GREEN CHEMISTRY
·
2014
·Vol. 16
·期 6
·3218-3223
·
IF 6.852
Dongling Xue,Ying Mu,Yu Mao,Tiankui Yang,Zhilong Xiu
The production of biodiesel from soybean oil and ethanol was investigated in switchable-polarity solvent (SPS) media of DBU and ethanol. The highest biodiesel yield catalyzed by DBU could reach 97.9% under optimized conditions, i.e. ethanol–oil molar ratio: 12 : 1, DBU–oil molar ratio: 2 : 1, reaction temperature: 70 °C, reaction time: 2 h. According to the kinetic analysis, the reaction order of oil was estimated to be 0.7, the apparent activation energy was 16.763 kJ mol−1, the pre-exponential factor was 561.31 mol0.3 mL−0.3 min−1 using the Arrhenius equation for the first time, which explains the high efficiency of the DBU catalyst. The DBU-catalyzed transesterification in the DBU–ethanol switchable-polarity solvent offered an interesting alternative, which would be used to simplify the transesterification and separation to a single step.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2023
·
IF 16.5
Xingzong Dong,Guangye Liu,Zhaoan Chen,Quan Zhang,Yunpeng Xu,Zhongmin Liu
Compared with the rapid deactivation of the Pd/AC catalyst, an eco-friendly Pd-[DBU][Cl]/AC ([DBU][Cl], 1,8-diazabicyclo[ 5.4.0 ]undec-7-ene hydrochloride) catalyst with enhanced stability was synthesized and applied in the hydrochlorination of acetylene. The Pd-20[DBU][Cl]/AC catalyst exhibits 96.7% acetylene conversion and 98.9% selectivity of vinyl chloride within the 24 h evaluation under the conditions of T = 180 °C, GHSV(C 2 H 2 ) = 360 h –1 and V (HCl)/ V (C 2 H 2 ) = 1.2. The enhanced stability of the Pd-[DBU][Cl]/AC catalyst is attributed to the prevention of the reduction of Pd(II) to Pd(0), the inhibition of the formation of coke deposition on the catalyst surface, and the reduction of the loss of Pd species during the reaction. TPD characterization and DFT theoretical simulations confirmed that the PdCl 2 -[DBU][Cl] complex has stronger adsorption of HCl and weaker adsorption of C 2 H 2 and C 2 H 3 Cl compared to PdCl 2 . Furthermore, the catalytic mechanism of acetylene hydrochlorination over the PdCl 2 and PdCl 2 -[DBU][Cl] site was put forward based on theoretical simulations. The good activity and stability of Pd-20[DBU][Cl]/AC in the 60 h lifetime test indicates that it is likely to be a promising alternative to HgCl 2 catalysts.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Wentao Zheng,Jialing Chen,Yujiao Jia,Nengqi Sun,Shiping Wang,Xianku Wu,Xuehua Zhang
A series of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)/N-heterocyclic DESs aqueous solutions were designed and synthesized as CO 2 capture agents. They showed excellent performance in absorption capacity, especially for the low-pressure CO 2 . The CO 2 loads in the absorbents were higher than 1.0 mol/mol when the pressure was just 0.1 bar. Through a combination of 13 C NMR spectra, FT-IR spectra and absorption experiments, a novel absorption mechanism was proposed. It was the shuttling role of the carbamate generated from CO 2 and nitrogen heterocycles, along with the synergistic roles of the DBU and water, that caused the high absorption capacity of the DBU/N-heterocyclic DESs for CO 2 . Meanwhile, the thermodynamic parameters, the activation energy and the regeneration efficiency were all measured to estimate the absorption performance of the DBU/N-heterocyclic DESs aqueous solutions for low-concentration CO 2 .
研究领域:
化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLUTION CHEMISTRY
·
2020
·Vol. 49
·期 3
·257-271
·
IF 1.273
Zhu Xiao,Song Mengling,Ling Baoping,Wang Sihan,Luo Xiaoyan
Abstract A novel anion-functionalized protic ionic liquid (IL), [DBUH][Triz], has been synthesized from 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) and 1,2,4-triazole (Triz). Density ( ρ ) and viscosity ( η ) of [DBUH][Triz] at different temperatures have been measured and the influence of temperature has been analyzed quantitatively. Then, the applications of [DBUH][Triz] in CO 2 absorption have been investigated. It has been detected that this ionic liquid, which was easily prepared, shows excellent reversibility and a high absorption capacity, about 1.5 mol CO 2 per 1 mol of IL (about 0.3 g CO 2 per 1 g of IL). In addition, the influence of temperature, pressure and moisture on the absorption performance of [DBUH][Triz] has been studied separately, indicating that absorption is promoted by lower temperature and higher CO 2 pressure. In addition, the mechanism of chemical absorption at two active sites has been deduced based on quantum-chemical calculations and 13 C NMR spectra coupled with IR spectra. Furthermore, the equilibrium constant of chemical absorption ( K ) was calculated from the CO 2 capacity at different temperatures ( T ) and a good linear relationship between the natural logarithm of the equilibrium constant ln K and 1/ T was obtained with R 2 of 0.996. From the slope and intercept of the fitted straight line, the molar reaction enthalpy change (Δ r H m ) and molar reaction entropy change (Δ r S m ) were analyzed, indicating that the capture of CO 2 is an exothermic process and the IL–CO 2 complex is less ordered than the pure ionic liquid. Graphic Abstract
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 15
·13054-13064
·
IF 3.201
Qingwen Gu,Jian Fang,Zichen Xu,Wenxiu Ni,Kang Kong,Zhenshan Hou
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) is an effective nucleophilic catalyst for the transesterification of dimethyl carbonate (DMC) with various alcohols and amines, which afforded unsymmetrical organic carbonate and carbamate. It was observed that the transesterification was accelerated under pressurized CO2 in this work. The activity is very high and the best result (89% conversion with 98% selectivity to unsymmetrical carbonate) was obtained for the DBU/alcohol/DMC/CO2 system. The addition of CO2 to DBU/ethanol generated the DBU cation salt, [DBUH][OCOOCH2CH3], which dissociated more favorably under increasing reaction temperature even under pressurized CO2. The salt could also help to activate DMC by H-bond interaction. The reaction system can be extended easily for the catalytic synthesis of carbamates from amines and DMC. After the reaction, the salt was separated from the reaction mixture and DBU can be recovered by the feasible thermal decomposition, offering a straightforward strategy for the recycling of DBU. On the basis of these results, a plausible mechanism involving the role of both DBU and CO2 has been proposed.
研究领域:
化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Lu Li,Sihong Xu,Liang Jin,Wenxing Chen,Shichang Chen
It is essential to find a depolymerization system with good catalytic activity, easy operation, and high efficiency for the degradation of waste PET. The synergistic catalytic effect of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and zinc 2-ethylhexanoate (ZnEH) in PET glycolysis was investigated. Waste PET can be more efficient when completely degraded than single organocatalyst or zinc salt or previous DBU/Zn(OAc) 2 , and the yield of BHET reaches 84.1 % under optimal reaction conditions with the molar ratio of 2:1 of DBU to ZnEH and the weight ratio of 3:1 of EG to PET, the temperature of 180 °C and at 60 minutes. By combining experimental results with density functional theory (DFT) calculations, the synergistic enhancing degradation mechanism that generates hydrogen and coordination bonds is proposed. The purified depolymerization product of BHET was repolymerized to PET, delightfully the r-PET was almost identical to virgin PET.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2018
·
IF 1.712
Ying Qing,Houfang Lu,Yingying Liu,Changjun Liu,Bin Liang,Wei Jiang
The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene (DBU) is developed in this work. Crude glycerol containing DBU and DBU/glycerol/CO 2 (DGC) ionic compounds reacts directly with dimethyl carbonate (DMC) to produce high value-added glycerol carbonate (GC) catalyzed by DBU and DGC. The catalytic performance of DBU and DGC, as well as the kinetics of the reaction catalyzed by DBU, were investigated. The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC. When the temperature is higher than 60 °C, DGC catalyzes the reaction jointly with DBU, which is produced from the decomposition of DGC. DBU has a good catalytic effect on the reaction between glycerol and DMC, with 90% conversion of glycerol and 84% selectivity to GC under the following conditions: DMC-to-glycerol molar ratio of 3:1, 4.0% DBU (based on glycerol mass), reaction time of 60 min, and reaction temperature of 40 °C. The apparent kinetics results show that the activation energies are 30.95 kJ·mol − 1 and 55.16 kJ·mol − 1 for the forward and reverse GC generation reactions, respectively, and the activation energy of the decomposition reaction of GC to glycidol (GD) is 26.58 kJ·mol − 1 .
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yun Li,Houfang Lu,Yingying Liu,Kejing Wu,Yingming Zhu,Bin Liang
Nano-SiO 2 was used to enhance the performance of CO 2 absorption and desorption in viscous DBU-glycerol solution with a viscosity of about 60 mPa·s. The effects of ultrasonic time in the preparation of nanofluids, solids loading and particle/cluster size of SiO 2 on absorbent properties and absorption performance were investigated. Meanwhile, the enhancements of heat transfer and mass transfer with nanoparticles in the desorption of CO 2 -loaded DBU-glycerol solutions were also analyzed. Proper ultrasonic vibration time and nano-SiO 2 loading can both decrease the average particle size in the system which can improve the absorption. The increase of interfacial area between gas and liquid with the addition of nano-SiO 2 dominates the enhancement of absorption and it has little effect on the enhancement factor when the nano-SiO 2 size is 102 nm or below. But when the particle size is higher than 102 nm, the enhancement factor decreases with the increase of particle/cluster size. The addition of 0.10 wt% SiO 2 nanoparticle with a particle size of 16 nm can increase the absorption rate by 31 % compared with base liquid. In desorption process, the desorption rate for CO 2 -loaded DBU-glycerol solutions can increase 18 % with the addition of 0.10 wt% nano-SiO 2 with a particle size of 32 nm. The main reason could be that nano-SiO 2 can improve the heating rate of the base fluid and supply plenty of nucleation sites for the formation of bubbles to improve the desorption rate. It shows that nano-SiO 2 can be used to enhance both the absorption and desorption processes in solutions with high viscosity.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2017
·Vol. 25
·期 1
·205-216
·
IF 3.417
Xu Qinqin,Song Longchu,Zhang Lihua,Hu Gang,Chen Qin,Liu Enhui,Liu Yu,Zheng Qiang,Xie Haibo,Li Nanwen
The reversible reaction of the hydroxyl groups in cellulose with CO 2 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) results in a rapid and effective derivative dissolution of cellulose in DMSO, by which a series of cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) with various degrees of substitution (DS) were synthesized controllably without adding external catalysts. Wherein DBU not only achieves the dissolution of cellulose, but also acts as an efficient organocatalyst for the subsequent cellulose derivatization. The DS of CAB and CAP can be tuned by changing the feed molar ratio of propionic (butyric) anhydride/acetic anhydride and the reaction temperature. The structural and thermal properties of the products were characterized by several analytical techniques including NMR, FT-IR, and TGA. The CO 2 /DBU/DMSO dissolution system provides a new platform for controllable synthesis of mixed cellulose esters with high efficiency under mild conditions.
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 39
·e202301413
·
IF 2.1
Tingting Chen,Yingjie Xu
Graphical A strategy to improve CO 2 capture of AmimCl-TEG DESs is proposed, that is addition of equimolar DBU to DESs, then H-bonds between DBU and O−H of TEG cause TEG to deprotonate to anion and react with CO 2 , and the CO 2 absorption capacity by DESs-DBU is up to 2.94 mol kg −1 and is 11 times that of pure DESs, and the interaction of DESs with CO 2 changes from physisorption to chemisorption. Microstructure of deep eutectic solvents (DESs) based on EmimCl or BmimCl ionic liquid (IL) and triethylene glycol (TEG) was studied by FT-IR spectra. The influence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) on CO 2 absorption behavior and mechanism of DESs was investigated. FT-IR spectra of pure EmimCl-TEG and BmimCl-TEG DESs show that O−H⋅⋅⋅Cl − hydrogen bond interaction formed by IL and TEG gradually strengths with the increase in the molar ratio of IL to TEG, resulting in a corresponding increase in viscosity. Due to the lack of a chemical interaction site, the CO 2 absorption capacity of pure DESs at 313.2 K and 1.0 bar is only between 0.15 and 0.56 mol kg −1 . Surprisingly, the addition of equimolar DBU to DESs can significantly improve the CO 2 absorption capacity, which is up to 2.94 mol kg −1 at the maximum and similar to that of amine-functionalized DESs. CO 2 absorption mechanism characterized by FT-IR spectra indicates that DBU can form hydrogen bond with O−H of TEG, which leads to deprotonation of O−H of TEG into basic anion under the synergistic effect of O−H⋅⋅⋅Cl − hydrogen bond to achieve efficient CO 2 chemisorption via carbonate formation. The obtained results provide a strategy for effectively improving the CO 2 capture capacity of EmimCl-TEG and BmimCl-TEG DESs.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Zhaoyang Qi,Songyu Li,Yaxin Cai,Rongkai Cui,Jie Chen,Changshen Ye,Ting Qiu
Methyl ethyl carbonate (EMC) is the primary raw material for the electrolyte of lithium-ion batteries. It is mainly prepared by the transesterification reaction of dimethyl carbonate (DMC) and EtOH. However, homogeneous alkaline catalysts such as sodium alcohol commonly used in industry are easy to deactivate and challenging to separate and recover. Therefore, the alkaline ionic liquid decorated zeolitic imidazolate frameworks (IL@ZIFs) heterogeneous catalysts were prepared using a simple method with DBU as an inducer. In the synthetic route of IL@ZIFs, the ligand of ZIFs can form an ionic liquid with DBU, and deprotonated ligands will rapidly coordinate with metal ions at room temperature. The DBU can also play the structural guidance and stabilizer, which is conducive to the rapid and effective preparation of ZIFs materials. Meanwhile, the DBU, which has a large molecular diameter, will be trapped in the pore cage and can combine with other protic materials (imidazole, triazole, 2-methylimidazole, phenol, etc.) to form alkaline ionic liquids. The prepared DBU-IL@ZIFs were used as heterogeneous catalysts for synthesizing EMC by transesterification reaction. The DBU-PO@ZIF-8 composite with phenol as anion has better catalytic activity. Under the appropriate reaction conditions, the yield of EMC can reach 55.7% with high selectivity of 94.7%. The catalytic mechanism of DBU-PO@ZIF-8 in the transesterification reaction was also explored and revealed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Mengshuai Liu,Jiao Guo,Yongqiang Gu,Jun Gao,Fusheng Liu
The application of ionic liquids in chemical recycling of waste polycarbonate (PC) via the simple hydrolytic strategy has shown great potential. Herein, a series of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) based ILs were facilely synthesized and characterized, and could efficiently catalyze the hydrolysis of PC in the absence of transition metal and solvent. The catalyst structures and reaction conditions were optimized, and 100% PC conversion with 97% bisphenol A (BPA) yield could be obtained under the conditions of n (H 2 O)/ n (PC) = 3:1, n (Cat.)/ n (PC) = 0.1:1, 140 °C for 3.0 h. Based on the experimental results and in-situ FT-IR analysis of the PC residues and BPA product, a feasible molecular activation and catalytic pathway for [HDBU][LAc] catalyzed hydrolysis of PC was proposed.
研究领域:
化学
·
环境科学
·
材料科学
✓ 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）