Alkylbisphenol composition and method for preparing the same

Abstract

This invention provides a high-purity recycled alkylbisphenol composition for use in the regeneration of polycarbonate, and a method for preparing the same. [Solution] The alkylbisphenol composition comprises 99.85% to 99.999% by weight of alkylbisphenol; 0.0001% to 0.01% by weight of a monophenol compound; 0.0001% to 0.01% by weight of a reaction adduct of alkylbisphenol; and 0.0001% to 0.1497% by weight of an aromatic compound, wherein the aromatic compound is not alkylbisphenol, monophenol compound, or reaction adduct of alkylbisphenol. The method for preparing the composition comprises a first step of passing polycarbonate waste through a depolymerization process to obtain a crude alkylbisphenol product; a second step of an extraction process; and a third step of precipitating the alkylbisphenol composition.

Description

Technical Field

[0001] The present disclosure relates to an alkyl bisphenol composition and a method for preparing the alkyl bisphenol composition.

Background Art

[0002] Conventional chemical processes for recycling polycarbonate (PC) often result in residual impurities due to the original materials, long-term use and degradation, or formed during the recycling process. These impurities remain in the converted monomer composition regardless of whether the raw material is post-industrial recycled (PIR) or post-consumer recycled (PCR) polycarbonate. It should be noted that the presence of these impurities directly affects the quality of the recycled polycarbonate (PC) and limits the possibilities for circular applications. For example, if the recovered monomer composition contains impurities such as monophenol compounds, the monophenol compounds can interfere with the polymerization during repolymerization due to an uncontrollable end protection effect, ultimately affecting the properties of the recycled polymer. Furthermore, impurities such as flame retardants, dyes, UV absorbers, mold release agents, or antioxidants not only affect the coloring performance but also change the properties of the recycled polycarbonate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] To improve the quality of recycled polycarbonate, conventional chemical recycling processes often involve additional purification steps such as filtration, washing, ion exchange, adsorption, distillation, and recrystallization to remove impurities from the crude monomer composition. However, these complex processes not only reduce overall recycling efficiency and increase processing costs, but also still fail to ensure that the recycled polycarbonate meets the desired quality standards.

[0005] Therefore, in order to solve the above-mentioned problems, there is a need for a novel polycarbonate recycling method that can produce high-purity monomer compositions. [Means for solving the problem]

[0006] This disclosure provides alkylbisphenol compositions and methods for preparing the same. According to embodiments of this disclosure, the alkylbisphenol composition comprises 99.85% to 99.999% by weight of alkylbisphenol; 0.0001% to 0.01% by weight of a monophenol compound; 0.0001% to 0.01% by weight of a reaction adduct of alkylbisphenol; and 0.0001% to 0.1497% by weight of an aromatic compound, wherein the aromatic compound is not alkylbisphenol, monophenol compound, or reaction adduct of alkylbisphenol.

[0007] This disclosure also provides a method for preparing an alkylbisphenol composition, comprising the following steps: Polycarbonate waste is subjected to a depolymerization process to obtain a crude alkylbisphenol product. The crude alkylbisphenol product is subjected to an extraction process in the presence of a first solvent, a second solvent, and water (a third solvent) to obtain a two-layer solution containing a first solution and a second solution, where the first solution contains the first solvent, and the second solution contains the second solvent, water, and alkylbisphenol, the first solvent being immiscible with water, and the second solvent being miscible with water. The second solvent is removed from the second solution, and the alkylbisphenol composition of this disclosure is precipitated from the second solution. [Effects of the Invention]

[0008] This disclosure provides alkylbisphenol compositions and methods for preparing the same. In alkylbisphenol compositions used for the regeneration of polycarbonate, the presence of impurities (such as monophenol compounds, incomplete depolymerization products (i.e., reaction adducts of alkylbisphenols), additives, or derivatives thereof) may affect the properties of the regenerated polycarbonate (PC), such as the degree of polymerization, final molecular weight, color specifications, and stability, thereby limiting the applicability of the final product. Therefore, it is important to reduce the impurity content in alkylbisphenol compositions recovered from polycarbonate. Due to their structural properties, many additives containing luminescent groups (such as flame retardants, dyes, UV absorbers, mold release agents, or antioxidants) exhibit strong intermolecular interactions with the aromatic ring structure of alkylbisphenols, making it difficult to efficiently and completely remove these impurities by simple adsorption, washing, or precipitation processes. Furthermore, even when high-temperature distillation is used to purify the recovered alkylbisphenol composition, impurities in the composition may undergo side reactions with alkylbisphenols at high temperatures, potentially leading to the formation of further impurities. Accordingly, this disclosure provides a method for preparing alkylbisphenol compositions using a specific multisolvent extraction process to significantly reduce the impurity content of the alkylbisphenol composition without impairing recovery. This process yields a regenerated alkylbisphenol composition with high purity (purity: ≥99.85%) and low APHA color (≤80), thereby improving the quality of the regenerated polycarbonate product.

[0009] This disclosure can be more fully understood by referring to the attached drawings and reading the subsequent detailed descriptions and embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] This is a flowchart illustrating a method for preparing an alkylbisphenol composition according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0011] Alkylbisphenol compositions and methods for preparing alkylbisphenol compositions are described in detail below. Numerous specific details and embodiments are provided in the following detailed description to facilitate a full understanding of the disclosure. The specific elements and structures described in the following detailed description are provided to clearly illustrate the disclosure. However, the exemplary embodiments described herein are for illustrative purposes only, and it will become clear that the inventive concept can be embodied in various forms without being limited to these exemplary embodiments. As used herein, the term “about” in quantitative terms means that there is an increase or decrease from an amount that is common and reasonable to those skilled in the art.

[0012] Furthermore, the use of sequential terms such as “first,” “second,” and “third” in the disclosure to modify elements does not in itself imply that any claimed element takes precedence, precedes, or is sequential to any other element, nor does it imply any temporal order in which they are formed. These terms are used merely as labels to distinguish a claimed element having a particular name from other elements having the same name (except for the use of sequential terms).

[0013] According to embodiments of this disclosure, the alkylbisphenol composition is 99.85% to 99.999% by weight (for example, 99.86%, 99.87%, 99.88%, 99.89%, 99.9%, 99.91%, 99.92%, 99.93%, 99.94%, 99.95%, 99.96%, 99.97%, 99.98%, 99.99%, 99.91%, 99.992%, 99.993%, 99.994%, 99.995%, 99.996% Alkylbisphenols in %, 99.997% by weight, or 99.998% by weight); 0.0001% by weight to 0.01% by weight (e.g., 0.0003% by weight, 0.0005% by weight, 0.001% by weight, 0.0015% by weight, 0.002% by weight, 0.0025% by weight, 0.003% by weight, 0.0035% by weight, 0.004% by weight, 0.0045% by weight, 0.005% by weight, 0.0055% by weight, 0.006% by weight, 0.0065% by weight, 0.007% by weight, 0.0075% by weight, 0.008% by weight, 0.0085% by weight, 0.00 9% by weight, or 0.0095% by weight) of a monophenol compound; 0.0001% to 0.01% by weight (e.g., 0.0003% by weight, 0.0005% by weight, 0.001% by weight, 0.0015% by weight, 0.002% by weight, 0.0025% by weight, 0.003% by weight, 0.0035% by weight, 0.004% by weight, 0.0045% by weight, 0.005% by weight, 0.0055% by weight, 0.006% by weight, 0.0065% by weight, 0.007% by weight, 0.0075% by weight, 0.008% by weight, 0.0085% by weight, 0.009% by weight, or 0 0.0095% by weight) of alkylbisphenol reaction adducts; and 0.0001% to 0.1497% by weight (e.g., 0.0001%, 0.0005%, 0.001%, 0.002%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.145%, 0.148%, or 0.The alkylbisphenol composition contains 149% by weight of an aromatic compound, the aromatic compound being neither an alkylbisphenol, a monophenol compound, nor a reaction adduct of an alkylbisphenol. That is, the impurities (i.e., components other than alkylbisphenol) in the alkylbisphenol composition of this disclosure may be less than 0.15% by weight (e.g., less than 0.14%, less than 0.13%, less than 0.12%, less than 0.11%, less than 0.10%, less than 0.09%, less than 0.08%, less than 0.07%, less than 0.06%, less than 0.05%, less than 0.04%, less than 0.03%, less than 0.02%, or less than 0.01%). According to embodiments of this disclosure, the components of the alkylbisphenol composition are analyzed using high-performance liquid chromatography (HPLC).

[0014] In alkylbisphenol compositions, if the monophenol compound content is high, the degree of polymerization and properties of recycled polycarbonate deteriorate due to an uncontrollable end-protection effect. Furthermore, if there is a large amount of residual alkylbisphenol reaction adducts or aromatic compounds, it not only affects the coloring performance but also further alters the properties of recycled polycarbonate.

[0015] According to embodiments of this disclosure, alkylbisphenol is of formula (I): [ka] It may have a structure represented by the formula, where each R 1 These are independently C1-C4 alkyl groups. According to embodiments of this disclosure, alkylbisphenol is [ka] It can be.

[0016] According to embodiments of this disclosure, the monophenol compound may be phenol, cresol, xylenol, or a combination thereof.

[0017] According to embodiments of the present disclosure, the reaction adduct of an alkyl bisphenol can be an incompletely depolymerized product formed during the depolymerization of a polycarbonate, such as a condensation product of an alkyl bisphenol and an alkyl carbonate ester.

[0018] According to embodiments of the present disclosure, the reaction adduct of an alkyl bisphenol has the structure represented by formula (II):

Chemical formula

[0019] According to embodiments of the present disclosure, the above-mentioned C1-C4 alkyl group may be a straight-chain or branched alkyl group. For example, the C1-C4 alkyl group may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0020] According to embodiments of the present disclosure, the aromatic compound is not an alkyl bisphenol, a monophenol compound, or a reaction adduct of an alkyl bisphenol. According to embodiments of the present disclosure, the aromatic compound can be an additive used in a polycarbonate product or an impurity derived therefrom, and the additive can be a flame retardant, a pigment, a UV absorber, a mold release agent, or an antioxidant. According to embodiments of the present disclosure, the impurity derived from the additive refers to an addition reaction adduct formed as a result of a side reaction during the preparation of the alkyl bisphenol composition.

[0021] According to embodiments of the present disclosure, the aromatic compound can be an anthraquinone compound, an azo compound, a benzotriazole compound, a benzopyran compound, or a combination thereof. According to embodiments of the present disclosure, the anthraquinone compound has the formula (III):

Chemical formula

[0022] According to embodiments of the present disclosure, the above-mentioned C1-C4 alkyl group may be a linear or branched alkyl group. For example, the C1-C4 alkyl group may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0023] According to embodiments of the present disclosure, the alkylbisphenol composition may have an APHA color of 80 or less, for example, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75. According to embodiments of the present disclosure, the APHA color of the alkylbisphenol composition may be in the range of 1 to 80. According to embodiments of the present disclosure, the APHA color is measured according to the method specified in ASTM D1209-05, where, prior to measurement, the test sample (5 g) is dissolved in methanol (7 mL).

[0024] In accordance with embodiments of the present disclosure, the present disclosure also provides methods for preparing alkylbisphenol compositions, such as a method for preparing alkylbisphenol compositions from polycarbonate waste. As shown in Figure 1, method 10 for preparing alkylbisphenol compositions includes the following steps: First, polycarbonate waste is subjected to a depolymerization process to obtain a crude alkylbisphenol product (step 12), where the crude alkylbisphenol product comprises alkylbisphenol (i.e., the main product obtained after the depolymerization of polycarbonate). Next, the crude alkylbisphenol product is subjected to an extraction process in the presence of a first solvent, a second solvent, and water (a third solvent) to obtain a two-layer solution containing a first solution and a second solution (step 14), where the first solution comprises the first solvent and the second solution comprises the second solvent, water, and alkylbisphenol (i.e., the alkylbisphenol is extracted in the extraction process by the second solvent and water). Next, the second solvent is removed from the second solution, and the alkylbisphenol composition of the present disclosure is precipitated from the second solution (Step 16) (the alkylbisphenol composition exhibits poor solubility in water). It should be noted that, compared to conventional two-solvent extraction processes, the method for preparing the alkylbisphenol composition described herein utilizes a multi-solvent (i.e., first solvent, second solvent, and water) extraction process to extract the alkylbisphenol. This approach not only increases the recovery rate (overcoming the problem of significant alkylbisphenol loss in conventional extraction processes) but also reduces the impurity content in the resulting alkylbisphenol composition, thereby improving the purity of the alkylbisphenol composition.

[0025] According to embodiments of the present disclosure, the crude alkylbisphenol product may be a mixture (also called a mixture containing alkylbisphenol (including the solvent)) obtained after carrying out a depolymerization process on polycarbonate waste. Furthermore, the crude alkylbisphenol product may also be the (solvent-free) result obtained by carrying out a depolymerization process on polycarbonate waste, followed by a concentration step. According to embodiments of the present disclosure, the order in which the first solvent, the second solvent, and water are added during the extraction process does not affect the extraction results. For example, the first and second solvents may be mixed first with the crude alkylbisphenol product, and then water may be added for the extraction process. Alternatively, the second solvent and water may be mixed first with the crude alkylbisphenol product, and then the first solvent may be added. Furthermore, the second solvent may be mixed first with the crude alkylbisphenol product, and then the first solvent and water may be added for the extraction process.

[0026] According to embodiments of the present disclosure, polycarbonate waste may be polycarbonate bottle flakes, polycarbonate films, polycarbonate light diffusers, polycarbonate automotive lamp housings, polycarbonate wafer carriers, or a combination thereof. According to embodiments of the present disclosure, polycarbonate waste may be prepared from a composition comprising additives and polycarbonate resin, the additives may be flame retardants, dyes, UV absorbers, mold release agents, or antioxidants.

[0027] According to embodiments of the present disclosure, polycarbonate waste is subjected to a depolymerization process in the presence of a depolymerization composition comprising a C1-C6 aliphatic monoalcohol, the process temperature of the depolymerization process can be 50°C to 80°C, and the process time of the depolymerization process can be 1 to 12 hours. According to embodiments of the present disclosure, controlling the upper limit of the depolymerization process temperature to 80°C prevents the formation of further impurities caused by side reactions between alkylbisphenols (products) or additives in the polycarbonate waste during depolymerization. On the other hand, controlling the lower limit of the depolymerization process to below 50°C results in insufficient energy supply, making it impossible to overcome the activation energy of the depolymerization reaction and further lowering the yield. According to embodiments of the present disclosure, the C1-C6 aliphatic monoalcohol can be methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, or a combination thereof. According to embodiments of the present disclosure, the depolymerization composition further comprises a cosolvent, which may be dichloromethane, chloroform, carbon tetrachloride, cyclohexanone, methyl ethyl ketone (MEK), acetone, toluene, xylene, dimethyl carbonate, diethyl carbonate, or a combination thereof. According to embodiments of the present disclosure, the depolymerization composition may further comprise a catalyst, which may be sodium hydroxide, potassium hydroxide, or a combination thereof. According to embodiments of the present disclosure, the amounts of C1-C6 aliphatic monoalcohols, cosolvents, and catalysts are not limited and can be arbitrarily modified by those skilled in the art. For example, the weight ratio of polycarbonate waste to C1-C6 aliphatic monoalcohols may be 2:1 to 1:5, and the weight ratio of C1-C6 aliphatic monoalcohols to cosolvents may be 1:9 to 9:1. The weight ratio of catalyst to polycarbonate waste may be 0.5:100 to 5:100.

[0028] According to embodiments of the present disclosure, the C1-C6 aliphatic monoalcohols, cosolvents, and catalysts of the crude alkylbisphenol product can be removed before the crude alkylbisphenol product is subjected to an extraction process.

[0029] In the extraction process, it should be noted that the first solvent is a solvent that does not readily dissolve alkylbisphenols, while the second solvent readily dissolves alkylbisphenols. That is, alkylbisphenols tend to dissolve more readily in the second solvent than in the first solvent. Since alkylbisphenols dissolve even more readily in the second solvent and water, after the extraction process, the alkylbisphenols are extracted with the second solvent and water, and the concentration of alkylbisphenols in the second solution becomes much higher than the concentration in the first solution. Furthermore, the main solvent in the first solution is the first solvent (i.e., the amount of the first solvent in the first solution is greater than the amount of water and the second solvent in the first solution). The main solvents in the second solution are the second solvent and water (i.e., the amount of the second solvent and water in the second solution is greater than the amount of the first solvent). According to embodiments of this disclosure, the first solvent is immiscible with water, while the second solvent is miscible with water.

[0030] According to embodiments of the present disclosure, the solubility of alkylbisphenol in the first solvent at 30°C is 2% by weight or less (e.g., 1.5% by weight or less, or 1% by weight or less), and the solubility of alkylbisphenol in the second solvent at 30°C is 5% by weight or more (e.g., 6% by weight or more, 7% by weight or more, or 8% by weight or more). A method for measuring the solubility of alkylbisphenol in a solvent includes the following steps: Add the alkylbisphenol to the solvent at 30°C (the weight ratio of alkylbisphenol to solvent is 1:1). Stir for 10 minutes, let stand for 1 hour, then measure the weight of the undissolved alkylbisphenol and measure the weight percentage (wt%) of alkylbisphenol dissolved in the solvent. According to embodiments of the present disclosure, the saturated vapor pressure of the second solvent is higher than that of water at temperatures between 25°C and 70°C. As a result, the second solvent is removed more easily than water.

[0031] According to embodiments of the present disclosure, the first solvent may be toluene, xylene, benzene, hexane, cyclohexane, heptane, octane, dichloromethane, chloroform, dichloroethane, dimethylbenzene, or a combination thereof. According to embodiments of the present disclosure, the second solvent may be methanol, ethanol, isopropanol, n-propanol, acetone, methyl ethyl ketone (MEK), ethyl acetate, dimethyl carbonate, tetrahydrofuran (THF), diethyl ether, acetonitrile, or a combination thereof.

[0032] According to embodiments of the present disclosure, the ratio of the weight of the second solvent to the total weight of the first solvent and water can be 1:1 to 1:5, and the weight ratio of the second solvent to water can be 1:1 to 1:8.

[0033] According to embodiments of the present disclosure, after the extraction process, the second solution may undergo an adsorption process, a precipitation process, or a combination thereof. For example, after obtaining the second solution, the second solvent may be removed, and the alkylbisphenol precipitates from the water. The resulting product may then undergo an adsorption process. According to embodiments of the present disclosure, in addition to the use of a cosolvent precipitation process, the alkylbisphenol can also be precipitated by adjusting the temperature of the solvent to utilize the difference in solubility of the alkylbisphenol. According to embodiments of the present disclosure, the adsorbent used in the adsorption process may be activated carbon, an ion exchange resin, diatomaceous earth, aluminum oxide, or a combination thereof.

[0034] According to embodiments of the present disclosure, the method for removing the second solvent from the second solution may be a low-temperature solvent removal method, such as vacuum concentration at 25°C to 65°C, or vacuum drying at 25°C to 65°C. [Examples]

[0035] Hereafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, so as can be easily recognized by those skilled in the art. The inventive concept can be embodied in various forms, but is not limited to the exemplary embodiments described herein. For clarity, descriptions of well-known parts have been omitted, and the same reference numbers refer to the same elements throughout the specification.

[0036] Example 1 Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0037] Extraction / Precipitation Process: The mixture containing alkylbisphenol was subjected to reduced-pressure concentration using a rotary evaporator at 25°C to remove the solvent, thereby obtaining the crude alkylbisphenol product. Next, 140 g of toluene (acting as the first solvent) and 60 g of methanol (acting as the second solvent) were added to the crude alkylbisphenol product. After mixing, a homogeneous solution was obtained. Next, 80 g of water was added to the homogeneous solution. After mixing, a two-layer solution (containing the first and second solutions) was obtained. Next, the aqueous layer (i.e., the second solution) of the two-layer solution was collected. Next, the aqueous layer was subjected to reduced-pressure concentration using a rotary evaporator at 25°C to obtain methanol. Next, the result was allowed to stand for 10 minutes. During this time, it was observed that white crystals precipitated from the water. After collecting the precipitate by filtration, it was vacuum-dried at 25°C to obtain white crystals (33.5 g).

[0038] Adsorption / Precipitation / Drying Process: The obtained white crystals were dissolved in 120 g of methanol, and 4 g of activated carbon was added. After stirring for 2 hours, the activated carbon was removed by filtration. The filtrate was then slowly added to water (1,200 g). During this time, it was observed that the white crystals precipitated from the water. The precipitate was collected by filtration, vacuum-dried at 25°C for 1 hour, and then vacuum-dried for a further 1 hour at 40°C to obtain regenerated alkylbisphenol A composition (1) (31.6 g).

[0039] Next, the APHA color of alkylbisphenol A composition (1) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (1) was analyzed using high-performance liquid chromatography (HPLC) with a mixed solvent of acetonitrile and methanol (in a 9:1 volume ratio) and water as the mobile phase. The volume ratio of the mixed solvent to water was gradually adjusted during the analysis, starting at 3:7 and changing to 9:1 after 30 minutes. The injection volume of the HPLC sample was 10 μL, and the mobile phase flow rate was 1.0 mL / min. The results are shown in Table 1. The HPLC sample was prepared as follows: Alkylbisphenol A composition (0.1 g), acetonitrile (1.7 g), and o-cresol solution (0.2 g) (o-cresol dissolved in acetonitrile at a concentration of 1% by weight) were mixed, and then filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.22 μm to obtain the HPLC sample. For the test, 5 g of the sample was dissolved in 7 mL of methanol, and the APHA color was measured according to ASTM D1209-05.

[0040] Example 2 Example 2 was carried out in the same manner as the preparation method for alkylbisphenol A composition (1) disclosed in Example 1, except for the following differences. In the depolymerization process, 70 g of ethanol was used instead of 60 g of methanol. In the extraction / precipitation process, 140 g of hexane was used as the first solvent instead of 140 g of toluene, and 210 g of ethanol was used as the second solvent instead of 60 g of methanol, and the amount of water was increased from 80 g to 350 g. Next, the APHA color of alkylbisphenol A composition (2) (30.52 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (2) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0041] Example 3 Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 120 g of methyl ethyl ketone (MEK), 120 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0042] Extraction / Precipitation Process: A mixture containing alkylbisphenol was subjected to reduced-pressure concentration using a rotary evaporator at 25°C to remove the solvent and obtain a crude alkylbisphenol product. Next, 100 g of dichloromethane (used as the first solvent) and 60 g of acetone (used as the second solvent) were added to the crude alkylbisphenol product and mixed to obtain a homogeneous solution. Next, 80 g of water was added to the homogeneous solution. After mixing, a two-phase solution (containing the first and second solutions) was obtained. Next, the aqueous layer of the two-phase solution (i.e., the second solution) was collected. Next, the aqueous phase was subjected to reduced-pressure concentration using a rotary evaporator at 25°C to remove the acetone. Next, the result was allowed to stand for 10 minutes. During this time, it was observed that white crystals precipitated from the water. After collecting the precipitate by filtration, it was vacuum-dried at 25°C to obtain white crystals.

[0043] Drying process: The white crystals were vacuum-dried at 25°C for 1 hour, and then vacuum-dried at 40°C for 1 hour to obtain regenerated alkylbisphenol A composition (3) (30.88 g).

[0044] Next, the APHA color of alkylbisphenol A composition (3) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (3) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0045] Example 4 Example 4 was carried out in the same manner as the preparation method for alkylbisphenol A composition (1) disclosed in Example 1, except for the following differences. In the depolymerization process, 140 g of ethanol and 20 g of dichloromethane were used instead of 60 g of methanol and 200 g of dimethyl carbonate. In the extraction / precipitation process, 100 g of hexane was used (as the first solvent) instead of 140 g of toluene, and 60 g of ethyl acetate was used (as the second solvent) instead of 60 g of methanol. Next, the APHA color of alkylbisphenol A composition (4) (29.45 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (4) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0046] Example 5 Example 5 was carried out in the same manner as the preparation method for alkylbisphenol A composition (3) disclosed in Example 3, with the following differences: In the depolymerization process, 120 g of dimethyl carbonate was used instead of 120 g of methyl ethyl ketone. In the extraction / precipitation process, 70 g of toluene (as the first solvent) was used instead of 100 g of dichloromethane, 350 g of ethyl acetate (as the second solvent) was used instead of 60 g of acetone, and the amount of water was increased from 80 g to 350 g. Next, the APHA color of alkylbisphenol A composition (5) (28.73 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (5) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0047] Example 6 Example 6 was carried out in the same manner as the preparation method for alkylbisphenol A composition (1) disclosed in Example 1, except that in the extraction / precipitation process, the amount of toluene was reduced from 140 g to 100 g, 60 g of ethyl acetate was used (as a second solvent) instead of 60 g of methanol, and the amount of water was increased from 80 g to 100 g. Next, the APHA color of alkylbisphenol A composition (6) (25.86 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (6) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0048] Example 7 Example 7 was carried out in the same manner as the preparation method for alkylbisphenol A composition (1) disclosed in Example 1, except for the following differences. In the depolymerization process, 60 g of ethanol was used instead of 60 g of methanol. In the extraction / precipitation process, 70 g of dimethylbenzene was used (as the first solvent) instead of 140 g of toluene, 140 g of ethanol was used (as the second solvent) instead of 60 g of methanol, and the amount of water was increased from 80 g to 280 g. Next, the APHA color of alkylbisphenol A composition (7) (20.14 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (7) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1.

[0049] Example 8 Example 8 was carried out in the same manner as the preparation method for alkylbisphenol A composition (1) disclosed in Example 1, with the following differences: In the depolymerization process, the amount of methanol was increased from 60 to 140 g, and 20 g of dichloromethane was used instead of 200 g of dimethyl carbonate. In the extraction / precipitation process, 100 g of dimethylbenzene was used (as the first solvent) instead of 140 g of toluene. Next, the APHA color of alkylbisphenol A composition (8) (28 g) was evaluated. The results are shown in Table 1. Alkylbisphenol A composition (8) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 1. [Table 1] TIFF2026116809000007.tif248149

[0050] As shown in Table 1, recycled bisphenol A compositions prepared in accordance with the Disclosure through a specific polycarbonate waste recycling process of the Disclosure (including a specific extraction step involving the simultaneous use of a first solvent, a second solvent, and water) can achieve a bisphenol A content greater than 99.85% by weight, a monophenol compound content of less than 0.01% by weight, a bisphenol A reaction adduct content of less than 0.01% by weight, and an aromatic compound (additive or additive-derived impurity) content of less than 0.13% by weight. Furthermore, the APHA color value of the recycled bisphenol A compositions is less than 55, and the purification process yield is favorable (for example, the purification process yield of alkylbisphenol A composition (1) in Example 1 is approximately 88%).

[0051] Comparative Example 1 Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0052] Extraction process: The mixture containing alkylbisphenol was subjected to reduced-pressure concentration using a rotary evaporator at 25°C to remove the solvent and obtain the crude alkylbisphenol product. Next, 50 g of hexane (used as the first solvent) and 100 g of ethyl acetate (used as the second solvent) were added to the crude alkylbisphenol product and mixed to obtain a heterogeneous solution. Next, the ethyl acetate extract layer from the heterogeneous solution was collected. Next, the ethyl acetate was removed by passing the resulting product through reduced-pressure concentration at 25°C using a rotary evaporator to obtain a white solid.

[0053] Precipitation / Drying Process: The obtained white solid was dissolved in methanol (120 g), and the resulting solution was slowly added to water (1,200 g). During this time, white crystals precipitated from the water. The precipitate was collected by filtration, vacuum-dried at 25°C for 1 hour, and then vacuum-dried at 40°C for 1 hour to obtain alkylbisphenol A composition (9) (25.9 g).

[0054] Next, the APHA color of alkylbisphenol A composition (9) was evaluated. The results are shown in Table 2. Alkylbisphenol A composition (9) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 2.

[0055] Comparative Example 2 Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0056] Washing process: The mixture containing alkylbisphenol was passed through a rotary evaporator under reduced pressure at 25°C to remove the solvent and obtain the crude alkylbisphenol product. Next, the crude alkylbisphenol product was added to toluene (100g) and mixed to obtain the first solution. The first solution was then heated to 80°C and subsequently cooled slowly to 25°C. After standing for 1 hour, the precipitate was collected by filtration to obtain a white solid.

[0057] Reducing agent addition process: The obtained white solid was mixed with 50 g of methanol and 50 g of water, and then sodium dithionite (Na2S2O4) (0.06 g) was added. The mixture was stirred to obtain a second solution.

[0058] Adsorption / Drying Process: 10 g of activated carbon was added to the second solution. After stirring for 2 hours, the activated carbon was removed by filtration. Next, the solvent in the filtrate was removed at 25°C using a rotary evaporator. The resulting product was then vacuum-dried for 1 hour at 25°C, followed by vacuum-dried for 1 hour at 40°C to obtain alkylbisphenol A composition (10) (30.9 g).

[0059] Next, the APHA color of alkylbisphenol A composition (10) was evaluated. The results are shown in Table 2. Alkylbisphenol A composition (10) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 2.

[0060] Comparative Example 3 Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0061] Adsorption / Precipitation / Drying Process: A mixture containing alkylbisphenol was passed through a rotary evaporator under reduced pressure at 25°C to remove the solvent and obtain a crude alkylbisphenol product. Next, the crude alkylbisphenol product was dissolved in methanol (120 g), and then 12 g of activated carbon was added. After stirring for 2 hours, the activated carbon was removed by filtration, and the filtrate was slowly added to water (1,200 g). During this time, white crystals precipitated from the water. The precipitate was collected by filtration, vacuum-dried for 1 hour at 25°C, and then vacuum-dried for 1 hour at 40°C to obtain alkylbisphenol A composition (11) (8.85 g).

[0062] Next, the APHA color of alkylbisphenol A composition (11) was evaluated. The results are shown in Table 2. Alkylbisphenol A composition (11) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 2.

[0063] Comparative Example 4 (according to US20230322653A1) Depolymerization process: 40 g of polycarbonate waste flakes (derived from polycarbonate carrier waste), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were added to a reaction bottle. The reaction bottle was then heated to a temperature of 60°C to 70°C and reacted for 5 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0064] Washing / Drying Process: The mixture containing alkylbisphenol was passed through a rotary evaporator under reduced pressure at 25°C to remove the solvent and obtain the crude alkylbisphenol product. Next, the crude alkylbisphenol product was added to toluene (100 g) and mixed to obtain the first solution. Next, the first solution was heated to 80°C and subsequently washed five times with water (100 g each time) to collect the organic phase. The organic phase was then slowly cooled to 25°C. After standing for 1 hour, the precipitate was collected by filtration to obtain a white solid. The white solid was then vacuum dried for 1 hour at 25°C and for 1 hour at 40°C to obtain alkylbisphenol A composition (12) (28 g).

[0065] Next, the APHA color of alkylbisphenol A composition (12) was evaluated. The results are shown in Table 2. Alkylbisphenol A composition (12) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 2.

[0066] Comparative Example 5 (according to US20230391702A1) Depolymerization process: Polycarbonate waste (41.5 g) and dichloromethane (226.9 g) were added to a reaction bottle. After mixing, the polycarbonate waste was dissolved in the dichloromethane. Next, methanol (42 g), ethanol (72.35 g), and sodium hydroxide (2.1 g) were added to the reaction bottle. Then, the reaction bottle was heated to 60°C and reacted for 6 hours. After the reaction bottle was cooled to room temperature, a mixture containing alkylbisphenol was obtained.

[0067] Adsorption process: Next, the mixture containing alkylbisphenol was cooled to 20°C, and hydrochloric acid (HCl) solution (10 g, 1N concentration) was added to the mixture containing alkylbisphenol to obtain a solution. Then, 12.45 g of activated carbon was added to the solution. After stirring for 2 hours, the activated carbon was removed by filtration, and the filtrate was passed through a rotary evaporator under reduced pressure at 25°C to remove the solvent.

[0068] Washing / Adsorption / Precipitation / Drying Process: Next, the resulting product was washed with dichloromethane (41.5 g) at 20°C. After filtration, the filtrate was washed with water (124.5 g) at 50°C, and this process was repeated twice. Next, 80.5 g of ethanol was added to the obtained solution. Next, 12.45 g of activated carbon was added to the solution. After stirring for 2 hours, the activated carbon was removed by filtration. Next, water (1,000 g) was mixed with the filtrate and stirred. After standing for 10 minutes, white crystals precipitated from the water. The precipitate was collected by filtration and dried in a vacuum oven at 30°C to obtain alkylbisphenol A composition (13) (4.71 g).

[0069] Next, the APHA color of alkylbisphenol A composition (13) was evaluated. The results are shown in Table 2. Alkylbisphenol A composition (13) was analyzed using high-performance liquid chromatography (HPLC). The results are shown in Table 2. [Table 2]

[0070] Comparative Example 1 did not utilize the extraction process (using the first solvent / second solvent / water simultaneously) and adsorption process described in Example 1. As shown in Table 2, the alkylbisphenol A composition (9) obtained in Comparative Example 1 had a significantly higher content of bisphenol A reaction adducts (>3% by weight) and additives (or impurities derived from additives) (>0.7% by weight), and its APHA color value was also greater than 300.

[0071] Comparative Example 2 did not utilize the extraction process described in Example 1 (using the first solvent / second solvent / water simultaneously). As shown in Table 2, even after applying additional washing and reducing agent addition processes, the alkylbisphenol A composition (10) obtained in Comparative Example 2 still contained significantly large amounts of monophenol compounds (about 0.03 wt%), bisphenol A reaction adducts (>1 wt%), and additives (or impurities derived from additives) (about 0.05 wt%), and the APHA color value exceeded 300.

[0072] Comparative Example 3 did not utilize the extraction process described in Example 1 (using the first solvent / second solvent / water simultaneously). As shown in Table 2, although subjected to adsorption, precipitation, and drying processes, the alkylbisphenol A composition (11) obtained in Comparative Example 3 still contained relatively high amounts of bisphenol A (>1% by weight) and additives (or impurities derived from additives) (>0.8% by weight), and the APHA color value was also greater than 300.

[0073] Comparative Example 4 did not utilize the extraction process described in Example 1 (using the first solvent / second solvent / water simultaneously). As shown in Table 2, although the purification process followed the method disclosed in US20230322653A1, the alkylbisphenol A composition (12) obtained in Comparative Example 4 still contained a significantly high amount of bisphenol A reaction adducts (about 0.05 wt%) and additives (or impurities derived from additives) (>4 wt%), and the APHA color value reached about 300.

[0074] Comparative Example 5 also did not utilize the extraction process described in Example 1 (using the first solvent / second solvent / water simultaneously). As shown in Table 2, although the depolymerization and purification processes followed the method disclosed in US20230391702A1, the alkylbisphenol A composition (13) obtained in Comparative Example 5 still showed a significantly large amount of additives (or additive-derived impurities) (>1% by weight) even after passing through the adsorption process twice, with an APHA color value greater than 300 and a low purification yield of less than 10%.

[0075] Therefore, by a specific multi-solvent extraction process, the method for preparing alkylbisphenol compositions according to this disclosure can significantly reduce the impurity content in the alkylbisphenol composition without impairing the recovery rate. This makes it possible to produce regenerated alkylbisphenol compositions with high purity (99.85% or higher) and low APHA color value (80 or lower), thereby improving the quality of the regenerated polycarbonate product.

[0076] It will become clear that various modifications and variations can be applied to the disclosed methods and materials. The specification and examples are to be considered merely illustrative, and the true scope of this disclosure is intended to be shown by the following claims and their equivalents.

Claims

1. Alkylbisphenol composition, 99.85% to 99.999% by weight of alkylbisphenols; 0.0001% to 0.01% by weight of a monophenol compound; 0.0001% to 0.01% by weight of alkylbisphenol reaction adducts; and It contains 0.0001% to 0.1497% by weight of aromatic compounds. The aromatic compound is not the alkylbisphenol, the monophenol compound, or a reaction adduct of the alkylbisphenol, and is an alkylbisphenol composition.

2. The alkylbisphenol is of formula (I): 【Chemistry 1-1】 It has a structure represented by the formula, where each R 1 The alkylbisphenol composition according to claim 1, wherein is independently a C1-C4 alkyl group.

3. The alkylbisphenol composition according to claim 1, wherein the monophenol compound is phenol, cresol, xylenol, or a combination thereof.

4. The reaction adduct of the alkylbisphenol is given by formula (II): 【Chemistry 1-2】 It has a structure represented by the formula, where R 2 and R 3 The alkylbisphenol composition according to claim 1, wherein is independently a C1-C4 alkyl group and n ≥ 1.

5. The alkylbisphenol composition according to claim 1, wherein the aromatic compound is an anthraquinone compound, an azo compound, a benzotriazole compound, a benzopyran compound, or a combination thereof.

6. The first step involves passing polycarbonate waste through a depolymerization process to obtain a crude alkylbisphenol product; A second step is to pass the crude alkylbisphenol product through an extraction process in the presence of a first solvent, a second solvent, and water to obtain a two-layer solution containing a first solution and a second solution, wherein the first solution contains the first solvent, and the second solution contains the second solvent, water, and alkylbisphenol, the first solvent is immiscible with water, and the second solvent is miscible with water; A third step is to remove the second solvent from the second solution and precipitate the alkylbisphenol composition according to claim 1 from the second solution; A method for preparing an alkylbisphenol composition containing [a specific compound].

7. The method for preparing an alkylbisphenol composition according to claim 6, wherein in the extraction process, the first solvent and the second solvent are first mixed with the crude alkylbisphenol product and then extracted with water.

8. The method for preparing an alkylbisphenol composition according to claim 6, wherein in the extraction process, the second solvent and water are first mixed with the crude alkylbisphenol product, and then extracted with the first solvent.

9. The method for preparing an alkylbisphenol composition according to claim 6, wherein in the extraction process, the second solvent is first mixed with the crude alkylbisphenol product, and then extracted with the first solvent and water.

10. A method for preparing an alkylbisphenol composition according to claim 6, wherein the first solvent is toluene, xylene, benzene, hexane, cyclohexane, heptane, octane, dichloromethane, chloroform, dichloroethane, dimethylbenzene, or a combination thereof, and the second solvent is methanol, ethanol, isopropanol, n-propanol, acetone, methyl ethyl ketone, ethyl acetate, dimethyl carbonate, tetrahydrofuran, diethyl ether, acetonitrile, or a combination thereof.

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