CHEMICAL PAPERS
·
2022
·Vol. 76
·期 4
·2145-2152
·
IF 2.146
Zhu Xingji,Kou Xinhui
We disclose a metal-free catalyst system of organic bases/protic acids for effective fully alternating copolymerization of cyclohexene oxide and phthalic anhydride. A series of commercial organic bases and protic acids were employed as binary catalysts, and the effects of different kinds and ratios of organic bases and protic acids were performed to find optimal conditions for achieving the highest catalytic performance. And our results indicated that DMAP/DPP showed higher activity (TOF = 574 h −1 at 140 °C) and perfectly alternating selectivity (ester > 99%), producing polymers with narrow polydispersity (Ð = 1.08 ~ 1.22). Moreover, analysis of the resultant polymers was confirmed by GPC, NMR spectra and MALDI-TOF MS techniques which revealed that P(PA- alt -CHO) polyester with well-defined alternating structure without formation of polyether and DMAP can act as an initiator in DMAP/DPP catalyst system, resulting more effective ring-opening alternating copolymerization. However, trace amount of phthalic acid as an impurity in the system also acted as a bifunctional initiator influencing the molecular weight of the polymer. In addition, the DMAP/DPP catalytic system remained stable at high temperature and the development of this simple catalytic process provided a new chance to exploit in organocatalyzed polymerization.
研究领域:
高分子化学
·
有机催化
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Tian Ma,Zhensheng Shen,Huan Li,An Li,Qian Feng,Yingqiang Sun,Shuguang Deng
Brønsted acid ionic liquids (BAILs) are effective to biodiesel production of in situ transesterification of wet algae due to their dual role as both solvents of cellulose and catalysts of transesterification. The cellulose solubilities of BAILs are depending on H-bonding of BAILs-cellulose in varied solvent conditions, which subsequently affect the biodiesel productions. For this reason, the effects of H-bonding between BAILs including [Bmim][H2PO4], [Bmim]2[HPO4], [Bmim][HSO4], and cellulose under different methanol and water conditions on cellulose extractions are experimentally and theoretically investigated. The cellulose extractions in BAILs are decreasing as [Bmim][H2PO4] > [Bmim]2[HPO4] > [Bmim][HSO4], contrary to the variation of their thermal stabilities and crystallinities caused by varied H-bonding of BAILs-cellulose. Increasing methanol is positive to cellulose extractions in [Bmim][HSO4], while negative to those in [Bmim][H2PO4] and [Bmim]2[HPO4], due to the solvent effect of methanol confirmed by cyclic voltammetry (CV) measurements. The effect of water on H-bonding of BAILs-cellobiose is contrary to the effect of methanol. It is confirmed via the bonding interaction of BAILs-cellobiose through the density functional theory (DFT) computational method. However, the biodiesel yields are varied differently due to the competition of H-bonding of BAILs-cellobiose and deprotonation of BAILs under different methanol and water conditions. This study might pave the way to neutralize the negative effect of water on in situ transesterification via enhancing the cellulose extractions of BAILs.
研究领域:
生物化学
·
能源科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Tao Chang,Xiaorui Gao,Li Bian,Xiying Fu,Mingxia Yuan,Huanwang Jing
A series of Brönsted acid ionic liquids (BAILs) containing a long chain Brönsted acid site in the cationic part and a Lewis basic site in the anionic part were designed, synthesized, and used as catalyst for the coupling of epoxides and carbon dioxide to cyclic carbonates without a co-catalyst or co-solvent. The effects of catalyst structure and other parameters on the catalytic performance were investigated. The long chain 2-( N,N -dimethyldodecylammonium) acetic acid bromide ([(CH 2 COOH)DMDA]Br) showed high catalytic activity and good reusability. This protocol was expanded to various epoxides, which gave the corresponding cyclic carbonates in good yields. The acidity of the catalyst influenced its catalytic activity.
研究领域:
化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2021
·Vol. 5
·期 16
·6145-6151
·
IF 6.482
Rui Zhao,Hui Peng,Faqiang Wang,Jianghong Zhen,Lu Li,Guofu Ma,Ziqiang Lei
Poly(4-aminodiphenylamine) (P(4-ADPA)) is a kind of polyaniline derivative and is promising as one of the alternatives to polyaniline because its monomer has a lower oxidation standard potential for oxidation and a faster oxidation rate than that of the aniline monomer. Herein, to explore the factors affecting the structural and electrochemical properties of novel conducting P(4-ADPA) materials, a series of P(4-ADPA) has been prepared by using different organic or inorganic proton acids as dopants and a cationic surfactant as the structure-directing agent. The result shows that the shape and stability of the self-assembled surfactant lamellar micelles are strongly affected by the species and the counter-ion size of proton acids, which in turn affects the morphology, crystallinity and the electrochemical properties of P(4-ADPA). Specifically, P(4-ADPA)-L with lactic acid as the dopant under a mild polymerization environment possesses a uniform intertwined nanosheet morphology and shows superior electrochemical properties with a high specific capacitance of 388 F g−1 at 0.5 A g−1 and a superlong cycle stability. In addition, P(4-ADPA)-S and P(4-ADPA)-P with sulfuric acid and perchloric acid as dopants, respectively, exhibit high conductivity and specific capacitance, and due to the high acidity of reaction solutions, a large size of counter-ions and thereby good crystallinity.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Yipeng Zheng,Zhennan Cao,Zheng Zhou,Gaodong Yang,Zhibing Zhang
A series of SO 3 -functional Brønsted acidic ionic liquids (SBAILs) were prepared to catalyze the N -formylation of aniline with DMF . The reaction conditions such as ionic liquid type, reaction temperature, catalyst loading and molar ratio of reactants were investigated. To the best of our knowledge, kinetic model for the N -formylation of aniline with DMF using SBAIL was firstly built and simulated. The studies on the reaction order of the reaction were evaluated by initial concentration method, and the kinetic parameters such as reaction rate constant and activation energy were proposed and used to explain the catalytic activities of the SBAILs catalysts. Accordingly, the recycling experiments showed that the SBAIL [Bsmim][HSO 4 ] can be easily recovered and reused with stable activity. Further, the temperature-controlled study emphasized that the ionic liquid was easy to be separated and environmentally friendly.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Guangxing Hu,Shuang Cui,Hongda Wang,Yan Shi,Zhuang Li
Molecularly imprinted electrochemical sensor is a kind of convenient, fast, and stable analyzer, but the conductivity of electrode materials and their affinity with the analyte affect its performance. A proton acid (PSS, SA , SSA) doping method was proposed to improve the electrochemical performance of the polypyrrole molecularly imprinted polymer (PPy-MIP), which promoted the electropolymerization of pyrrole , reduced the charge transfer resistance, and increased the electrochemical surface area . In terms of both improving conductivity and affinity, the response of the proton acids doped the polypyrrole molecularly imprinted electrochemical sensors (PPy-MIECS) to urea was improved by 25-fold (PSS), 5-fold (SA), and 3-fold (SSA) over that of PPy-MIECS. In addition, the PSS-PPy-MIECS was validated for the practical application with a linear detection range from 0.1 mM to 100 mM, high selectivity (α = 39.73), reusability (RSD% = 4.54 %), reproducibility (RSD% = 0.93 %), and stability (11 days). The advantage of proton acid doping method in PSS-PEDOT-MIECS to urea and PSS-PPy-MIECS to glucose extended its application in the performance enhancement of MIECS design.
研究领域:
分析化学
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生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Waste and Biomass Valorization
·
2018
·Vol. 11
·期 5
·1983-1988
·
IF 1.874
Chang Fei,Zhou Quan
Brønsted acidic ionic liquid supported on magnetic Fe 3 O 4 [ β -CD-6-Im-(CH 2 ) 3 -HSO 3 ][HSO 4 ]-Fe 3 O 4 was synthesized successfully, the catalyst was characterized via TGA, FT-IR, XRD, SEM, BET and acidity determination, and used to catalyze the high-acidic untreated Jatropha carcass L. seed crude oil (46.0 mg KOH/g) for biodiesel production in a single pot. The results showed that 94.70% yield of FAME was obtained under the optimized reaction conditions of temperature of 130 °C, 10:1 molar ratio of methanol to oil, 3 wt% of catalyst dosage, 3 h reaction time. In addition, the catalyst activity was not significantly decreased after five recycles.
研究领域:
化学工程
·
可再生能源
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催化化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 3
·1602-1611
·
IF 3.9
Jialin Guo,Kai Zhang,Piao Luo,Nanjie Wu,Shigui Peng,Lanlan Wei,Yufei Liu,Min He,Jie Yu,Shuhao Qin,Qiao Fan,Tingting Luo,Jun Xiao
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely used because of its excellent performance. We report the synthesis of two PEDOT:PSS dispersions. The two dispersions differ by the addition of additional protonic acid in the oxidative polymerization system. Although there are examples of the introduction of acids into the polymerization system, the effects of acid on the structure and properties of these materials, in particular their mechanisms of action, have not been elucidated. We describe the chemical structure and molecular weight of two PEDOT polymers using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis-NIR spectroscopy, and density functional theory calculations. The carrier concentration, carrier mobility, and surface morphology of the composites are characterized by UV-vis-NIR spectroscopy, electron spin resonance, Raman spectra, Hall effect measurements, and atomic force microscopy. The crystallinity of PEDOT:PSS was measured by X-ray diffraction patterns. We show that the addition of a proper amount of protonic acid to the oxidative polymerization system can effectively reduce the formation of the terminal carbonyl group of PEDOT chains, which is conducive to the growth of polymer chains, and further improve the carrier concentration, which leads to an improvement of conductivity. Our results highlight the optimization of the chemical structure of PEDOT in order to increase its molecular weight and ultimately its conductivity.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 26
·50628
·
IF 3.125
Ying Zhang,Yulun Tao,Kequan Wang,Shuai Zhao,Jinbo Zhu,Hao Cheng
In previous studies, polyaniline nanofiber sensor on interdigital electrode is sensitive to light. Herein, we prepared a flexible hydrogel sensor with polyaniline nanofiber as the active material and polyacrylamide hydrogel as the flexible substrate. Comparing the properties of above two different kinds of sensors with polyaniline nanofiber, the photocurrent generated by PANI-hydrogel sensor under external light stimulation is about 1 ~ 2 orders of magnitude higher than interdigital electrode sensor, indicating the PANI-hydrogel sensor is more sensitive. The two sensors can all respond to different wavelengths of monochromatic light, especially sensitive to light of smaller wavelengths such as ultraviolet light (380 nm) and blue light (475 nm). Moreover, the volt-ampere characteristic curve in response to external light stimulation can be clearly distinguished only when the appropriate concentration of proton acid is doped (3 g citric acid, 7 g acetic acid, and 3 ml HCl).
研究领域:
材料科学
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传感器技术
·
光电材料
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Wenhao Xu,Xiaofeng Gao,Xian Zhou,Yongkang Huang,Houhong Song,Siyu Yao
Prins condensation of methyl tert-butyl ether (MTBE) with formaldehyde (FA) is an important route for isoprene synthesis. Traditionally, the production capacity of isoprene in a liquid-phase batch reactor is significantly limited due to the high ratio of MTBE/FA and the addition of an excessive amount of solvent. In this study, we evaluated different acid catalysts aiming at enhancing the selectivity and recyclability of catalysts under the condition of stoichiometric MTBE/FA in a concentrated solution. A Brønsted sulfonic ionic liquid ([HSO3-bmin] PTS) showed remarkable performance. The study of the reaction network confirmed that 4,4-dimethyl-1,3-dioxane (DMD) was the key reaction intermediate for isoprene synthesis. Sufficient acid strength of the ionic liquid catalysts was necessary for the conversion of intermediates to isoprene. The influence of reaction conditions including reaction time, reaction temperature, solvent, SO3H-functionalized ionic liquid (SFIL) concentration, and the amount of MTBE and formaldehyde was investigated in detail to maximize the yield of isoprene. Under the optimal conditions, the capacity of isoprene production reached 55.0 g/L, 1 order higher than that in previous studies. The [HSO3-bmin] PTS ionic liquid exhibited excellent recyclability and maintained its activity and selectivity after being reused seven times.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2020
·
IF 2.463
Chulei Zhao,Ke Gao,Chaoyun Ma,Mei Wu,Kaihang Cao,Yuxiao Yang,Chenglin Hong,Xiuwen Qiao
A “label-free” electrochemical immunosensor was developed to detect α-fetoprotein (AFP) sensitively. HCS@PANI (High carbonized nanospheres@Polyaniline) is used as an electrochemical sensing platform to improve conductivity and enhanche the amount of AFP antibody (anti-AFP) immobilized on the electrode surface. PANI, which is involved by protonic acid, exhibits excellent electrochemical activity and can be used as a direct electron mediator to further amplify electrochemical signals. Under optimal conditions, the electrochemical immunosensor has a linear range of 0.001–80 ng/mL and a minimum detection limit of 0.33 pg/mL. The immunosensor is expected to be used in clinical laboratories to detect AFP and other tumor markers in human plasma for precancerous screening or cancer surveillance.
研究领域:
分析化学
·
生物化学
·
材料科学
·
医学诊断
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Shuai Yuan,Jin Yang
Protonic acid doping of heat-resistant and conductive polyurethane elastomers (PCPU) can significantly enhance their electrical conductivity. By doping with different types of protonic acids and varying molar amounts of camphorsulfonic acid (CSA), the doping mechanism and molecular structure changes of PCPU were systematically investigated using multiple characterization techniques such as Fourier-transform infrared (FTIR), X-ray diffraction (XRD), UV–vis and so on. Meanwhile, the effects of protonic acid doping on the thermal stability and mechanical properties of PCPU were further evaluated using thermo-gravimetric analysis (TGA), Differential scanning calorimetry (DSC), and stress–strain testing. Although protonic acid doping reduces the thermal stability and fracture strength of PCPU, the acid-doped PCPU can form an ionic gel network, which facilitates the uniform dispersion of electromagnetic wave (EMW) absorbers within the matrix. Additionally, protonic acid doping endows the electromagnetic wave absorbing materials (EMWAMs) prepared from PCPU and nanographite (Gr) with tunable electromagnetic matching characteristics and enhanced wave attenuation capabilities, exhibiting excellent EMW absorption performance across a broad frequency range. For instance, the 10% Gr-PCPU-2CSA composite achieves a minimum reflection loss of −27.98 dB and an effective absorption bandwidth of 5.3 GHz at a thickness of 2.5 mm. Therefore, this study provides novel insights for the development of high-performance EMW-absorbing matrix materials.
研究领域:
材料科学
·
高分子化学
·
电磁功能材料
·
导电高分子
·
微波吸收技术
✓ 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）