Method for hydrodepolymerizing bisphenol A polycarbonate plastic into phenol and 4-isopropyl phenol

Abstract

The invention discloses a method for hydrodepolymerizing bisphenol A polycarbonate into phenol and 4-isopropyl phenol, a metal salt, a ligand and an auxiliary agent are used as catalysts, in the method, a metal organic complex catalytic system realizes hydrodepolymerization of waste polycarbonate into phenol and 4-isopropyl phenol; the metal organic complex catalytic system has dual catalytic functions of breaking ester bonds and carbon-carbon bonds, the conversion rate of polycarbonate is greater than 99%, the highest yield of phenol is greater than or equal to 99%, and the highest yield of 4-isopropyl phenol is greater than or equal to 99%.

Description

Technical Field

[0001] The invention belongs to the technical field of waste plastic resource utilization, and specifically relates to a method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol. Background Art

[0002] Bisphenol A polycarbonate plastic (BPA-PC, CAS: 25037-45-0) is a polycarbonate plastic containing bisphenol A structural units in the molecule. It is widely used and consumed 5.5 million tons per year worldwide. However, waste bisphenol A polycarbonate plastics bring serious environmental problems and resource waste, especially the biological toxicity of bisphenol A. Therefore, it is of great significance to convert waste polycarbonate into chemicals, such as bisphenol A, dimethyl carbonate, diphenyl urea, benzene, aviation fuel, etc., through hydrolysis, alcoholysis, aminolysis and hydrogenolysis.

[0003]

[0004] Phenol is an important oxygen-containing chemical with a wide range of applications. It is currently mainly synthesized by the cumene oxidation method. However, the cumene method produces phenol as a byproduct of acetone, and acetone is in a state of overcapacity (Applied Catalysis A: General, 2005, 280, 89-103). In recent years, non-fossil resource phenol synthesis routes have been developed. For example, Han Buxing, Meng Qinglei and others developed HY molecular sieve-catalyzed lignin Csp2-Csp2 bond cleavage to obtain phenol with a yield of 10.9% (Sci. Adv. 2020; 6: eabd1951). Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and to briefly introduce some preferred embodiments.

[0006] As one aspect of the present invention, the present invention provides a method for hydrogenating and decomposing bisphenol A polycarbonate plastic to produce phenol and 4-isopropylphenol, which adopts a homogeneous catalytic system, and the homogeneous catalytic system includes a transition metal salt, a ligand and an auxiliary agent; wherein the transition metal is one or more of iridium, palladium, ruthenium, cobalt, nickel, and copper; the transition metal salt is one or more of chloride, acetate, nitrate, acetylacetonate or a hydrated metal salt thereof; the ligand is shown in formula L1 or formula L2:

[0007]

[0008] Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R6 One independently selected from a linear or isomeric alkane having 1 to 18 carbon atoms, a linear or isomeric alkoxy having 1 to 18 carbon atoms, a phenyl group, a phenoxy group, fluorine, chlorine, bromine, iodine or hydrogen;

[0009] The auxiliary agent includes one or more of methanesulfonic acid, trifluoromethanesulfonic acid, bistrifluoromethanesulfonimide, lithium trifluoromethanesulfonate, copper trifluoromethanesulfonate, lanthanum trifluoromethanesulfonate, samarium trifluoromethanesulfonate, tin trifluoromethanesulfonate, aluminum trifluoromethanesulfonate, and indium trifluoromethanesulfonate.

[0010] As a preferred embodiment of the method for hydrogenating and decomposing bisphenol A polycarbonate plastic to produce phenol and 4-isopropylphenol, the method comprises adding a transition metal salt, a ligand, an additive, bisphenol A polycarbonate and a solvent into a pressure autoclave, sealing the autoclave and injecting hydrogen to carry out a hydrogenation reaction.

[0011] The molar ratio of the transition metal salt to the bisphenol A polycarbonate plastic is (0.001-0.5):1; preferably (0.001-0.4):1, and more preferably (0.05-0.4):1;

[0012] The molar ratio of the ligand to the bisphenol A polycarbonate is (0.001-0.5):1; preferably (0.001-0.4):1, and more preferably (0.05-0.4):1;

[0013] The molar ratio of the auxiliary agent to the bisphenol A polycarbonate plastic is (0.001-1.0):1; preferably (0.1-1):1, and more preferably (0.1-0.5):1;

[0014] The molar ratio of the solvent to the bisphenol A type polycarbonate plastic is (0.1-100):1, preferably (0.1-50):1, and more preferably (0.1-40):1.

[0015] The solvent is one or more of benzene, toluene, ethylbenzene, isopropylbenzene, o-xylene, m-xylene, p-xylene, tetrahydrofuran, dioxane, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, and tert-pentanol.

[0016] The pressure of the hydrogen is 0.1 to 10 MPa, preferably 0.1 to 8 MPa, more preferably 0.5 to 8 MPa; more preferably 3 to 6 MPa.

[0017] The reaction temperature is 80 to 200°C, preferably 80 to 180°C, more preferably 100 to 180°C;

[0018] The reaction time is 1 to 48 hours, preferably 1 to 24 hours, and more preferably 3 to 24 hours.

[0019] Beneficial effects of the present invention: The transition metal organic complex catalytic system provided by the present invention comprises a transition metal salt, a ligand and an auxiliary agent. In the present invention, the transition metal organic complex catalytic system realizes the hydrogenation and decomposition polymerization of waste bisphenol A type polycarbonate plastic into phenol and 4-isopropylphenol, and the transition metal organic complex catalytic system has a dual catalytic function of breaking ester bonds and carbon-carbon bonds, the conversion rate of bisphenol A type polycarbonate plastic is greater than 99%, the maximum yield of phenol is greater than or equal to 49.5%, the maximum yield of 4-isopropylphenol is greater than or equal to 49.5%, and the total yield of phenol products (phenol and 4-isopropylphenol) is greater than or equal to 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following briefly introduces the drawings required for describing the embodiment, wherein:

[0021] Figure 1 The gas chromatogram is a graph showing the hydrogenation and depolymerization of waste bisphenol A polycarbonate plastics into phenol and 4-isopropylphenol according to the present invention.

[0022] Figure 2 are other ligand structural formulas used in Examples 12-15 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments.

[0024] Embodiment 1-11:

[0025] Reaction conditions: 1.0mmol bisphenol A polycarbonate plastic (Mw~26000, n~100), 0.1mmol transition metal salt, 0.1mmol ligand (1,1,1-tris(diphenylphosphinomethyl)ethane), 0.2mmol auxiliary agent (indium trifluoromethanesulfonate), and 2mL ethanol solvent are sequentially loaded into a pressure autoclave, sealed, and filled with 4MPa hydrogen. Subsequently, the pressure autoclave is moved to an oil bath at 140°C and stirred for 24h. After the reaction is completed, the reactor is cooled naturally to room temperature. The conversion rate of BPA-PC is calculated by weighing the mass of BPA-PC remaining after the reaction is completed; the product is qualitatively analyzed by gas chromatography-mass spectrometry; the product is quantitatively analyzed by gas chromatography, and biphenyl is used as the internal standard to calculate the yield of phenol and 4-isobutylphenol by the standard curve method.

[0026] Table 1 Study on the hydrogenation and depolymerization of bisphenol A polycarbonate plastics catalyzed by different transition metal salts in Examples 1 to 11

[0027]

[0028]

[0029] As shown in Table 1, RuCl3 efficiently catalyzes the hydrogenation and decomposition of bisphenol A polycarbonate to produce phenol and 4-isopropylphenol, which is consistent with previous research results (ruthenium has excellent catalytic hydrogenation activity). Subsequently, RuCl3 was used as the transition metal salt.

[0030] Embodiment 11-14:

[0031] Using RuCl3 in Example 8 as the transition metal salt and adopting the same other reaction conditions as in Example 8, a study on the hydrogenation depolymerization of bisphenol A polycarbonate plastic was conducted under different ligands. The results are listed in Table 2.

[0032] Table 2 Reaction conditions and reaction results of Examples 11 to 14

[0033]

[0034] Embodiment 15-22:

[0035] Using RuCl3 in Example 8 as the transition metal salt and triphos as the ligand, the same reaction conditions as in Example 8 were adopted to study the hydrogenation and depolymerization of bisphenol A polycarbonate plastic in the presence of different additives. The results are listed in Table 3.

[0036] Table 3 Reaction conditions and reaction results of Examples 15 to 22

[0037]

[0038] Embodiment 24-28:

[0039] Using RuCl3 in Example 8 as the transition metal salt, triphos as the ligand, and In(OTf)3 as the auxiliary agent, and adopting the same other reaction conditions as in Example 8, the hydrogenation and depolymerization of bisphenol A polycarbonate plastic was studied at different temperatures. The results are listed in Table 4.

[0040] Table 4 Reaction conditions and reaction results of Examples 24 to 28

[0041]

[0042]

[0043] Embodiment 29-35:

[0044] Using RuCl3 in Example 8 as the transition metal salt, triphos as the ligand, In(OTf)3 as the auxiliary agent, the reaction temperature was 140°C, and the other reaction conditions were the same as in Example 8. The hydrogenation and depolymerization of bisphenol A polycarbonate plastic was studied under different hydrogen pressures. The results are listed in Table 5.

[0045] Table 5 Reaction conditions and reaction results of Examples 29 to 35

[0046]

[0047] Embodiment 36:

[0048] Using RuCl3 in Example 8 as the transition metal salt, triphos as the ligand, In(OTf)3 as the auxiliary agent, the reaction temperature was 140°C, the hydrogen pressure was 4 MPa, and other reaction conditions were the same as in Example 8. The hydrogenation and depolymerization of bisphenol A polycarbonate were studied at different substrate amounts. The results are listed in Table 6.

[0049] Table 6 Reaction conditions and reaction results of Example 36

[0050]

[0051] Embodiment 37-38:

[0052] Using RuCl3 in Example 8 as the metal salt and adopting the same other reaction conditions as in Example 8, the hydrogenation and depolymerization of bisphenol A polycarbonate was studied under different practical application scenarios. The results are listed in Table 7.

[0053] Table 7 Reaction conditions and reaction results of Examples 37-39

[0054]

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol, characterized in that: A catalyst system comprising a transition metal salt, a ligand and an additive is used, wherein the transition metal is one or more of iridium, palladium, ruthenium, cobalt, nickel and copper; The ligand is represented by formula L1 or formula L2: Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 One independently selected from a linear or isomeric alkane having 1 to 18 carbon atoms, a linear or isomeric alkoxy having 1 to 18 carbon atoms, a phenyl group, a phenoxy group, fluorine, chlorine, bromine, iodine or hydrogen; The auxiliary agent includes one or more of methanesulfonic acid, trifluoromethanesulfonic acid, bistrifluoromethanesulfonimide, lithium trifluoromethanesulfonate, copper trifluoromethanesulfonate, lanthanum trifluoromethanesulfonate, samarium trifluoromethanesulfonate, tin trifluoromethanesulfonate, aluminum trifluoromethanesulfonate, and indium trifluoromethanesulfonate.

2. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 1, characterized in that: The transition metal salt is one or more of chloride, acetate, nitrate, acetylacetonate or hydrated metal salts thereof.

3. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 1 or 2, characterized in that: Add transition metal salt, ligand, additive, bisphenol A type polycarbonate plastic and solvent into a pressure autoclave, seal it and fill it with hydrogen to carry out hydrogenation reaction.

4. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 3, characterized in that: The solvent includes one or more of benzene, toluene, ethylbenzene, isopropylbenzene, o-xylene, m-xylene, p-xylene, tetrahydrofuran, dioxane, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, and tert-pentanol.

5. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 1 or 2, characterized in that: The molar ratio of the transition metal salt to the bisphenol A type polycarbonate plastic is (0.001-0.5):1; the molar ratio of the ligand to the bisphenol A type polycarbonate plastic is (0.001-0.5):1; and the molar ratio of the auxiliary agent to the bisphenol A type polycarbonate plastic is (0.001-1.0):

1.

6. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 3, characterized in that: The molar ratio of the solvent to the bisphenol A type polycarbonate plastic is (0.1-100):

1.

7. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 3, characterized in that: The pressure of the hydrogen is 0.1-10 MPa, and the hydrogenation reaction temperature is 80-200°C.

8. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 3, characterized in that: The pressure of the hydrogen is 3-6 MPa, and the hydrogenation reaction temperature is 100-180°C.

9. The method for hydrogenating and decomposing bisphenol A type polycarbonate plastic to produce phenol and 4-isopropylphenol according to claim 3, characterized in that: The hydrogenation reaction time is 1 to 48 hours.

Images