Table of Content

10 May 2024, Volume 45 Issue 5

Previous Issue   

Content

Cover and Content of Chemical Journal of Chinese Universities Vol.45 No.5(2024)

2024, 45(5):  1-6. 

Asbtract ( )   PDF (21516KB) ( )  

Related Articles | Metrics

Review

Electrochemical Analysis of Intracellular Molecules at Single Cells Based on Nanoelectrodes

LIU Kang, PAN Rongrong, JIANG Dechen

2024, 45(5):  20240027.  doi:10.7503/cjcu20240027

Asbtract ( )   HTML ( )   PDF (5183KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Single-cell analysis enables more accurate acquisition of biological information and avoids the loss of single-cell heterogeneity features from averaging analysis， which is essential for studies to elucidate cell metabolism and signaling pathways. Electrochemical analysis techniques based on nanoelectrodes are widely used in single-cell analysis because of their high selectivity， high sensitivity and high spatiotemporal resolution. In this review， the latest research progress of the quantitative analysis of intracellular biomolecules in single cells using nanoelectrodes is reviewed. Moreover， its application in biological research and the challenges are introduced.



Research Progress in Efficient Azide Methods

LONG Lei, WEI Wei, LUO Yunjun, LI Xiaoyu

2024, 45(5):  20230511.  doi:10.7503/cjcu20230511

Asbtract ( )   HTML ( )   PDF (2115KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Organic azide compounds are a class of multifunctional compounds that are useful precursors for synthesizing a range of therapeutic drugs， bioactive compounds， functional materials， and high-energy compounds. They are widely used in click chemistry and Staudinger reactions. In the past few decades， a large number of synthesis strategies have been developed to prepare structurally diverse organic azides， but not all reactions can be carried out efficiently. As the concept of green chemistry deepens in people’s hearts， traditional azide methods with low safety， universality， and efficiency are gradually being phased out， and the development of new and efficient azide methods is urgent. This review focuses on the efficient synthesis methods for preparing aliphatic azide compounds and azide polymers in recent years. A brief overview of the synthesis of aliphatic azide compounds is provided from the azide strategies of C—C multiple bonds and C—H bonds. The synthesis methods and potential novel synthesis strategies of azide polymers are also discussed， and the future development of azide chemistry is summarized and discussed.



Article: Inorganic Chemistry

Synergistic Effects of Hierarchically Interconnected Porous Structure and Fe Modification on Zeolite ZSM-5 for Efficient Benzyl Alcohol Alkylation

SONG Yuhang, LIU Zhan, LYU Jiamin, YU Shen, LI Xiaoyun, SUN Minghui, CHEN Lihua, SU Baolian

2024, 45(5):  20240095.  doi:10.7503/cjcu20240095

Asbtract ( )   HTML ( )   PDF (5275KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Constructing hierarchically porous structures and embedding metal species into zeolite frameworks can effectively enable fast diffusion and synergistic catalysis. We report a one-step synthesis method to synthesize hierarchically macro-meso-microporous zeolite ZSM-5 single crystals containing Fe metal nanoclusters， that has advantages compared to multistep methods such as impregnation and ion exchange. Zeolite ZSM-5-Fe catalysts were prepared by steam assisted crystallization with addition of hierarchically porous carbon template and a Fe precursor. The catalyst was systematically characterized by means of X-ray diffraction（XRD）， ultraviolet-visible spectroscopy （UV-Vis）， H₂-temperature program reduction（H₂-TPR）， and X-ray photoelectron spectroscopy（XPS）. The results indicated that the isolated Fe（III） located at ion exchange sites and ferrite octahedron（six-coordinate） were the main redox-active centers. At a loading amount（mass fraction） of 1%， the highest benzyl alcohol conversion rate reached 59.3%， with a product selectivity of 83.2%， and a final yield of 49.3%. The catalyst maintained high catalytic activity even after five cycles， demonstrating its remarkable stability.



Analytical Chemistry

Fluorescent Probe for Detection of Hg²⁺ and S^2- Based on N-Doped Ti₃C₂ MXene Quantum Dots

ZHANG Huilian, YANG Xinjie, LI Jun, LI Quan, ZHANG Fujuan, ZHANG Yanli, WANG Hongbin, YANG Wenrong, PANG Pengfei

2024, 45(5):  20230504.  doi:10.7503/cjcu20230504

Asbtract ( )   HTML ( )   PDF (3557KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

A novel fluorescent "on-off-on" method for the detection of Hg²⁺ and S^2- was developed based on N-doped Ti₃C₂ MXene quantum dots（N-Ti₃C₂ MQDs） and complexation. The prepared N-Ti₃C₂ MQDs emitted blue fluorescence（λ_em=440 nm） with a fluorescence quantum yield of 15.7%. Hg²⁺ can selectively coordinate with functional groups of —NH₂， —COOH， and —OH on the surface of N-Ti₃C₂ MQDs through electrostatic interaction， resulting in fluorescent quenching of the N-Ti₃C₂ MQDs system. After the addition of S^2-， HgS precipitation is formed due to the strong binding force between S^2- and Hg²⁺， leading to the fluorescent recovery of the N-Ti₃C₂ MQDs. Based on this principle， a fluorescent "on-off-on" sensing method was constructed to quantitatively detect Hg²⁺ and S^2-. The fluorescenty of the N-Ti₃C₂ MQDs probe is proportional to Hg²⁺ and S^2- concentrations in the range of 0.02—200 μmol/L and 0.07—150 μmol/L， with a detection limit of 10 nmol/L and 30 nmol/L（S/N=3）， respectively. This proposed method has the advantages of low cost， simple operation， high sensitivity， and good selectivity， which has been used for the determination of Hg²⁺ and S^2- in real water samples.



Organic Chemistry

Photorelease and Antioxidant Activity of Avobenzone-Ferulic Acid

ZHANG Tianlong, CHEN Guang

2024, 45(5):  20240056.  doi:10.7503/cjcu20240056

Asbtract ( )   HTML ( )   PDF (4762KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Ferulic acid is an effective antioxidant that is widely used in the cosmetics due to its ability to resist oxidative stress and delay skin aging. However， its photosensitivity challenges its application. In order to overcome this limitation， we developed a binary molecule composed of avobenzone（AB） and ferulic acid（FA）. This design is based on the existence of photoremovable benzoyl methyl in the avobenzone to protect ferulic acid from photodamage and maintain its antioxidant activity. The results showed that FA was successfully released， and AB had an effectively photoprotective effect on FA. In vitro experiments showed that AB-FA molecules and their photolysis products had significant activity of scavenging free radical， while cell experiments confirmed their low cytotoxicity and excellent ability to reactive oxygen species（ROS） scavenging.



Photoinduced Trifluoromethyl/arylation Reaction of Carbon Carbon Double Bond Involving CF₃Br for the Synthesis of CF₃-substituted 1,1-Diaryl Alkane Derivatives

MA Ransong, BI Jili, HU Yulai

2024, 45(5):  20240048.  doi:10.7503/cjcu20240048

Asbtract ( )   HTML ( )   PDF (1652KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

A synergistic catalytic strategy combining photocatalysis and transition metal catalysis was employed to achieve the carbon carbon double bond trifluoromethyl/arylation reaction in which the inexpensive and readily available bromotrifluoromethane and aromatic amines were used as substrates. A series of potentially biologically active CF₃-substituted 1，1-diaryl alkane derivatives was synthesized. This work explores the possibility of aromatic amines as arylation reagents， enriches the types of arylation reagents， clarifies the conditions for the arylation process and explores the reaction mechanism. This method has the characteristics of simple operation， low cost and easy availability， providing a concise and effective approach for the synthesis of trifluoromethyl substituted 1，1-diaryl alkanes derivatives.



Synthesis of Thieno［2，3-b］thiopyran-4-one Derivatives by Palladium Catalysts

REN Chuanqing, JI Xiaohui, ZHANG Qiang, CAO Xiaoyan, JI Jianwei, LIU Bo

2024, 45(5):  20240033.  doi:10.7503/cjcu20240033

Asbtract ( )   HTML ( )   PDF (813KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Thieno［2，3-b］thiopyrans are important core structures found in a variety of natural products and other biologically important molecules with a wide range of biological activities. In this work， a series of thieno［2，3-b］thiopyran-4-one derivatives was constructed from 1，6-disubstituted group-4-（1，3-dithiolan-2-ylidene）-1-en-5-yn-3-one via palladium-catalyzed cycloaddition reactions. Optimization experiments showed that the best experimental conditions were as follows： using Pd（OAc）₂ （30%， molar fraction） as catalyst， the substrate（1.0 mmol） and K₂CO₃（1.2 mmol） reacted at 100 ℃ for 8 h in N，N-dimethylformamide（DMF）， thieno［2，3-b］thiopyran-4-one derivatives were synthesized with a yield of 87%. The composition and structure has been characterized by menas of nuclear magnetic resonance（¹H NMR and ¹³C NMR） and high resolution mass spectrometer（electrospray ionization）［HRMS（ESI）］. The mechanism for the reaction was proposed. The menthod had the advantages of mild conditions， safe operation and higher yields.



Physical Chemistry

Study on Diffusion Mechanism of CaO/Ca（OH）₂ Molecules During Thermochemical Energy Storage Process Based on Molecular Dynamics

FANG Yi, LI Yingjie, ZHANG Youhao, REN Yu, HAN Kuihua, ZHAO Jianli

2024, 45(5):  20240052.  doi:10.7503/cjcu20240052

Asbtract ( )   HTML ( )   PDF (5155KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In CaO/Ca（OH）₂ energy storage process， the energy storage and mechanical performance are related to the structure of CaO grains. This work investigated the lattice structure and molecular motion of CaO/Ca（OH）₂ grains during CaO/Ca（OH）₂ energy storage process using molecular dynamics simulations. The result indicates that during the dehydration stage， the movement of Ca（OH）₂ molecules is consistent with the bulk diffusion mechanism. The diffusion pre-exponential factor for O/H atoms is 7.9×10^‒8 m²/s， while that for Ca atom is only 4.7×10^‒8 m²/s. The rapid diffusion of O/H destroys the original lattice structure， leading to a reduction in the crystallinity of CaO after dehydration. In the hydration stage， the diffusion pre-factor for outer molecules of CaO grains is 3.2×10^‒8 m²/s， which is 2.5 times higher than that of inner molecules. Consequently， the molecular motion of CaO molecule is consistent with the surface diffusion mechanism. The diffusion strength of CaO molecule is weak during the hydration stage， resulting in minimal impact on the CaO lattice structure. The simulation determines the diffusion mechanisms of CaO/Ca（OH）₂ molecules in the thermochemical energy storage process. This is crucial to understand the crystal structure evolution of CaO-based materials in CaO/Ca（OH）₂ energy storage process.



Construction and Visible Photocatalytic Hydrogen Performance of Hydrangea-like ZnIn₂S₄/CoWO₄ S-scheme Heterojunction

ZHAO Yutong, WANG Shikai, ZHAO Fuping, CHEN Zhihe, ZHAO Lijie, ZHANG Dafeng, GE Bo, PU Xipeng

2024, 45(5):  20240055.  doi:10.7503/cjcu20240055

Asbtract ( )   HTML ( )   PDF (10957KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Rational design of heterojunction structures to accelerate photocatalytic hydrogen evolution plays an indispensable role in the development of photocatalytic materials. ZnIn₂S₄（ZIS） has been widely used in the field of photocatalytic hydrogen evolution due to its excellent photoelectric properties and negative conduction band position， but it still has serious problems of photogenerated carrier recombination and aggregation. Therefore， the band structure and electron transfer path of ZnIn₂S₄/CoWO₄（ZIS/CWO） S-scheme heterojunction were predicted by theoretical calculation， and the electron exchange at the interface of the heterojunction was determined by electron localization function and charge density difference. Subsequently， CWO nanoparticles were dispersed and fixed on the surface of ZIS flower balls by ultrasonic-agitation-calcination method， and the hydrangea-like ZIS/CWO S-scheme heterojunction was obtained. Owing to the tight interface and the formation of internal electric field between ZIS and CWO， the photogenerated electron-hole pairs in ZIS/CWO S-scheme heterojunction can be effectively separated， thus enhancing the photocatalytic hydrogen evolution performance. Meanwhile， the experimental results confirmed the formation of S-scheme heterojunction and carrier transport path， revealing the in-depth mechanism of photocatalytic hydrogen evolution. This work offers novel insights and approaches for the design， construction， and theoretical calculation of S-scheme heterojunction photocatalysts.



Preparation of Efficient and Stable Perovskite Solar Cells Based on Amino Acid Derivative Hydrochloride Additives

HU Die, SUN Qing, MENG Xiangxin, LING Jinxiang, CHENG Bin, KANG Bonan

2024, 45(5):  20240044.  doi:10.7503/cjcu20240044

Asbtract ( )   HTML ( )   PDF (5217KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

The rapid development of perovskite solar cells（PSCs） has made them one of the most competitive photovoltaic devices in the field of new energy. However， there is still great room for improvement in photoelectric conversion efficiency（PCE） and stability. Here， an amino acid derivative hydrochloride was introduced as an additive in perovskite， D-phenylglycine methyl ester hydrochloride（PGMECl）. PGMECl contains a benzene ring， an ester group， —NH₃⁺ terminal and Cl^- ions. The multiple functional groups worked together to react with uncoordinated Pb²⁺， passivating defects in perovskite. The perovskite grains became denser， surface roughness decreased， and non-radiative recombination of charge carriers was reduced. By adjusting the energy level arrangement， it is more suitable for charge transfer in inverted perovskite solar cells. The results showed that the champion power conversion efficiency（PCE） of PGMECl modification device is 21.04%， which is much higher than that of control devices（17.79%）. The decrease in hysteresis effect also indicates a decrease in ion migration. Under unencapsulated conditions， devices containing PGMECl additives can still maintain a PCE of 70% of the initial efficiency after aging in the dark in air［（40±5）% relative humidity（RH）］ for 1000 h， while the efficiency of the basic device decreases to 50% after 500 h of storage.



Nitrogen-doped Carbon Material MG-T Heterogeneous Catalyzed Hydrogenation of Nitrobenzene to Aniline

GAO Yongping, LIU Bai, KANG Jianing, LYU Jieqiong, YU Zeguang, ZHANG Zhihui, GAO Wenxiu

2024, 45(5):  20240040.  doi:10.7503/cjcu20240040

Asbtract ( )   HTML ( )   PDF (3092KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Aniline， as an important chemical intermediate， is mainly prepared by catalyzing the hydrogenation of nitrobenzene. In this study， a sacrificial template MCA was prepared using melamine and cyanuric acid， and the precursor MG was synthesized using glucose as the carbon source， and nitrogen-doped carbon material MG-T（T/℃， denotes the carbonation temperature） was obtained by high-temperature carbonization， which was used in the heterogeneous catalytic nitrobenzene hydrogenation to aniline reaction. A preliminary study of the reaction mechanism was carried out by combining the results of material characterisation and catalytic evaluation. The experimental results indicated that the carbonisation temperature affects the change of nitrogen species configuration in MG-T， and the graphitic nitrogen plays a key role in the hydrogenation activity of the catalysts. The catalyst MG-800 reacted in ethanol solvent with hydrazine hydrate as the reducing agent at 80 ℃ for 4 h. The conversion of nitrobenzene was 96%， the product selectivity was 100%， and the catalyst could be recycled at least 9 times， with good stability and recyclability， which is a class of recyclable heterogeneous catalysts for the hydrogenation of nitrobenzene to aniline.



Oxygen Framework Mechanism of Layered Lithium-rich Manganese-based Materials Stabilized by High-valent Element Mo Based on First-principles Calculations

ZHANG Shuo, ZHAO Liuyang, HUANG Hao, WU Aimin, LI Aikui

2024, 45(5):  20240035.  doi:10.7503/cjcu20240035

Asbtract ( )   HTML ( )   PDF (7122KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Density functional theory（DFT） first-principles calculations were employed to elucidate the stabilization mechanism of lithium-rich manganese-based materials through Mo substitution for Mn. Mo doping mitigated the volume change rate， decreasing it from ‒2.95% to ‒0.53% and improved lattice distortion both before and after lithiation. Results from vacancy formation energy and Bader charge analysis revealed a marked increase in the formation energy of seven oxygen vacancies， and the average Bader charge of the first-coordination oxygen escalated from 1.13 e to 1.18 e， which effectively suppressed unstable oxygen precipitation. The change in Bader charge of oxygen atoms before and after lithiation decreased from 0.51 e to 0.11 e， which was indicative of the robust stability of the oxygen framework during cycling. Differential charge density calculations illustrated that Mo can compensate for charge after the removal of Li. Furthermore， Mo doping enhanced lithium ion migration rates， reducing the minimum barrier from 0.55 eV to 0.42 eV. This study provides a rigorous theoretical foundation for the doping of high-valence elements in lithium-ion battery cathode materials.



MgCl₂-AlCl₃-EMImBF₄/Organic Ether for Rechargeable Magnesium Battery Electrolytes

WEN Jiaxin, YE Junliu, WEI Xin, YANG Jingdong, YIN Xuejiao, LI Lingjie

2024, 45(5):  20240010.  doi:10.7503/cjcu20240010

Asbtract ( )   HTML ( )   PDF (3852KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Rechargeable magnesium batteries（RMBs） are considered to be one of the next most promising energy storage systems. The electrolyte has an important influence on the performance of RMBs. The RMBs electrolyte system of MACC-EMImBF₄/organic ether（MACCE） was prepared by the addition of 1-ethyl-3-methyl-1H-imidazol-3-ium tetrafluoroborate（EMImBF₄） into the magnesium aluminum chloride complex（MACC） electrolyte. The electrochemical performance and full cell performance of the MACCE electrolyte were tested by cyclic voltammetry（CV）， linear scanning voltammetry（LSV）， electrochemical impedance spectroscopy（EIS）， and galvanostatic charge- discharge curves（GCD）. The surface of the electrodes with MACCE electrolyte after circulation was analyzed by field emission scanning electron microscopy（FESEM）， X-ray powder diffractometry（XRD） and X-ray photoelectron spectroscopy（XPS）. The results show that the addition of EMImBF₄ can effectively improve the electrolyte performance， and the optimum molar ratios of MgCl₂-AlCl₃ to EMImBF₄ is 5∶1. MACCE electrolyte has superior electrochemical performances with a high ionic conductivity（ca. 3.94 mS/cm）， a low overpotential（ca. 59 mV）， a high Coulombic efficiency（more than 97.5%）， a high anodic stability［ca. 2.8 V（vs. Mg/Mg²⁺）］， and a long-term（more than 500 h） cycling stability. The analysis results demonstrate that a nanoparticles layer can be formed on the surface of Mg anode during cycling， which is helpful to improve the cycling stability. Moreover， MACCE displays good compatibility with the Mo₆S₈ cathode material. The Mo₆S₈|MACCE|Mg full cell delivers a discharge specific capacity of 64.4 mA∙h/g（12.88 mA/g， 0.1C）， which can retain ca. 73.2% even after 100 cycles. MACCE electrolyte is simple to be prepared， low cost， and can be applied to RMBs， which is of great significance to accelerate the commercial application of RMBs.



Rapid Room-temperature Synthesis and Tetracycline Adsorption of Novel Ga-based Metal-organic Gels

LIU Zhi, GU Junhong, LI Ningning, LIU Zhisheng, LIU Bin, LI Yangxue

2024, 45(5):  20230485.  doi:10.7503/cjcu20230485

Asbtract ( )   HTML ( )   PDF (3141KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

In this research， Ga-based metal-organic gels（Ga-TATB） were synthesized at room temperature through a rapid and simple strategy. Ga-TATB could effectively remove tetracycline（TC） from aqueous solution due to the large specific surface area， unique porous structure and excellent structural stability. The adsorption process of TC by Ga-TATB kept well to the pseudo-second-order kinetic model and the Freundlich isotherm model， and the maximum adsorption capacity could reach 149.92 mg/g at pH=6.00 and 25 ℃. Furthermore， the effect of solution pH， Ga-TATB dosage， ionic strength， coexisting inorganic ions， contact time and TC concentration on the adsorption process was systematically investigated， and the possible mechanism of Ga-TATB adsorption towards TC was proposed based on the experimental results. It is worth noting that the strong anti-interference ability and stable reusability make Ga-TATB a good application prospect in tetracycline antibiotic wastewater remediation.



Polymer Chemistry

Preparation and Oil-water Separation Performance of Superhydrophobic Porous Organic Polymers

GAO Changyuan, XIANG Tingting, CHEN Shixin, SUN Qiqi, WANG Jiale, ZHENG Guiyue, ZHAO Ziyi, LIU Ziyu, CUI Bo, YAN Zhuojun, BU Naishun, WU Yue

2024, 45(5):  20240061.  doi:10.7503/cjcu20240061

Asbtract ( )   HTML ( )   PDF (10770KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A superhydrophobic porous organic polymer denominated as LNU-40 was synthesized via a Suzuki coupling reaction of 4-（4，4，5，5-tetramethyl-1，3，2-dioxaborolan-2-yl）-N，N-bis［4-（4，4，5，5-tetramethyl-1，3，2- dioxaborolan-2-yl）phenyl］aniline， 3，6-dibromocarbazole， tetrakis（triphenylphosphine）-palladium， and N，N- dimethyl-2-（piperazin-1-yl）benzamide oxalate. LNU-40 possesses a specific surface area of 32 m²/g and manifests thermal stability. Dissolution or decomposition does not occur when it is dispersed in commonly encountered organic solvents. LNU-40 is characterized by a low surface energy and a water contact angle of 152.4°， demonstrating excellent resistance to acidic and alkaline environments. This property enables the fabrication of a superhydrophobic surface with outstanding self-cleaning capabilities. The superhydrophobic flexible fabric prepared with LNU-40 achieves a separation efficiency of over 90% for organic solvents and exhibits an oil adsorption capacity ranging from 3 to 8 times of its own mass. The superior adsorption and separation performance make it suitable for the treatment of oily wastewater containing organic solvents in industries such as petrochemicals， food， and pharmaceuticals.



Influence of Interface Adsorption on the Dewetting Kinetics of Polymer Liquid Films

ZHANG Yining, WEI Lai, SHI Tongfei, XU Lin

2024, 45(5):  20240046.  doi:10.7503/cjcu20240046

Asbtract ( )   HTML ( )   PDF (6687KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Polymer films have broad applications in coatings， optoelectronic devices and sensing devices， with their interface stability being a key factor significantly affecting these applications. During the application of these films， stability not only in air but also under various environmental conditions， including in water or organic solvents is required. To date， the systematic elucidation of the influence of solvent-restricted interface adsorption of polymer films on their stability has not been fully explored. In this work， focusing on linear polystyrene（LPS） films and 3-arm star-shaped polystyrene（3SPS） films， we explored the influence of polymer chain interface adsorption in confined systems on the interfacial stability of polymer solution films. We found in our experimental results that the polymer chains adsorbed on the substrate form a drag force， which drives the dewetting of the film and increases the resistance to film dewetting. As the annealing time increases， the adsorption of linear and 3-arm star-shaped chains on the substrate gradually increases， LPS and 3SPS films transit from instability to stability in acetone vapor， with the rim becoming stable during the film dewetting process， the dewetting speed gradually decreasing， and the equilibrium contact angle progressively decreasing. At the same annealing time， 3SPS films exhibit a lower dewetting speed in acetone vapor than LPS films， and after dewetting， 3SPS films on the substrate have a smaller equilibrium contact angle than LPS films， indicating that the capillary driving force of 3SPS films is less than that of LPS films.



Preparation of Acidic Ionic Liquids and Their Catalytic Performance in Synthesis of Biobased Poly（ethylene 2，5-furandicarboxylate）

ZHOU Qiao, ZHAO Yuanyuan, GUO Liying, SHI Yafei, ZHENG Rongrong

2024, 45(5):  20230488.  doi:10.7503/cjcu20230488

Asbtract ( )   HTML ( )   PDF (1650KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Five acidic ionic liquid catalysts， ［DA-2PS］［X］₂， were prepared， characterized and tested for their chemical structures， Brønsted acidity and thermal properties using a Fourier transform infrared（FTIR） spectrometer， a nuclear magnetic resonance instrument（¹H NMR）， an ultraviolet（UV-Vis） spectrosmeter， and a thermal gravimetric analyser（TGA）. The acidic ionic liquid catalysts were then used to replace conventional metal catalysts to catalyze the direct esterification of 2，5-furanodicarboxylic acid（FDCA） with ethylene glycol（EG） to poly（ethylene 2，5-furandicarboxylate）（PEF）， and the effect of the strength of Brønsted acidity on the catalytic performance was discussed， in which the ［DA-2PS］［HSO₄］₂ with the strongest Brønsted acidity had the best catalytic performance. The optimal parameters obtained from orthogonal tests are as follows： the catalyst dosage was 0.10% of the molar number of FDCA， the feeding ratio was n（EG）∶n（FDCA）=2∶1， the esterification temperature was 210 ℃， the polycondensation temperature was 240 ℃， and the polycondensation time was 6 h. Experiments were carried out under the optimal conditions process parameters， and the conversion rate of FDCA was 98.1%， the intrinsic viscosity of PEF was 0.63 dL/g， the number average molecular weight of PEF reached 25592. The structural characterization and thermal properties of PEF were tested by FTIR， ¹H NMR， TGA and differential scanning calorimetry（DSC） analyzer， and the results showed that the synthesized substance is the target product， and it had the comparable thermal properties to those of PEF synthesized by the traditional metal catalysts.