ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Yong-Bo Liu,Li-Mei Peng,Rui-Ying Bao,Ming-Bo Yang,Wei Yang
Because of its rather low melt strength, polylactide (PLA) has yet to fulfill its promise as advanced biobased and biodegradable foams to replace fossil-based polymer foams. In this work, PLA vitrimers were prepared by two-step reactive processing from commercial PLA thermoplastics, glycerol, and diphenylmethane diisocyanate (MDI) using Zn(II)-catalyzed addition and transesterification chemistry. The transesterification reaction of PLA and glycerol occurs with zinc acetate as the catalyst, and chain scission will take place due to the alcoholysis of the PLA chains by the free hydroxyl groups from the glycerol. Long-chain PLA with hydroxyl groups can be obtained and then cross-linked with MDI. Rheological analysis shows that the formed cross-linked network can significantly improve melt strength and promote strain hardening under extensional flow. PLA vitrimers still maintain the ability of thermoplastic processing via extrusion and compression. The enhanced melt strength and the rearrangement of network topology facilitate the foaming processing. An expansion ratio as large as 49.2-fold and microcellular foam with a uniform cell morphology can be obtained for PLA vitrimers with a gel fraction of 51.8% through a supercritical carbon dioxide foaming technique. This work provides a new way with the scale-up possibility to enhance the melt strength of PLA, and the broadened range of PLA applicability brought by PLA vitrimers is truly valuable in terms of the realization of a sustainable society.
研究领域:
材料科学
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化学工程
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可持续发展
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DOI
PubMed
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 14
·9347-9352
·
IF 3.9
Yu-Fen Bao,Yi-Jie Wang,Yu-Chen Wang,Ding-Hua Liu
In the synthesis of dimethyl carbonate (DMC) by transesterification, CH3ONa has been commonly applied as a homogeneous catalyst due to its high catalytic activity, but its stability is unsatisfactory. Here, by studying the influence of ionic liquid base strength on transesterification, we prepared an organic base catalyst, potassium imidazole (KIm), with high catalytic activity and stability, which solved the problem of catalyst deactivation in transesterification. The results showed that when KIm was used in the synthesis of DMC from propylene carbonate (PC) and methanol (MeOH), the chemical equilibrium could be reached within 3 minutes and the yield of DMC reached 73.03%, indicating that KIm performed better in transesterification than the majority of previously reported catalysts. In addition, the activity of the catalyst had hardly decreased after ten cycles of reaction, which can well meet the requirements of industrial production.
研究领域:
化学工程
·
催化科学
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产品关联
DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Zhixing Huang,Yujie ChenYang,Xiaohang Wang,Rui Cai,Benyong Han
In this study, twelve choline-based amino acid ionic liquids ([Cho][AA]-ILs) were synthesized employing amino acids and choline as raw materials. [Cho][AA]-ILs were effectively employed as catalysts in the biodiesel preparation via the transesterification of soybean oil with methanol. Among the synthesized [Cho][AA]-ILs, cholinium arginate ([Cho][Arg]) was selected as the appropriate catalyst. To optimize the primary experimental reaction conditions (methanol to oil molar ratio, catalyst load, reaction temperature, and reaction time), an experimental design was achieved by the A response surface methodology (RSM) based on the Box-Behnken design (BBD). The maximum biodiesel conversion of 98.58% was achieved with the [Cho][Arg] catalyst under the following optimal conditions: methanol to oil molar ratio of 9.13:1, catalyst load of 14.75%, a reaction time of 56.44 min and temperature 81.41 °C. A first-order kinetic of [Cho][Arg]-catalyzed transesterification of soybean oil with methanol was shown with activation energy and a pre-exponential factor of 10.06 kJ·mol −1 and 1.1707 min −1 , respectively. The ionic liquid [Cho][Arg] is a promising, easy to synthesize, and biodegradable catalyst that can replace traditional catalysts for the synthesis of biodiesel.
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2017
·
IF 3.531
Qiang He,Qing Zhang,Shurui Liao,Changsheng Zhao,Xingyi Xie
An overall picture of the reaction pathways towards the side products and final polymers during the transesterification synthesis of biodegradable aliphatic carbonates (APCs) were delineated for the first time. Catalysed by sodium ethoxide, the normal reaction between α,ω-diols (carbon number n = 2–6) and diethyl carbonate generates APC oligomers with propagating terminal alkoxide anions. These anions can backbite at the nearest carbonate carbons or the nearest carbonate α-CH 2 carbons in the same APC chains, eliminating corresponding cyclic carbonates or cyclic ethers. Also, each alkoxide anion can randomly attack a carbonate α-CH 2 carbon in another APC chain, generating ether linkages in the final polymers whose percentages are about 100%, 1.35%, 0.08% and 0% for n = 2, 3, 4 and 5, respectively. The content of cyclic carbonates shows a similar decreasing trend; ethylene carbonate (n = 2) even predominates over the final polymer while trimethylene carbonate (n = 3) and 1,4-butylene carbonate (n = 4) are only minor by-products. Moreover, the latter two cyclic carbonates are not stable enough and can further decarboxylate, forming relatively high amount of allyl alcohol and tetrahydrofuran, respectively. However, trimethylene oxide (n = 3) and tetrahydropyran (n = 5) are minor cyclic ethers. The thorough understanding of the chemical process is essential to improve the APC synthesis.
研究领域:
化学
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材料科学
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DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 23
·13048-13053
·
IF 2.936
Wei Liu,Feifei Duan,Yanlan Bi
Epoxidized soybean oil methyl esters were prepared via transesterification of epoxidized soybean oil (ESBO) with methanol catalyzed by cheap and stable sodium hydroxide (NaOH). The transesterification could be completed in only 5 min at room temperature (25 °C) without loss of the epoxide function and the transesterification rate was promoted significantly while the utilization of 5% acetone as co-solvent. The afforded products epoxidized methyl esters represent a renewable substrate that is readily converted into surfactants, fuel additives and other valuable industrial products.
研究领域:
化学工程
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可再生资源利用
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工业化学
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DOI
PubMed
高影响因子
PROCESS BIOCHEMISTRY
·
2020
·
IF 2.952
Jian Ou,Xin Yuan,Yu Liu,Panliang Zhang,Weifeng Xu,Kewen Tang
Enzyme immobilization in MOFs offers retained enzyme integrity and activity, enhanced stability, and reduced leaching. In this work, Pseudomonas cepacia lipase (PCL) was successfully immobilized into the Zeolitic imidazolate framework-8 (ZIF-8) by physical adsorption. The amounts of PCL in the immobilized enzyme (PCL@ZIF-8) was determined to be 16.7 % (200.5 mg PCL/g ZIF-8). Furthermore, the immobilized enzyme was applied as efficient bio-catalyst for enantioselective hydrolysis of 2-phenylpropionic acid (2-PPA) ester enantiomers and enantioselective transesterification of 1-phenylethanol enantiomers. The enzymatic activity of the immobilized enzyme was three times more than that of free PCL in enantioselective hydrolysis system, and the enantiomeric excess was maintained above 99 %. There was no significant difference in enzyme activity between immobilized PCL and free PCL in transesterification system. In addition, the immobilized enzyme showed good reusability in both hydrolysis (30.57 % of initial activity, 4 cycle) and transesterification reaction systems (64.38 % of initial activity, 6 cycle).
研究领域:
生物化学
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酶工程
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材料科学
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DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2019
·
IF 3.074
Qi Fu,Qiming Yan,Xiang Jiang,Heqing Fu
Dynamic combinatorial chemistry (DCC) involves reversible reactions which can be controlled by thermodynamics method . Transesterification is one of the most widely explored DCC reactions. In this paper, transesterification was used to synthesize self-healing network. First, a three-arm star -shaped hydroxyl-terminated polyglycolide (HTPG) was fabricated though the ring-opening polymerization (ROP) of glycolide by using triethanolamine (TEA) as initiator and tetrabutyl titanate (TBT) as catalyst. Then the self-healing network i.e. isocyanate-based crosslinked star -shaped polyglycolide (ICSPG) was prepared through the crosslink between hexamethylene diisocyanate trimer (HDIT) and HTPG. In order to explore the mechanism of the self-healing, a polyurethane based on a tri-functional polyether polyol (PPPU)was synthesized. The structures of HTPG, ICSPG and PPPU were characterized by fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy ( 1 H NMR). The mechanical properties and self-healing properties were characterized by dynamic mechanical thermal analysis (DMTA) and polarizing optical microscopy (POM). And the welding test was used to further characterize the self-healing properties of ICSPG. It was found that mechanical recovery is about 70%. The POM results showed that ICSPG exhibited self-healing properties at high temperature.
研究领域:
材料科学
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聚合物化学
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自愈合材料
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动态组合化学
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 30
·e52676
·
IF 3.057
Jie Li,Shufen Zhang,Benzhi Ju
Most of the vitrimers based on transesterification (TE) highly rely on the usage of large amounts of catalysts to promote exchange reactions to obtain re-processability, which brings additional concerns on human health or environmental issues. Herein, we demonstrate that TE vitrimers with soft networks (low T g ), though free of catalysts nor any other special design, can be still dynamic enough to be easily re-processed. In this paper, fully bio-based and catalyst-free thermosets from epoxidized soybean oil (ESO) and bio-dicarboxylic acids (DA) were synthesized and found to possess decent re-processability. By means of compressive remolding (10 MPa, 160°C), the ESO-DA thermosets heal visible defects within 30 min and restore the mechanical strength within 3 h. Upon 3 times of mechanical recycling, the mechanical strengths remain nearly unchanged compared with those of pristine thermosets. Stress relaxation experiments confirm the network rearrangement at high temperatures (≥150°C) as well as vitrimeric flow of the materials. The materials are also capable of being welded without solvents under a small pressure. Lastly, a facile fusion method was employed to tune the mechanical strength of the recycled ESO vitrimers.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2026
·Vol. 65
·期 34
·18145-18158
·
IF 3.9
He Yiruo,Su Weiyi,Song Jianheng,Liu Qidong,Wang Na,Yu Xiong,Wang Honghai
The
combination of immobilized enzymes and microreactors offers
great advantages in green biomanufacturing. However, improving the
catalytic loading and reusability of immobilized enzymes remains a
challenge. This study developed a magnetically separable immobilized
enzyme system for continuous-flow biocatalysis. Candida antarctica lipase B (CALB) was covalently immobilized onto polydopamine-modified
Fe 3 O 4 nanoparticles to prepare a magnetic nanoimmobilized
enzyme (CALB@PNMNs). Compared to free enzymes, CALB@PNMNs exhibited
enhanced stability in organic solvents and storage stability. CALB@PNMNs
microreactor was constructed, with CALB@PNMNs immobilized on its inner
walls by an external magnetic field. This layer of magnetic particles
allows for the convenient recovery and reuse of the catalyst by removing
the applied magnetic field. After optimizing the immobilization process,
the actual CALB loading per unit area was 0.30 mg/cm 2 ,
and the adsorption yield reached 86.89%. The microreactor was applied
to the transesterification of n -butanol and ethyl
acetate, with the optimal conditions identified as an alcohol–ester
ratio of 1:3, a total flow rate of 10 μL/min, and a reaction
temperature of 60 ° C, yielding an n -butanol
conversion of 63.72%. After short-term continuous operation for 6
h, the microreactor retained 87.63% of the enzyme adsorption capacity
and CALB@PNMNs maintained a n -butanol conversion
above 50% after 8 reuse cycles. This work has established a stable
magnetically controlled immobilized enzyme microreactor (IMER) platform,
offering application potential for continuous-flow bioprocesses.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Yidong Zhou,Zhijian Ke,Jiazhuo Zhang,Wenbin Chang,Yarong Cui,Yimiao Chen,Yirui Huang,Chunli Xia,Wenjia Zhong,Zifa Deng,Dayong Jin
Microorganisms are constantly evolving to resist the toxicity of artificial antibiotics and preservatives released into the environment. Parabens, a group of alkyl and aryl esters of p -hydroxybenzoate, are a class of widely used antimicrobial preservatives, particularly effective against Gram-positive bacteria and fungi. Previous studies have reported the degradation of parabens by numerous Gram-negative strains and activated sludge, with degradation processes often involving transesterification. However, the physiological significance of transesterification has received little attention. Here, a Gram-positive bacterium, Microbacterium sp. S1037 was isolated and characterized for its ability to degrade eight parabens and completely mineralize them through p -hydroxybenzoate and protocatechuate ( β -ketoadipate pathway). Moreover, strain S1037 also possesses the ability of paraben-transesterification. Alcohols compete with water molecules for the active center of enzymes, accelerating the transesterification of parabens and inhibiting hydrolysis. Considering that the fate of the transesterification product is still hydrolysis, we speculated and proved that such a “superfluous” mechanism is a detoxification strategy, and could be used in the bioremediation of parabens in wastewater. Microbial transesterification of parabens has been reported worldwide, and we speculated that it might be a common detoxification choice in the evolution of microorganisms worldwide.
研究领域:
微生物学
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环境科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Xiangsheng Zheng,Xiaohong Hao,Yan Wang,Siyu Gao,Dantong Wen,Jinchuan Wang
The development of novel biocatalysts is essential to promote the commercialization of biodiesel production by transesterification reaction. In this paper, Rhizopus oryzae lipase (ROL) was immobilized on an amino-functionalized zirconium-based metal organoskeleton by interfacial adsorption. The immobilization conditions were optimized and the enzymatic properties were tested, and the resulting novel biocatalysts exhibited higher stability and heat resistance. SEM, XRD and BET analyses were used to characterize the biocatalysts and carrier materials. The catalytic performance of ROL@UiO-66-NH 2 in the production of biodiesel by transesterification reaction was explored, and the production process was optimized by response surface method. The results showed that the conversion rate of FAEE reached 82.05% at molar ratio of ethanol/oil of 15.43:1, reaction temperature of 50.28°C, reaction time of 120.9 min, DES addition of 48.08 wt%, biocatalyst addition of 3 wt%, and ultrasonic power of 90 W. In addition, ROL@UiO-66-NH 2 demonstrated good recyclability, with the catalytic efficiency remaining at 71.87% after five cycles.
研究领域:
生物化学
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催化材料
·
可再生能源
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产品关联
DOI
高影响因子
Polymers
·
2025
·Vol. 17
·期 17
·2387
·
IF 4.9
Haidan Lin,Kai Dong,Jingyao Luan,Chenggang Li,Di Zhao,Chengji Zhao,Xuefeng Li
Developing high-performance bio-based epoxy resins as sustainable alternatives to petroleum-derived bisphenol A (BPA) epoxies for recyclable carbon fiber-reinforced polymers (CFRPs) is pivotal in materials research. Herein, the bio-based bisphenol monomer BDEF was synthesized from the lignin derivative 4-propylguaiacol. The derived epoxy monomer BDEF-EP was cured with adipic acid to form a bio-based vitrimer. Stress relaxation synergistically accelerates through intrinsic dynamic carboxylic acid ester exchange and enhanced chain mobility from the flexible propyl structure. At 220 °C, this vitrimer shows rapid stress relaxation (τ* < 30 s) and repairs ~90% of surface scratches in 30 min. It exhibits tensile and flexural strengths of 69 MPa and 105 MPa, respectively. BDEF-EP’s low viscosity reduces diluent needs in composite fabrication, lowering costs and improving efficiency. The resulting bio-based CFRP achieves tensile and flexural strengths of 543 MPa and 414 MPa, respectively, which are comparable to commercially available petroleum-derived CFRP. In addition, CFRP containing dynamic crosslinked networks demonstrates degradable recyclability in ethylene glycol solvent, preserving the surface morphology and chemical structure of recovered carbon fibers. The results demonstrate that this bio-based epoxy vitrimer has promising potential for developing sustainable, degradable, and recyclable CFRP composites.
研究领域:
材料科学
·
高分子化学
·
可持续工程
·
复合材料技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）