JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2023
·
IF 2
Miao Qiao,Xin Hua,Yongjun Yuan,Xi Cao
This work attempts to achieve the enrichment of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in acylglycerols as well as biodiesel production by investigating the performance of various lipases in ethanolysis. The ethanolysis activities of five immobilized lipases in decreasing order were as follows: Lipozyme TL IM, Novozym 40086/Lipozyme RM IM, Novozym 435 and Rhizopus oryzae lipase immobilized on polypropylene (RO PP). EPA could be enriched to a certain content by Lipozyme TL IM, Novozym 40086, Lipozyme RM IM, and RO PP. The enrichment of DHA was achieved well by those four sn -1,3 regioselective lipases, and DHA contents in acylglycerols were the highest when Lipozyme TL IM and Novozym 40086 were used, reaching 2.87-fold and 2.81-fold of the initial content. However, Novozym 435 could not enrich EPA and DHA effectively. Fatty acid ethyl esters produced in this work contained abundant palmitic acid and palmitoleic acid, which could be ideal biodiesel considering their chain length. The competitive factors of five lipases towards DHA were all significantly higher than those towards EPA. When Lipozyme TL IM and Novozym 40086 achieved the maximum DHA contents, their DHA recoveries in acylglycerols reached 91.87% and 89.00%, respectively. The DHA recoveries were all significantly higher than the corresponding EPA recoveries in the reactions catalyzed by five lipases. Moreover, Lipozyme TL IM could be a potential lipase for the separation of EPA and DHA. This study may promote the full use of fish oil and broaden the application of lipases.
研究领域:
生物化学
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食品科学
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酶工程
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产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 10
·2359
·
IF 5
Xiaohua Gu,Xiaoyao Wang,Xinyu Guo,Siwen Liu,Chunhua Lou,Yan Liu
In this paper, the high-efficiency degradation and alcoholysis recovery of waste polyurethane foam were realized using a combination of a high-efficiency alkali metal catalyst (CsOH) and two-component mixed alcoholysis agents (glycerol and butanediol) in different proportions, using recycled polyether polyol and one-step foaming to prepare regenerated thermosetting polyurethane hard foam. The foaming agent and catalyst were adjusted experimentally to prepare regenerated polyurethane foam, and a series of tests were conducted on the viscosity, GPC, hydroxyl value, infrared spectrum, foaming time, apparent density, compressive strength, and other properties of the degradation products of the regenerated thermosetting polyurethane rigid foam. The resulting data were analyzed, and the following conclusions were drawn: The optimal conditions of alcoholysis were obtained when the mass ratio of glycerol to butanediol was 3:2, the amount of cesium hydroxide was 0.08%, the reaction temperature was 170 °C, and the reaction time was 2.5 h. Regenerated polyurethane foam with an apparent density of 34.1 kg/m3and a compressive strength of 0.301 MPa was prepared under these conditions. It had good thermal stability, complete sample pores, and a strong skeleton. At this time, these are the best reaction conditions for the alcoholysis of waste polyurethane foam, and the regenerated polyurethane foam meets various national standards.Keywords:polyurethane foam;high-efficiency catalyst;recycling;glycolysis
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2024
·
IF 2.5
Yiyin Yang,Lei Zhang,Fansen Meng,Donglin Tang
ZnO is considered to be a good catalyst for the synthesis of polyurethanes (PUs) by alcoholysis of bisureas (BUs). ZnO tends to form Zn(NCO) 2 (NH 3 ) 2 in the presence of urea at high temperature, so does it in the alcoholysis of BUs. Here, attempt is made to understand the role Zn(NCO) 2 (NH 3 ) 2 plays in the alcoholysis of BUs. A loading of Zn(NCO) 2 (NH 3 ) 2 at 5 mol% is found to be sufficient to catalyze the polymerization and the reaction time is greatly cut from 40 h (catalyzed by ZnO) to 26 h, with similar chemical structures and properties. The tensile strength, elongation at break, and toughness for PU–Zn-5 can reach 43.8 MPa, 330%, and 94.0 J cm −3 , respectively. One-pot synthetic strategy is then further introduced to improve the efficiency of the polymerization. Zn(NCO) 2 (NH 3 ) 2 , BU, and PU can be synthesized in one-pot, by adding ZnO, urea, diamine, LiBr, and diol sequentially. The feasibility of this one-pot method is verified, indicated by the similar reaction time, chemical structures, molecular weight, thermal and mechanical properties. This one-pot synthetic strategy offers an efficient way to synthesize PUs directly and simply from urea, diamines, and diols, which is beneficial for improving the molecular diversity of PUs.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Chunrui Rong,Dongxia Yan,Jiabao Li,Jian Feng,Jiayu Xin,Qing Zhou,Yi Li,Junli Xu,Xingmei Lu
The increase in the usage of polyethylene terephthalate (PET) leads to the generation of a large amount of waste, which may cause carbon emissions and waste of petroleum resources. The methanolysis method has attracted global attention, but limited by high reaction temperature and excessive use of methanol. We report here an efficient catalyst, tetramethylguanidine/1,5-diazabicyclo[4.3.0]-5-non-ene (TMG/DBN), converting waste PET into regenerated dimethyl terephthalate (rDMT) under 100 °C with almost equivalent methanol, achieving 100 % PET conversion and 93.1 % yield of rDMT. A series of analytical methods and theoretical calculations were used to reveal the enhanced interaction between the catalyst and reactants, which facilitates the degradation of PET at low methanol dosages. In addition, a kinetic model was also developed with a relatively low activation energy of 84.9 kJ/mol. This work provides an effective strategy for the up-grading recycling of waste PET under mild reaction conditions.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 2
·413
·
IF 5
Jialin Xu,Kuo Zhou,Linlin Qin,Zaiming Tan,Shijing Huang,Peigao Duan,Shimin Kang
The chemical recycling of end-of-life polylactic acid (PLA) plays roles in mitigating environmental pressure and developing circular economy. In this regard, one-pot tandem alcoholysis and hydrogenation of PLA was carried out to produce 1,2-propanediol, which is a bulk chemical in polymer chemistry. In more detail, the commercially available Raney Co was employed as the catalyst, and transformation was conducted in ethanol, which acted as nucleophilic reagent and solvent. Single-factor analysis and Box–Behnken design were used to optimize the reaction conditions. Under the optimized condition, three kinds of PLA materials were subjected to degradation. Additionally, 74.8 ± 5.5%, 76.5 ± 6.2%, and 71.4 ± 5.7% of 1,2-propanediol was yielded from PLA powder, particle, and straws, respectively, which provided a recycle protocol to convert polylactic acid waste into value-added chemicals.Keywords:polylactic acid;alcoholysis;hydrogenation;1,2-propanediol;PLA straws
研究领域:
化学工程
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 13
·期 22
·6561-6569
·
IF 5
Songlei Mo,Yong Guo,Xiaohui Liu,Yanqin Wang
The glycolysis of polyethylene terephthalate (PET) is considered as the most promising PET recycling strategy due to its mild reaction conditions and circularity. Herein, several metal-doped SBA-15 (M/SBA-15) as heterogeneous Lewis acid catalysts were investigated to screen the best catalyst and to understand the essence for their differences in PET glycolysis. It is found that the catalytic activity is positively correlated with the acid amount in different metal-doped SBA-15 and Ti/SBA-15 with different Ti loadings, with the exception of Nb/SBA-15. 4Ti/SBA-15 with abundant Lewis acid sites shows excellent PET glycolysis ability, with the yield of bis(2-hydroxyethyl) terephthalate (BHET) reaching 87.2% within 45 min at 190 °C (isolated yield 73%). While 4Nb/SBA-15 has a similar acid amount as that in 4Ti/SBA-15, but it has very low catalytic activity probably due to its strong oxygen affinity. Acetone–methanol-adsorption DRIFTS confirms its strong oxygen affinity, which would poison the acid sites by ethylene glycol (EG) and result in very low activity. This study demonstrates that PET glycolysis activity is really correlated with the amount of Lewis acid sites, but species with very strong oxygen affinity would lower its activity. Further diffuse reflection ultraviolet-visible (DR UV-vis) spectra analysis confirms that tetrahedral Ti4+ species in Ti/SBA-15 is the real active center. In addition, 4Ti/SBA-15 has good reusability and can be used in common real PET (dyed polyester fabric, PET bottles) glycolysis. These results indicate that increasing the amount of Lewis acid sites is a promising way to enhance PET glycolysis and 4Ti/SBA-15 with high activity and stability is a potential catalyst for industrial application.
研究领域:
材料科学
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催化化学
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环境科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2024
·
IF 4.7
Yingdan Ye,Han Wang,Yibin Zhang,Huaiyuan Zhao,Weichen Du,Ping Chen,Zhaoyin Hou
Chemical upcycling of end-of-life plastics is an economically and environmentally feasible way to tackle plastics crisis. Among them, methanol alcoholysis of polylactic acid (PLA) is a promising approach, which can produce methyl lactate (MLA) that can be further converted to lactide to achieve a sustainable development. In this work, a series of WO x /ZrP catalysts with WO x active sites in low coverage and high surface area were synthesized via anchoring WO x species on the surface of zirconium phosphate (ZrP). Characterizations indicated that the strong interaction between WO x and ZrP promoted the formation of WO x active sites in low coverage. In particular, 10 %WO x /ZrP catalyst was highly active and stable for the alcoholysis of PLA plastics under mild conditions due to the abundant WO x active sites and strong acidity. The yield of MLA over 10 %WO x /ZrP catalyst reached 94.5 % within 4 h at 160 °C, which was superior to the performance of traditional solid acids ( α -ZrP, HZSM-5, H β and Amberlyst-45). In addition, 10 %WO x /ZrP was versatile for the alcoholysis of discarded PLA-based products and could be recycled at least five times. The prominent performance of 10 %WO x /ZrP catalyst and the possible reaction mechanism were discussed.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2024
·
IF 5.2
Yushuai Sang,Mingze Yang,Hong Chen,Yongdan Li
Catalytic lignin solvolysis (CLS) holds promise for efficient lignin utilization, yielding small molecules with minimal or no char formation. However, the role of different active sites of catalyst in CLS are rarely discussed. Here, Ni catalysts on different supports, i.e., SiO 2 , Al 2 O 3 , MgO, and ZrO 2 , were prepared with the aim of manipulating the relative importance of metal and acid-base functionalities to investigate the role of different active sites in the enzymatic hydrolysis of lignin (EHL) ethanolysis. The main ether linkage, i.e., β-O-4, in EHL is cleaved without the participation of a catalyst. Metal sites suppress repolymerization through hydrogenating active intermediates, while acid and base sites facilitate the conversion of phenolic monomers into complex alkylated and etherified products and also promote repolymerization reactions. Among the catalysts, Ni/SiO 2 demonstrated the highest hydrogenation activity and yielded the most monomers (24.7 wt %) at 280 °C for 6 h under 2 MPa H 2 in ethanol. These findings shed light on the catalytic mechanisms in CLS, offering valuable insights for future catalyst design.
研究领域:
化学工程
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催化科学
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生物质利用
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产品关联
DOI
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2022
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IF 6.056
Duan Zhou,Mouming Zhao,Jiankang Wang,Muniba Faiza,Xuefeng Chen,Junjie Cui,Ning Liu,Daoming Li
Punicic acid (PA)-enriched diacylglycerol (DAG) possesses both the beneficial effects of PA and DAG. However, few studies have focused on the preparation of PA-enriched DAG. Here, we report a novel and highly efficient method for the preparation of PA-enriched DAG through Lipozyme 435-catalyzed ethanolysis of pomegranate seed oil (PSO). Firstly, PSO was obtained through microwave-assisted extraction. Subsequently, four lipases were screened for their capability in the preparation of PA-enriched DAG through ethanolysis of PSO (containing 82.98% PA), and Lipozyme 435 was selected. Under the optimal conditions, the resultant mixture containing 32.86% DAG was obtained. Interestingly, Lipozyme 435 maintained superior operational stability after ten successive cycles. A scale-up reaction was then conducted under the optimized conditions and the purified product containing 51.83% DAG (containing 81.95% PA) was obtained. The final product with a low peroxide value (1.45 mmol/kg) and undetectable acid value reached edible quality. This is the first study for the preparation of PA-enriched DAG through ethanolysis and Lipozyme 435 exhibited superior capability and recyclability. Compared with other approaches for DAG preparation, this approach favored shorter reaction time and better quality of the product. This study provides useful information for further studies involving DAG preparation and modification of PSO.
研究领域:
食品科学
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生物化学
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DOI
高影响因子
GREEN CHEMISTRY
·
2021
·Vol. 23
·期 4
·1871-1882
·
IF 10.182
Xiaoling Qu,Guangyuan Zhou,Rui Wang,Bolei Yuan,Min Jiang,Jun Tang
Alcoholysis is a potential method for the degradation of polyesters to their precursor building blocks, which can then be polymerized again to form new qualified polyester materials. This method therefore makes recycling possible in a permanent polymer–monomer–polymer loop. In this study, a series of metal-free tetrabutylphosphonium-based ionic liquids (ILs) were prepared as catalysts for the methanolysis of poly(ethylene 2,5-furandicarboxylate) (PEF), which is well known as an ideal alternative to the petroleum-based plastic poly(ethylene terephthalate) (PET). It was found that anions with stronger electronegativity were more efficient for the methanolysis of PEF. By adjusting the structures of the anions and cations of ILs, 1-butyl-3-methylimidazole acetate ([BMIm][OAc]) exhibited excellent catalytic activity in the methanolysis of PEF. The optimization of reaction parameters enabled the [BMIm][OAc]-catalyzed methanolysis of PEF with nearly 100% PEF degradation and a 77.6% dimethyl furan-2,5-dicarboxylate (DMFD) yield at 130 °C for 30 min. Furthermore, [BMIm][OAc] could keep high-activity after using for six times under the optimum conditions. Assisting with 1H NMR, FT-IR and density functional theory (DFT) calculations, an in-depth study was performed on the feasible synergetic catalytic mechanism of [BMIm][OAc] for the methanolysis of PEF, induced by hydrogen bonds formed between reactants and [BMIm][OAc]. Finally, on the basis of experimental results and scanning electron microscopy (SEM), it was confirmed that PEF with the spiral motif could be degraded under milder conditions than PET. Therefore, this strategy of using adjustable cation and anion structures in ILs provides an opportunity to develop other more efficient ILs for the alcoholysis of furan-based polymers via a green and mild pathway.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2024
·
IF 3.8
Yanling Xu,Yi Ji,Yue Liu,Weihua Deng,Fei Huang,Fan Zhang
Graphical Here, we have developed an environmentally friendly and cost-effective catalyst for the alcoholysis of C−O-linked plastics. Our catalyst is made of polymeric carbon nitride nanosheets, which are free of metals. It has shown excellent performance in the methanolysis of polycarbonate (PC), polyethylene terephthalate (PET), and polylactic acid (PLA), producing pure monomer products. Through characterization and experiments, we have determined that the amino group is the main active site of the catalyst. Improper end-of-life treatments of C−O-linked plastics have caused serious environmental crises and resource waste. One effective method to solve this issue is the catalytic alcoholysis of these plastics. Traditional homogeneous catalysts or metal-based heterogeneous catalysts for alcoholysis have some drawbacks, such as difficulty in complete separation, environmental threats, and economic burden. Thus, finding a green, low-cost, recyclable, and highly efficient catalyst substitute is critical. Here, we reported that polymeric carbon nitride nanosheets can serve as a metal-free heterogeneous catalyst for the methanolysis of polycarbonate, polyethylene terephthalate, and polylactic acid. The catalyst exhibits remarkable performance and could be reused at least four times. NH x was found to be the predominant active site of the catalyst by characterization and experiments. These results show promise for the design of metal-free heterogeneous catalysts to depolymerize C−O-linked plastics.
研究领域:
材料科学
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环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Leqing He,Shuangbai Li,Chongpin Huang
In the context of composite materials that elude classification via conventional pretreatment methodologies such as crushing, granulating, and flotation—specifically within the domains of food packaging, construction materials, and engineering plastics—this research employed a one-step methanolysis-separation technique for the graded recycling of polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) in mixed plastics. Employing methanol as the reaction solvent, the benign and eco-friendly ionic liquid BMIMOH as the catalyst for the degradation of PET. PET was methanolized to produce dimethyl terephthalate (DMT), while PP and PE remained highly stable, were separated after the reaction, and subjected to subsequent recycling. The stability of PP and PE under methanolysis conditions was revealed through structural and thermodynamic analyses. Single-factor analysis and response surface methodology were employed to determine the optimal conditions for the methanolysis reaction. Additionally, the impact of different contents of PP and PE on the recovery of PET from the mixed plastics during the swelling-condensation process at high temperatures was explored. Under the optimal conditions, the yield of DMT was 94 % for the degradation of single PET, and when the ratio of PET in the mixed plastics was 50 %, the yield of DMT could still reach 90 %.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）