Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid （HPA） supported on acid-treated clay montmorillonite （K10）. 20% （w/w） dodecatungestophosphoric acid （DTPA） supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% （w/w） DTPA/K10 for optimization of the activity.

Kinetics of Levulinic Acid Formation from Glucose Decomposition at High Temperature

Levulinic acid is a kind of new green platform chemical with wide application. The kinetics of levulinic acid formation from glucose decomposition at high temperature was investigated. Glucose containing 1%, 3% or 5% H2SO4 was treated at 170℃ or 190℃. For the various experimental conditions assayed, the time-courses of glucose and glucose degradation products (including 5-hydroxymethylfurfural and levulinic acid) were established. These variables were cor-related with the reaction time based on the equations derived from a pseudo-homogeneous, first-order kinetic model, which provided a satisfactory interpretation of the experimental results. The set of kinetic parameters from regression of experimental data provided useful information for understanding the levulinic acid formation mechanism.

Optimization on the Conversion of Bamboo Shoot Shell to Levulinic Acid with Environmentally Benign Acidic Ionic Liquid and Response Surface Analysis

Levulinic acid（LA） has been identified as a promising green,biomass derived platform chemical.Response surface analysis（RSA） with a four-factor-five-level central composite design（CCD） was applied to optimize the hydrolysis conditions for the conversion of bamboo（Phyllostachys Praecox f.preveynalis） shoot shell（BSS） to LA catalyzed with ionic liquid [C4mim]HSO4.The effects of four main reaction parameters including temperature,time,C[C4mim]HSO4（initial [C4mim]HSO4 concentration） and XBSS（initial BSS intake） on the hydrolysis reaction for yield of LA were analyzed.A quadratic equation model for yield of LA was established and fitted to the data with an R2 of 0.9868,and effects of main factors and their corresponding relationships were obtained with RSA.Model validation and results of CCD showed good correspondence between actual and predicted values.The analysis of variance（ANOVA） of the results indicated that the yield of LA in the range studied was significantly（P＆lt;0.05） affected by the four factors.The optimized reaction conditions were as follows：temperature of 145 ℃,time of 103.8 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2.04%（by mass）,respectively.A high yield [（71±0.41）%（by mol）,triplicate experiment] was obtained at the optimum conditions of temperature of 145 ℃,time of 104 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2%（by mass）,which obtained from the real experiments,concurred with the model prediction [73.8%（by mol） based on available C6 sugars in BSS or 17.9%（by mass） based on the mass of BSS],indicating that the model was adequate for the hydrolysis process.

An efficient and reusable bimetallic Ni_3Fe NPs@C catalyst for selective hydrogenation of biomass-derived levulinic acid toγ-valerolactone

Bimetallic nanostructures have attracted great interest as efficient catalyst to enhance activity,selectivity and stability in catalytical conversion.Herein,we report a facile one‐pot carbothermal route to in‐situ controllable synthesize heterogeneous bimetallic Ni3Fe NPs@C nanocatalyst.The X‐ray diffraction,transmission electron microscopy,X‐ray photoelectron spectroscopy and N2 adsorption‐description results reveal that the Ni3Fe alloy nanoparticles are evenly embedded in carbon matrix.The as‐prepared Ni3Fe NPs@C catalyst shows excellent selective hydrogenation catalytic performance toward the conversion of levulinic acid(LA)toγ‐valerolactone(GVL)via both direct hydrogenation(DH)and transfer hydrogenation(TH).In DH of LA,the bimetallic catalyst achieved a 93.8%LA conversion efficiency with a 95.5%GVL selectivity and 38.2 mmol g–1 h–1 GVL productivity(under 130°C,2MPa H2 within 2 h),which are 6 and 40 times in comparison with monometallic Ni NPs@C and Fe NPs@C catalysts,respectively.In addition,the identical catalyst displayed a full conversion of LA with almost 100%GVL selectivity and 167.1 mmol g–1 h–1 GVL productivity at 180°C within 0.5 h in TH of LA.Under optimal reaction conditions,the DH and TH catalytic performance of 500‐Ni3Fe NPs@C(3:1)catalyst for converting LA to GVL is comparable to the state‐of‐the‐art noble‐based catalysts.The demonstrated capability of bimetallic catalyst design approach to introduce dual‐catalytic functionality for DH and TH reactions could be adoptable for other catalysis processes.

In situ synthesis of biomass-derived Ni/C catalyst by self-reduction for the hydrogenation of levulinic acid to γ-valerolactone

Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.

Kinetic Studies on Wheat Straw Hydrolysis to Levulinic Acid

Levulinic acid is considered as a promising green platform chemical derived from biomass.The kinetics of levulinic acid accumulation in the hydrolysis process of wheat straw was investigated in the study.Using dilute sulfuric acid as a catalyst,the kinetic experiments were performed in a temperature range of 190-230°C and an acid concentration range of 1%-5% (by mass) .A simple model of first-order series reactions was developed,which provided a satisfactory interpretation of the experimental results.The kinetics of main intermediates including sugar and 5-hydroxymethylfurfural(5-HMF) were also established.The kinetic parameters provided useful information for understanding the hydrolysis process.

The hydrogenation of levulinic acid to γ-valerolactone over Cu–ZrO2 catalysts prepared by a pH-gradient methodology

A novel pH gradient methodology was used to synthesise a series of Cu–ZrO2 catalysts containing different quantities of Cu and Zr.All of the catalysts were highly selective to the desired product,γ-valerolactone, and are considerably more stable than Cu–ZrO2 catalysts prepared by other co-precipitation methods for this reaction.Characterisation and further investigation of these catalysts by XRD, BET, SEM and XPS provided insight into the nature of the catalytic active site and the physicochemical properties that lead to catalyst stability.We consider the active site to be the interface between Cu/CuOxand ZrOx and that lattice Cu species assist with the dispersion of surface Cu through the promotion of a strong metal support interaction.This enhanced understanding of the active site and roles of lattice and surface Cu will assist with future catalyst design.As such, we conclude that the activity of Cu–ZrO2 catalysts in this reaction is dictated by the quantity of Cu–Zr interface sites.

Role of the Cu-ZrO_(2) interface in the hydrogenation of levulinic acid to γ-valerolactone

Here we exquisitely fabricated Cu/ZrO_(2)-dp catalysts with plentiful Cu-ZrO_(2)interfaces by depositing amorphous ZrO_(2)onto Cu nanoparticles for the hydrogenation of levulinic acid(LA)to y-valerolactone(GVL).With the created plentiful CU-ZrO_(2)interfaces,the optimal catalyst 3 Cu/ZrO_(2)-dp exhibited exceptional catalytic performance under mild reaction conditions,and achieved the highest GVL mass productivity of 266.0 mmol GVL·h^(-1)·g^(-1)Cu,which was 12.5 and 2.3 times of CU/ZrO_(2)catalysts with equivalent Cu loadings prepared by traditional impregnation(3 Cu/ZrO_(2)-im)or co-precipitation(3 Cu/ZrO_(2)-cp).As far as we know,this GVL mass productivity stood at the highest level compared with those obtained using non-noble metal catalysts under similar reaction conditions.By systematic investigation with multiple characterizations,density functional theory(DFT)calculations,and kinetic studies,it was found that interfacial active centers were created at Cu-ZrO_(2)interfaces,which contained oxygen vacancies(O_(v)),negatively charged Cu^(δ)-and partially reduced Zr^(3+)The O_(v) favored the adsorption and activation of LA via its ketone group,while negatively charged Cu^(δ)-was able to enhance heterolysis of H2,which resulted in the formation of H^(+)-Cu^(δ)-and Zr^(3+)-H^(-)active species via hydrogen spillover.Also,plentiful acid sites,which derived from coordinatively unsaturated and defective Zr species,generated at Cu-ZrO_(2)interfaces.With the cooperation of interfacial active centers(Cu^(δ-)-O_(v)-Zr^(3+))and acid sites,the fabricated 3 Cu/ZrO_(2)-dp with plentiful Cu-ZrO_(2)interfaces achieved excellent catalytic performance for the hydrogenation of LA to GVL.Hence,the synergistic catalysis of Cu-ZrO_(2)interfaces provided an effective strategy for designing catalysts with a satisfactory performance for the hydrogenation of LA,which also can be expanded to other hydrodeoxygenation reactions.

Aqueous-phase hydrogenation of levulinic acid over carbon layer protected silica-supported cobalt-ruthenium catalysts

The hydrogenation of levulinic acid(LA)to c-valerolactone(GVL)by using water as solvent is a crucial process in the production of fine chemicals from biomass.An ultrathin carbon layer coating CoRu bimetallic catalyst supported on silica(CoRu@C/SiO2)is prepared by using tannis-ligated cobalt-ruthenium complex on silica as precursors,and applied for catalyzed synthesis of GVL from LA.Because of the synergistic effect between cobalt and ruthenium,the addition of small amounts of Ru to Co catalysts can increase the catalytic activity in the aqueous hydrogenation of LA.The ultrathin carbon layer covered on the CoRu bimetallic catalyst can greatly reduce the leaching of active metals.The CoRu@C/SiO2 catalyst achieves high stability and is reused up to 5 runs without significant loss of performance in aqueous hydrogenation of levulinic acid.

Co encapsulated N-doped carbon nanotubes as robust catalyst for valorization of levulinic acid in aqueous media

The construction of an acid resistant catalyst for synthesis of γ-valerolactone from levulinic acid in aqueous media is an important but highly challenging goal.Herein,an efficient Co@NCNT-800(after 800℃ pyrolysis) catalyst was constructed by confining Co in N-doped carbon nano-tubes(NCNT) from low cost materials by a facile strategy.Combined with the characterization results and control experiments,the in situ formed Co and Co-Ox, but not Co-Nx, proved to be the main synergistic active sites of the catalyst.It was also found that Co species are completely isolated within the bamboo-like NCNT,which could protect the metal nanoparticles from agglomeration and leaching in the strong acid reaction system.The γ-valerolactone yield of no less than 99.9% can be obtained under a relatively mild condition,and the catalytic performance has not been significantly reduced within five cycles.Therefore,this work may pave a way for the design of robust non-noble catalyst,and has potential for the production of γ-valerolactone from biomass in large-scale industries.

Preliminary Optimization and Kinetics of SnCl_(2)-HCl Catalyzed Hydrothermal Conversion of Microcrystalline Cellulose to Levulinic Acid

Levulinic acid(LA)is a platform biorefinery chemical from biomass which can be converted to green solvents,plasticizers,polymer precursors,biobased cleaning agents,fuels and fuel additives.This study assessed the potential of SnCl_(2)-based mixed acid systems as catalyst in the hydrothermal conversion of microcrystalline cellulose to levulinic acid.Maximum LAyield of 36.2 mol%was achieved using 0.2 M SnCl_(2) concentration at test conditions of 3 h,180℃ and 1%w/v cellulose loading.To reduce precipitate formation and further improve LA yield,the strategy employed was to combine SnCl_(2)(a Lewis acid)with conventional mineral acids(Bronsted acids).Evaluation of the catalytic performance of SnCl_(2)-HCl,SnCl_(2)-H_(2)SO_(4),SnCl_(2)-HNO_(3),and SnCl_(2)-H_(3)PO_(4)(1:1 molar ratio,0.2 M total acid concentration)were done with highest LA yield of 47.0 mol%obtained using the SnCl_(2)-HCl system at same test conditions.Response surface methodology optimization employing Box-Behnken design generated a quadratic model with a high coefficient of determination(r2)of 0.964.A maximum LA yield of 63.5 mol%can be achieved at 0.17 M catalyst concentration,198℃,and 5.15 h reaction time.Rate constants were estimated using nonlinear regression,while activation energies were determined using Arrhenius equation.Cellulose hydrolysis was determined to be the rate-limiting step in the overall process.Low activation energy of 63.3 kJ/mol for glucose dehydration to hydroxymethylfurfural supports the action of SnCl_(2) as Lewis acid in the mixed-acid system.LA yield simulations for plug flow reactor(PFR)and continuous stirred tank reactor(CSTR)were done suggesting a similar PFR-CSTR configuration with the established Biofine process.Lastly,a reaction scheme was presented to explain the synergy between SnCl_(2) and HCl in LA production from cellulose.

Highly active and stable Co nanoparticles embedded in nitrogen-doped mesoporous carbon nanofibers for aqueous-phase levulinic acid hydrogenation

Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanoparticles(NPs)embedded in nitrogen-doped mesoporous carbon nanofibers as an efficient catalyst for aqueous-phase LA hydrogenation to GVL.The Co zeolitic imidazolate framework(ZIF-67)nanocrystals were anchored on the sodium dodecyl sulfate modified wipe fiber(WF-S),yielding one-dimensional(1-D)structured composite(ZIF-67/WF-S).Subsequently,Co NPs were uniformly embedded in nitrogen-doped mesoporous carbon nanofibers(Co^(R)NC/SMCNF)through a pyrolysis-reduction strategy using ZIF-67/WF-S as the precursor.Benefiting from introducing modified wipe fiber WF-S to enhance the dispersion of Co NPs,and Co^(0) with Co-N_xdual active sites,the resulting Co^(R)NC/SMCNF catalyst shows brilliant catalytic activity(206 h^(-1) turnover frequency).Additionally,the strong metal-support interactions greatly inhibited the Co NPs from aggregation and leaching from the mesoporous carbon nanofibers,and thus increasing the reusability of the Co^(R)NC/SMCNF catalyst(reusable nine times without notable activity loss).

Direct conversion of furfural to levulinic acid/ester in dimethoxymethane:Understanding the mechanism for polymerization

This study investigated the conversion of furfural to 5-hydroxymethylfurfural(HMF)and further to levulinic acid/ester in dimethoxymethane under acidic conditions,with the particular focus on understanding the mechanism for polymer formation.The results showed that furfural could react with dimethoxymethane via electrophilic substitution reaction to form HMF or the ether/acetal of HMF,which were further converted to levulinic acid and methyl levulinate.The polymerization of furfural and the cross-polymerization between dimethoxymethane and the levulinic acid/ester produced were the main side reactions leading to the decreased yields of levulinic acid/ester.Comparing to the other solvent,methanol as the co-solvent helped to alleviate but not totally inhibited the occurrences of the polymerization,as the polymerization reactions via aldol condensation did not eliminate the C=O functionalities.As a consequence,the polymerization reactions continued to proceed.Other co-solvent used such as guaiacol,dimethyl sulfoxide and acetone interfered with the transformation of furfural to HMF or aided the polymerization reactions.The polymer produced from the reactions between furfural and DMM was different from that produced from levulinic acid/ester.The former had a higher crystallinity,while the latter was more aliphatic.The DRIFTS and TG-MS studies showed that the polymer had the carboxylic group,methyl group and the aliphatic structure in the skeleton.The removal of these functionalities was accompanied by the aromatization of the polymer.The condensation of DMM with levulinic acid/ester was the key reason for the diminished production of levulinic acid/ester.

Selectively reductive amination of levulinic acid with aryl amines to N-substituted aryl pyrroles

Synthesizing nitrogen(N)-containing molecules from biomass derivatives is a new strategy for production of this kind of chemicals.Herein,for the first time we present the synthesis of N-substituted aryl pyrroles via reductive amination/cyclization of levulinic acid(LA)with primary aromatic amines and hydrosilanes(e.g.,PMHS)over Cs F,and a series of N-substituted aryl pyrroles could be obtained in good to excellent yields at 120○C.The mechanism investigation indicates that the reaction proceeds in two steps:the cyclization between amine and LA occurs first to form intermediate 5-methyl-N-alkyl-1,3-dihydro-2H-pyrrolones and their isomeride(B),and then the chemo-and region-selective reduction of intermediates take place to produce the final products.This approach for synthesis of N-substituted aryl pyrroles can be performed under mild and green conditions,which may have promising applications.

Enzymatic Conversion of Biobased Levulinic Acid into an Alternative Biofuel Candidate--Methyl Levulinate

Methyl levulinate(ML)is a promising green candidate for bio-based diesel fuel and fuel additives.An efficient enzyme-catalyzed process to synthesize ML from levulinic acid(LA)in methanol was developed.The catalytic activity of a series of lipases including Novozyme 435(N435),NRTL IM,and 40086 was screened,and the N435 was identified as the optimal biocatalyst for the process.The effects of lipase amount,methyl tert-butyl ether(MTBE)volume,methanol to LA molar ratio,reaction temperature,and magnetic stirrer speed on LA conversion and ML yield were investigated.The response surface methodology was adopted to optimize the enzymatic conversion process,and the model validation experiments showed that the predicted values corresponded well with the experimental values.A LA conversion of 90.1%and a ML yield of 89.8%were achieved under reaction conditions covering:a temperature of 45°C,a reaction time of 4.6 h,a N435 dosage of 26 mg,a methanol to LA molar ratio of 3.6:1,a MTBE volume of 3.85 mL,and a stirrer speed of 150 r/min.The N435 recycling experiment indicated that the lipase activity was quite high after 12 cycles.However,upon using crude LA prepared from carbohydrates as the reactant,the conversion of LA and the ML yield decreased due to impurities existing in the crude LA.

Synthesis and evaluation of 4-substituted semicarbazones of levulinic acid for anticonvulsant activity

Objective: A series of 4-aryl substituted semicarbazones of levulinic acid (4-oxo pentanoic acid) was designed and synthesized to meet the structural requirements essential for anticonvulsant activity. Methods: All the compounds were evaluated for anticonvulsant activity. Anticonvulsant activity was determined after intraperitoneal (i.p.) administration to mice by maximal electroshock (MES) and subcutaneous metrazol (ScMet) induced seizure methods and minimal motor impairment was determined by rotorod test. Results: A majority of the compounds exhibited significant anticonvulsant activity after intraperitoneal administration. In the present study 4-(4'-fluoro phenyl) levulinic acid semicarbazone emerged as the most active molecule, showing broad spectrum of activity with low neurotoxicity. Unsubstituted levulinic acid semicarbazone was found to be inactive in all the screens. Conclusion: The results obtained validate the hypothesis that presence of an aryl group near the semicarbazone moiety is essential for anticonvulsant activity. The results also indicate that the hydrophilic-hydrophobic site can accommodate hydrophilic groups.

Liquid–liquid extraction of levulinic acid from aqueous solutions using hydrophobic tri-n-octylamine/alcohol-based deep eutectic solvent

Levulinic acid(LA)is one of the top-12 most promising biomass-based platform chemicals,which has a wide range of applications in a variety of fields.However,separation and purification of LA from aqueous solution or actual hydrolysate continues to be a challenge.Among various downstream separation technologies,liquid-liquid extraction is a low-cost,effective,and simple process to separate LA.The key breakthrough lies in the development of extractants with high extraction efficiency,good hydrophobicity,and low cost.In this work,three hydrophobic deep eutectic solvents(DESs)based on tri-n-octylamine(TOA)as hydrogen bond acceptor(HBA)and alcohols(butanol,2-octanol,and menthol)as hydrogen bond donors(HBDs)were developed to extract LA from aqueous solution.The molar ratios of HBD and HBA,extraction temperature,contact time,solution pH,and initial LA concentration,DES/water volume ratios were systematically investigated.Compared with 2-octanol-TOA and menthol-TOA DES,the butanol-TOA DES exhibited the superior extraction performance for LA,with a maximum extraction efficiency of 95.79±1.4%.Moreover,the solution pH had a great impact on the LA extraction efficiency of butanol-TOA(molar ratio=3:1).It is worth noting that the extraction equilibrium time was less than 0.5 h.More importantly,the butanol-TOA(3:1)DES possesses good extraction abilities for low,medium,and high concentrations of LA.

Synthesis, isolation and characterization of methyl levulinate from cellulose catalyzed by extremely low concentration acid

A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this study.Effects of different process variables towards the catalytic performance were performed as a function of reaction time.The results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl levulinate.An optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/L.The resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy fraction.The light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl levulinate.The chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR techniques.Methyl levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.

乙酰丙酸环氧甘油单酯缩酮乙酯的合成及其增塑性能

以乙酰丙酸乙酯、甘油、油酸等大宗生物基化学品为原料,通过酯化反应、缩酮反应及环氧化反应初步制备了一种潜在具有增塑性能的新型化合物乙酰丙酸环氧甘油单酯缩酮乙酯(ELMG),并将其与聚氯乙烯(PVC)、环氧大豆油(ESO)、硬脂酸盐压制成膜,通过FT-IR、XRD、DSC、万能试验机等探讨了合成工艺对ELMG结构的影响,以及ELMG的添加对PVC膜的性能的影响。研究结果表明:采用先缩酮反应,再酯化反应,最后环氧化反应可制得ELMG;ELMG对PVC结晶具有一定的破坏,且与ESO复配使用后效果得到显著提升;ELMG复配ESO可明显提高PVC薄膜的塑化性能,其中50%ELMG增塑的ELMG50/PVC薄膜的断裂伸长率为316.5%,达到了ESO/PVC薄膜的98%,拉伸强度为24.63 MPa,达到了ESO/PVC薄膜的89%。ELMG复配ESO使PVC薄膜的迁移性也得到了明显的改善,其中ELMG50/PVC薄膜在大豆油中的质量损失率为0.71%,仅为ESO/PVC薄膜的67%。

双功能炭基固体酸的制备及其催化纤维二糖醇解

以壳聚糖为碳源,通过金属浸渍、高温炭化制备负载铁的含氮活性炭(ACN-Fe),再进一步水热磺化制备了一系列金属负载型双功能炭基固体酸(ACN-Fe-SO_(3)H),并将其应用于催化纤维二糖醇解反应,利用X射线衍射(XRD)、拉曼(Raman)光谱、红外(FT-IR)光谱、N_(2)吸附/脱附、X射线光电子能谱(XPS)、电感耦合等离子体发射光谱(ICP-OES)和酸碱滴定等手段对催化剂进行了详细的表征。研究结果显示:固体酸中的不饱和三价铁离子具有路易斯酸性,磺酸基具有布朗斯特酸性,炭化温度800℃下制备的固体酸(800-ACN-Fe-SO_(3)H)具有最强的酸性(酸度0.81 mmol/g)和最大的比表面积(85.7 m^(2)/g),催化性能最佳。800-ACN-Fe-SO_(3)H用量0.20 g时,在反应温度200℃,反应时间5 h的条件下,纤维二糖的转化率为99.6%,产物乙酰丙酸(LA)和乙酰丙酸甲酯(ML)产率分别为15.6%和62.1%。催化剂经过5次循环回收,纤维二糖的转化率为93.1%,LA和ML的总产率为51.1%,表明催化剂具有良好的重复使用性,此外还初步探索了纤维二糖醇解的反应机理。