MAGNETIC RESONANCE IN CHEMISTRY
·
2025
·
IF 1.4
Xiaoyan Zhang,Yaozuo Yuan,Yang Liu,Caiyu Zhang,Huiwen Deng,Songzi Jiang,Li Gan,Hui Fu,Xiaojuan Deng,Baoning Su,Jing Zhang,Fan Wu,Xingxiang Lv,Tong Liu,Yang Liu,Taijun Hang,Haiwei Shi
The research team established a quantitative 1 H NMR method to determine the relative ethoxy content ( EO %) in ethylcellulose using a CDCl 3 /TFA-d solvent mixture. High-field NMR spectroscopy enabled direct measurement without the use of internal or external calibrants by integrating the methyl proton signals (δ 1.15 ppm) and the methylene/methine proton signals (δ 2.5–5.5 ppm), and using their equivalent 1 H numbers and corresponding mass fractions for calculations. The EO % was calculated as: EO % = 315 r 486 − 614 r $$ \frac{315r}{486-614r} $$ × 100, where r = I A I A + I B $$ \frac{I_A}{I_A+{I}_B} $$ (I A methyl 1 Hs integral; Iᴃ methylene/methine 1 Hs integral). Round robin multi-laboratory validation testing showed that the qNMR results deviated by less than 3% from the certificate of analysis (COA) values (44%–51%). The COA values, derived using the pharmacopeial gas chromatography-flame ionization detection (GC-FID) method, may be affected by factors related to incomplete derivatization and the volatility and instability of the product (iodoethane) and the inert internal reference standard (n-octane). Therefore, the qNMR method with its operational simplicity, reduced chemical hazards, and robust performance presents an alternative for quality control of pharmaceutical-grade ethylcellulose.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL PAPERS
·
2024
·
IF 2.1
Zonghao Wang,Yanyan Nie,Peiyuan Shang,Zheng Chen,Bin Cheng
The primary objective of this investigation was to explore the electrochemical oxidation behavior of Sorbitan monolaurate (Span 20) under high-voltage environments. We designed and prepared working electrodes using a mixture containing Span 20 and conductive carbon black as an electron transport material. Linear sweep voltammetry (LSV) served as the technique to monitor the reactions undergone by Span 20. The oxidative products were subjected to analysis using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance hydrogen spectrum ( 1 H NMR). LSV reveals the decomposition of Span 20 occurring at voltages exceeding 4.2 V, involving two distinct reactions. Further insights from XPS and 1 H NMR demonstrated that Span 20 underwent a two-electron-two-proton electrochemical reaction, producing triketone and 1, 3-diketone with a hydroxyl group positioned at the 2 position. To elucidate these results, a reasoning mechanism was proposed.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2016
·Vol. 18
·期 29
·19731-19737
·
IF 4.449
Yingna Cui,Jingmei Yin,Changping Li,Shenmin Li,Ailing Wang,Guang Yang,Yingping Jia
The compositions and structures of amine-based functionalized protic ionic liquids (PILs), namely N,N-dimethyl(cyanoethyl)ammonium propionate (DMCEAP) and N,N-dimethyl(hydroxyethyl)ammonium propionate (DMEOAP) have been investigated systematically by IR and 1H NMR spectroscopy and density functional theory (DFT) calculations. Analysis of the IR spectra suggests that both DMCEAP and DMEOAP are composed of neutral and ionized species in the liquid phase, the former one mainly existing in the state of precursor molecules, and the latter mainly as ion-pairs. The ratio of precursor molecules to ion-pairs in the liquid phase depends on the types of precursors, especially the functional groups of cations. 1H NMR spectra indicate that there is a dynamic equilibrium between the neutral and ionized species, probably due to the formation of some intermediates in the PILs. The DFT calculations have been carried out to reveal the conformation, and obtain the corresponding IR and 1H NMR spectra of the neutral and ionized species, so that the theoretical support to the experimental results can be provided. The present study will help understand the properties of PILs and provide guidance for further applications of PILs.
研究领域:
物理化学
·
离子液体化学
·
光谱学
·
理论化学
·
分析化学
·
材料化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2020
·
IF 7.182
Renliang Lyu,Ting Xia,Cheng Liang,Cheng Zhang,Zeqin Li,Lichun Wang,Yi Wang,Ming Wu,Xiaogang Luo,Jiayu Ma,Cunwen Wang,Caili Xu
Three kinds of novel environmentally benign and high-efficiency crude oil demulsifiers were prepared using methoxy polyethylene glycol (MPEG) to modify alkylated carboxymethyl chitosan (ACMC). Structures of the demulsifiers were confirmed using FT-IR and 1 H NMR, and the relationship between surface tension and concentration was tested. Demulsification performance was investigated using the bottle test method with oil-in-water (O/W) emulsions that were prepared in lab conditions. The demulsification efficiency was as high as 79.1 %–84.9 %, and the possible mechanism of the demulsification process is discussed. Results show that MPEG-grafted ACMC (MPEG-ACMC) has a promising application as a demulsifier for dealing with emulsified O/W crude oil.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 41
·34039-34048
·
IF 4.6
Chuan Cao,Pingping Huang,Jing Guo,Deming Li
We successfully used co-precipitation to integrate four common aromatic compounds with different functional groups into macrocyclic dextrin, and we provided a detailed description of the inclusion complexes that occurred. Combining X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance hydrogen spectroscopy (1H NMR) allowed for confirmation of the inclusion complexes' formation. The thermal stability of the aromatic compounds is also supported by the inclusion complexes' higher structural stability. In the industrial and culinary sectors, LRCD is anticipated to function effectively as a solid matrix carrier for encapsulating aromatic chemicals.
研究领域:
超分子化学
·
材料科学
·
食品科学
·
制药技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2020
·
IF 1.349
Changjie Yin,Qiuyu Zhang
The copolymer of styrene/butadiene/γ-(methacryloxypropyl) trimethoxy silane (random -Bd-St-MPS- copolymer) was synthesized by the semi-batch emulsion terpolymerization. The copolymer of random -Bd-St- and -Bd-St-MPS- copolymer were characterized by fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) analysis, respectively. From FTIR and 1H NMR, the random -Bd-St- and -Bd-St-MPS- copolymers were synthesized successfully. The effect of the St:Bd:MPS ratio on the solids content, particle size, fraction of gel, thermal properties, and mechanical properties were studied. The particle size distribution of emulsion was uniform. The thermal stability of the random -Bd-St-MPS- copolymer was better than that of -Bd-St-, and increased with the increasing of MPS feed content. When the mass of MPS was 2 phr, the tensile strength of silica reinforced -Bd-St-MPS- copolymer was 10.35 MPa.
研究领域:
高分子科学
·
材料工程
·
化学合成
·
物理化学
✓ 已验证
DOI
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2022
·Vol. 194
·期 8
·3453-3467
·
IF 3.094
Ye Hangyu,Li Xiaojun,Li Luyuan,Zhang Yinjun,Zheng Jianyong
Aspergillus niger has been used for homologous and heterologous expressions of many protein products. In this study, the α-L-rhamnosidase from A. niger (Rha-N1, GenBank XP_001389086.1) was homologously expressed in A. niger 3.350 by Agrobacterium tumefaciens -mediated transformation. The enzyme activity of Rha-N1 was 0.658 U/mL, which was obtained by cultivation of engineered A. niger in a 5-L bioreactor. Rha-N1 was purified by affinity chromatography and characterized. The optimum temperature and optimum pH for Rha-N1 were 60 °C and 4.5, respectively. Enzyme activity was promoted by Al 3+ , Li + , Mg 2+ , and Ba 2+ and was inhibited by Mn 2+ , Fe 3+ , Ca 2+ , Cu 2+ , and organic solvents. The result indicated that rutin was the most suitable substrate for Rha-N1 by comparison with the other two flavonoid substrates hesperidin and naringin. The transformed products of isoquercitrin, hesperetin-7-O-glucoside, and prunin were identified by LC–MS and 1 H-NMR.
研究领域:
生物化学
·
分子生物学
·
生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 33
·e55847
·
IF 2.7
Chao Zhang,Erlei Yu,Heyun Wang,Dong Huang,Guojun Ding,Zhonghua Zhao,Zhong Wei
In response to the health and environmental concerns associated with the plasticizer dioctyl phthalate (DOP), this research explores the utilization of methyl oleate (MO) derived from plant oil, 1,2,4-Benzeneticarboxylic anhydride (TMA) and isobutyric anhydride (IA) as a precursor for synthesizing a hyperbranched polyester named IA-MO-TMA. This polyester serves as an alternative plasticizer for Polyvinyl chloride (PVC). The chemical structure of IA-MO-TMA was thoroughly characterized using Fourier Transform Infrared Spectrometer (FTIR) and nuclear magnetic resonance hydrogen spectra, and its molecular weight was assessed. The PVC film, plasticized with IA-MO-TMA, underwent comprehensive testing using techniques such as differential scanning calorimetry, scanning electron microscopy, and thermogravimetric analysis. Notably, the glass transition temperature ( T g ) of the plasticized PVC film exhibited a significant reduction from 75°C to −6.7°C. The plasticized film demonstrated an elongation at break of 318.1%, a tensile strength of 19.2 MPa, and a plasticizing efficiency of 109.9%. Moreover, the use of IA-MO-TMA as a plasticizer increased the initial decomposition temperature of PVC film from 235.6 to 264.1°C. Additionally, the extraction rate of IA-MO-TMA in petroleum ether was found to be 35.6% lower than that of DOP.
研究领域:
材料科学
·
高分子化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FERROELECTRICS
·
2024
·
IF 0.6
Chenghong Huang,Xiaorong Huang,Qi Yin,Xuehan Hu,Ying Fang,Hongjie Chen,Lin Zhang,Kang Yang,Hao Li,Fang Yang,Xiaoling Lu,Zeng Yang
Chitosan (CS) is lack of applications in pharmaceutical industry due to its lower compression density and instability during tablet process. This study mainly focus on the synthesis of ethyl vanillin incorporated CS(EV/CS) via Schiff base reaction and the evaluation of application as pharmaceutic excipient. Results of FT-IR showed that there is a typical amide peak in EV/CS that the 1640 cm−1 can be attributed to –C = N– bond and 1518 cm−1 can be attributed to backbone of benzene but not in CS raw material. Compared with the control, XRD of EV/CS have additional 2θ angle of 44°, 64° and 77° diffraction peaks except that the 2θ = 20° of EV is still existed. More slower weight loss of EV/CS than that of CS in the range of 248–760 °C is also demonstrated by TGA analysis. 1H NMR indicated there are intrinsic 7.5 and 7.1 ppm as well as emerging 4.2 ppm of chemical shift in EV/CS. The physical finger spectra from twelve indexes of EV/CS powder denotes quite differences in compressibility, fluidity and stability with that of CS. 5% content EV/CS of designed formulation can at most decrease the friability and disintegration time of the compressed tablet. In conclusion, the developed EV/CS is inclined to suitable for tablet as an excipient.
研究领域:
药学
·
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2019
·
IF 1.163
Zhenqi Cheng,Zhengfeng Dong,Mingji Su,Yuhong Zhang,Zhiguo Wang,Peixin He
In order to improve the flocculent efficiency of wastewater treatment, a cationic flocculant poly (acrylamide-[2-(methacryloyloxy) ethyl] trimethyl ammonium chloride) (P (AM-DMC)) (CPAM) has been synthesized successfully via an inverse emulsion polymerization. Acrylamide (AM) and [2-(methacryloyloxy) ethyl] trimethyl ammonium chloride (DMC) were served as monomers. The molecular structure of CPAM was characterized by Fourier transform infrared spectra (FT-IR) and 1H nuclear magnetic resonance spectrum (1H-NMR). The morphology of CPAM particles has been investigated by transmission electron microscope (TEM). Results showed that CPAM was the copolymer of AM and DMC and the particles of CPAM were uniform spheres (the size was about 200 nm). The synthetic conditions of CPAM have been studied and optimized by single-factor experiments. An optimized product was obtained at an intrinsic viscosity of 560 mL/g with a total monomer concentration of 25% and initiator concentration V50 of 0.2% (based on the total monomer mass). The amount of emulsion was 6% and the HLB (Hydrophile-Lipophile-Balance) of emulsion was 7.3. In addition, the flocculation property of CPAM was evaluated with kaolin suspension using jar test, and the result demonstrated that the flocculation property of CPAM performed better than kaolin flocculation.
研究领域:
环境工程
·
高分子科学
·
化学工程
·
材料科学
·
水处理技术
✓ 已验证
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Min Shi,Jiaming Liu,Jingjing Qin,Dingsong Wang,Liyan Liang
Given the fossil fuel energy crisis and serious environmental pollution in recent years, one way to alleviate the problem is to introduce dynamic covalent chemistry into thermosetting resins to give the material processable and recyclable properties, creating a new type of eco-friendly material. Hindered urea bonds can undergo reversible exchange reactions at high temperatures to decompose into amine and isocyanate . This reversible addition reaction is currently a prominent research focus in the development of reprocessable thermosets . In this work, we synthesize a novel curing agent with hindered urea bonds without any catalysts. Then characterize the resulting epoxy vitrimers based on hindered urea bond (HUG-EP) using FT-IR and 1 H NMR, confirming the successful introduction of hindered urea bonds into the epoxy resin . A variety of tests are carried out, such as those to assess thermal stability, swelling, shape-memory, re-processability and tensile strength . The results demonstrate that HUG-EP can rapidly self-healed within 20 min at 160 °C, with the tensile strength was maintained at 87.15 % of the original during the welding experiments. Furthermore, it can also be reprocessed by hot-pressing several times at 160 °C. Thus, the introduction of hindered urea bonds into the crosslinked network proves to be an effective and practicable approach for producing thermosetting resins with reprocessing, self-healing, and shape memory capabilities.
研究领域:
材料科学
·
化工
·
高分子化学
·
可持续材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2014
·
IF 0.74
Yunyan Xue,Dandan Ma,Tianzhu Zhang,Siyan Lin,Shengnan Shao,Ning Gu
In this study, a series of comb-like methoxy polyethylene glycol (MPEG) functionalized polyurethanes (PUs) (PU–g–MPEG) were successfully prepared via ‘click’ chemistry and polyaddition reaction. The copper catalyzed Huisgen 1,3-dipolar cycloaddition was firstly carried out between 3,5-bis(hydroxymethyl)-1-propargyloxybenzene (PBM) and methoxy polyethylene glycol azide (MPEG–N3) to obtain MPEGylated diol PBM (MPEG–PBM). Then, the comb-like PUs having MPEG located on the backbones (PU–g–MPEG) were synthesized through the polyaddition of MPEGylated diol PBM and hexamethylene diisocyanate (HDI). Fourier transform infrared (FTIR), 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermo gravimetric analyses (TGA) were used to characterize these synthesized MPEG-functionalized comb-like PUs (PU–g–MPEG). Compared with PU without MPEG grafts, PU–g–MPEG show a better wettability.
研究领域:
高分子化学
·
材料科学
·
有机合成
·
表面化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）