Synergistic recycling of polycarbonate: efficient BPA recovery integrated with CO₂ utilization to produce valuable chemicals

Abstract

The chemical recycling of polycarbonate (PC) plastics offers a sustainable solution to address resource depletion and environmental pollution caused by bisphenol A (BPA) release. While hydrolysis is a promising method, it is hindered by significant CO₂ emissions resulting from the breakdown of carbonate groups in the PC structure, limiting its carbon utilization efficiency and practical application. To address this challenge, we developed a synergistic strategy that integrates PC hydrolysis with the high-value utilization of by-product CO₂. Using a [Bmim][Br]/ZnBr₂/K₂CO₃ catalytic system and styrene oxide (SO) as a CO₂ capture reagent, this one-pot process achieved complete PC conversion, with BPA and 4-phenyl-1,3-dioxolan-2-one (PDO) yields of 99.6% and 99.0%, respectively. The method also demonstrated excellent substrate versatility, achieving BPA yields ≥91.1% and cyclic carbonate yields ≥76.1% across various epoxides and real-world waste plastic systems. Mechanistic studies revealed that trace water and in situ formed N-heterocyclic carbenes (NHCs) are the key factors for PC depolymerization. Furthermore, kinetic studies demonstrated that the SO-triggered cycloaddition further promotes the depolymerization of PC. This work establishes a sustainable and efficient pathway for PC recycling, eliminating CO₂ emissions, maximizing carbon utilization, and offering a promising solution for managing waste PC plastics.

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Green foundation

1. This pioneering work converts CO₂ from polycarbonate (PC) hydrolysis into value-added chemicals, enabling full carbon utilization without CO₂ emissions and offering a new strategy for CO₂ management in plastic depolymerization.

2. This strategy enables the in situ capture of waste CO₂ generated from PC hydrolysis using epoxides, producing BPA and cyclic carbonate in high yields of 91.1–98.1% and 96.0–99.7%, respectively. The catalytic system can be efficiently separated by extraction and directly reused after vacuum drying, showing excellent recyclability with no significant deactivation over at least four consecutive cycles. The main product, BPA, can be readily isolated by extraction with a purity of 99%.

3. This study can further explore the potential of waste PC as a sustainable carbon source for synthesizing CO₂-derived chemicals.

1. Introduction

Plastic has become an indispensable component of our modern life.¹ However, inadequate disposal practices and excessive production have caused widespread plastic pollution, which has emerged as a significant global issue.^2–6 Polycarbonate (PC), recognized for its exceptional material properties, ranks among the most extensively utilized engineering plastics, with an annual production of 6 million tons and a market value projected to reach USD 25.37 billion.^7,8 Conventional disposal strategies, such as landfilling and incineration, not only exacerbate environmental and health hazards but also squander valuable carbon resources. Mechanical recycling is constrained by inevitable polymer degradation, resulting in inferior material quality and limited reuse potential.^4,9–11 Even biodegradation, often portrayed as a green solution, suffers from slow kinetics and narrow substrate compatibility, leaving it confined to preliminary research with little practical applicability.^12–14

Chemical recycling has emerged as a promising alternative for industrial application, offering improved resource efficiency and reduced environmental impact.^15,16 This method not only facilitates the production of a diverse range of value-added chemicals through the recombination and formation of chemical bonds but also mitigates the environmental exposure of waste PC to bisphenol A (BPA), thereby reducing the continuous accumulation of toxicity.^17–20 The prevailing techniques for the chemical recycling of PC primarily encompass pyrolysis,^21,22 hydrogenolysis,^23–26 and solvolysis.^27–31 Pyrolysis and hydrogenolysis depolymerize PC through high-temperature cracking and hydrodeoxygenation, respectively, producing small-molecule aromatics or value-added hydrocarbon fuels.^21,25,32,33 Despite their potential for resource recovery, these routes face practical constraints: pyrolysis requires elevated temperatures and yields complex, poorly controlled product mixtures, while hydrogenolysis depends on high-pressure hydrogen and noble-metal catalysts, resulting in high cost and safety concerns.

Compared to other chemical recycling methods, solvolysis preserves the structural integrity of the resultant monomer (BPA), allowing its reuse in the synthesis of new PC plastics.³⁴ This process significantly reduces fossil fuel consumption and greenhouse gas emissions associated with the production of virgin plastics.^17,18,35,36 Solvolysis such as alcoholysis,^37–39 glycolysis,⁴⁰ and aminolysis³¹ can efficiently recover BPA and enable the value-added conversion of carbonyl units into byproducts like carbonates or oxazolidinones. In alcoholysis and aminolysis, nucleophiles attack the carbonate moieties of PC, selectively cleaving the C–O bonds while retaining the carbonyl groups as carbonate or amide functionalities, thereby promoting carbon valorization. However, hydrolysis of PC suffers from low carbon utilization efficiency due to continuous CO₂ release from carbonate bond cleavage, resulting in a loss of carbon resources. In addition, the process generally requires relatively harsh reaction conditions (Table S1).^41,42 These issues not only limit the economic and sustainability appeal of PC hydrolysis but also hinder its practical application. Considering the unique advantages of hydrolysis, which stands out as a particularly green option by using water as the depolymerization agent and avoiding organic solvents, developing strategies to improve carbon utilization and enable milder reaction conditions is essential to enhance the efficiency and practical feasibility of PC chemical recycling.

While CO₂ is a significant contributor to climate change as a greenhouse gas, it also serves as an important carbon resource.^43,44 In recent years, the research focusing on the synthesis of high-value-added chemicals using CO₂ as a C1 building block has attracted considerable attention.^45–47 Cyclic carbonate is a multifunctional chemical with extensive application prospects in the production of lithium battery electrolytes, organic solvents, and polymers.^48,49 The related studies have shown that the production of carbonates from CO₂ and epoxides as feedstocks constitutes an industrially mature and atom-economical reaction pathway.^50,51 Considering the limitations of plastic hydrolysis and the potential for resource utilization of the by-product CO₂, it is desirable to fulfill the synergistic conversion of PC and the by-product CO₂ to achieve the full recycling of PC polymer.

Herein, we propose a synergistic strategy for the simultaneous conversion of PC and its hydrolyzed by-product CO₂ into high-value products: BPA and 4-phenyl-1,3-dioxolan-2-one (PDO), respectively. This process employs a ternary catalytic system comprising an ionic liquid (IL) and a Lewis acid/base, with styrene oxide (SO) as a CO₂ capture reagent. The strategy effectively addresses the issue that the carbonyl units of PC are often converted to CO₂ during hydrolysis, leading to carbon resource loss, achieving complete PC conversion with 99% yields for both BPA and PDO. The universality and practicality of this approach were further validated through substrate scope expansion experiments with various CO₂ capture reagents and commercial waste plastic samples. Kinetic studies revealed that the trace water in the system initiated the reaction, and the SO cycloaddition reaction consumed PC depolymerization intermediates, effectively driving the depolymerization process forward. Full carbon utilization from PC was achieved, with no detectable CO₂ gas released during the reaction. Overall, this work provides a potential solution for the high-value utilization of carbon resources from PC hydrolysis through the synergistic recovery of BPA and the in situ conversion of by-product CO₂ without CO₂ emission, which is of significant value for advancing the development and potential applications of PC chemical recycling.

2. Results and discussion

2.1. Exploration of the catalytic system and reaction conditions

The valorization of PC through a synergistic process combining depolymerization and CO₂ cycloaddition with styrene oxide (SO) was systematically investigated. Initial experiments confirmed that without adding the IL or when replacing it with other conventional organic solvents, the conversion of PC to BPA and 4-phenyl-1,3-dioxolan-2-one (PDO) did not occur or it gave relatively low yields (Fig. S1). This result indicated that the IL in the reaction system functioned not only as a solvent but also as a catalyst, significantly promoting the depolymerization process. To further investigate the influence of the IL type, a series of imidazolium-based ILs with varying cations and counterions were evaluated (Fig. 1a). The results underscore the critical influence of both the cation and the anion on catalytic performance. Among them, [Bmim][Br] exhibited the highest catalytic activity, achieving BPA and PDO yields of 99.6% and 99.0% at 100 °C for 4 hours, respectively. Specifically, the IL activated the carbonyl oxygen of PC through electrostatic interactions, thereby promoting the reaction.⁵² Additionally, in the rate-determining step of the cycloaddition reaction, [Bmim][Br] acts as a nucleophile, attacking the carbon atoms with low spatial potential resistance in epoxides to facilitate ring opening.^53,54 A notable observation was that extending the alkyl chain length of the IL cation enhanced the reaction rate. This effect is attributed to increased steric hindrance, which weakens the electrostatic interaction between the IL's cation and anion, thereby enhancing the nucleophilicity of the anion.^55,56

Fig. 1 Optimization of reaction conditions. Effects of different ILs (a), Lewis acids (b), bases (c), ZnBr₂/K₂CO₃ loadings (d), PC/SO molar ratios (e), and temperatures (f). Reaction conditions unless otherwise specified: PC (0.254 g, 1 mmol of structural unit), SO (1.5 mmol), [Bmim][Br] (2 mmol)/ZnBr₂/K₂CO₃ (5 mol%), 100 °C, 4 h. Yields were detected by ¹H NMR with 1,3,5-trioxane as an internal standard.

The addition of Lewis acids further improved the yields of BPA and PDO. This enhancement arises from the coordination of Lewis acids with the oxygen atoms of epoxides, which increases the electrophilicity of the carbon atoms, thereby facilitating nucleophilic attack. Experimental results confirmed that the absence of Lewis acids significantly reduced the PDO yields (Fig. 1b). Among the tested Lewis acids (AlCl₃, ZnCl₂, ZnBr₂, and ZnI₂), ZnBr₂ exhibited superior catalytic performance, highlighting the critical role of the halide in zinc halides. To further investigate the role of bases in the reaction, a range of inorganic bases (NaOH, KOH, Na₂CO₃, and K₂CO₃) was evaluated (Fig. 1c). Mild bases, such as Na₂CO₃ and K₂CO₃, produced the highest yields, likely due to their ability to efficiently deprotonate imidazolium salts, forming N-heterocyclic carbenes (NHCs), which are known to play a pivotal role in CO₂ capture and conversion.^57–60 Furthermore, controlled experiments confirmed that K₂CO₃ did not participate in the formation of cyclic carbonate (Fig. S2). In addition, given that the phase states of Lewis acids and bases can influence their catalytic activity, Fig. S3 and S4 compare their performance under identical phase conditions, showing that the ZnBr₂/K₂CO₃ pair still exhibits superior activity.

In summary, the ternary catalytic system comprising [Bmim][Br], ZnBr₂, and K₂CO₃ demonstrated exceptional efficiency for the depolymerization of PC. Increasing the amounts of ZnBr₂ and K₂CO₃ did not enhance the product yields, whereas reducing their concentrations led to suboptimal yields of BPA (69.5%) and PDO (54.0%) (Fig. 1d). The effect of the PC to SO ratio was also examined (Fig. 1e). Insufficient SO resulted in incomplete CO₂ capture and cycloaddition, decreasing the PC conversion. Conversely, using 1.5 equivalents of SO enabled complete PC conversion to BPA and PDO. Temperature optimization experiments revealed that increasing the reaction temperature accelerated PC depolymerization without affecting product yields, whereas lower temperatures led to incomplete depolymerization (Fig. 1f). Furthermore, as shown in Fig. S5, PC can undergo depolymerization even at low [Bmim][Br] loadings. Although the initial yields are relatively low, the introduction of trace amounts of water and the extension of the reaction time enhance the yields of BPA and PDO, demonstrating the promising depolymerization potential under low ionic liquid conditions. While this catalytic system is relatively complex, it can be effectively separated via extraction, and the entire catalytic system can be directly reused in the next cycle after vacuum drying, exhibiting excellent recyclability with no significant deactivation over at least four consecutive cycles (Fig. S6 and S7). A slight decrease in yield was observed in the fifth cycle due to catalyst loss from repeated extractions, but after replenishing the catalyst, the yield was restored in the sixth cycle, further demonstrating its potential for practical application. Moreover, the main product BPA could be readily isolated by extraction, achieving a purity of 99% (Fig. S8). To further enhance catalyst recyclability, we developed a heterogeneous catalytic system by synthesizing a polyionic liquid (PIL)-based composite, PIL–[VBim][Br]–Zn²⁺ (Fig. S10). Under slightly harsher reaction conditions compared to the homogeneous system, the heterogeneous catalyst still afforded excellent yields of 99.2% for BPA and 98.0% for PDO in γ-valerolactone (Table S2). These results indicate that both the homogeneous and heterogeneous systems exhibit considerable economic viability and industrial feasibility.

2.2. Scope of epoxides on PC valorization

To further explore the versatility of the proposed strategy for synthesizing diverse cyclic carbonates, we extended our investigation to assess the applicability of various epoxide substrates in the depolymerization of PC, as illustrated in Fig. 2. Initially, alkyl epoxides and ether-based epoxides with varying chain lengths were evaluated. The results demonstrated efficient conversion of PC into BPA and its corresponding carbonates (4b–4e), achieving yields of 97.7–99.4% and 91.3–99.5%, respectively. Subsequently, aromatic epoxide compounds were tested, which also underwent facile conversion to the corresponding carbonates, yielding BPA and carbonates with 95.3–99.7% and 76.1–94.3% yields, respectively. These results demonstrate that the developed method is highly adaptable to a wide variety of epoxide substrates, showcasing its potential for versatile applications. Furthermore, this work serves as a novel example of synthesizing CO₂-derived chemicals using waste PC plastics as the readily available feedstock.

Fig. 2 Substrate expansion of epoxides. ^a Reaction conditions: PC (0.254 g, 1 mmol of structural unit), epoxides (1.5 mmol), [Bmim][Br] (2 mmol)/ZnBr₂/K₂CO₃ (5 mol%) at 100 °C for 2 h. ^b Reaction conditions: PC (0.254 g, 1 mmol of structural unit), epoxides (1.5 mmol), [Bmim][Br] (2 mmol)/ZnBr₂/K₂CO₃ (10 mol%) at 100 °C for 8 h. Yields were detected by ¹H NMR with 1,3,5-trioxane as an internal standard.

2.3. Practical application to commercial waste PC

Subsequently, the generality of the developed strategy was demonstrated through the transformation of various types of commercial waste PC, as illustrated in Fig. 3A. A wide range of PC waste materials was investigated, including buckets, junction boxes, optical discs, plastic casks, hollow sheets, tubes, insulator films, and electronic shells. It is worth noting that, based on the mechanism of PC hydrolysis, the formation of PDO is not directly related to that of BPA, and differences in raw material composition can lead to slightly more pronounced yield variations in real-world PC systems compared to model systems, but do not affect the overall trends. Remarkably, all tested PC waste materials were completely depolymerized, achieving BPA and PDO yields of 91.1–97.5% and 96.0–99.7%, respectively. These results highlight the practicality and efficiency of the developed strategy in processing complex commercial PC waste. To gain deeper insights into the depolymerization process of complex real-world plastics, the effects of [Bmim][Br] on the physical structure of PC buckets were examined using scanning electron microscopy (SEM). As shown in Fig. 3B, significant changes in the surface morphology of a PC water bucket were observed at 100 °C over different time periods. As the dissolution process progressed, the surface of the PC water bucket transitioned from smooth (0 min) to distinct cracks (90 min). This phenomenon indicated that [Bmim][Br] facilitated the swelling and dissolution of PC plastic, thereby promoting the depolymerization of the polymer.

Fig. 3 (A) Real PC plastic waste depolymerization. Reaction conditions: PC plastic waste (0.254 g, 1 mmol of structural unit), SO (1.5 mmol), [Bmim][Br] (2 mmol)/ZnBr₂/K₂CO₃ (5 mol%) at 100 °C for 5 h. (B) SEM images of PC buckets in [Bmim][Br] for different heating times: (a) raw PC buckets, (b) 100 °C for 30 min, (c) 100 °C for 60 min, and (d) 100 °C for 90 min. Yields were detected by ¹H NMR with 1,3,5-trioxane as an internal standard.

2.4. Mechanistic studies on synergistic conversion of PC

To validate the effectiveness of the proposed PC hydrolysis integrated with the CO₂ valorization strategy, gas chromatography was employed to analyze the gas generated during the reaction. The results showed that PC depolymerization without the addition of an SO trapping agent yielded only 84% of BPA even after 6 h of reaction at 150 °C, and CO₂ release was clearly detected (Fig. 4a). Notably, with the introduction of SO, efficient depolymerization of PC could be achieved under much milder conditions. More importantly, no significant CO₂ release was detected during the reaction. Subsequently, control experiments confirmed that trace water plays a key role in the PC depolymerization process. When external water was introduced into the system from 0 to 70 μL, the yields of BPA and PDO increased from 73.5% and 77.2% to 99.5% and 99.9% at 100 °C over 20 min. However, further increasing the water content to 150 μL led to a decrease in BPA and PDO yields to 60.1% and 41.9%, respectively (Fig. 4b). In contrast, when [Bmim][Br] was pre-dried with 4 Å molecular sieves (Fig. S12), the BPA and PDO yields under identical optimal reaction conditions (100 °C, 4 h) dropped sharply from 99.6% and 99.0% to 59.4% and 48.5%, respectively. These results demonstrate a clear volcano-type dependence of the product yield on water content: trace amounts promote depolymerization, whereas excess water suppresses it. From an application perspective, this means that maintaining water content within a moderate range is essential for achieving high depolymerization efficiency, with the breadth of this range providing both flexibility and robustness for industrial operation.

Fig. 4 (a) CO₂ gas detection: PC (0.508 g), [Bmim][Br] (4 mmol)/ZnBr₂/K₂CO₃ (10 mol%) at 150 °C for 6 h (PC hydrolysis). (b) Exogenous water content control experiment: 20 min. (c) Two possible PC depolymerization into BPA and PDO pathways (Path A or B). (d) Kinetic investigation experiment. Reaction 1: PC (0.254 g, 1 mmol of structural unit), Reaction 2: CO₂ (0.15 MPa) and SO (1 mmol). (e and f) Comparative studies of ¹³C NMR spectra for three mixed solution systems: [Bmim][Br]/DPC (2 : 1), [Bmim][Br]/K₂CO₃/DPC (1 : 0.05 : 1)/0.3 mL of THF and [Bmim][Br]/ZnBr₂/K₂CO₃/DPC/SO (1 : 0.05 : 0.05 : 1 : 1)/0.3 mL of THF were reacted at 100 °C for 4 h, respectively. (g) Proposed two-step tandem reaction mechanism for PC depolymerization into BPA and PDO. Reaction conditions unless otherwise specified: PC/SO (1 : 1.5), [Bmim][Br] (2 mmol)/ZnBr₂/K₂CO₃ (5 mol%) at 100 °C.

Trace amounts of water in the system are proposed to participate in the reaction via two pathways. First, water directly facilitates PC hydrolysis. Second, water can induce the hydrolytic ring-opening of SO to form styrene glycol (SG), which in turn triggers PC alcoholysis. However, experimental results showed that SG-induced PC alcoholysis is considerably less efficient than the SO-mediated process. Specifically, only 81.8% BPA and 58.1% PDO were obtained by replacing SO with its hydrolysate SG (Fig. 4c). The reduced efficiency was attributed to the larger steric hindrance of SG, which impeded its nucleophilic attack on the carbonyl carbon of PC. Notably, no depolymerized monomers were detected during the early stages of the PC alcoholysis reaction (0–20 min), indicating that the initial depolymerization process of PC was mainly direct hydrolysis in the PC/SO system. This conclusion was further supported by ¹H NMR characterization of the depolymerization solution in the PC/SO system (Fig. S14). The results showed a gradual decrease in SO concentration within the first 0–10 minutes, with SO completely consumed by 20 minutes. Importantly, no ring-opening hydrolysis products of SO were detected during this stage. The above results further confirmed the dominance of the hydrolysis mechanism in the PC depolymerization process.

Based on the results of the main mechanism of PC hydrolysis, it is proposed that the conversion process of PC to BPA and PDO follows a two-step tandem reaction mechanism. The first step is the hydrolysis of PC to generate BPA and CO₂, and the second step is the cycloaddition reaction of in situ generated CO₂ with SO to produce PDO. Subsequently, a detailed kinetic study was conducted to gain deeper insights into the conversion process of PC. As shown in Fig. 4d, the hydrolysis of PC showed a low efficiency, and the yield of BPA was only 23.9% after 4 hours of reaction. In contrast, the BPA yield of Reaction 3 was significantly higher, reaching 99.6%. This significant difference indicated that the cycloaddition reaction of SO greatly promoted the depolymerization of PC, thereby improving the efficiency of the whole reaction. Moreover, investigations into the effect of SO on the swelling and dissolution behavior of PC revealed that SO accelerates both processes, which may in turn facilitate depolymerization (Fig. S16). In addition, the kinetics of Reaction 3 is closely related to the kinetics of Reaction 2, indicating that the depolymerization of PC is the rate-determining step in this process.

Subsequently, diphenyl carbonate (DPC) was employed as a PC model compound to comparatively analyze the ¹³C NMR spectra of three mixed systems ([Bmim][Br]/DPC, [Bmim][Br]/K₂CO₃/DPC, and [Bmim][Br]/ZnBr₂/K₂CO₃/DPC/SO). There was no significant chemical shift for the carbonyl carbon of DPC in the ¹³C NMR spectrum of the [Bmim][Br]/DPC mixture, and no new species were detected (Fig. 4e). This result demonstrated that [Bmim][Br] did not directly initiate PC depolymerization as nucleophiles. In the [Bmim][Br]/K₂CO₃/DPC system, new characteristic absorption peaks were clearly observed in the ¹³C NMR spectrum (Fig. 4f), which further confirmed the critical role of K₂CO₃. Based on these results, it was speculated that K₂CO₃ deprotonated the imidazolium cation to form a highly reactive N-heterocyclic carbene (NHC), which then acted as a nucleophile to directly attack the carbonyl carbon of DPC, leading to the cleavage of the ester bond and generating phenol (PhOH)⁶¹ and PhCOO–NHC (Fig. 4f). The formation of the PhCOO–NHC intermediate was confirmed by an obvious movement of the chemical shift to the low-field (197.13 ppm) of the carbonyl carbon in the PhCOOH.⁶² It is noteworthy that upon introduction of SO into the system, the ¹³C NMR spectrum exhibited not only characteristic peaks of PDO, but also a significant enhancement in the relative intensity of the PhOH signal. This observation clearly indicated that the presence of SO facilitated the conversion of the PhCOO–NHC intermediate into PDO and PhOH.

Finally, we proposed two potential mechanisms for the conversion of PC into BPA and PDO based on the relevant literature and obtained data.^63,64 The first mechanism follows a two-step tandem reaction pathway where trace amounts of water initiate the hydrolysis of PC, catalyzed by [Bmim][Br], which results in the cleavage of the C–O bond in the carbonate unit (Fig. 4g). This process leads to the subsequent release of CO₂ from the carbonic acid functional group of intermediate A. The generated CO₂ then reacts with carbene intermediates derived from the reaction of K₂CO₃ and [Bmim][Br], producing NHC–CO₂. Subsequently, intermediate B undergoes an intermolecular nucleophilic attack on intermediate C (formed from the epoxide ring opening catalyzed by both ZnBr₂ and Br⁻) to yield intermediate D. Intermediate D then undergoes intramolecular nucleophilic cyclization, yielding the high-value product PDO. Concurrently, PC is gradually depolymerized into smaller oligomers, ultimately leading to the formation of valuable BPA and PDO. The second mechanism involves direct nucleophilic attack by NHC, initiating PC depolymerization. These mechanistic studies establish an important theoretical foundation for understanding the chemical recycling process of PC.

3. Conclusions

In conclusion, this study presents a novel and environmentally friendly strategy for the hydrolysis of PC, integrated with the high-value utilization of the byproduct CO₂. Using the [Bmim][Br]/ZnBr₂/K₂CO₃ ternary catalytic system, PC was efficiently depolymerized into BPA and PDO. Substrate expansion experiments demonstrated the versatility of this method, achieving excellent yields of BPA and five-membered cyclic carbonates with a variety of epoxides. The practical applicability of this strategy was also validated with commercial waste PC plastics, achieving BPA and PDO yields of 91.1–98.1% and 96.0–99.7%, respectively. Then, kinetic studies revealed that the cycloaddition reaction of SO significantly promoted the depolymerization of PC. Mechanistic analysis demonstrated that the depolymerization of PC was primarily driven either by trace water in the system or by the NHC species generated via K₂CO₃-induced deprotonation of [Bmim][Br]. Overall, this study addressed the critical issue of CO₂ release during PC hydrolysis through in situ valorization and enriched the chemical recycling pathways for PC.

Author contributions

Yue Bai: Data curation, formal analysis, investigation, writing – original draft. Minghao Zhang: Methodology, formal analysis, writing – review and editing. Siming Zhu: Writing – review and editing. Zhuo Wang: Funding acquisition, writing – review and editing. Yu Liu: Formal analysis. Jianxiu Hao: Funding acquisition, writing – review and editing. Huacong Zhou: Formal analysis, funding acquisition, resources, supervision, writing – review and editing. Qingqing Mei: Conceptualization, formal analysis, funding acquisition, resources, supervision, writing – review and editing.

Data availability

The data supporting this article have been included as part of the supplementary information (SI). The supplementary information provides detailed experimental procedures, investigations of reaction parameters and catalyst recyclability, and comprehensive NMR data and spectra for all compounds. See DOI: https://doi.org/10.1039/d5gc02387d.

Conflicts of interest

There are no conflicts to declare.

Acknowledgements

This work was supported by the Key Research and Development Program of Zhejiang Province (2024C03112, 2024C03128), the National Natural Science Foundation of China (22209146, 22376183, 22468035, and 22468036), the Fundamental Research Funds for the Central Universities (226-2023-00041, 226-2023-00077), the Natural Science Foundation of Inner Mongolia (2024QN02018), the Science Fund for Distinguished Young Scholars of Inner Mongolia (2022JQ04), the Postdoctoral Fellowship Program of the CPSF (GZC20232274), and the China Postdoctoral Science Foundation (2024M762839).

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Footnote

† These authors contributed equally.

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