Molecular Catalysis
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2018
·
IF 0
Chaokun Yang,Mengshuai Liu,Jiaxu Zhang,Xin Wang,Yichen Jiang,Jianmin Sun
The cycloaddition of CO 2 to epoxides is an important reaction and has got increasing attention. In this work, a series of DBU-based ionic liquids (DILs) were synthesized via facile neutralization of superbase 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) with corresponding hydrogen bond donor acids, such as D(−)-tartaric acid (TA), malic acid (MA) and succinic acid (SA). The DILs cooperated with ZnI 2 were first evaluated in detail for catalyzing the coupling reaction of CO 2 with propylene oxide (PO), and DIL-1 exhibited obviously enhanced catalytic activity under 80 °C, 3 MPa and solvent-free conditions. The effects of reaction parameters on the activity for propylene carbonate (PC) synthesis were thoroughly investigated, and a possible synergistic catalytic mechanism was proposed. The catalytic system reported here could be separated by simple centrifugation from the products after reaction and then reused efficiently. Moreover, the catalytic system showed the advantages of simple synthesis, high catalytic activity, low cost, and substrate versatility for CO 2 conversion to cyclic carbonates.
研究领域:
化学工程
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催化材料科学
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DOI
CHINESE JOURNAL OF CHEMISTRY
·
2018
·Vol. 36
·期 4
·293-298
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IF 2.378
Wei Li,Weiguo Cheng,Xia Yang,Qian Su,Lihui Dong,Pan Zhang,Yunan Yi,Bin Li,Suojiang Zhang
In this work, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), and imidazole (MIM)-derived bromide ionic liquids (ILs) were synthesized and used to catalyze the cycloaddition reactions of carbon dioxide (CO 2 ) with several kinds of epoxides to form cyclic carbonates. The DBU derived bromide ionic liquid system was found to have the best catalytic activity among all the tested ILs. The influences of reaction conditions (including temperature, pressure and reaction time) on the reaction of CO 2 to propylene oxide (PO) were studied to show the best conditions of 120 °C, 1 MPa, 2.5 h catalyzed by 2 mol% DBU-derived bromide ionic liquid, with the conversion of PO and the selectivity of propylene carbonate (PC) reaching 99% and 99%, respectively. Under the optimum reaction conditions, the ionic liquid system could be reused at least five times without decrease in selectivity and conversion. NMR spectroscopy and DFT calculations were used to reveal the hydrogen-bond interaction between ionic liquids and reagent, based on which the reaction mechanism was proposed.
研究领域:
化学
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催化
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绿色化学
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材料科学
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DOI
高影响因子
CELLULOSE
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2018
·Vol. 25
·期 12
·6935-6945
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IF 3.809
Chen Huaxin,Yang Fahui,Du Jiehao,Xie Haibo,Zhang Lihua,Guo Yuanlong,Xu Qinqin,Zheng Qiang,Li Nanwen,Liu Yu
Abstract The transesterification reaction between cellulose and vinyl esters is regarded as a clean and facile strategy for the tunable synthesis of cellulose esters. In this study, a series of cellulose esters with degrees of substitution from 0.58 to 3.0 have been prepared successfully under mild conditions without adding any external catalysts when cellulose was dissolved in the 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/DMSO/CO 2 solvent system and then followed by adding equimolar amounts of long chain fatty, aromatic, branched and steric vinyl esters. The optimization study of different reaction parameters like reaction time, temperature and amounts of substrates demonstrates that the reaction can proceed smoothly even at room temperature. This is evidenced by a cellulose benzoate with a DS of 2.6 obtained when the reaction is performed at 25 °C in 4 h. The as-prepared cellulose esters structure has been confirmed by 1 H NMR, 13 C NMR and FTIR, and material thermal properties were evaluated by DSC and TGA for an in-depth understanding the relationship between the cellulose esters structure and properties. It is believed that the DBU not only acts as a reagent for the CO 2 -derivative dissolution of cellulose in DMSO, but also acts as an in situ organocatalyst for the subsequent transesterification reaction. Graphical abstract Cellulose esters have been prepared successfully at low temperature using long chain fatty acids, aromatic, branched and steric vinyl esters as acyl donors in the DMSO/DBU/CO 2 solvents system, and the DBU not only acts as reagents for the CO 2 -derivative dissolution of cellulose in DMSO, acts as an organocatalyst for the subsequent derivatisation.
研究领域:
材料科学
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化学工程
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有机化学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Chenjing Qu,Xiaolong Han,Haiyun Wang,Ruidong Wang,Yifei Zhang,Weiwei Sun,Ziqian Shi,Yuting Wang,Penggang Yin
The widespread use of poly(ethylene terephthalate) (PET) has led to severe environmental pollution and significant resource depletion. The depolymerization of waste PET into bis(2-hydroxyethyl) terephthalate (BHET) offers considerable potential for chemical recycling. Although conventional glycolysis faces challenges such as low degradation efficiency and high energy requirements, an efficient catalytic method was developed herein to convert postconsumer PET into BHET under milder conditions. The incorporation of the cosolvent dimethyl sulfoxide (DMSO) into the reaction system reduced the degradation temperature to 150 °C, significantly lower than the temperature observed without cosolvents, which exceeded 190 °C. Under optimized conditions, the combination of a metal catalyst and the organic nitrogen heterocycle 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) enabled complete depolymerization of PET within 90 min, yielding BHET at 80.11%. In addition, the recrystallized product was repolymerized into PET, enabling closed-loop resource recycling. Life cycle assessment (LCA) indicates that this closed-loop approach is not only technically feasible but also environmentally beneficial, reducing energy consumption by approximately 64.54% and greenhouse gas emissions by 37.32%. This strategy offers a practical low-carbon solution for the sustainable recycling of waste PET.
研究领域:
高分子化学
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催化
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绿色化学
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废弃物回收
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材料科学
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产品关联
DOI
高影响因子
ChemCatChem
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2024
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IF 3.8
Cong Luo,Haoru Tang,Houfang Lu,Kejing Wu,Yingying Liu,Yingming Zhu,Binshen Wang,Bin Liang
Graphical A high glycerol carbonate yield of 90 % is achieved by the one–pot reaction of CO 2 , propylene oxide, and glycerol catalysed by DBU–based PIL, which can be facilely recovered and steadily reused without deactivation. The development of efficient heterogeneous catalysts for upgrading CO 2 , a greenhouse gas, and glycerol (Gly), an untapped biomass resource, into glycerol carbonate (GC) remains a challenge. Herein, 1,8-diazabicyclo[5.4.0] undec–7–ene (DBU)–based poly (ionic liquid)s (PILs) were constructed for the one–pot synthesis of GC from CO 2 , Gly, and propylene oxide. Among them, P−DVB−DBUVBI–1 exhibited the best catalytic performance, achieving a GC yield of 90 % under optimal reaction conditions (100 °C, 6 h). The PIL catalyst was easily recovered and reused, as demonstrated by stable activity over five cycles. Density functional theory calculations showed that owing the strong positive charge delocalization ability of DBU onium, DBU–based PILs exhibit high nucleophilicity, which is the key to their efficient catalytic performance in the one–pot reaction.
研究领域:
化学
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材料科学
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环境科学
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催化
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DOI
高影响因子
Polymers
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2019
·Vol. 11
·期 6
·994
·
IF 3.164
Longming Jin,Jianyun Gan,Gang Hu,Long Cai,Zaiquan Li,Lihua Zhang,Qiang Zheng,Haibo Xie
Cellulose films are regarded as sustainable materials having wide applications in food packaging, separation, etc. Their preparation substantially relies on sufficient dissolution. Herein, various celluloses adequately dissolved in a new solvent system of carbon dioxide,1, 8-diazabicyclo [5.4.0] undec-7-ene and dimethyl sulfoxide (CO2/DBU/DMSO) were made in to films using different regeneration reagents. The films regenerated from ethanol and methanol presented homogeneous and smooth surfaces, while those from 5 wt % NaOH (aq.) and 5 wt % H2SO4(aq.) showed rough surfaces, as analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films regenerated from 5 wt % NaOH (aq.) and 5 wt % H2SO4(aq.) rendered cellulose II structures, while those regenerated from alcohols had amorphous structures as evidenced using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results. The films made of microcrystalline cellulose had a good light transmittance of about 90% at 800 nm with a tensile strength of 55 MPa and an elongation break of 6.5%, while those from wood pulp cellulose demonstrated satisfactory flexibility with a tensile strength of 91 MPa and an elongation break of 9.0%. This research reports a simple, environmental, and sustainable method to prepare cellulose films of good mechanical properties.Keywords:CO2;cellulose dissolution;cellulose films;regeneration
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
RSC Advances
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2021
·Vol. 11
·期 50
·31226-31234
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IF 3.361
Dapeng Li,Peng Zhang,Suxiang Ge,Guofu Sun,Qin He,Wenjun Fa,Yun Li,Juntao Ma
Exploring the environmentally friendly and low-cost synthesis strategies of phthalocyanine (Pc) crystals in just one step is an absolute challenge. The solvothermal synthesis of phthalocyanine crystals shows the advantages of high-quality crystalline products, facile reaction and purification, and low cost. Nevertheless, only a few metal phthalocyanine crystals have been successfully synthesized via solvothermal reactions. In this study, we found that the crystalline β metal-free phthalocyanine needles could be directly prepared via the tetrapolymerization of phthalodinitrile catalyzed by DBU in solvothermal reactions. Similar to the preparation of β-phthalocyanine crystals, the α metal-free phthalocyanine crystals with the specific multiply-laminated structures can be obtained through solvothermal reactions assisted by DBN. SEM characterization showed that the individual β metal-free phthalocyanine has a well-defined quadrangular shape with smooth faces. However, the α metal-free phthalocyanine exhibits a distinctive undulating surface morphology. Both phthalocyanines showed satisfactory thermal stability (from room temperature to about 300 °C), excellent resistance to acid/alkali solution, and fast photoelectric response properties (order of magnitude of response time, 10−6 s) as tested by TG-DSC and TPV, respectively. It is noted that ethanol was used as the reaction medium and the resulting phthalocyanine crystals can be facilely purified using hot ethanol to dissolve the impurities adsorbed on the surfaces of phthalocyanine crystals. Compared to the traditional methods, no re-crystallization operation was carried out for our method. To the best of our knowledge, this is the first report on the solvothermal synthesis of metal-free phthalocyanine crystals with controllable crystal form adjusted by DBU/DBN in one step.
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
GREEN CHEMISTRY
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2016
·Vol. 18
·期 9
·2871-2876
·
IF 8.506
Xi Liu,Shuai Zhang,Qing-Wen Song,Xiao-Fang Liu,Ran Ma,Liang-Nian He
A bifuncational catalytic system consisting of CaBr2 and 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) was developed for the efficient fixation of CO2 with epoxides to cyclic carbonates. Such a dual catalysis facilitates the reaction to proceed smoothly at atmospheric CO2 pressure, presumably due to the simultaneous activation of CO2 by DBU and epoxides by CaBr2. In addition, the activation role of CaBr2 was also studied using density functional theory (DFT) calculations. A plausible mechanism involving the DBU–CO2 adduct-assisted ring opening path and the bromide anion-promoted ring opening path is proposed, in combination with the activation of epoxides by the calcium cation. This process represents a simple, cost-effective and biocompatible route to obtain cyclic carbonates from CO2 under mild conditions, especially at atmospheric CO2 pressure.
研究领域:
化学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2024
·
IF 4
Qianqian Xing,Xiaoliang Jia,Shiyu Jia,Yongqin Qi,Yuqi Wang,Yingxiong Wang,Xianglin Hou
The traditional synthesis methods of cyclopropyl methyl ketone (CPMK) have some disadvantages such as low yield, slow reaction rate and unclear catalytic mechanism. To solve these problems, a new strategy is developed to synthesize CPMK from 5‑chloro-2-pentanone (CPE) using 1,8-diazabicyclo[5.4.0]undec‑7-ene (DBU). Experiment results show that the yield of CPMK reached a maximum of 96.5 % in DBU at 40 °C for 30min. The mechanism study shows that the hydrogen bond between DBU and CPE is the key to drive the deprotonation and cyclization of CPE. The hydrogen bond is formed between the N atom on C = N of DBU and the α-H on the methylene group associated with the carbonyl group on CPE. The catalyst DBU is converted into [DBUH] + Cl − , which can be reclaimed and recycled completely. The density functional theory (DFT) calculation confirmed the existence of molecular hydrogen bonds and proved that the hydrogen bond driving force is the key to the reaction. The hydrogen bond driven mechanism provides a new idea for the basic research of cyclization reaction.
研究领域:
有机化学
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催化反应
✓ 已验证
产品关联
DOI
高影响因子
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
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2014
·
IF 0.827
Hui-Xuan Chen,Lin-Jie Huang,Jin-Biao Liu,Jiang Weng,Gui Lu
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2021
·
IF 4.598
Wenhao Xiao,Hongli Xu,Jie Zhang,Yang Chen,Zhixian Dong,Anfu Chen,Jinbao Xu,Caihong Lei
The characteristics of brush copolymers enable them applicable materials in catalysis, pharmaceutical and compatibilizer, and the scope of the application could be greatly expanded through the regulating of grafted branches. In this manuscript, the one-shot orthogonal preparation of heterografted brush copolymers has been achieved successfully with 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as the catalyst of ring-opening polymerization (ROP) and ligand of atom transfer radical polymerization (ATRP), avoiding the tedious purification processes in the two-step procedure for the synthesis of heterografted brush copolymers. Well-defined brush copolymers with various contents of poly(trimethylene carbonate) (PTMC) and poly( tert -butyl methacrylate) (P t BMA) graftings have been successfully prepared and the range of this method was further evaluated with a variety of cyclic and vinyl monomers in one-shot. Amphiphilic brush copolymer has also been successfully prepared allowing for the formation of micelles in water through self-assembling.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2021
·
IF 5.909
Leizhi Zheng,Guoqiang Yang,Xingbang Hu,Zhibing Zhang
The capture and conversion of carbon dioxide (CO 2 ) into useful and valuable chemicals are receiving more and more research interesting. Herein, we designed a new and efficient route to synthesize methyl phenyl carbonate (MPC) via the carbonylation of phenol (PhOH) with CO 2 and methanol (CH 3 OH). PhOH and CH 3 OH react with 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) to form ionic liquids [DBUH][PhO] and [DBUH][CH 3 O]. The DBU-based ionic liquids exhibited outstanding performance in CO 2 capture and in situ conversion at room temperature. The reusability of the system had no obviously change after 6 cycles. This protocol provides a sustainable and environmentally friendly preferential technique for the production of MPC, and extends the chemical utilization of CO 2 .
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）