from the first aqueous extraction stream. The methods, therefore, may include separating mono-propylene glycol from the first aqueous extraction stream.

In some embodiments, the methods described herein also include distilling at least one of the organic stream or the first organic extraction stream. The distilling may include a single distilling step or two or more distilling steps. In some embodiments, the distilling of at least one of the organic stream or the first organic extraction stream includes separating at least one of the organic stream or the first organic extraction stream into (i) a first distilled stream including ethyl benzene, styrene, or a combination thereof, (ii) a second distilled stream including benzaldehyde, (iii) a third distilled stream including α-methyl benzyl alcohol, acetophenone, or a combination thereof, or (iv) a combination thereof.

In some embodiments, the methods also include (i) disposing the first distilled stream in a liquid-liquid extraction unit, (ii) recycling the first distilled stream to a process for co-producing propylene oxide and styrene monomer, or (iii) a combination thereof. In some embodiments, the methods also include recycling the third distilled stream to a process for co-producing propylene oxide and styrene monomer.

<FIG> is a schematic of a system <NUM> that may be used to perform embodiments of the methods described herein. The system <NUM> includes a settling tank <NUM> and a liquid-liquid extraction unit <NUM>. In the embodiment depicted at <FIG>, three purge streams (<NUM>, <NUM>, <NUM>) from a POSM process are combined and then disposed in the settling tank <NUM>. In the settling tank <NUM>, the three purge streams (<NUM>, <NUM>, <NUM>) separate into an organic stream <NUM> and an aqueous stream <NUM>. The weight ratio of the organic stream <NUM> to the aqueous stream <NUM> in the settling tank may be <NUM>-<NUM>:<NUM>-<NUM>; for example, <NUM>:<NUM>. The three purge streams (<NUM>, <NUM>, <NUM>), in some embodiments, are Stream <NUM>, Stream <NUM>, and Stream <NUM>, respectively, of Example <NUM>. The aqueous stream <NUM> and an organic extraction liquid <NUM> are disposed in the liquid-liquid extraction unit <NUM>. The contacting and subsequent separation of the aqueous stream <NUM> and the organic extraction liquid <NUM> produces an organic extraction stream <NUM> and an aqueous extraction stream <NUM>. The aqueous extraction stream <NUM> is then forwarded to a coalescer <NUM>, which removes organic material <NUM> from the aqueous extraction stream <NUM> to produce a coalesced aqueous extraction stream <NUM>, which is contacted with an activated carbon bed <NUM> to produce a cleaned coalesced aqueous extraction stream <NUM>, which is disposed in a drying column <NUM> to isolate mono-propylene glycol <NUM> from water <NUM>. The organic stream <NUM> from the settling tank <NUM>, the organic extraction stream <NUM> from the liquid-liquid extraction unit <NUM>, and the organic material <NUM> from the coalescer <NUM> are disposed in a column <NUM> that separates a light phase <NUM> (that includes the organic extraction liquid <NUM> and styrene) from a heavy phase <NUM> (that includes benzaldehyde, α-methyl benzyl alcohol, and acetophenone). The light phase <NUM> may be recycled by disposing the light phase <NUM> in the liquid-liquid extraction unit <NUM>. The light phase <NUM> may be disposed directly in the liquid-liquid extraction unit <NUM>, or combined, as shown, with the organic extraction liquid <NUM> prior to being disposed in the liquid-liquid extraction unit <NUM>. The light phase <NUM> may be recycled into the POSM process <NUM> from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn. In some embodiments, the light phase <NUM> is recycled [<NUM>] to the liquid-liquid extraction unit <NUM> only, [<NUM>] to the POSM process <NUM> only, or [<NUM>] to both the liquid-liquid extraction unit <NUM> and the POSM process <NUM>. The heavy phase <NUM> may be disposed into a column <NUM> to separate a stream including benzaldehyde <NUM> from a stream including α-methyl benzyl alcohol/acetophenone <NUM>. The stream including α-methyl benzyl alcohol/acetophenone <NUM> may be used as fuel and/or recycled to the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn.

<FIG> is a schematic of a system <NUM> that may be used to perform embodiments of the methods described herein. The system <NUM> includes a settling tank <NUM> and a liquid-liquid extraction unit <NUM>. In the embodiment depicted at <FIG>, three purge streams (<NUM>, <NUM>, <NUM>) from a POSM process are combined and then disposed in the settling tank <NUM>. Alternatively, the three purge streams (<NUM>, <NUM>, <NUM>) may be directly disposed in the settling tank <NUM>. In the settling tank <NUM>, the three purge streams (<NUM>, <NUM>, <NUM>) separate into an organic stream <NUM> and an aqueous stream <NUM>. The weight ratio of the organic stream <NUM> to the aqueous stream <NUM> in the settling tank may be <NUM>-<NUM>:<NUM>-<NUM>; for example, <NUM>:<NUM>. The three purge streams (<NUM>, <NUM>, <NUM>), in some embodiments, are Stream <NUM>, Stream <NUM>, and Stream <NUM>, respectively, of Example <NUM>. The aqueous stream <NUM> and an organic extraction liquid <NUM> are disposed in the liquid-liquid extraction unit <NUM>. The contacting and subsequent separation of the aqueous stream <NUM> and the organic extraction liquid <NUM> produces an organic extraction stream <NUM> and an aqueous extraction stream <NUM>. The aqueous extraction stream <NUM> is then forwarded to a coalescer <NUM>, which removes organic material <NUM> from the aqueous extraction stream <NUM> to produce a coalesced aqueous extraction stream <NUM>, which is contacted with an activated carbon bed <NUM> to produce a cleaned coalesced aqueous extraction stream <NUM>, which is disposed in a drying column <NUM> to isolate mono-propylene glycol <NUM> from water <NUM>. The organic stream <NUM> from the settling tank <NUM>, the organic extraction stream <NUM> from the liquid-liquid extraction unit <NUM>, and the organic material <NUM> from the coalescer <NUM> are disposed in a column <NUM> that separates the combined streams into a first stream <NUM> (that includes the organic extraction <NUM> and styrene), a second stream <NUM> that includes benzaldehyde, and a third stream <NUM> that includes α-methyl benzyl alcohol, and acetophenone. The first stream <NUM> may be recycled by disposing the first stream <NUM> in the liquid-liquid extraction unit <NUM>. The first stream <NUM> may be disposed directly in the liquid-liquid extraction unit <NUM>, or combined, as shown, with the organic extraction liquid <NUM> prior to being disposed in the liquid-liquid extraction unit <NUM>. The first stream <NUM> may be recycled into the POSM process <NUM> from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn. In some embodiments, the first stream <NUM> is recycled [<NUM>] to the liquid-liquid extraction unit <NUM> only, [<NUM>] to the POSM process <NUM> only, or [<NUM>] to both the liquid-liquid extraction unit <NUM> and the POSM process <NUM>. The third stream <NUM> including α-methyl benzyl alcohol/acetophenone may be used as fuel and/or recycled to the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn.

<FIG> is a schematic of a system <NUM> that may be used to perform embodiments of the methods described herein. The system <NUM> includes a settling tank <NUM> and a column <NUM>. In the embodiment depicted at <FIG>, three purge streams (<NUM>, <NUM>, <NUM>) from a POSM process are combined and then disposed in the settling tank <NUM>. Alternatively, the three purge streams (<NUM>, <NUM>, <NUM>) may be directly disposed in the settling tank <NUM>. In the settling tank <NUM>, the three purge streams (<NUM>, <NUM>, <NUM>) separate into an organic stream <NUM> and an aqueous stream <NUM>. The weight ratio of the organic stream <NUM> to the aqueous stream <NUM> in the settling tank <NUM> may be <NUM>-<NUM>:<NUM>-<NUM>; for example, <NUM>:<NUM>. The three purge streams (<NUM>, <NUM>, <NUM>), in some embodiments, are Stream <NUM>, Stream <NUM>, and Stream <NUM>, respectively, of Example <NUM>. The aqueous stream <NUM> may be contacted with an organic extraction liquid as described herein. The organic stream <NUM> from the settling tank <NUM> is disposed in a column <NUM> that separates the stream into a first stream <NUM> that includes styrene, a second stream <NUM> that includes benzaldehyde, and a third stream <NUM> that includes α-methyl benzyl alcohol and acetophenone. The first stream <NUM> may be recycled into a POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn. The third stream <NUM> including α-methyl benzyl alcohol/acetophenone may be used as fuel and/or recycled to a POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn.

<FIG> is a schematic of a system <NUM> that may be used to perform embodiments of the methods described herein. The system <NUM> includes a settling tank <NUM> and a liquid-liquid extraction unit <NUM>. The liquid-liquid extraction unit <NUM> may be a counter current liquid-liquid extraction unit having a packed-bed style. In the embodiment depicted at <FIG>, three purge streams (<NUM>, <NUM>, <NUM>) from a POSM process are combined and then disposed in the settling tank <NUM>. Alternatively, the three purge streams (<NUM>, <NUM>, <NUM>) may be directly disposed in the settling tank <NUM>. In the settling tank <NUM>, the three purge streams (<NUM>, <NUM>, <NUM>) separate into an organic stream <NUM> and an aqueous stream <NUM>. The weight ratio of the organic stream <NUM> to the aqueous stream <NUM> in the settling tank may be <NUM>-<NUM>:<NUM>-<NUM>; for example, <NUM>:<NUM>. The three purge streams (<NUM>, <NUM>, <NUM>), in some embodiments, are Stream <NUM>, Stream <NUM>, and Stream <NUM>, respectively, of Example <NUM>. The aqueous stream <NUM> and an organic extraction liquid <NUM> are disposed in the liquid-liquid extraction unit <NUM>. The contacting and subsequent separation of the aqueous stream <NUM> and the organic extraction liquid <NUM> produces an organic extraction stream <NUM> and an aqueous extraction stream <NUM>. The aqueous extraction stream <NUM> is then forwarded to a coalescer <NUM>, which removes organic material <NUM> from the aqueous extraction stream <NUM> to produce a coalesced aqueous extraction stream <NUM>, which is contacted with an activated carbon bed <NUM> to produce a cleaned coalesced aqueous extraction stream <NUM>, which is disposed in a drying column <NUM> to isolate mono-propylene glycol <NUM> from water <NUM>. The organic stream <NUM> from the settling tank <NUM>, the organic extraction stream <NUM> from the liquid-liquid extraction unit <NUM>, and the organic material <NUM> from the coalescer <NUM> are disposed in a column <NUM> that separates the combined streams into a first stream <NUM> (that includes the organic extraction <NUM> and styrene), a second stream <NUM> that includes "heavies" or "bottom organics" (e.g., benzaldehyde, α-methyl benzyl alcohol, acetophenone, or a combination thereof). The first stream <NUM> may be recycled by disposing the first stream <NUM> in the liquid-liquid extraction unit <NUM>. The first stream <NUM> may be disposed directly in the liquid-liquid extraction unit <NUM>, or combined, as shown, with the organic extraction liquid <NUM> prior to being disposed in the liquid-liquid extraction unit <NUM>. The first stream <NUM> may be recycled into the POSM process <NUM> from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn. In some embodiments, the first stream <NUM> is recycled [<NUM>] to the liquid-liquid extraction unit <NUM> only, [<NUM>] to the POSM process <NUM> only, or [<NUM>] to both the liquid-liquid extraction unit <NUM> and the POSM process <NUM>. The second stream <NUM> may be used as fuel and/or recycled to the POSM process from which the three purge streams (<NUM>, <NUM>, <NUM>) are drawn.

In some embodiments, the methods also include separating mono-propylene glycol, benzaldehyde, α-methyl benzyl alcohol, acetophenone, or a combination thereof from the first aqueous extraction stream, a first organic extraction stream, or a combination thereof. The separation may be achieved using any one or more known apparatuses or methods, or apparatuses or methods described herein.

In the descriptions provided herein, the terms "includes," "is," "containing," "having," and "comprises" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to. " When methods and systems are claimed or described in terms of "comprising" various components or steps, the systems and methods can also "consist essentially of" or "consist of" the various components or steps, unless stated otherwise.

The terms "a," "an," and "the" are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of "a stream," "an organic extraction liquid," "a settling tank", , are meant to encompass one, or mixtures or combinations of more than one stream, organic extraction liquid, settling tank, , unless otherwise specified.

Various numerical ranges may be disclosed herein. When Applicant discloses or claims a range of any type, Applicant's intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of sub-ranges encompassed therein, unless otherwise specified. Moreover, all numerical end points of ranges disclosed herein are approximate. As a representative example, Applicant discloses, in one embodiment, a temperature in a liquid-liquid extraction unit is " <NUM> to <NUM>". This range should be interpreted as encompassing temperatures of <NUM> and <NUM>, and further encompasses " " each of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, including any ranges and sub-ranges between any of these values.

The present disclosure is further illustrated by the following exmaples.

In this example, three purge streams from a POSM processes were collected and analyzed. The streams are arbitrarily labeled "<NUM>", "<NUM>", and "<NUM>" in the following tables, which also provide the average weight percentages of the components of the streams.

The foregoing table provides the average weight percentages of each component of Stream <NUM>.

Although one or more of the streams of this example were subjected to the processes described in the following examples, other streams from POSM processes may be subjected to the methods described herein, including those of the following examples.

In this example, a liquid-liquid extraction was performed with ethyl benzene on an aqueous stream separated from Sample A of Stream <NUM>. Sample A, prior to extraction, was subjected to GC-FID analysis, which revealed three significant peaks that corresponded to mono-propylene glycol, benzaldehyde, and α-methyl benzyl alcohol/acetophenone.

A <NUM>: <NUM> weight ratio of [<NUM>] ethyl benzene and [<NUM>] the aqueous stream separated from Sample A of Stream <NUM> were disposed in a liquid-liquid extraction unit at ambient temperature and ambient pressure. The contents of the extraction unit were mixed for <NUM> seconds, and allowed to separate for <NUM> hour.

The liquid-liquid extraction unit included an organic stream and an aqueous stream, which were subjected to GC-FID analysis. The analysis of the aqueous stream after the extraction with ethyl benzene revealed three peaks, the first corresponding to mono-propylene glycol, the second corresponding to ethyl benzene, and the third corresponding to α-methyl benzyl alcohol and acetophenone. The benzaldehyde peak, which appeared in the GC-FID analysis prior to extraction, was no longer present. Also observed was a reduction of α-methyl benzyl alcohol and acetophenone, compared to the GC-FID analysis conducted prior to the extraction. The ethylene benzene was then removed.

The GC-FID analysis of the organic stream of this example after the extraction revealed three peaks, the first corresponding to ethyl benzene, the second corresponding to benzaldehyde, and the third corresponding to α-methyl benzyl alcohol and acetophenone.

The extraction efficiency for the three consecutive passes of this example are provided in the following table.

Although a sample of Stream <NUM> was used in this example, the procedure of this example may be applied to other streams, including, but not limited to, Stream <NUM>, Stream <NUM>, and/or other streams, including purge streams, from a POSM process; or the procedure may be applied to a combination of streams, including, but not limited to, a combination that includes at least two of Stream <NUM>, Stream <NUM>, Stream <NUM>, another stream from a POSM process, or a combination thereof.

Although the contents of the liquid-liquid extraction unit of this example were subjected to ambient temperature and ambient pressure, other temperatures and/or pressures may be used.

In this example, a liquid-liquid extraction was performed with n-octane on an aqueous stream separated from Sample A of Stream <NUM>. As in Example <NUM>, Sample A, prior to extraction, was subjected to GC-FID analysis, which revealed three significant peaks that corresponded to mono-propylene glycol, benzaldehyde, and α-methyl benzyl alcohol/acetophenone.

A <NUM>:<NUM> weight ratio of [<NUM>] n-octane and [<NUM>] the aqueous stream separated from Sample A of Stream <NUM> were disposed in a liquid-liquid extraction unit at ambient temperature and ambient pressure. The contents of the extraction unit were mixed for <NUM> seconds, and allowed to settle for <NUM> hour.

After separating, the liquid-liquid extraction unit included an organic stream and an aqueous stream, which were subjected to GC-FID analysis in order to determine the extraction efficiency. After three passes, the GC-FID data indicated a very low concentration of mono propylene glycol in the organic stream.

The results of this example were indicative of the very low solubility of n-octane in the aqueous stream that included water and mono propylene glycol. This feature of n-octane reduced the complexity of the glycol purification process of this example. Also, due to the fact that mono propylene glycol has a very low solubility in n-octane, the loss of mono propylene glycol in the organic stream was reduced or minimized in this example.

The n-octane of this example was purified and recycled via distillation, which was a relatively simple process due at least in part to the fact that n-octane has a much lower boiling point than most, if not all, of the other components of the organic stream. Moreover, n-octane is already used in many POSM processes, which can provide an option for integration.

In this example, a liquid-liquid extraction was performed with toluene on an aqueous stream separated from Sample A of Stream <NUM>. As in Examples <NUM> and <NUM>, Sample A, prior to extraction, was subjected to GC-FID analysis, which revealed three significant peaks that corresponded to mono-propylene glycol, benzaldehyde, and α-methyl benzyl alcohol/acetophenone.

A <NUM>: <NUM> weight ratio of [<NUM>] toluene and [<NUM>] the aqueous stream separated from Sample A of Stream <NUM> were disposed in a liquid-liquid extraction unit at ambient temperature and ambient pressure. The contents of the extraction unit were mixed for <NUM> seconds, and allowed to settle for <NUM> hour.

After separating, the liquid-liquid extraction unit included an organic stream and an aqueous stream, which were subjected to GC-FID analysis in order to determine the extraction efficiency.

The results of this example were indicative of the very low solubility of toluene in the aqueous stream that included water and mono propylene glycol. This feature of toluene reduced the complexity of the glycol purification process of this example. Also, due to the fact that mono propylene glycol has a very low solubility in toluene, the loss of mono propylene glycol in the organic stream was reduced or minimized in this example.

The toluene of this example was purified and recycled via distillation, which was a relatively simple process due at least in part to the fact that toluene has a much lower boiling point than most, if not all, of the other components of the organic stream. Moreover, toluene is already used in many POSM processes, which can provide an option for integration.

This example illustrates how the organic layer is separated into three fractions using a vacuum distillation column. A <NUM> tray <NUM> inch internal diameter Oldershaw glass vacuum column was used for this experiment. The batch distillation was conducted at approximately <NUM> Pa (<NUM> Hg). Different vacuum pressures can be used, however, distillation at pressures higher than <NUM> Pa (<NUM> Hg) will lead to higher bottom temperatures, thus, higher energy usage. From a <NUM> gr organic phase containing <NUM>% benzaldehyde, via vacuum distillation, three fractions were collected as in the following Table <NUM>.

This example illustrates how the aqueous phase is extracted with ethylbenzene to reduce the organic content, and then water is removed from the mixture using vacuum distillation. Table <NUM> provides the composition of the aqueous phase before being processed.

A single liquid-liquid extraction on the above aqueous phase with ethyl benzene (<NUM>:<NUM> ratio) at ambient temperature and atmospheric pressure. The water in the resulting aqueous extraction stream was then reduced using a <NUM> tray, <NUM> inch internal diameter Oldershaw glass vacuum distillation column at <NUM> mmHg. The composition of the bottom product is provided in Table <NUM>.

Claim 1:
A method for recovering one or more chemicals, the method comprising:
providing at least one stream from a process for co-producing propylene oxide and styrene monomer;
disposing the at least one stream in a settling tank to separate the at least one stream into an aqueous stream and an organic stream, wherein the aqueous stream comprises (i) mono-propylene glycol, and (ii) a first amount of α-methyl benzyl alcohol, a first amount of benzaldehyde, a first amount of acetophenone, or a combination thereof; and
contacting the aqueous stream with an organic extraction liquid in a liquid-liquid extraction unit to form a first aqueous extraction stream and a first organic extraction stream;
wherein the first aqueous extraction stream comprises (i) mono-propylene glycol, and (ii) a second amount of α-methyl benzyl alcohol, a second amount of benzaldehyde, a second amount of acetophenone, or a combination thereof; and
the second amount of α-methyl benzyl alcohol, the second amount of benzaldehyde, and the second amount of acetophenone are less than the first amount of α-methyl benzyl alcohol, the first amount of benzaldehyde, and the first amount of acetophenone, respectively; wherein the organic extraction liquid is toluene.