POLYETHER POLYCARBONATE POLYOLS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No.

62/738,480 filed on September 28, 2018, the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

[0002] Embodiments of the present disclosure are generally related to purification of polyether polycarbonate polyols, and are specifically related to removal of alkylene carbonate from polyether polycarbonate polyols.

BACKGROUND

[0003] In the catalytic polymerization of alkylene oxides and carbon dioxide, alkylene carbonates can be produced as one of the products. However, the presence of alkylene carbonates is typically undesirable in the polyether polycarbonate polyol product, particularly at concentrations typical of the crude polyether polycarbonate polyol effluent.

[0004] Conventionally, vaporization and/or gas stripping under reduced pressure may be used to reduce the alkylene carbonate concentration. While effective, such processes may be cost-prohibitive and may expose the polyol product to elevated temperatures, which may lead to product quality issues.

[0005] Accordingly, there is a need for alternative processes for reducing alkylene carbonate concentrations in the crude polyether polycarbonate polyol effluent.

SUMMARY

[0006] Various embodiments described herein provide an aqueous extraction using an aqueous wash solution including an inorganic salt, which enhances phase separation between the organic phase and the aqueous phase dissolving the alkylene carbonate, thereby reducing the alkylene carbonate byproduct in the organic phase. According to one embodiment, a process for reducing alkylene carbonate content in a crude polyether polycarbonate polyol effluent comprising the alkylene carbonate and polyether polycarbonate polyol, which is the polymerized reaction product of alkylene oxide and carbon dioxide in the presence of a suitable catalyst, includes mixing the crude polyether polycarbonate polyol effluent with an aqueous wash solution including an inorganic salt. The alkylene carbonate mixes with the aqueous wash solution. The process further includes allowing the mixture of crude polyether polycarbonate polyol effluent and aqueous wash solution to separate into a first aqueous phase including alkylene carbonate, and a first organic phase including the polyether polycarbonate polyol and an amount of alkylene carbonate that is less than the amount of alkylene carbonate in the crude polyether polycarbonate polyol effluent.

[0007] Embodiments also provide using the first organic phase to produce a polyurethane, and recovering the alkylene carbonate from the aqueous layer.

DETAILED DESCRIPTION

[0008] Embodiments are directed to processes for reducing alkylene carbonate content in a crude polyether polycarbonate polyol effluent by mixing the crude polyether polycarbonate polyol effluent with an aqueous wash solution including an inorganic salt and allowing the mixture to separate into a first aqueous phase including alkylene carbonate and a first organic phase including the polyether polycarbonate polyol and an amount of alkylene carbonate that is less than the amount of alkylene carbonate in the crude polyether polycarbonate polyol effluent. By crude polyether polycarbonate polyol effluent, it is meant the mixture of alkylene carbonate and polyether polycarbonate polyol that is the polymerized reaction product of alkylene oxide and carbon dioxide in the presence of a catalyst.

[0009] Although alkylene carbonate is very soluble in water, because the density of water is very close to the typical density of the crude polyether polycarbonate polyol effluent, the use of water to remove alkylene carbonate from the crude polyether polycarbonate polyol effluent can result in an emulsion, which can be time-consuming to separate, thereby reducing the viability of an aqueous wash as a means for reducing the amount of alkylene carbonate in the polyol. However, in various embodiments, an inorganic salt is added to the aqueous wash solution to increase the density of the aqueous wash solution relative to the polyol, enabling the separation of the aqueous wash solution from the polyol as separate phases. [0010] In various embodiments, a process for reducing alkylene carbonate content in a crude polyether polycarbonate polyol effluent is provided. Polyether polycarbonate polyols are conventionally produced by the addition-polymerization reaction of an alkylene oxide and C0 ₂ onto H-functional starter substances in the presence of a catalyst. The resulting reaction mixtures include the polyether polycarbonate polyols along with an amount of alkylene carbonate. As used herein, the term“reaction mixture” refers to the mixture of starting materials and reaction products present in the reactor.

[0011] As used herein, the term“H-functional starter substance” refers to compounds having H atoms which are active for alkoxylation. Groups which have active H atoms and are active for alkoxylation can include, for example, -OH, -NH ₂ (primary amines), -NH- (secondary amines), - SH, and -C0 ₂ H. H-functional starter substances may include, by way of example, one or more mono- or polyfunctional alcohols, thiols, amino alcohols, thioalcohols, polyether polyols, polyester polyols, polyester ether polyols, polycarbonate polyols, polyethyleneimines, polyether triols, amines, acids, or mixture thereof. The particular H-functional starter substance may be selected based on the desired polyether polycarbonate polyol to be produced.

[0012] The catalyst may be, for example, a double metal cyanide (DMC) catalyst, a metal salen-type catalyst, a zinc carboxylate catalyst, or a zinc diiminate-type catalyst, or the like.

[0013] In embodiments, the alkylene oxide used for making the polyether polycarbonate polyol may be ethylene oxide, propylene oxide, or mixtures thereof. The amount of alkylene oxide in the reaction mixture may be from greater than 0 wt% to 40 wt%, greater than 0 wt% to 25 wt%, greater than 0 wt% to 15 wt%, or greater than 0 wt% to 10 wt% based on a total weight of the reaction mixture.

[0014] Carbon dioxide may be incorporated into the reaction mixture for forming the polyether polycarbonate polyol in an amount of from 0.5 wt% to 40 wt%, 1.5 wt% to 20 wt%, or from 2.5 wt% to 15 wt% of the reaction mixture. The alkylene oxide and the carbon dioxide may be mixed together in a reactor for polymerization of the polyether polycarbonate polyols. In some embodiments, one or both of the alkylene oxide and the carbon dioxide are metered continuously into the reactor. Amounts of alkylene oxide and carbon dioxide may be calculated using data for the H-functional starter substances and the resultant polyether carbonate polyol. For example, the hydroxyl number of a polyfunctional polyol used as a H-functional starter substance and the desired hydroxyl number of the polyether carbonate polyol to be synthesized may serve as a basis for the amounts of alkylene oxide and carbon dioxide. In other embodiments, amine numbers or acid numbers of the H-functional starter substances may be employed.

[0015] In various embodiments, the total amount of H-functional starter substance(s) may be placed in a reactor together with the DMC catalyst and the alkylene oxide may be metered in. The carbon dioxide may be added all at once or may be metered in over the reaction time before or simultaneously with the addition of the alkylene oxide. In embodiments, the reaction may be carried out at a temperature of greater than or equal to 60 °C and less than or equal to 150 °C, greater than or equal to 70 °C and less than or equal to 140 °C, or greater than or equal to 80 °C and less than or equal to 130 °C. The reaction may be carried out at a pressure of greater than or equal to 0 bar and less than or equal to 20 bar, greater than or equal to 1 bar and less than or equal to 15 bar, or greater than or equal to 3 bar and less than or equal to 10 bar. It is contemplated that any particular combination of pressure and temperature conditions may be used for the reaction, and the combination of pressure and temperature may be selected based on the desired polyether carbonate polyol. Additionally, it is contemplated that reactor pressure and/or temperature may be varied during the polymerization reaction.

[0016] In various embodiments, following polymerization of the alkylene oxide and carbon dioxide in the presence of the DMC catalyst, a crude polyether polycarbonate polyol effluent including the polyether polycarbonate polyol and alkylene carbonate is present in the reactor. Although the amount of alkylene carbonate may vary depending on a variety of factors, including without limitation reactor pressure, temperature, and rate of addition of C0 ₂ , in embodiments, the alkylene carbonate is present in the crude polyether polycarbonate polyol effluent in an amount of greater than or equal to about 4 wt% or even greater than or equal to about 5 wt% based on a total weight of the crude polyether polycarbonate polyol effluent.

[0017] According to various embodiments, the crude polyether polycarbonate polyol effluent is mixed with an aqueous wash solution in order to reduce alkylene carbonate content in the crude polyether polycarbonate polyol effluent. The crude polyether polycarbonate polyol effluent may be mixed with the aqueous wash solution using any suitable mixing apparatus, including, but not limited to, static or dynamic mixing devices. Other devices suitable for enhancing mass transfer may additionally or alternatively be employed. When the aqueous wash solution is mixed with the crude polyether polycarbonate polyol effluent, a portion of the alkylene carbonate transfers to and mixes with the aqueous wash solution because the alkylene carbonate is soluble in water.

[0018] In various embodiments, the aqueous wash solution includes one or more inorganic salts. Without being bound by theory, it is believed that the presence of the inorganic salt in the aqueous wash solution can increase the density of the aqueous wash solution such that the aqueous wash solution can be separated from an organic phase including the polyether polycarbonate polyol as an aqueous phase. Additionally or alternatively, the salt may impact the alkylene carbonate solubility and/or polarity within the aqueous phase.

[0019] The inorganic salt may be, by way of example and not limitation, a monovalent, divalent, or higher valency inorganic salt, such as alkali and alkali earth salts of chloride, sulfate, phosphate, carbonate, citrate, acetate, or the like. In some embodiments, the inorganic salt may include NaCl, KC1, NaHC0 ₃ , KHC0 ₃ , Na ₂ S0 ₄ , MgS0 ₄ , NaH ₂ P0 ₄ , Na ₂ HP0 ₄ , trisodium citrate, NaOAc, or combinations thereof. Other inorganic salts may be used, depending on the particular embodiment, provided that such inorganic salts do not adversely impact downstream processing steps that may be employed. For example, it is contemplated that although the inorganic salt remains primarily in the aqueous phase, some minor amount of the inorganic salt may be present in the organic phase after separation of the phases, and should not adversely impact further processing of the organic phase.

[0020] In embodiments, the aqueous wash solution may include greater than or equal to 5 wt% of the inorganic salt based on a total weight of the aqueous wash solution. For example, the inorganic salt may be present in an amount of from 5 wt% to 30 wt% based on a total weight of the aqueous wash solution, 5 wt% to 20 wt% based on a total weight of the aqueous wash solution, or from 10 wt% to 20 wt% based on a total weight of the aqueous wash solution. Other amounts of inorganic salt may be included in the aqueous wash solution. For example, the inorganic salt may be included in the aqueous wash solution up to the solubility limit of the inorganic salt. Accordingly, in various embodiments, water may be present in the aqueous wash solution in an amount of less than or equal to 99.9 wt%, from 70 wt% to 95 wt%, from 80 wt% to 95 wt%, or from 80 wt% to 90 wt%. [0021] The aqueous wash solution may optionally include additives such as, by way of example and not limitation, antioxidants, acids, emulsifiers, dispersants and/or surfactants. For example, in some embodiments, acids may be added to improve polyol stability during processing. Antioxidants and other components typically found in isocyanate reacting mixtures for use in polyurethane reactions may be included in the aqueous wash solution as a means to add the component to the organic phase. Emulsifiers, dispersants, and/or surfactants may optionally be added to the aqueous wash solution to enhance phase separation between the organic phase and the aqueous phase.

[0022] In various embodiments, the aqueous wash solution may have a pH of from 4 to 11, from 4.5 to 10.5, from 5 to 10, from 5.5 to 9.5, from 6 to 8, or from 6.5 to 7.5. However, it is contemplated that in some embodiments, the pH may be adjusted based on the inorganic salt selected or the amount of salt employed.

[0023] The aqueous wash solution may be mixed with the crude polyether polycarbonate polyol effluent at a weight ratio (crude polyether polycarbonate polyol effluent: aqueous wash solution) of from 0.1 to 10, from 0.5 to 5, or from 0.5 to 2. The particular weight ratio of crude polyether polycarbonate polyol effluent: aqueous wash solution may vary depending on the specific embodiment and, in particular, at least in part on the specific inorganic salt employed.

[0024] In other embodiments, the crude polyether polycarbonate polyol effluent is mixed with the aqueous wash solution at a temperature of greater than or equal to 25 °C to less than or equal to 150 °C. For example, the crude polyether polycarbonate polyol effluent may be mixed with the aqueous wash solution at a temperature of from 25 °C to 150 °C, from 30 °C to 140 °C, from 50 °C to 130 °C, or from 70 °C to 120 °C. The particular temperature selected may vary depending on the particular embodiment. Without being bound by theory, it is believed that increasing the temperature may increase the rate of phase separation and may enable a decrease in the amount of inorganic salt in the aqueous wash solution.

[0025] After the crude polyether polycarbonate polyol effluent is mixed with the aqueous wash solution, the mixture is allowed to separate into an aqueous phase and an organic phase. In various embodiments, the aqueous phase includes alkylene carbonate. The organic phase includes the polyether polycarbonate polyol and an amount of alkylene carbonate that is less than the amount of alkylene carbonate present in the crude polyether polycarbonate polyol effluent. The amount of alkylene carbonate may be reduced by 40 % or greater, 50 % or greater, or even 70 % or greater as compared to the concentration of alkylene carbonate in the crude polyether polycarbonate polyol effluent.

[0026] In embodiments, the phases are allowed to separate for a time of greater than or equal to 20 minutes, or greater than or equal to 30 minutes. The amount of time may vary depending on the particular embodiment, and may depend on the type and amount of inorganic salt included in the aqueous wash solution, other phase separation aids present in the aqueous wash solution, the weight ratio (crude polyether polycarbonate polyol effluent: aqueous wash solution), and the temperature. In various embodiments, the phases are allowed to separate at a temperature from 25 °C to 150 °C. Process equipment useful for liquid-liquid extraction known to those skilled in the art include centrifugal contactors, reciprocating plate columns, raining bucket contactors, mixer settlers, static packed or tray columns, and mechanically agitated columns. As is well-recognized by those skilled in the art, such equipment can be used in batch processes, co-current continuous processes, or counter-current continuous processes, depending on the desired application.

[0027] According to various embodiments, after the phases are allowed to separate, the aqueous phase may be removed and the remaining organic phase may be mixed with a second aqueous wash solution. The second aqueous wash solution may have the same composition as the aqueous wash solution mixed with the crude polyether polycarbonate polyol effluent, or may have a different composition. For example, the first aqueous wash solution may have a first inorganic salt and the second aqueous wash solution may have a second inorganic salt, or the first aqueous wash solution may include an inorganic salt at a first concentration and the second aqueous wash solution may include the inorganic salt at a second concentration. After mixing, the mixture of the second aqueous wash solution and the first organic phase are allowed to separate into a second aqueous phase and a second organic phase. The second aqueous phase includes alkylene carbonate, and the second organic phase includes the polyether polycarbonate polyol and an amount of alkylene carbonate that is less than the amount of the alkylene carbonate in the first organic phase. Further iterations are contemplated.

[0028] In embodiments, the mixing and separation may occur in a continuous manner, or may be performed batchwise. For example, in some embodiments, the aqueous phase may be removed from the mixing apparatus as it separates from the organic phase, and fresh aqueous wash solution may be continuously added. Alternatively, in some embodiments, a series of batch separation steps may be performed.

[0029] According to various embodiments, the aqueous phase may be processed in order to recover the alkylene carbonate. Recovery can be performed according to any suitable method known in the art.

[0030] In various embodiments, the organic phase may be used to produce a polyurethane. In particular, the organic phase may be reacted with an isocyanate component. The organic phase may be reacted with the isocyanate component as separated from the aqueous phase, or it may undergo one or more additional processing steps prior to being reacted with the isocyanate component. For example, in some embodiments, the organic phase may be subjected to a water removal step to remove excess water from the polyol. Other processing steps, such as ion exchange, distillation, aqueous extraction, and the like, may be performed on the organic phase in some embodiments.

[0031] Various compositions are considered suitable for the isocyanate component. The isocyanate component includes one or more polyisocyanates (as interchangeable referred to as polyisocyanurates) and may optionally include one or more isocyanate-terminated prepolymers derived from one or more polyisocyanates. The amount of isocyanate component may vary based on application.

[0032] In some embodiments, the resulting polyurethane resin composition may further include other components, including, but not limited to, reactive diluents, tougheners, catalysts, inhibitors, activators, accelerators, and gel time retarders. Other ingredients may be also included in the resin composition, such as internal mold release agents, fillers, and the like. For example, internal mold release agents may be included to facilitate the release of the polymerized composite article from the mold in which it has been prepared. When included, the internal mold release agents may be present in an amount from about 0.1 wt% to about 5 wt% based on a total weight of the resin composition. Examples of suitable internal mold release agents include those available for composite applications from Axel Plastics Research Laboratories, Inc. (Woodside, NY) or from E. and P. Wiirtz GmbH & Co. KG (Germany). Other additives having specific functions, as known in the industry, may also be included in the resin composition, including but not limited to, air release agents, adhesion promoters, leveling agents, wetting agents, UV absorbers and light stabilizers.

[0033] Upon reacting, the mixture produces a polyurethane polymer which is then allowed to cure, either partially or fully. Suitable conditions for promoting the curing of the urethane resin composition include a temperature of from about 15 °C to about 150 °C. In some embodiments, the urethane resin composition may be curable at temperatures near room temperature, for example, from about 15 °C to about 30 °C. In some embodiments, the curing is performed at a temperature of from about 20 °C to about 75 °C. In other embodiments, the curing is performed at a temperature of from about 20 °C to about 60 °C. In various embodiments, the temperature selected for curing may be selected at least in part based on the amount of time required for the urethane resin composition to gel and/or cure at that temperature. Cure time will also depend on other factors, including, for example, the particular components (e.g., catalysts and quantities thereof), and the thickness of the article to be cured.

Examples

[0034] The following examples are provided to illustrate various embodiments, but are not intended to limit the scope of the claims. All parts and percentages are by weight unless otherwise indicated. Approximate properties, characters, parameters, etc., are provided below with respect to various working examples, comparative examples, and the materials used in the working and comparative examples.

Alkylene Carbonate Concentration in Polyol Test Method

[0035] Polyol samples (0.1 g) are dissolved in methanol (0.5) and analyzed using a laboratory gas chromatograph (GC) according to the method summarized in Table 1. A calibration curve is generated using standards of known concentrations of propylene carbonate in polyether polyol (0.1 to 5.0 wt%). [0036] Table 1:

Water Concentration in Polyol Test Method

[0037] A polyol sample (0.05 - 0.10 g) is collected using a pre-weighed, disposable polypropylene syringe, and titrated for water on a Karl Fisher apparatus (Mettler Toledo V20 Volumetric Titrator).

[0038] In the following examples, polyol A is a glycerin-initiated triol having a M _N of 3500 g/mol, prepared from a feed composition including 2.63 wt% glycerin, 11.00 wt% ethylene oxide, 2.90 wt% carbon dioxide, and 83.47 wt% propylene oxide.

Comparative Experiment A

[0039] Polyether polycarbonate polyol A (5.0 g) containing 2.14 wt% total alkylene carbonates is weighed into a glass vial, followed by deionized water (5.0 g). The biphasic solution is inverted for 60 seconds and magnetically stirred at room temperature (25 °C) for 30 minutes. Stirring is discontinued and the mixture phase-separates at room temperature for 30 minutes. Poor phase separation is observed after 30 minutes.

Comparative Experiment B

[0040] Comparative Experiment A is repeated except that the aqueous solution is 1 wt% aqueous sodium chloride. Poor phase separation is observed after 30 minutes. Comparative Experiment C

[0041] Comparative Experiment A is repeated except that the aqueous solution is 2.5 wt% aqueous sodium chloride. Poor phase separation is observed after 30 minutes.

Comparative Experiment D

[0042] Comparative Experiment C is repeated except that the extraction and phase separation temperature is 65 °C. Poor phase separation is observed after 30 minutes.

Examples 1 and 2

[0043] Comparative Experiment A is repeated except that the aqueous solution is either 5 wt% aqueous sodium chloride (Example 1) or 15 wt% aqueous sodium chloride (Example 2). Effective phase separation is observed after 30 minutes. The polyol phase is sampled for GC analysis. The results are summarized in Table 2.

[0044] Table 2:

[0045] As shown in Table 2, treatment with 5 wt% aqueous sodium chloride or 15 wt% aqueous sodium chloride leads to a significant reduction in the alkylene carbonate concentration dissolved in the polyol.

Examples 3 and 4

[0046] Examples 1 and 2 are repeated except that the extraction and phase- separation temperature is 45 °C. The polyol phase is sampled for GC analysis. The results are summarized in Table 3. [0047] Table 3:

Examples 5 and 6

[0048] Examples 1 and 2 are repeated except that the extraction and phase- separation temperature is 65 °C. The polyol phase is sampled for GC analysis. The results are summarized in Table 4.

[0049] Table 4:

Examples 7 and 8

[0050] Examples 1 and 2 are repeated except that the extraction and phase- separation temperature is 85 °C. The polyol phase is sampled for GC analysis. The results are summarized in Table 5.

[0051] Table 5:

[0052] As shown in Tables 3 - 5, increasing the temperature of the extraction and phase- separation leads to a further reduction of the alkylene carbonate concentration dissolved in the polyol.

Examples 9 - 12

[0053] Examples 1 - 2 and 5 - 6 are repeated except that the aqueous solution is either 5 wt% aqueous potassium chloride (Examples 9 and 11) or 15 wt% aqueous potassium chloride (Examples 10 and 12). The results are summarized in Table 6.

[0054] Table 6:

[0055] As shown in Table 6, treatment with 5 wt% aqueous potassium chloride or 15 wt% aqueous potassium chloride leads to a significant reduction in the alkylene carbonate concentration dissolved in the polyol.

Examples 13 - 16

[0056] Examples 1 - 2 and 5 - 6 are repeated except that the aqueous solution is either 5 wt% aqueous sodium acetate (Examples 13 and 15) or 15 wt% aqueous sodium acetate (Examples 14 and 16). The results are summarized in Table 7. [0057] Table 7:

[0058] As shown in Table 7, treatment with 5 wt% aqueous sodium acetate or 15 wt% aqueous sodium acetate leads to a significant reduction in the alkylene carbonate concentration dissolved in the polyol.

Examples 17 - 20

[0059] Examples 5 - 6 are repeated except that the aqueous solution is 5 wt% aqueous sodium sulfate (Example 17), 15 wt% aqueous sodium sulfate (Example 18), 5 wt% aqueous magnesium sulfate (Example 19), or 15 wt% aqueous magnesium sulfate (Example 20). The results are summarized in Table 8.

[0060] Table 8:

Examples 21 - 28

[0061] Examples 5 - 8 are repeated except that the aqueous solution is 5 wt% aqueous sodium bicarbonate (Examples 21 and 23), 15 wt% aqueous sodium bicarbonate (Examples 22 and 24), 5 wt% aqueous potassium bicarbonate (Examples 25 and 27), or 15 wt% aqueous potassium bicarbonate (Examples 26 and 28). The results are summarized in Table 9. [0062] Table 9:

[0063] As shown in Table 9, treatment with 5 wt% or 15 wt% aqueous sodium bicarbonate or aqueous potassium bicarbonate leads to a significant reduction in the alkylene carbonate concentration dissolved in the polyol.

Examples 29 - 32

[0064] Examples 5 - 6 are repeated except that the aqueous solution is 5 wt% aqueous sodium dihydrogen phosphate (Example 29), 15 wt% aqueous sodium dihydrogen phosphate (Example 30), 5 wt% aqueous sodium hydrogen phosphate (Example 31), or 15 wt% aqueous sodium hydrogen phosphate (Example 32). The results are summarized in Table 10.

[0065] Table 10:

Examples 33 - 34 [0066] Examples 5 - 6 are repeated except that the aqueous solution is 5 wt% aqueous trisodium citrate (Example 33) or 15 wt% aqueous trisodium citrate (Example 34). The results are summarized in Table 11.

[0067] Table 11:

Example 35

[0068] Example 29 is repeated except that the polyol phase (5.0 g): aqueous phase (20.0 g) is 1:4 (w:w) instead of 1:1 (w:w). The results are summarized in Table 12.

[0069] Table 12:

[0070] As shown in Table 12, increasing the polyol phase: aqueous phase (w:w) leads to a further reduction in the alkylene carbonate concentration dissolved in the polyol as compared to the reduction in the alkylene carbonate concentration dissolved in the polyol in Example 29.

Examples 36 - 38

[0071] Polyether polycarbonate polyol A (50.0 g) containing 2.14 wt% total alkylene carbonates is weighed into a glass vial, followed by an aqueous wash solution (50.0 g). The biphasic solution is inverted for 60 seconds and magnetically stirred at 65 °C for 30 minutes. Stirring is discontinued and the mixture phase- separates at 65 °C for 30 minutes. The polyol phase is recovered, dried on a rotary evaporator, and vacuum filtered through a 100 mL fritted funnel (coarse frit). The polyol is sampled for GC analysis. The results are summarized in Table 13.

[0072] Table 13:

[0073] As shown in Table 13, drying of the polyol phase on a rotary evaporator reduced the residual water concentration to £ 1.00 wt% in Examples 36 - 38.

[0074] Various embodiments described provide a process for reducing alkylene carbonate concentrations in crude polyether polycarbonate polyol effluents using aqueous extraction. Such embodiments may reduce the alkylene carbonate concentrations without being cost prohibitive, since they employ aqueous wash solutions, without exposing the polyol product to conditions which may result in product quality issues. Accordingly, various embodiments described herein may be employed to reduce alkylene carbonate concentrations during the preparation of polyether polycarbonate polyols for use in polyurethane reactions.

[0075] It is further noted that terms like“generally,”“commonly,” and“typically” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

[0076] It will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.