Method for alcoholysis of 2, 5-furandicarboxylic acid polyester

Abstract

The invention discloses a method for alcoholysis of 2, 5-furandicarboxylic acid polyester, and the method comprises the following steps: in a closed reactor, carrying out a depolymerization reaction on a mixture containing an alcohol compound, 2, 5-furandicarboxylic acid polyester and a catalyst to obtain a 2, 5-furandicarboxylic acid glycol ester product. The supported ionic liquid is used as a catalyst for alcoholysis of 2, 5-furandicarboxylic acid polyester, the supported ionic liquid retains the advantages of good thermal stability, chemical stability, non-volatility and high catalytic activity of the ionic liquid, and the catalyst is easier to separate products, so that the catalyst can be recycled, and the cost is reduced. Importantly, the carriers are various nano materials and different nano material carriers, so that the ionic liquid has excellent catalytic performance after being loaded.

Description

Technical Field

[0001] The present application relates to a method for alcoholysis of 2,5-furandicarboxylic acid-based polyester, belonging to the technical field of chemical production. Background Art

[0002] Poly(ethylene 2,5-furandicarboxylate) (PEF) is a 100% recyclable biobased polymer produced using renewable raw materials derived from plants. PEF is called the next-generation polyester and has great potential to replace polyethylene terephthalate (PET), a durable polymer derived from traditional synthetic resources. Compared with PET, PEF has many advantages. It not only reduces the overall carbon footprint of the product, but also improves the sustainability of packaging. Compared with PET, PEF has higher gas barrier properties to oxygen, carbon dioxide, and water vapor, and thus can be regarded as an interesting alternative for packaging applications such as bottles, films, and food trays.

[0003] Although 2,5-furandicarboxylic acid-based polyesters provide an idea for solving the over-reliance of the traditional polyester industry on petroleum resources, these polyesters are still difficult to degrade under natural conditions, which is not only unfavorable for the development of the ecological environment but also wastes resources. Therefore, the recyclable recycling of poly(2,5-furandicarboxylate) has very practical significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for highly efficient alcoholysis of 2,5-furandicarboxylic acid-based polyester using a supported ionic liquid catalyst with high catalytic activity, high selectivity for target products, mild alcoholysis conditions, easy separation of products, and recyclability.

[0005] According to one aspect of the present application, there is provided a method for alcoholysis of 2,5-furandicarboxylic acid-based polyester, the method comprising:

[0006] In a closed reactor, depolymerize a mixture containing an alcohol compound, 2,5-furandicarboxylic acid-based polyester, and a catalyst to obtain a 2,5-furandicarboxylic acid diol ester product;

[0007] The catalyst is a supported ionic liquid catalyst;

[0008] The supported ionic liquid catalyst has the structure shown in Formula I:

[0009]

[0010] Wherein, m is a positive integer, 1 ≤ m ≤ 16;

[0011] R is selected from one of C1-C16 alkyl and C1-C16 substituted alkyl;

[0012] Among them, the substituents of the C1-C16 substituted alkyl groups are selected from one of hydroxyl, carboxyl, and sulfonic acid groups;

[0013] X⁻ is selected from at least one of bis(trifluoromethanesulfonate), p-toluenesulfonate, lactate, bis(trifluoromethanesulfonimide), hydrogen sulfate, acetate, trifluoromethanesulfonate, 2-(2-hydroxyethoxy)acetate, phenolate, 2,2,2-trifluoroethoxide, trifluoroacetate, and tetrafluoroborate.

[0014] Optionally, the depolymerization product 2,5-furandicarboxylic acid diol ester includes ethylene 2,5-furandicarboxylate, propylene 2,5-furandicarboxylate, and butylene 2,5-furandicarboxylate.

[0015] Optionally, the supported ionic liquid catalyst includes a support.

[0016] Optionally, the support is selected from at least one of nano-silica, nano-aluminum oxide, and nano-zinc oxide.

[0017] Optionally, the size of the support is 5-100 nm.

[0018] Optionally, the preparation method of the supported ionic liquid catalyst includes:

[0019] Reacting a mixture containing a support, a compound having the structure shown by R, a coupling agent, imidazole, and an anion salt to obtain the supported ionic liquid catalyst.

[0020] Optionally, the anion salt is selected from at least one of strontium bis(trifluoromethanesulfonate), sodium p-toluenesulfonate, sodium lactate, lithium bis(trifluoromethanesulfonimide), sodium hydrogen sulfate, sodium acetate, sodium trifluoromethanesulfonate, sodium 2-(2-hydroxyethoxy)acetate, sodium phenolate, sodium 2,2,2-trifluoroethoxide, sodium trifluoroacetate, and sodium tetrafluoroborate.

[0021] Optionally, the compound containing the structure represented by R is selected from at least one of 1-bromoethanol, 3-bromo-1-propanol, 1-bromo-2-butanol, 1-bromopentanol, 6-bromo-1-hexanol, 7-bromo-1-heptanol, 8-bromo-1-octanol, 9-bromo-1-nonanol, 10-bromo-1-decanol, 11-bromo-1-undecanol, 12-bromo-1-dodecanol, 13-bromo-1-tridecanol, 14-bromo-1-tetradecanol, 15-bromo-1-pentadecanol, 16-bromo-1-hexadecanol, bromoacetic acid, 3-bromopropionic acid, 4-bromobutyric acid, 5-bromovaleric acid, 6-bromohexanoic acid, 7-bromoheptanoic acid, 8-bromooctanoic acid, 9-bromononanoic acid, 10-bromodecanoic acid, 11-bromoundecanoic acid, 12-bromododecanoic acid, 13-bromotridecanoic acid, 14-bromotetradecanoic acid, 15-bromopentadecanoic acid, 16-bromohexadecanoic acid, 2-bromoethylsulfonic acid, 3-bromopropanesulfonic acid, 4-bromobutanesulfonic acid, 5-bromopentanesulfonic acid, 6-bromohexanesulfonic acid, 7-bromoheptanesulfonic acid, 8-bromooctanesulfonic acid, 9-bromononanesulfonic acid, 10-bromodecanesulfonic acid, 11-bromoundecanesulfonic acid, 12-bromododecanesulfonic acid, 13-bromotridecanesulfonic acid, 14-bromotetradecanesulfonic acid, 15-bromopentadecanesulfonic acid, 16-bromohexadecanesulfonic acid.

[0022] Optionally, the coupling agent is selected from at least one of silane coupling agents, titanate coupling agents, aluminate coupling agents, metal composite coupling agents, phosphate coupling agents, and borate coupling agents.

[0023] Optionally, the mass ratio of the carrier to the imidazole is 1:0.01 - 20%.

[0024] Optionally, the mass ratio of the carrier to the imidazole is 1:0.01 - 20%.

[0025] Optionally, the mass ratio of the imidazole to the compound containing the structure represented by R is 1:0.01 - 20%.

[0026] Optionally, the mass ratio of the imidazole to the anion salt is 1:0.01 - 20%.

[0027] Optionally, the temperature of the reaction is 40 - 100 °C, and the reaction time is 6 - 24 h.

[0028] Optionally, the alcohol compound is selected from at least one of methanol, hexanediol, heptanediol, 1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 2-propanol, ethanol, 1-butanol, tert-butanol, 1-pentanol, 2-butanol, 3-methyl-2-butanol, 3-methyl-1-butanol, 2-pentanol, 3-pentanol, ethylene glycol, propylene glycol, undecanediol, dodecanediol, butanediol, 2,2-dimethyl-1-propanol, pentanediol, tridecanediol, octanediol, nonanediol, decanediol, tetradecanediol.

[0029] Optionally, the 2,5-furandicarboxylic acid-based polyester is selected from at least one of poly(propylene 2,5-furandicarboxylate), poly(butylene 2,5-furandicarboxylate), poly(ethylene glycol 2,5-furandicarboxylate-co-terephthalate), poly(octylene 2,5-furandicarboxylate), poly(ethylene glycol 2,5-furandicarboxylate), poly(heptylene 2,5-furandicarboxylate), poly(pentylene 2,5-furandicarboxylate), poly(1,4-cyclohexanedimethanol 2,5-furandicarboxylate), poly(isosorbide 2,5-furandicarboxylate), poly(2,2,4,4-tetramethyl-1,3-cyclobutanediol 2,5-furandicarboxylate), and poly(hexylene 2,5-furandicarboxylate).

[0030] Optionally, the amount of the catalyst used is 0.1 to 10 wt.% of the mass of the 2,5-furandimethyl-based polyester.

[0031] Optionally, the upper limit of the amount of the catalyst used, independently selected, is 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.% of the mass of the 2,5-furandimethyl-based polyester; the lower limit, independently selected, is 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%.

[0032] Optionally, the amount of the catalyst used is 0.2 to 8 wt.% of the mass of the 2,5-furandimethyl-based polyester.

[0033] Optionally, the mass ratio of the selected 2,5-furandicarboxylic acid-based polyester to the alcohol compound is 1:0.5 to 10.

[0034] Optionally, the upper limit of the mass ratio of the selected 2,5-furandicarboxylic acid-based polyester to the alcohol compound, independently selected, is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10; the lower limit, independently selected, is 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9.

[0035] Optionally, the mass ratio of the selected 2,5-furandicarboxylic acid-based polyester to the alcohol compound is 1:1 to 6.

[0036] Optionally, the temperature of the depolymerization reaction is 40 to 180 °C.

[0037] Optionally, the upper limit of the temperature of the depolymerization reaction is independently selected from 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C; the lower limit is independently selected from 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C.

[0038] Optionally, the temperature of the depolymerization reaction is 50 to 150 °C.

[0039] Optionally, the time of the depolymerization reaction is 0.2 to 10 h.

[0040] Optionally, the upper limit of the time of the depolymerization reaction is independently selected from 0.3 h, 0.4 h, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h; the lower limit is independently selected from 0.2 h, 0.3 h, 0.4 h, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h.

[0041] Optionally, the time of the depolymerization reaction is 0.3 to 8 h.

[0042] Optionally, the time of the depolymerization reaction is 0.5 to 6 h.

[0043] In the present application, the supported ionic liquid catalyst is prepared according to the following preparation method: in the first step, various nano-carriers are grafted with a coupling agent; in the second step, imidazole is further grafted on the basis of the coupling agent; in the third step, a pure alkyl chain or a chain with a hydroxyl group, a carboxyl group or a sulfonic acid group at the end is grafted on the basis of imidazole; in the fourth step, the target supported ionic liquid catalyst is obtained by replacing the original anion with the target anion by an ion exchange method.

[0044] The preparation process of the supported ionic liquid catalyst is as follows:

[0045] 1) Add various forms of nano-carriers and a coupling agent into a flask equipped with a reflux tube and a stirring device, heat, cool after the reaction is completed, and obtain the primary product (1) by centrifugation;

[0046] 2) Add the product (1) and imidazole into a flask equipped with a reflux tube and a stirring device, heat, cool after the reaction is completed, and obtain the product (2) by centrifugation;

[0047] 3) Add the product (2) and the raw material of pure alkyl or containing hydroxyl group, carboxyl group, sulfonic acid group into a flask equipped with a reflux pipe and a stirring device, heat it, cool it after the reaction is completed, and obtain the product (3) by centrifugation;

[0048] 4) Add the product (3) and the salt containing the target anion into a flask equipped with a stirring device, stir, and obtain the supported ionic liquid described in this patent by centrifugation after the reaction is completed.

[0049] Optionally, the 2,5-furandicarboxylic acid-based polyester has the structure shown in formula (2):

[0050]

[0051] In formula (2), m is any positive integer ≥ 2, and n is any positive integer ≥ 2.

[0052] Optionally, when m = 2, the polyester is ethylene glycol 2,5-furandicarboxylate (PEF).

[0053] Optionally, it includes the following steps:

[0054] (1) Add the 2,5-furandicarboxylic acid-based polyester, alcohol and the supported ionic liquid catalyst into a closed reaction vessel to obtain a mixed solution;

[0055] (2) Heat the mixed solution to 40 - 180 °C, and the depolymerization time described is 0.2 - 10 h;

[0056] (3) After the reaction is completed, wait for the whole system to cool to room temperature, and obtain the 2,5-furandicarboxylic acid diol ester product by separation.

[0057] As a specific implementation manner, the reaction general formula (1) of the present invention is:

[0058]

[0059] The present invention provides a method for highly efficient alcoholysis of 2,5-furandicarboxylic acid-based polyester with a supported ionic liquid catalyst having high catalytic activity, high selectivity for target products, mild alcoholysis conditions, easy separation of products, and recyclability. The supported ionic liquid described is composed of imidazole cations and various anions, and the carrier is at least one of nano-silica, nano-aluminum oxide, and nano-zinc oxide. The general structural formula (Ⅱ) is as follows:

[0060]

[0061] The present invention provides a method for highly efficient alcoholysis of 2,5-furandicarboxylic acid-based polyester with a supported ionic liquid catalyst having high catalytic activity, high selectivity for target products, mild alcoholysis conditions, easy separation of products, and recyclability.

[0062] The beneficial effects that can be produced by this application include:

[0063] 1) In the method for alcoholysis of 2,5-furandicarboxylic acid-based polyester provided by this application, the catalyst used is a supported ionic liquid catalyst without metal ions. This catalyst has good thermal stability and is simple and easy to obtain.

[0064] 2) Compared with the conventional method of alcoholyzing polyester with a catalyst, for the supported catalyst provided by this application, the selected supported ionic liquid catalyst has less dosage, significantly improved catalytic activity and catalytic efficiency, making the reaction conditions milder and reducing energy consumption. This supported ionic liquid catalyst has good recyclability and is an environmentally friendly production process with good industrial application prospects.

[0065] 3) The carrier provided by this application is at least one of nano-silica, nano-aluminum oxide, and nano-zinc oxide, and the cation is an imidazole cation. This catalyst is used in the reaction of alcoholyzing 2,5-furandicarboxylic acid-based polyester. It has less dosage, good catalytic activity and catalytic efficiency. After the reaction is completed, the supported ionic liquid can be easily recovered, which is beneficial to the recycling of the ionic liquid. Importantly, the carrier is various nano-materials, and different nano-material carriers endow the ionic liquid with excellent catalytic performance after loading. Detailed implementation manners

[0066] The following further describes this application in detail with reference to embodiments, but this application is not limited to these embodiments.

[0067] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0068] Unless otherwise specified, the test methods are all conventional methods, and the instrument settings are all the settings recommended by the manufacturers.

[0069] In this application, the degradation rate of 2,5-furandicarboxylic acid-based polyester is calculated according to formula (1), where m0 is the initial mass of 2,5-furandicarboxylic acid-based polyester and m1 is the mass of undegraded 2,5-furandicarboxylic acid-based polyester:

[0070]

[0071] The yield of the so-called alcoholysis product is calculated according to formula (2):

[0072]

[0073] In this application, "room temperature" refers to 25 °C.

[0074] The preparation method of 2,5-furandicarboxylic acid-based polyester is the direct esterification method. Taking polyethylene 2,5-furandicarboxylate (PEF) as an example, 15.6 g of 2,5-furandicarboxylic acid and 9.9 g of ethylene glycol are added to a reaction flask, and 0.05 g of tetraisopropyl titanate is used as a catalyst. Under nitrogen protection, the reaction is stirred at 210 °C for 2 h to form a prepolymer; the prepolymer is evacuated to 110 Pa, and the reaction is stirred at 240 °C for 3 - 9 h to finally obtain polyethylene 2,5-furandicarboxylate with a degree of polymerization of 1000.

[0075] In this application, taking titanium dioxide nanosheets supported 3-hydroxypropylimidazolium bis(trifluoromethanesulfonate) as an example, it is prepared according to the following preparation method:

[0076] (1) 1 g of nano-titanium dioxide is dispersed in a toluene solution, 0.5 ml of 3-chloropropyltriethoxysilane is added, stirred at 150 rpm, and reacted at 100 °C for 6 h, and refluxed under N2 protection.

[0077] (2) After the reaction product is centrifuged, it is dispersed in a toluene solution, 0.5 g of imidazole is added, stirred at 150 rpm, and reacted at 100 °C for 24 h, and refluxed under N2 protection.

[0078] (3) After the reaction product is centrifuged, it is dispersed in a toluene solution, 0.5 g of propanol is added, stirred at 150 rpm, and reacted at 100 °C for 18 h, and refluxed under N2 protection.

[0079] (4) After the reaction product is centrifuged, it is dispersed in an anhydrous ethanol solution, 0.5 g of strontium bis(trifluoromethanesulfonate) is added, stirred at 150 rpm, and reacted at room temperature for 18 h.

[0080] (5) The final product is washed with anhydrous ethanol, first dried in a common oven at 70 °C for 4 h, and then dried in a vacuum drying oven at 100 °C for 24 h to obtain titanium dioxide supported 3-hydroxypropylimidazolium bis(trifluoromethanesulfonate), where the size of titanium dioxide in the raw material is 5 - 100 nm.

[0081] Example 1

[0082] The reactants PEF, methanol, and silica supported 3-carboxyimidazolium bis(trifluoromethanesulfonate) are successively added to a stainless steel sealed high-temperature and high-pressure reaction kettle equipped with a stirrer and a thermometer. Among them, the mass of PEF is 3 g, the mass ratio of PEF to methanol is 1:1, and silica supported 3-carboxyimidazolium bis(trifluoromethanesulfonate) accounts for 0.5% of the mass of PEF; the reaction system is heated in a water bath at 70 °C and maintained for 3 h; after the reaction is completed, the reaction kettle is quickly cooled to room temperature in an ice-water bath, and the reaction solution is filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The calculated degradation rate of PEF is 100%, and the yield of dimethyl 2,5-furandicarboxylate is 99%.

[0083] Example 2

[0084] The reactants PEF, methanol, and silica-supported 3-hydroxyimidazolium bis(trifluoromethanesulfonate) were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the silica-supported 3-hydroxyimidazolium bis(trifluoromethanesulfonate) accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 99%, and the yield of dimethyl 2,5-furandicarboxylate was 97%.

[0085] Example 3

[0086] The reactants PEF, methanol, and silica-supported 3-carboxymethylimidazolium bis(trifluoromethanesulfonate) were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the silica-supported 3-carboxymethylimidazolium bis(trifluoromethanesulfonate) accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 99%, and the yield of dimethyl 2,5-furandicarboxylate was 98%.

[0087] Example 4

[0088] The reactants PEF, methanol, and silica-supported 3-carboxymethylimidazolium trifluoromethanesulfonate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the silica-supported 3-carboxymethylimidazolium trifluoromethanesulfonate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 97%, and the yield of dimethyl 2,5-furandicarboxylate was 95%.

[0089] Example 5

[0090] The reactants PEF, methanol, and silica-supported 3-carboxymethylimidazolium tetrafluoroborate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the silica-supported 3-carboxymethylimidazolium tetrafluoroborate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 98%, and the yield of dimethyl 2,5-furandicarboxylate was 96%.

[0091] Example 6

[0092] The reactants PEF, methanol, and alumina-supported 3-carboxyimidazolium lactate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the alumina-supported 3-carboxyimidazolium lactate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 98%, and the yield of dimethyl 2,5-furandicarboxylate was 95%.

[0093] Example 7

[0094] The reactants PEF, methanol, and alumina-supported 3-carboxymethylimidazolium lactate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the alumina-supported 3-carboxymethylimidazolium lactate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 97%, and the yield of dimethyl 2,5-furandicarboxylate was 96%.

[0095] Example 8

[0096] The reactants PEF, methanol, and aluminum oxide-supported 3-carboxymethylimidazolium acetate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the aluminum oxide-supported 3-carboxymethylimidazolium acetate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction ended, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 99%, and the yield of dimethyl 2,5-furandicarboxylate was 97%.

[0097] Example 9

[0098] The reactants PEF, methanol, and aluminum oxide-supported 3-carboxymethylimidazolium hydrogensulfate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the aluminum oxide-supported 3-carboxymethylimidazolium hydrogensulfate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction ended, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 96%, and the yield of dimethyl 2,5-furandicarboxylate was 95%.

[0099] Example 10

[0100] The reactants PEF, methanol, and aluminum oxide-supported 3-carboxymethylimidazolium trifluoroacetate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the aluminum oxide-supported 3-carboxymethylimidazolium trifluoroacetate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction ended, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 95%, and the yield of dimethyl 2,5-furandicarboxylate was 94%.

[0101] Example 11

[0102] The reactants PEF, methanol, and zinc oxide-supported 3-hydroxyimidazole trifluoroacetate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the zinc oxide-supported 3-hydroxyimidazole trifluoroacetate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 96%, and the yield of dimethyl 2,5-furandicarboxylate was 93%.

[0103] Example 12

[0104] The reactants PEF, methanol, and zinc oxide-supported 3-hydroxyimidazole trifluoroacetate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the zinc oxide-supported 3-hydroxyimidazole trifluoroacetate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 100 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 95%, and the yield of dimethyl 2,5-furandicarboxylate was 91%.

[0105] Example 13

[0106] The reactants PEF, methanol, and zinc oxide-supported 3-sulfonylimidazole trifluoroacetate were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the zinc oxide-supported 3-hydroxyimidazole trifluoroacetate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 96%, and the yield of dimethyl 2,5-furandicarboxylate was 94%.

[0107] Example 14

[0108] The reactants PEF, methanol, and zinc oxide-supported 3-sulfonylimidazole bis(trifluoromethanesulfonimide) were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the zinc oxide-supported 3-hydroxyimidazole bis(trifluoromethanesulfonimide) accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 98%, and the yield of dimethyl 2,5-furandicarboxylate was 95%.

[0109] Example 15

[0110] The reactants PEF, methanol, and zinc oxide-supported 3-sulfonylimidazole bis(trifluoromethanesulfonimide) were successively added to a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and the zinc oxide-supported 3-hydroxyimidazole bis(trifluoromethanesulfonimide) accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C for 5 h. After the reaction, the reactor was quickly cooled to room temperature in an ice bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 95%, and the yield of dimethyl 2,5-furandicarboxylate was 92%.

[0111] Example 16

[0112] Titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) has very good stability in the reaction system and can be easily recovered from the filtrate. After six repeated recycling uses, there is no obvious loss of activity, which indicates that titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) has persistent high catalytic activity for the methanolysis reaction of PEF. Through calculation of the recovery, the molar ratio of titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) to EG is about 2.41, and the mass ratio is about 7.70. In order to reduce the interference of EG, according to the calculated amount of titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) in the recovered catalyst, until the mass of titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) is equal to the initial weight of pure titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) (0.15 mol% of the methanol molar amount). The experimental results show that the residues of furan oligomers and EG have no obvious effect on the catalytic activity of the recovered ionic liquid. Therefore, titanium dioxide-supported 3-methylsulfonylimidazole bis(trifluoromethanesulfonylimide) shows excellent catalytic activity and reusability in the methanolysis of PEF under mild conditions, which is in line with the concept of modern green and sustainable chemistry.

[0113] Comparative Example 1

[0114] The reactants PEF, methanol, and tetrabutyl titanate were successively added into a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and tetrabutyl titanate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 100 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 88%, and the yield of dimethyl 2,5-furandicarboxylate was 79%.

[0115] Comparative Example 2

[0116] The reactants PEF, methanol, and tetrabutyl titanate were successively added into a stainless-steel sealed high-temperature and high-pressure reactor equipped with a stirrer and a thermometer. Among them, the mass of PEF was 3 g, the mass ratio of PEF to methanol was 1:1, and tetrabutyl titanate accounted for 0.5% of the mass of PEF. The reaction system was heated in a water bath at 70 °C and maintained for 3 h. After the reaction, the reactor was quickly cooled to room temperature in an ice-water bath. The reaction solution was filtered, washed, and rotary evaporated to obtain pure dimethyl 2,5-furandicarboxylate. The degradation rate of PEF was calculated to be 91%, and the yield of dimethyl 2,5-furandicarboxylate was 85%.

[0117] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for alcoholysis of 2,5-furandicarboxylic acid-based polyester, characterized in that, The method includes: In a closed reactor, depolymerize a mixture containing an alcohol compound, a 2,5-furandicarboxylic acid-based polyester, and a catalyst to obtain a 2,5-furandicarboxylic acid diol ester product; The catalyst is a supported ionic liquid catalyst; The supported ionic liquid catalyst has the structure shown in Formula I: Wherein, m is a positive integer, 1 ≤ m ≤ 16; R is selected from one of C1-C16 alkyl groups and C1-C16 substituted alkyl groups; Wherein, the substituent of the C1-C16 substituted alkyl group is selected from one of a hydroxyl group, a carboxyl group, and a sulfonic acid group; X - Selected from at least one of bis(trifluoromethanesulfonate), p-toluenesulfonate, lactate, bis(trifluoromethanesulfonimide), hydrogen sulfate, acetate, trifluoromethanesulfonate, 2-(2-hydroxyethoxy)acetate, phenolate, 2,2,2-trifluoroethoxide, trifluoroacetate, and tetrafluoroborate.

2. The method according to claim 1, characterized in that, The supported ionic liquid catalyst includes a carrier; Preferably, the carrier is selected from at least one of nano-silica, nano-aluminum oxide, and nano-zinc oxide; Preferably, the size of the carrier is 5-100 nm.

3. The method according to claim 1, characterized in that, The preparation method of the supported ionic liquid catalyst includes: React a mixture containing a carrier, a compound having the structure shown by R, a coupling agent, imidazole, and an anion salt to obtain the supported ionic liquid catalyst.

4. The method according to claim 3, characterized in that, The anion salt is selected from at least one of strontium bis(trifluoromethanesulfonate), sodium p-toluenesulfonate, sodium lactate, lithium bis(trifluoromethanesulfonimide), sodium bisulfate, sodium acetate, sodium trifluoromethanesulfonate, sodium 2-(2-hydroxyethoxy)acetate, sodium phenoxide, sodium 2-2-2-trifluoroethanolate, sodium trifluoroacetate, and sodium tetrafluoroborate; Preferably, the compound having the structure shown by R is selected from at least one of 1-bromoethanol, 3-bromo-1-propanol, 1-bromo-2-butanol, 1-bromopentanol, 6-bromo-1-hexanol, 7-bromo-1-heptanol, 8-bromo-1-octanol, 9-bromo-1-nonanol, 10-bromo-1-decanol, 11-bromo-1-undecanol, 12-bromo-1-dodecanol, 13-bromo-1-tridecanol, 14-bromo-1-tetradecanol, 15-bromo-1-pentadecanol, 16-bromo-1-hexadecanol, bromoacetic acid, 3-bromopropionic acid, 4-bromobutyric acid, 5-bromovaleric acid, 6-bromohexanoic acid, 7-bromoheptanoic acid, 8-bromooctanoic acid, 9-bromononanoic acid, 10-bromodecanoic acid, 11-bromoundecanoic acid, 12-bromododecanoic acid, 13-bromotridecanoic acid, 14-bromotetradecanoic acid, 15-bromopentadecanoic acid, 16-bromohexadecanoic acid, 2-bromoethylsulfonic acid, 3-bromopropanesulfonic acid, 4-bromobutanesulfonic acid, 5-bromopentanesulfonic acid, 6-bromohexanesulfonic acid, 7-bromoheptanesulfonic acid, 8-bromooctanesulfonic acid, 9-bromononanesulfonic acid, 10-bromodecanesulfonic acid, 11-bromoundecanesulfonic acid, 12-bromododecanesulfonic acid, 13-bromotridecanesulfonic acid, 14-bromotetradecanesulfonic acid, 15-bromopentadecanesulfonic acid, and 16-bromohexadecanesulfonic acid; Preferably, the coupling agent is selected from at least one of a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, a metal composite coupling agent, a phosphate coupling agent, and a borate coupling agent.

5. The method according to claim 3, characterized in that, The mass ratio of the carrier to the imidazole is 1:0.01-20%; Preferably, the mass ratio of the carrier to the imidazole is 1:0.01-20%; Preferably, the mass ratio of the imidazole to the compound having the structure shown by R is 1:0.01-20%; Preferably, the mass ratio of the imidazole to the anionic salt is 1: 0.01-20%; Preferably, the temperature of the reaction is 40-100 °C, and the reaction time is 6-24 h.

6. The method according to claim 1, characterized in that, The alcohol compound is selected from at least one of methanol, hexanediol, heptanediol, 1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 2-propanol, ethanol, 1-butanol, tert-butanol, 1-pentanol, 2-butanol, 3-methyl-2-butanol, 3-methyl-1-butanol, 2-pentanol, 3-pentanol, ethylene glycol, propylene glycol, undecanediol, dodecanediol, butanediol, 2,2-dimethyl-1-propanol, pentanediol, tridecanediol, octanediol, nonanediol, decanediol, tetradecanediol; Preferably, the 2,5-furandicarboxylic acid-based polyester is selected from at least one of poly(propylene 2,5-furandicarboxylate), poly(butylene 2,5-furandicarboxylate), poly(ethylene glycol 2,5-furandicarboxylate-co-ethylene terephthalate), poly(octylene 2,5-furandicarboxylate), poly(ethylene glycol 2,5-furandicarboxylate), poly(heptylene 2,5-furandicarboxylate), poly(pentylene 2,5-furandicarboxylate), poly(1,4-cyclohexanedimethanol 2,5-furandicarboxylate), poly(isosorbide 2,5-furandicarboxylate), poly(2,2,4,4-tetramethyl-1,3-cyclobutanediol 2,5-furandicarboxylate), poly(hexylene 2,5-furandicarboxylate); 7. The method according to claim 1, characterized in that, The dosage of the catalyst is 0.1-10 wt.% of the mass of the 2,5-furandimethyl-based polyester; Preferably, the dosage of the catalyst is 0.2-8 wt.% of the mass of the 2,5-furandimethyl-based polyester.

8. The method according to claim 1, characterized in that, The mass ratio of the selected 2,5-furandicarboxylic acid-based polyester to the alcohol compound is 1: 0.5-10; Preferably, the mass ratio of the selected 2,5-furandicarboxylic acid-based polyester to the alcohol compound is 1: 1-6.

9. The method according to claim 1, characterized in that, The temperature of the depolymerization reaction is 40-180 °C; Preferably, the temperature of the depolymerization reaction is 50-150 °C.

10. The method according to claim 1, characterized in that,The time of the depolymerization reaction is 0.2-10 h; Preferably, the time of the depolymerization reaction is 0.3-8 h; Preferably, the time of the depolymerization reaction is 0.5-6 h.

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