ChemistrySelect
·
2024
·Vol. 9
·期 4
·e202304217
·
IF 1.9
Jinfa Yu,Zhaoqin Luo,Xiangying Sun
Graphical NCDs-1, which is the first carbon dot by the microwave method using ethylenediamine and L-arginine, can serve as an efficient heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides with CO 2 and Knoevenagel condensation under mild and solvent-free condition. A simple and convenient method for catalytic reactions with amine-terminated carbon dots was developed. Carbon dots (CDs) as new efficient catalysts have been developed for the Knoevenagel condensation reaction and the synthesis of cyclic carbonates under solvent-free conditions. Six kinds of carbon dots with different numbers of amino groups were synthesized. The amine-terminated carbon dot (NCDs-1) was synthesized using arginine and ethylenediamine by a microwave technique, and its catalytic action was studied. NCDs-1 with the highest numbers of amino groups was used as new metal-free and effective heterogeneous catalysts to perform essential Knoevenagel condensation and cycloaddition reactions in solvent-free conditions. 1 H NMR was used to demonstrate the Knoevenagel condensation mechanism, in situ Fourier infrared spectroscopy was used to investigate CO 2 cycloaddition and a catalytic mechanism was postulated. NCDs-1 showed a yield of 96.3±1.5 % for Knoevenagel condensation of benzaldehyde and malononitrile. In addition, NCDs-1/TBAB showed a yield of (97.0±1.0 %) of 4-phenyl-1,3-dioxolan-2-one for styrene oxide at 100 °C and 0.1 MPa in 1.5 h. A simple and convenient method for catalytic reactions with amine-terminated carbon dots was developed.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Yuhao Zhang,Hui Wang,Dexin Sun,Liang Zhao,Jinsen Gao,Chunming Xu
The separation of olefin from aromatics and sulfides by using propylene carbonate (PC) solvent was studied by the ternary liquid–liquid equilibrium (LLE) of PC + aromatics/sulfide +olefin. The effects of aromatic, sulfide, and olefin structures were investigated by a combination of experiments and quantum chemical calculations. The aromatics and sulfides without side chains were easier to dissolve in PC. Efficient olefin separation was observed because the side chain did not change the positive charge enrichment region of the molecule, and instead increased the steric space when combined with solvent molecules. The olefin separation factor S in the separation of 1-hexene and thiophene is 12.96, which is 1.64 times higher than that in the separation of 1-hexene and 3-methylthiophene. In addition, the binary parameters between the PC and fluid catalytic cracking (FCC) naphtha components for NRTL and UNIQUAC thermodynamic models were obtained using the ternary LLE data to make up for the blank in Aspen simulation for the separation of FCC naphtha by PC solvent. Then, the correlation of NRTL and UNIQUAC models was compared, which the root-mean square deviation (RMSD) of these two models is lower than 0.0043. The NRTL model shows a better correlation with experimental data.
研究领域:
化学工程
·
石油炼制工程
·
量子化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Hangtian Zhang,Fang Zhang,Yixian Wu
Thermoplastic polyurethane (TPU) elastomers based on polyoxytetramethylene glycol (PTMG) with 2000 g·mol–1 as soft segments (SSs) and isocyanates as well as their reaction with butanediol as hard segments (HSs) were synthesized. The three-dimensional supramolecular networks were constructed in TPU by the formation of physical HSs-rich domains via microphase separation, hydrogen bonding, and microcrystallization, which are dominated by the chemical structure of HSs. The robust stretchable TPU with an excellent tensile strength of 32 MPa and elongation of 1378% at break could be successfully prepared, and no crystallization happened to keep the elasticity even at a low temperature (−90 °C) when the steric semisymmetric bis(4-isocyanatocyclohexyl)methane (HMDI) was introduced into HSs-rich domains. The crystallinity and ordered hydrogen bonding content decreased in HSs-rich domains with increases in steric hindrance and asymmetry of diisocyanates. A new approach was developed to construct the high-performance TPUs by introducing long PTMG SSs for the flexibility and elasticity and steric semisymmetric HMDI hard segments.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
RENEWABLE ENERGY
·
2022
·
IF 8.634
Xiu Gao,Chao Chen,Wenlu Zhang,Yanping Hong,Chunrong Wang,Guoqiang Wu
A series of sulfated TiO 2 supported Mo ( x Mo/1.5ST) catalysts were synthesized successfully and evaluated for the transesterification of Jatropha seed oil (JO) to biodiesel. Extensive characterization exhibits that the well dispersed Mo oxide species, with Mo 6+ and Mo 5+ oxidation states, were formed on the surface of the sulfated TiO 2 . The results indicate the presence of many sulfates species leads to the reduction of Mo 6+ species to Mo 5+ species. Furthermore, the catalytic activity of the x Mo/1.5ST catalysts gradually increases with the increase of Mo-loading, although the sulfates content and the total acid intensity decrease. The transesterification process was fully investigated, and the 10Mo/1.5ST shows the highest yield of biodiesel of up to 97.42%. Additionally, the possible mechanism for the JO transesterification over Mo/1.5ST was described, and the fuel properties of the as-synthesized biodiesel conformed to the current international standards.
研究领域:
化学工程
·
可再生能源
✓ 已验证
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 18
·10081-10088
·
IF 2.936
Xiaofeng Li,Haixia Xu,Guanglei Zhao,Hui Wu,Yigang Yu,Furao Lai,Xinglong Xiao
Acylation modification of phenol glycosides is currently of great interest due to the improved bioavailability and multiple functions. In this work, mono- or diesters of arbutin, an important phenol glycoside derivative, can be controllably synthesized by using whole-cell biocatalytic systems. Among fourteen microbial strains selected, Candida parapsilosis cells showed the best catalytic activity and high organic solvent tolerance. Compared with the best pure solvent tetrahydrofuran, the use of a binary solvent pyridine-isooctane gave a slightly lower conversion (98.3% vs. 97.2%) and selectivity (85.3% vs. 80.5%) and much higher substrate solubility (37.1 vs. 214.0 mg mL−1), in a 24 h bioconversion of arbutin with a VP-arbutin molar ratio of 15 and whole cell dosage of 30 mg mL−1. The production of various arbutin esters with different fatty acid chain lengths can be realized by using this whole-cell strategy, with the substrate conversion and 6′-regioselectivity of 54.1–98.3% and 83.2–99.0%, respectively.
研究领域:
生物化学
·
药物化学
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
MOLECULES
·
2010
·Vol. 15
·期 8
·5139-5152
·
IF 1.738
Lu Lin,Ying Liu
A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physico-chemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The results indicated that Ni/Al HTlcs with layered structures could be successfully prepared by the coprecipitation method, and the characteristic HTlcs reflections were also observed in the XRD analysis. The NiO and Ni0phases were identified in all Ni-based catalysts, which displayed randomly interconnected pores and no layer structures. In addition, the studies also found the Ni/Al HTlcs and Ni-based catalysts had high specific surface areas, low pore volumes and low pore diameters. The catalytic hydrogenation of ethyl acetate to ethanol with Ni-based catalysts was also investigated. Among the studied catalysts, RE1NASH-110-3 showed the highest selectivity and yield of ethyl acetate to ethanol, which were 68.2% and 61.7%, respectively. At the same time, a major by-product, butyl acetate, was formed due to an ester-exchange reaction. A proposed hydrogenation pathway for ethyl acetate over Ni-based catalysts was suggested.Keywords:hydrogenation;ethyl acetate;ethanol;Ni/Al hydrotalcite-like compounds
研究领域:
化学工程
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Z.T. Wang,H.J. Luo,L. Zhang,J. Zhang,H.W. Chen,H. Jiang
Basalt fiber is one of high performance inorganic fibers. As a promising textile material, basalt fiber has to be equipped with a coating to avoid abrasion during the handling and textile process. Starch phosphate sizing agent with different content of phosphate groups were prepared and coated on basalt fiber surface to improve its mechanical properties. The results showed that the fiber surface was successfully covered by a uniform and compact layer and modified by starch phosphates. The breaking force of the optimal sized fiber can be 47.8% higher than that of nonsized fiber, and the breaking elongation was also 12.6% higher than that of the original fiber.
研究领域:
材料科学
·
纺织工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Tianhong Nie,Xing Yang,Hanbo Chen,Karin Müller,Sabry M. Shaheen,Jörg Rinklebe,Hocheol Song,Song Xu,Fengchang Wu,Hailong Wang
In this study, the influence of the aging process of pig-(PB) and P. orientalis -(POB) derived biochars on the sorption capacity of the biochar-treated soils for cadmium (Cd) and zinc (Zn) with and without the co-existence of diethyl phthalate (DEP) was investigated. Additionally, the surface and internal characteristics of biochars were determined before and after their aging in soils. The PB-treated soil had a higher sorption capacity for Cd 2+ and Zn 2+ than the POB-treated soil. The sorption capacity of the biochar-treated soils for Cd 2+ and Zn 2+ increased with biochar application rates. After aging, the abundance of oxygen-containing functional groups on the biochar surface, and the pH and organic carbon content of the biochar-treated soils significantly increased, thereby improving the sorption capacity for Cd 2+ and Zn 2+ . The sorption capacities of biochar-treated soils for Cd 2+ and Zn 2+ followed the order of 1-month aging > 6-month aging > fresh. The co-existence of DEP enhanced the sorption capacity of the fresh biochar-treated soils for Cd 2+ and Zn 2+ , whereas this enhancing effect disappeared for the aged biochar treatments. Our findings provide insights into the interactions between mixed contaminants in biochar-amended soils and the long-term efficacy of biochar treatments on metal sorption to soils.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2019
·Vol. 28
·期 2
·647-656
·
IF 2.765
Feng Libang,Bian Yaohui,Chai Changsheng,Qiang Xiaohu
Given its thermal reversibility, high yield, and minimal side reactions, the Diels–Alder (DA) reaction is a particularly desirable technique for the preparation of polymeric materials with heat-stimulated self-healing properties. A linear self-healing polyurethane containing thermally reversible DA bonds (PU-DA) was developed in this study. Results revealed that the introduction of DA bonds conferred outstanding mechanical property and thermal reversibility to PU-DA films. Thus, the as-prepared PU-DA films demonstrated excellent self-healing performance. The self-healing behavior of the PU-DA films under various heat treatments was examined through qualitative observation and quantitative measurements. The PU-DA underwent self-repair through the combination of two healing actions, i.e., the thermal movement of molecular chains and the thermally reversible DA reaction. Moreover, the self-healing behavior of the PU-DA was repeatable, and the PU-DA continued to present high strength even after undergoing three damage–repair cycles at the same site. In addition, the as-prepared PU-DA exhibited excellent macro-scale self-healing behavior, and it endowed the PU-DA presented reprocessing performance. The PU-DA can be recycled given its excellent self-healing and outstanding reprocessing performances.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Chenchen Wang,Panpan Huang,Chunsheng Qiu,Jing Li,Shuailong Hu,Liping Sun,Yaohui Bai,Fu Gao,Chaocan Li,Nannan Liu,Dong Wang,Shaopo Wang
This study was to investigate the occurrence, migration and health risk of phthalic acid esters (PAEs) in tap water , barreled water and bottled water in Tianjin, China. Six priority controlled PAEs were measured, among which the detection frequency of butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) was 100%, while the others were not detected. The concentration of DEHP was higher than BBP and DBP in all the samples. The initial ∑ 3 PAEs concentrations in tap water, barreled water and bottled water were 2.409 ± 0.391 μg/L, 1.495 ± 0.213 μg/L and 1.963 ± 0.160 μg/L, respectively. Boiling tap water could reduce the PAEs content to an extent, but they increased significantly in hot tap water contacting with disposable plastic cups. The migration of PAEs in barreled water and bottled water were positively correlated with storage time and temperature, which could be described by exponential models. The hazard indexes of PAEs in different types of drinking water were very low. However, the human carcinogenic risks of DEHP will reach the maximum acceptable risk level of 10 −6 when bottled water is stored for 8.8 days at 40 °C, 7.7 days at 50 °C, or 6.1 days at 60 °C.
研究领域:
环境科学
·
公共卫生
✓ 已验证
DOI
高影响因子
Chemical Engineering Journal Advances
·
2021
·
IF 0
Qing Liu,Jiayun Shi,Taishan Wang,Wenwen Dong,Weixing Li,Weihong Xing
Ester have important applications in medicine chemical industry, but esterification is a typical reversible reaction controlled by thermodynamic equilibrium. In the study, a new type of catalytic composite membrane (CCM) with SA-MoS 2 /PAN as separation layer was reported. By-product water was proposed by pervaporation membrane reactor to improve the conversion rate of acetic acid. In 10 wt% ethanol-water solution, the separation factor of the catalytic composite membrane is 145 and the flux is 547 g m −2 h −1 . Under the optimal condition, the acetic acid conversion rate reached 94.3%, which was 29% higher than that of batch reaction. The effects of single-layer catalytic membrane and double-layer catalytic membrane on acetic acid conversion rate were studied, which showed that the double-layer catalytic membrane had higher stability in esterification reaction.It is proved that high crosslinking degree can improve the stability of the membrane and reduce the conversion rate of acetic acid.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 12
·51842
·
IF 3.125
Kun Cong,Zhenhui Liu,Jiyu He,Rongjie Yang
Polyether polyurethane elastomers prepared by polyisocyanate N100 and ethylene oxide-tetrahydrofuran copolymer (PET) were compared to that polytriazole polyethylene oxide-tetrahydrofuran (PTPET) elastomers prepared by alkynyl-terminated polyethylene oxide-tetrahydrofuran (ATPET) and glycidyl azide polymer (GAP) at a comparative molecular weight. The polyether polyurethane (PET-N100) elastomers turned out to have better mechanical properties than that of PTPET/GAP elastomer. In order to explore the effectiveness of nitrogen-enriched structures in the field of flame-retardancy, PET-N100 and PTPET/GAP elastomers were tested by cone calorimetry. The PET-N100 elastomer exhibited an inferior performance of flame-retardancy to that of PTPET/GAP elastomer. Therefore, a modification of the terminal hydroxyl group in GAP with 4,4′-methylene-bisphenyl-isocyanate (MDI) and flame-retardant diethyl bis(2-hydroxyethyl) amino methyl phosphonate (DBMAP) was attempted and characterized by FT-IR, NMR, and gel permeation chromatography. It was found that the synthesized GAP-MDI-DBAMP could serve as a novel curing agent for ATPET, which would endow the novel PTPET elastomer a combination of the advantageous properties, that is, the outstanding mechanical properties from PET-N100 elastomer, favorable flame-retardancy from PTPET/GAP elastomer and DBAMP. The thermogravimetry analysis/DTG, DSC, tensile strength test, and swelling analysis proved that PTPET/GAP-MDI-DBAMP elastomer had excellent thermal stability and mechanical strength.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）