Alkyl diphenol compositions and methods for making the same

Abstract

This invention provides an alkyl bisphenol composition and a method for preparing the same. The alkyl bisphenol composition comprises 99.85 wt% to 99.999 wt% of alkyl bisphenol; 0.0001 wt% to 0.01 wt% of an aromatic monoalcohol; 0.0001 wt% to 0.01 wt% of an alkyl bisphenol reactive adduct; and 0.0001 wt% to 0.1497 wt% of a compound, wherein the compound is not an alkyl bisphenol, an aromatic monoalcohol, or an alkyl bisphenol reactive adduct.

Description

Technical Field

[0001] This invention relates to an alkyl diphenol composition and its preparation method. Background Technology

[0002] Polycarbonate (PC) possesses excellent mechanical, electrical, heat, cold, and transparency properties, making it widely used in various fields such as lenses, building materials, automotive parts, office equipment housings, and camera bodies. In recent years, the demand for polycarbonate has continued to grow. However, with this increased demand, a large amount of waste PC products are disposed of through incineration or landfill. This not only accelerates the depletion of petroleum resources but also further exacerbates the degradation of the Earth's environment.

[0003] Therefore, the recycling of waste plastics has become particularly important. In response to international plastic restriction regulations, the global demand for recycled polyester is expected to increase dramatically. Currently, commercial waste polycarbonate recycling is mostly based on physical recycling. However, it is well known that physical recycling of waste polycarbonate leads to changes in its physicochemical properties and deterioration in its mechanical properties, limiting its applications. Therefore, developing chemical recycling methods for waste polycarbonate, decomposing waste polycarbonate into monomer compositions for use in polycarbonate reprocessing, is crucial for achieving a green circular economy.

[0004] However, in traditional polycarbonate chemical recycling processes, regardless of whether the raw materials are post-industrial recycled (PIR) or post-consumer recycled (PCR) polyester sources, impurities inherent in the raw materials (or those degraded over long-term use) or formed during the recycling process can easily remain in the converted monomer composition. It is worth noting that these impurities directly affect the properties of the recycled polycarbonate, limiting its potential for circular applications. For example, if the converted monomer composition contains monophenolic compounds, the uncontrollable end-capping effect will affect the degree of polymerization and polymer properties when used in polycarbonate recycling. Furthermore, the residue of impurities such as flame retardants, dyes, UV absorbers, mold release agents, or oxidants not only affects the material's color performance but also further alters the properties of the polycarbonate.

[0005] To improve the quality of recycled polycarbonate, traditional chemical recycling processes involve further steps such as filtration, washing, ion exchange, adsorption, distillation, and recrystallization to remove impurities from the resulting crude monomer composition. However, this complex process not only further reduces the polycarbonate recovery rate and increases processing costs, but also fails to guarantee that the resulting recycled polycarbonate meets the required quality standards.

[0006] Based on the above, the industry needs a novel polycarbonate recycling method to form high-purity monomer compositions and solve the problems encountered by previous technologies. Summary of the Invention

[0007] This invention provides an alkylbisphenol composition and a method for preparing the same. According to embodiments of the invention, the alkylbisphenol composition comprises 99.85 wt% to 99.999 wt% of alkylbisphenol; 0.0001 wt% to 0.01 wt% of an aromatic monoalcohol; 0.0001 wt% to 0.01 wt% of an alkylbisphenol reactive adduct; and 0.0001 wt% to 0.1497 wt% of a compound, wherein the compound is not an alkylbisphenol, an aromatic monoalcohol, or an alkylbisphenol reactive adduct.

[0008] This invention provides a method for preparing an alkyldiphenol composition, comprising the following steps: A polycarbonate waste is subjected to a depolymerization process to obtain a crude alkyldiphenol product; the crude alkyldiphenol product is then subjected to an extraction process using a first solvent, a second solvent, and water to separate a first solution from a second solution, wherein the first solution contains the first solvent, and the second solution contains the second solvent, water, and the alkyldiphenol, wherein the first solvent is immiscible with water, and the second solvent is miscible with water; and the second solvent is removed from the second solution, causing the alkyldiphenol composition of this invention to precipitate. Attached Figure Description

[0009] Figure 1 A flowchart illustrating the steps of method 10 for preparing an alkyldiphenol composition according to an embodiment of the present invention.

[0010] In the attached figures, the following labels are used:

[0011] 10. Methods for forming patterned photoresist layers; and

[0012] Steps 12, 14, and 16. Detailed Implementation

[0013] The following provides a detailed description of the alkyl diphenol composition and its preparation method according to the present invention. It should be understood that the following description provides many different embodiments for implementing different variations of the invention. The specific components and arrangements described below are merely for illustrative purposes. Of course, these are illustrative only and not intended to limit the invention. In this invention, the term "about" means that the specified amount can be increased or decreased by an amount that is generally and reasonably understood by those skilled in the art.

[0014] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the components of the claims does not imply or represent any prior ordinal number of the claimed component, nor does it represent the order of one claimed component with another, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a claimed component with a certain name to be clearly distinguished from another claimed component with the same name.

[0015] The specific embodiments are merely illustrative of particular ways in which the invention is used and are not intended to limit the invention. Unless otherwise defined, all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary knowledge in the art to which this invention pertains.

[0016] This invention provides an alkyl diphenol composition and a method for preparing the same. In alkyl diphenol compositions used for polycarbonate reprocessing, the presence of impurities (e.g., aromatic monools, incompletely depolymerized products (i.e., alkyl diphenol reactive adducts), additives (or their derivatives)) can affect the properties of the reprocessed polycarbonate (e.g., degree of polymerization, final molecular weight, color specifications, and stability), thus limiting the product's applicability. Therefore, reducing the impurity content of alkyl diphenol compositions recovered from polycarbonate is crucial. Due to their structural characteristics, many additives with luminescent groups (e.g., flame retardants, dyes, UV absorbers, mold release agents, or oxidants) have strong intermolecular forces with alkyl diphenols containing benzene ring structures, making them difficult to remove completely and effectively through simple adsorption, washing, or precipitation processes. Furthermore, even when purifying the recovered alkyl diphenol composition using high-temperature distillation, impurities in the composition may undergo side reactions with the alkyl diphenol at high temperatures, leading to the formation of other impurities. Based on the above, the present invention provides a method for preparing an alkyl diphenol composition. Through a specific multi-element solvent extraction process, the impurity content of the alkyl diphenol composition can be significantly reduced without reducing the recovery rate, and a high-purity (purity greater than or equal to 99.85%) and low APHA color (less than or equal to 80) regenerated alkyl diphenol composition can be obtained, which can improve the quality of regenerated polycarbonate products.

[0017] According to embodiments of the present invention, the alkyl diphenol composition comprises 99.85 wt% to 99.999 wt% (e.g., 99.86 wt%, 99.87 wt%, 99.88 wt%, 99.89 wt%, 99.9 wt%, 99.91 wt%, 99.92 wt%, 99.93 wt%, 99.94 wt%, 99.95 wt%, 99.96 wt%, 99.97 wt%, 99.98 wt%, 99.99 wt%, 99.991 wt%, 99.992 wt%, 99.993 wt%, 99.994 wt%, 99.995 wt%, 99.996 wt%, 99.997 wt%, or 99.998 wt%) of alkyl diphenol. bisphenol); 0.0001 wt% to 0.01 wt% (e.g., 0.0003 wt%, 0.0005 wt%, 0.001 wt%, 0.0015 wt%, 0.002 wt%, 0.0025 wt%, 0.003 wt%, 0.0035 wt%, 0.004 wt%, 0.0045 wt%, 0.005 wt%, 0.0055 wt%, 0.006 wt%, 0.0065 wt%, 0.007 wt%, 0.0075 wt%, 0.008 wt%, 0.0085 wt%, 0.009 wt%, or 0.0095 wt%) of aromatic monools. Monoalcohol); 0.0001 wt% to 0.01 wt% (e.g., 0.0003 wt%, 0.0005 wt%, 0.001 wt%, 0.0015 wt%, 0.002 wt%, 0.0025 wt%, 0.003 wt%, 0.0035 wt%, 0.004 wt%, 0.0045 wt%, 0.005 wt%, 0.0055 wt%, 0.006 wt%, 0.0065 wt%, 0.007 wt%, 0.0075 wt%, 0.008 wt%, 0.0085 wt%, 0.009 wt%, or 0.0095 wt%) of alkyl diol reactive adducts. ; and, 0.0001 wt% to 0.1497 wt% (e.g., 0.0001 wt%, 0.0005 wt%, 0.001 wt%, 0.002 wt%, 0.005 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.11 wt%, 0.12 wt%, 0.13 wt%, 0.14 wt%, 0.145 wt%, 0.148 wt%, or 0.149 wt%) of compounds, wherein the compound is not an alkyl bisphenol, an aromatic monohydric alcohol, or an alkyl bisphenol reactive adduct.In other words, the impurities (components other than alkyldiphenol) in the alkyldiphenol composition of the present invention can be less than 0.15 wt% (e.g., less than 0.14 wt%, less than 0.13 wt%, less than 0.12 wt%, less than 0.11 wt%, less than 0.10 wt%, less than 0.9 wt%, less than 0.8 wt%, less than 0.7 wt%, less than 0.6 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, or less than 0.1 wt%). According to an embodiment of the present invention, the alkyldiphenol composition is analyzed using high-performance liquid chromatography (HPLC).

[0018] In recycled alkyl diphenol compositions, a high content of aromatic monools can lead to uncontrollable end-capping effects, affecting the degree of polymerization and polymer properties during polycarbonate reprocessing. Furthermore, high levels of alkyl diphenol reactive adducts or other residual compounds can not only affect the material's color performance but also further alter the properties of the polycarbonate.

[0019] According to an embodiment of the present invention, the alkyl diphenol has the structure shown in formula (I):

[0020] ,

[0021] Where R 1 It is independently a C1-C4 alkyl group. According to embodiments of the present invention, the alkyl diphenol may be...

[0022]

[0023] According to an embodiment of the present invention, the aromatic monool is phenol, cresol, xylenol, or a combination thereof.

[0024] According to embodiments of the present invention, the alkyl diphenol reactive adduct can be an incompletely depolymerized product formed during the depolymerization of polycarbonate (e.g., a condensate of alkyl diphenol and alkyl carbonate). According to embodiments of the present invention, the alkyl diphenol reactive adduct can have the structure shown in formula (II).

[0025] ,

[0026] Where R 2 and R 3 Independently defined as C1-C4 alkyl; and 1000≥n≥1.

[0027] According to embodiments of the present invention, the compound is not an alkyl bisphenol, an aromatic monohydric alcohol, or an alkyl bisphenol reactive adduct. According to embodiments of the present invention, the compound may be an additive or its derivative impurity used in polycarbonate articles, wherein the additive may be a flame retardant, dye, UV absorber, mold release agent, or oxidant. According to embodiments of the present invention, the additive derivative impurity refers to an additive reactive adduct formed due to a side reaction during the preparation of the recycled alkyl bisphenol composition.

[0028] According to embodiments of the present invention, the compound may be an anthraquinone compound, an azo compound, a benzotriazole compound, a benzopyran compound, or a combination thereof. According to embodiments of the present invention, the anthraquinone compound may have the structure shown in formula (III).

[0029] ,

[0030] Where R 4It can be hydrogen, C1-C4 alkyl, or amino group independently. For example, the anthraquinone compound can be 2-methyl anthraquinone, 2-ethylanthraquinone, 1,3-dimethylanthraquinone, 2,3-dimethylanthraquinone, 1,4-dimethylanthraquinone, 2,7-dimethylanthraquinone, 2-n-propylanthraquinone, 2-isopropylanthraquinone, 2-sec... (e.g., 1,4-butylanthraquinone), 2-tert-butylanthraquinone, 2-sec-pentylanthraquinone, 2-tert-pentylanthraquinone, 2-aminoanthraquinone, 1,4-diaminoanthraquinone, 1,5-diaminoanthraquinone, 2,6-diaminoanthraquinone, or combinations thereof. According to embodiments of the present invention, the azo compound may be an azo dye. According to embodiments of the present invention, the benzotriazole compound may be 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, or 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole.5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)-2H-benzotriazole 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methylphenyl]-benzotriazole The compounds can be zotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], or combinations thereof. According to embodiments of the present invention, the benzopyrone compound can be a benzopyrone dye.

[0031] According to embodiments of the present invention, the APHA color value of the alkyl diphenol composition may be less than 80, 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 invention, the APHA color value of the alkyl diphenol composition may be between 1 and 79. According to embodiments of the present invention, the APHA color is determined according to the method specified in ASTM D1209-05 (the analyte (5 g) is dissolved in methanol (7 mL) before measurement).

[0032] According to embodiments of the present invention, the C1-C4 alkyl group can be a straight-chain or branched alkyl group. For example, the C1-C4 alkyl group can be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0033] According to embodiments of the present invention, the present invention also provides a method for preparing an alkyldiphenol composition, such as a method for preparing a recycled alkyldiphenol composition using polycarbonate waste. Please refer to... Figure 1 The preparation method 10 of the alkyl diphenol composition may include the following steps. First, a polycarbonate waste is subjected to a depolymerization process to obtain a crude alkyl diphenol product (step 12), wherein the crude alkyl diphenol product contains alkyl diphenol (i.e., the main product after polycarbonate depolymerization). Next, the crude alkyl diphenol product is subjected to an extraction process using a first solvent, a second solvent, and water to separate a first solution from a second solution (step 14), wherein the first solution contains the first solvent; the second solution contains the second solvent, water, and alkyl diphenol (i.e., in the extraction process, the alkyl diphenol is extracted by the second solvent and water). Next, the second solvent is removed from the second solution, precipitating the alkyl diphenol composition of the present invention (step 16) (utilizing the characteristic that the alkyl diphenol composition has poor solubility in water). It is worth noting that, compared with the traditional extraction process using two solvents, the method for preparing the alkyl diphenol composition of the present invention uses a multi-solvent extraction process (i.e., a first solvent, a second solvent, and water) to extract alkyl diphenols. In addition to increasing the recovery rate (overcoming the problem of large alkyl diphenol loss after traditional extraction), it can also reduce the impurities in the obtained alkyl diphenol composition and improve the purity of the alkyl diphenol composition.

[0034] According to embodiments of the present invention, the crude alkyldiphenol product can be the product (containing solvent) obtained after a depolymerization process of the polycarbonate waste. Alternatively, the crude alkyldiphenol product can also be the product (excluding solvent) obtained after a depolymerization process of the polycarbonate waste and subsequent concentration. According to embodiments of the present invention, 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 solvent and the second solvent can be mixed with the crude alkyldiphenol product first, and then water can be added for the extraction process. Alternatively, the second solvent and water can be mixed with the crude alkyldiphenol product first, and then the first solvent can be added for the extraction process. Furthermore, the second solvent can be mixed with the crude alkyldiphenol product first, and then the first solvent and water can be added for the extraction process.

[0035] According to embodiments of the present invention, the polycarbonate waste may be polycarbonate bottle flakes, polycarbonate films, polycarbonate light-transmitting covers, polycarbonate automotive lamp housings, polycarbonate wafer boxes, or combinations thereof. According to embodiments of the present invention, the polycarbonate waste may be made from a composition comprising additives and polycarbonate resin, wherein the additives may be flame retardants, dyes, UV absorbers, release agents, or oxidants.

[0036] According to an embodiment of the present invention, the polycarbonate waste is subjected to a depolymerization process in the presence of a depolymerization composition comprising C1-C6 aliphatic unit alcohols, and the depolymerization process temperature can be from 50°C to 80°C, and the process time can be from 1 to 12 hours. According to an embodiment of the present invention, when the upper limit of the depolymerization process temperature is controlled at 80°C, the generation of other impurities due to side reactions of alkyldiphenols (products) or additives in the waste can be avoided during the depolymerization of the polycarbonate waste; when the lower limit of the depolymerization process temperature is controlled below 50°C, the yield will be low due to insufficient energy provided and the inability to cross the activation energy of the depolymerization reaction. According to embodiments of the present invention, the C1-C6 aliphatic unit alcohols may be methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, or combinations thereof. According to embodiments of the present invention, the depolymerization composition further comprises a co-solvent, wherein the co-solvent is dichloromethane, chloroform, carbon tetrachloride, cyclohexanone, methyl ethyl ketone, acetone, toluene, xylene, dimethyl carbonate, diethyl carbonate, or combinations thereof. According to embodiments of the present invention, the depolymerization composition may further comprise a catalyst, wherein the catalyst is sodium hydroxide, potassium hydroxide, or a combination thereof. According to embodiments of the present invention, the amounts of C1-C6 aliphatic unit alcohols, co-solvents, and catalysts are not particularly limited, and can be adjusted as needed by those skilled in the art. For example, the weight ratio of polycarbonate waste to the C1-C6 aliphatic unit alcohol can be 2:1 to 1:5; the weight ratio of the C1-C6 aliphatic unit alcohol to the co-solvent can be 1:9 to 9:1. The weight ratio of the catalyst to the polycarbonate waste can be 0.5:100 to 5:100.

[0037] According to an embodiment of the present invention, before performing the extraction process on the first solvent, residual C1-C6 aliphatic unit alcohols, co-solvents, and catalysts in the first solution can be removed first.

[0038] It is worth noting that the first solvent used in this extraction process is a solvent that is less soluble in alkyl diphenols, while the second solvent is a solution that is more soluble in alkyl diphenols. In other words, alkyl diphenols tend to dissolve more readily in the second solvent than in the first solvent. Since alkyl diphenols are also readily soluble in the second solvent and water compared to the first solvent, after the extraction process, the alkyl diphenols in the first solution will be extracted by the second solvent and water, resulting in a much higher content of alkyl diphenols in the third solution than in the second solution. Furthermore, the primary solvent in the second solution is the first solvent (i.e., the content of the first solvent in the second solution is greater than the content of water and the content of the second solvent in the second solution), and the primary solvent in the third solution is the second solvent and water (i.e., the content of the second solvent in the third solution is greater than the content of the first solvent in the third solution). According to embodiments of the present invention, the first solvent is immiscible with water, and the second solvent is miscible with water.

[0039] According to an embodiment of the present invention, the solubility of the alkyl diphenol in the first solvent at 30°C is less than or equal to 2 wt% (e.g., less than or equal to 1.5 wt%, or less than or equal to 1 wt%); and the solubility of the alkyl diphenol in the second solvent at 30°C is greater than or equal to 5 wt% (e.g., greater than or equal to 6 wt%, greater than or equal to 7 wt%, or greater than or equal to 8 wt%). The measurement of the solubility of the alkyl diphenol in the solvent is performed as follows: the alkyl diphenol is added to the solvent at 30°C (wherein the weight ratio of alkyl diphenol to solvent is 1:1). After stirring for 10 minutes and standing for 1 hour, the weight of the undissolved alkyl diphenol is measured, and the weight percentage (wt%) of the alkyl diphenol dissolved in toluene is analyzed. According to an embodiment of the present invention, at 25°C to 70°C, the saturated vapor pressure of the second solvent is greater than the saturated vapor pressure of water. Therefore, the second solvent is more easily removed relative to water.

[0040] According to embodiments of the present invention, the first solvent may be toluene, xylene, benzene, hexane, cyclohexane, heptane, octane, dichloromethane, chloroform, dichloroethane, or a combination thereof. According to embodiments of the present invention, 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.

[0041] According to embodiments of the present invention, the weight ratio 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.

[0042] According to embodiments of the present invention, after the extraction process, the third solution can be subjected to an adsorption process, a precipitation process, or a combination thereof. For example, after obtaining the third solution, the second solvent in the third solution can be removed first, causing the alkyldiphenol to precipitate from the water, and then the resulting product can be subjected to an adsorption process. According to embodiments of the present invention, in addition to a precipitation process using a co-solvent, the alkyldiphenol can be precipitated by utilizing the difference in solubility of the alkyldiphenol due to temperature changes in the solvent. According to embodiments of the present invention, the adsorbent used in the adsorption process can be activated carbon, ion exchange resin, diatomaceous earth, alumina, or a combination thereof.

[0043] According to an embodiment of the present invention, the method for removing the second solvent from the third solution can 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.

[0044] To make the above-mentioned and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings.

[0045] Example 1

[0046] Depolymerization process: 40 g of polycarbonate waste fragments (source: waste polycarbonate wafer casks), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0047] Extraction / precipitation process: The mixture of alkyl diphenols was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude alkyl diphenol product. Next, toluene (140 g) (as the first solvent) and methanol (60 g) (as the second solvent) were added to the crude alkyl diphenol product and mixed thoroughly to obtain a first solution (homogeneous solution). Then, water (80 g) was added to the first solution and mixed thoroughly to obtain a second solution (heterogeneous solution). The second solution was then extracted, and the aqueous layer was collected. Next, the aqueous layer was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the methanol. The resulting product was allowed to stand for 10 minutes, during which time white crystals were observed precipitating from the water. The precipitate was collected by filtration and then vacuum dried at 25°C to obtain white crystals (33.5 g).

[0048] Adsorption / precipitation / drying process: The obtained white crystals were dissolved in methanol (120 g) and 4 g of activated carbon were added. After stirring for 2 hours, the activated carbon was removed by filtration, and the resulting filtrate was slowly added to water (1,200 g). At this time, white crystals were observed to precipitate from the water. After collecting the precipitate by filtration, it was vacuum dried at 25 °C for 1 hour and vacuum dried at 40 °C for 1 hour to obtain the regenerated bisphenol A composition (1) (31.6 g).

[0049] Next, the APHA colorimetry of the bisphenol A composition (1) was evaluated, and the results are shown in Table 1. The bisphenol A composition (1) was analyzed using high performance liquid chromatography (HPLC) with a mixed solvent of acetonitrile and methanol / water as the mobile phase. The volume ratio of the acetonitrile to methanol mixed solvent was 9:1, and the volume ratio of the mixed solvent to water in the mobile phase changed steadily with the analysis time. Initially, the volume ratio of the mixed solvent to water was 3:7, and after 30 minutes, the volume ratio was changed to 9:1. The HPLC sample injection volume 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: 0.1 g of bisphenol A composition, 1.7 g of acetonitrile, and 0.2 g of o-cresol solution (o-cresol dissolved in acetonitrile, concentration 1 wt%) were mixed and then filtered through a polytetrafluoroethylene (PTFE) membrane (pore size 0.22 μm) to obtain the HPLC sample. APHA colorimetry was performed according to the method specified in ASTM D1209-05 (5 g of the analyte was dissolved in 7 mL of methanol before measurement).

[0050] Example 2

[0051] Example 2 was prepared according to the method for preparing the regenerated bisphenol A composition (1) described in Example 1, except that: (1) in the depolymerization process, ethanol (70 g) was used instead of methanol (60 g); and (2) in the extraction / precipitation process, hexane (140 g) was used instead of toluene (140 g) as the first solvent, ethanol (210 g) was used instead of methanol (60 g) as the second solvent, and the amount of water was increased from 80 g to 350 g. Next, the APHA color of the regenerated bisphenol A composition (2) (30.52 g) obtained in Example 2 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (2) was analyzed using high performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0052] Example 3

[0053] Depolymerization process: 40 g of polycarbonate waste (source: waste polycarbonate wafer casks), 120 g of methyl ethyl ketone, 120 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0054] Extraction / precipitation process: The mixture of alkyl diphenols was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude alkyl diphenol product. Next, dichloromethane (100 g) (as the first solvent) and acetone (60 g) (as the second solvent) were added to the crude alkyl diphenol product and mixed thoroughly to obtain a first solution (homogeneous solution). Then, water (80 g) was added to the first solution and mixed thoroughly to obtain a second solution (heterogeneous solution). The second solution was then extracted, and the aqueous layer was collected. Next, the aqueous layer was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the acetone. The resulting product was allowed to stand for 10 minutes, during which time white crystals were observed precipitating from the water. The precipitate was collected by filtration and then vacuum dried at 25°C to obtain white crystals.

[0055] Drying process: The obtained white crystals were vacuum dried at 25°C for 1 hour and vacuum dried at 40°C for 1 hour to obtain the regenerated bisphenol A composition (3) (30.88 g).

[0056] Next, the APHA color of the bisphenol A composition (3) was evaluated, and the results are shown in Table 1; and the bisphenol A composition (3) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0057] Example 4

[0058] Example 4 was prepared according to the method for preparing the regenerated bisphenol A composition (1) described in Example 1, except for the following differences: (1) in the depolymerization process, ethanol (140 g) and dichloromethane (20 g) were used instead of methanol (60 g) and dimethyl carbonate (200 g); and (2) in the extraction / precipitation process, hexane (100 g) was used instead of toluene (140 g) as the first solvent, and ethyl acetate (60 g) was used instead of methanol (60 g) as the second solvent. Next, the APHA color of the regenerated bisphenol A composition (4) (29.45 g) obtained in Example 4 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (4) was analyzed using high performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0059] Example 5

[0060] Example 5 was prepared according to the method for preparing the regenerated bisphenol A composition (3) described in Example 3, except for the following differences: (1) in the depolymerization process, dimethyl carbonate (120 g) was used instead of butanone (120 g); and (2) in the extraction / precipitation process, toluene (70 g) was used instead of dichloromethane (100 g) as the first solvent, ethyl acetate (350 g) was used instead of acetone (60 g) as the second solvent, and the amount of water was increased from 80 g to 560 g. Next, the APHA color of the regenerated bisphenol A composition (5) (28.73 g) obtained in Example 5 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (5) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0061] Example 6

[0062] Example 6 was prepared according to the method for regenerated bisphenol A composition (1) described in Example 1, except that the amount of toluene was reduced from 140 g to 100 g in the extraction / precipitation process, ethyl acetate (60 g) was used instead of methanol (60 g) as the second solvent, and the amount of water was increased from 80 g to 100 g. Next, the APHA color of the regenerated bisphenol A composition (6) (25.86 g) obtained in Example 6 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (6) was analyzed using high-performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0063] Example 7

[0064] Example 7 was prepared according to the method for preparing the regenerated bisphenol A composition (1) described in Example 1, except for the following differences: (1) in the depolymerization process, ethanol (60 g) was used instead of methanol (60 g); and (2) in the extraction / precipitation process, dimethylbenzene (70 g) was used instead of toluene (140 g) as the first solvent, ethanol (140 g) was used instead of methanol (60 g) as the second solvent, and the amount of water was increased from 80 g to 280 g. Next, the APHA color of the regenerated bisphenol A composition (7) (20.14 g) obtained in Example 7 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (7) was analyzed by high-performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0065] Example 8

[0066] The preparation method of the regenerated bisphenol A composition (1) described in Example 1 was followed, except that: (1) in the depolymerization process, the amount of methanol was increased from 60 g to 140 g, and dichloromethane (20 g) was used instead of dimethyl carbonate (200 g); and (2) in the extraction / precipitation process, dimethylbenzene (100 g) was used instead of toluene (140 g) as the second solvent. Next, the APHA color of the regenerated bisphenol A composition (8) (28 g) obtained in Example 8 was evaluated, and the results are shown in Table 1; and the bisphenol A composition (8) was analyzed using high-performance liquid chromatography (HPLC), and the results are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070]

[0071]

[0072] As shown in Table 1, through the specific polycarbonate waste recycling process described in this invention (including a specific extraction step (using a first solvent / a second solvent / water simultaneously)), the bisphenol A content of the regenerated bisphenol A composition prepared by this invention can be greater than 99.85 wt%, the aromatic monool content can be less than 0.01 wt%, the bisphenol A reaction adduct can be less than 0.01 wt%, and the additives (or their derivative impurities) can be less than 0.13 wt%. Furthermore, the APHA color of the regenerated bisphenol A composition described in this invention can be less than 55, and it has a good purification process yield (for example, the purification process yield of the regenerated bisphenol A composition (1) described in Example 1 can be about 88%).

[0073] Comparative Example 1

[0074] Depolymerization process: 40 g of polycarbonate waste (source: waste polycarbonate wafer cassette), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0075] Extraction process: The first solution was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude alkyldiphenol product. Next, hexane (50 g) (as the first solvent) and ethyl acetate (100 g) (as the second solvent) were added to the crude alkyldiphenol product and mixed thoroughly to obtain a first solution (a heterogeneous solution). The first solution was then extracted, and the ethyl acetate extract layer was collected. The resulting product was then concentrated under reduced pressure at 25°C using a rotary evaporator to remove the ethyl acetate, yielding a white solid.

[0076] 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). At this time, white crystals were observed to precipitate from the water. The precipitate was collected by filtration and then vacuum dried at 25 °C for 1 hour and at 40 °C for 1 hour to obtain the regenerated bisphenol A composition (9) (25.9 g).

[0077] Next, the APHA color of the regenerated bisphenol A composition (9) was evaluated, and the results are shown in Table 2; and the bisphenol A composition (9) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 2.

[0078] Comparative Example 2

[0079] Depolymerization process: 40 g of polycarbonate waste (source: waste polycarbonate wafer cassette), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0080] Washing process: The mixture of alkyl diphenols was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude alkyl diphenol product. Next, the crude alkyl diphenol product was added to toluene (100 g) and mixed thoroughly to obtain a first solution. The first solution was then heated to 80°C, followed by slow cooling to 25°C. After standing for 1 hour, the precipitate was collected by filtration, yielding a white solid.

[0081] Reducing agent addition procedure: Mix the obtained white crystals with methanol (50 g) and water (50 g), and add sodium dithionite (Na2S2O4) (0.06 g). After mixing evenly, a second solution is obtained.

[0082] 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. Then, the solvent was removed from the resulting filtrate using a rotary evaporator at 25°C, and the result was vacuum dried at 25°C for 1 hour and vacuum dried at 40°C for 1 hour to obtain a regenerated bisphenol A composition (10) (30.9 g).

[0083] Next, the APHA color of the regenerated bisphenol A composition (10) was evaluated, and the results are shown in Table 2; and the bisphenol A composition (10) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 2.

[0084] Comparative Example 3

[0085] Depolymerization process: 40 g of polycarbonate waste (source: waste polycarbonate wafer cassette), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0086] Adsorption / precipitation / drying process: The mixture of alkyl diphenols was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude monoalkyl diphenol product. Next, the crude alkyl diphenol product was dissolved in methanol (120 g) and 12 g of activated carbon was added. After stirring for 2 hours, the activated carbon was removed by filtration, and the resulting filtrate was slowly added to water (1,200 g). White crystals were observed precipitating from the water. The precipitate was collected by filtration and then vacuum dried at 25°C for 1 hour and at 40°C for 1 hour to obtain a regenerated bisphenol A composition (11) (8.85 g).

[0087] Next, the APHA color of the regenerated bisphenol A composition (11) was evaluated, and the results are shown in Table 2; and the bisphenol A composition (11) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 2.

[0088] Comparative Example 4 (based on US20230322653A1)

[0089] Depolymerization process: 40 g of polycarbonate waste (source: waste polycarbonate wafer cassette), 200 g of dimethyl carbonate, 60 g of methanol, and 1.4 g of sodium hydroxide were placed in a reaction flask. The reaction flask was then heated to 60-70°C and reacted for 5 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0090] Washing / Drying Process: The mixture of alkyl diphenols was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent, yielding a crude alkyl diphenol product. The crude alkyl diphenol product was then added to toluene (100 g) and mixed thoroughly to obtain a first solution. The first solution was then heated to 80°C and washed five times with water (100 g each time), and the organic layer was collected. The organic layer was then slowly cooled to 25°C. After standing for 1 hour, the precipitate was collected by filtration, yielding a white solid. The white solid was then vacuum dried at 25°C for 1 hour and then vacuum dried at 40°C for 1 hour to obtain a regenerated bisphenol A composition (12) (28 g).

[0091] Next, the APHA color of the regenerated bisphenol A composition (12) was evaluated, and the results are shown in Table 2; and the bisphenol A composition (12) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 2.

[0092] Comparative Example 5 (based on US20230391702A1)

[0093] Depolymerization process: Polycarbonate waste (41.5 g) and dichloromethane (226.9 g) were added to a reaction flask and mixed thoroughly to dissolve the polycarbonate waste in the dichloromethane. Next, methanol (42 g), ethanol (72.35 g), and sodium hydroxide (2.1 g) were added to the reaction flask. The reaction flask was then heated to 60°C and reacted for 6 hours. After cooling to room temperature, a mixture of monoalkyldiphenols was obtained.

[0094] Adsorption process: Next, the alkyldiphenol mixture was cooled to 20°C, and 10 g of hydrochloric acid (HCl) aqueous solution (1N concentration) was added to the alkyldiphenol mixture at 20°C to obtain a second solution. Then, 12.45 g of activated carbon was added to the second solution. After stirring for 2 hours, the activated carbon was removed by filtration, and the resulting filtrate was concentrated under reduced pressure at 25°C using a rotary evaporator to remove the solvent from the first solution.

[0095] Washing / Adsorption / Precipitation / Drying Process: Next, the obtained 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, repeated twice. Next, 80.5 g of ethanol was added to the resulting solution. Then, activated carbon (12.45 g) was added to the resulting solution. After stirring for 2 hours, the activated carbon was removed by filtration, and water (1,000 g) was added to the resulting filtrate (while stirring). After standing for 10 minutes, white crystals were observed to precipitate from the water. The precipitate was collected by filtration and dried in a vacuum oven at 30°C to obtain a bisphenol A composition (13) (4.71 g).

[0096] Next, the APHA color of the regenerated bisphenol A composition (13) was evaluated, and the results are shown in Table 2; and the bisphenol A composition (13) was analyzed by high performance liquid chromatography (HPLC), and the results are shown in Table 2.

[0097] Table 2

[0098]

[0099]

[0100] Comparative Example 1 did not utilize the extraction process described in Example 1 (using both the first solvent / second solvent / water) and the adsorption process. As shown in Table 2, the regenerated bisphenol A composition (9) obtained in Comparative Example 1 had significantly higher bisphenol A reactive adduct content (>3 wt%) and additive (or its derivative impurities) content (>0.7 wt%), and the APHA color of the regenerated bisphenol A composition (9) was also greater than 300. Comparative Example 2 did not utilize the extraction process described in Example 1 (using both the first solvent / second solvent / water). As shown in Table 2, although a washing procedure and a reducing agent addition procedure were added, the regenerated bisphenol A composition (10) obtained in Comparative Example 2 still had significantly higher aromatic monool content (>0.02 wt%), bisphenol A reactive adduct content (>1 wt%), and additive (or its derivative impurities) content (approximately 0.05 wt%), and the APHA color of the regenerated bisphenol A composition (10) was also greater than 300. Comparative Example 3 did not utilize the extraction process described in Example 1 (using both the first solvent / second solvent / water). As shown in Table 2, although the adsorption, precipitation, and drying processes were still performed, the content of bisphenol A reactive adduct (approximately 0.05 wt%) and the content of additives (or their derivatives) (>4 wt%) in the regenerated bisphenol A composition (11) obtained in Comparative Example 3 were still significantly higher, and the APHA color of the regenerated bisphenol A composition (11) was also greater than 300. 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 described in US20230322653A1 was followed, the content of bisphenol A reactive adduct (>1 wt%) and the content of additives (or their derivatives) (>0.8 wt%) in the regenerated bisphenol A composition (12) obtained in Comparative Example 4 were still significantly higher, and the APHA color of the regenerated bisphenol A composition (12) was also greater than 300. Comparative Example 5 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 content of additives (or their derivative impurities) in the regenerated bisphenol A composition (13) obtained in Comparative Example 5 is still significantly higher (>1 wt%) according to the depolymerization and purification process described in US20230391702A1, the APHA color of the regenerated bisphenol A composition (13) is also greater than 300, and the purification process yield is less than 10% due to the two adsorption processes.

[0101] Based on the above, through a specific multi-solvent extraction process, the preparation method of the alkyl diphenol composition of the present invention can significantly reduce the impurity content of the alkyl diphenol composition without reducing the recovery rate, and can obtain a high-purity (purity greater than or equal to 99.85%) and low APHA color (less than or equal to 80) regenerated alkyl diphenol composition, which can improve the quality of regenerated polycarbonate products.

[0102] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Anyone with common knowledge in the art can make any modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the appended claims.

Claims

1. An alkyldiphenol composition comprising: Alkyl diphenols, ranging from 99.85 wt% to 99.999 wt%. 0.0001 wt% to 0.01 wt% of aromatic monohydric alcohols; 0.0001 wt% to 0.01 wt% of alkyl diphenol reactive adducts; and 0.0001 wt% to 0.1497 wt% of a compound, wherein the compound is not an alkyl diphenol, an aromatic monohydric alcohol, or an alkyl diphenol reactive adduct.

2. The alkyldiphenol composition according to claim 1, wherein the alkyldiphenol has the structure shown in formula (I): ， wherein R 1 independently C1-C4alkyl.

3. The alkyl diphenol composition according to claim 1, wherein the aromatic monool is phenol, cresol, xylenol, or a combination thereof.

4. The alkyldiphenol composition according to claim 1, wherein the alkyldiphenol reactive adduct has the structure shown in formula (II): ， wherein R 2 and R 3 are independently C1-C4alkyl; and n > 1.

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

6. The alkyl diphenol composition according to claim 1, wherein the APHA color value of the alkyl diphenol composition is less than 80.

7. A method for preparing an alkyldiphenol composition, comprising: A depolymerization process was performed on polycarbonate waste to obtain crude alkyl diphenol product. An extraction process is used to separate a first solution and a second solution from the crude alkyl diphenol product by using a first solvent, a second solvent, and water. The first solution contains the first solvent, and the second solution contains the second solvent, water, and the alkyl diphenol. The first solvent is immiscible with water, and the second solvent is miscible with water. The second solvent is removed from the second solution, causing the alkyl diphenol composition of claim 1 to precipitate from the second solution.

8. The method for preparing the alkyldiphenol composition according to claim 7, further comprising: After the extraction process, the second solution is subjected to an adsorption process, a precipitation process, or a combination of the above.

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

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

11. The method for preparing the alkyldiphenol composition according to claim 7, wherein in the extraction process, the second solvent is first mixed with the crude alkyldiphenol product, and then extracted with the first solvent and water.

12. The method for preparing the alkyldiphenol composition according to claim 7, wherein the alkyldiphenol has a solubility of less than or equal to 2 wt% in the first solvent at 30°C.

13. The method for preparing the alkyl diphenol composition according to claim 11, wherein the alkyl diphenol has a solubility in the second solvent at 30°C greater than or equal to 5 wt%.

14. The method for preparing the alkyldiphenol composition according to claim 7, wherein the first solvent is toluene, xylene, benzene, hexane, cyclohexane, heptane, octane, dichloromethane, trichloromethane, dichloroethane, or a combination thereof.

15. The method for preparing the alkyldiphenol composition according to claim 7, wherein the second solvent is methanol, ethanol, isopropanol, n-propanol, acetone, butanone, ethyl acetate, dimethyl carbonate, tetrahydrofuran, diethyl ether, acetonitrile, or a combination thereof.

16. The method of making an alkyl diphenol composition according to claim 7, wherein, At temperatures between 25°C and 70°C, the saturated vapor pressure of the second solvent is greater than that of water.

17. The method for preparing the alkyldiphenol composition according to claim 7, wherein the polycarbonate waste is subjected to the depolymerization process in the presence of a depolymerization composition, wherein the depolymerization composition comprises a C1-C6 aliphatic unit alcohol.

18. The method for preparing the alkyldiphenol composition according to claim 17, wherein the C1-C6 aliphatic unit alcohol is methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, n-pentanol, isopentanol, n-hexanol, or a combination thereof.

19. The method for preparing the alkyldiphenol composition according to claim 17, wherein the depolymerization composition further comprises a co-solvent, wherein the co-solvent is dichloromethane, trichloromethane, carbon tetrachloride, cyclohexanone, butanone, acetone, toluene, xylene, dimethyl carbonate, diethyl carbonate, or a combination thereof.

20. The method for preparing the alkyldiphenol composition according to claim 17, wherein the depolymerization composition further comprises a catalyst, wherein the catalyst is sodium hydroxide, potassium hydroxide, or a combination thereof.

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