CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yuhang He,Hua Ke,Yangcheng Lu
Controlled alcoholysis of ethylene–vinyl acetate copolymer (EVA) is very important both to industry and academic research. To this end, accurate kinetic model is an important tool, but traditional methods for studying reaction kinetics involving polymers are usually laborious and time consuming due to the need of product purification. Therefore, we developed a new method to study the alcoholysis of EVA with 32 mol% ethylene content based on in situ FTIR spectroscopy. The feasibility and accuracy of this method was carefully studied. A kinetic model for predicting reaction rate was obtained using this method. The applicability of the kinetic model was further verified by performing flow alcoholysis in microflow reactor. It was found that this kinetic model is pretty accurate for conversions up to around 60 %, even at a relatively high temperature. The in situ FTIR method may also be suitable for monitoring industrial production process and other alcoholysis systems like PVA.
研究领域:
高分子化学
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化工工程
·
分析化学
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DOI
高影响因子
VIBRATIONAL SPECTROSCOPY
·
2023
·
IF 2.5
Liwei Ni,Shiying Yang,Wenze Qiu,Jialei Jin,Qiyue Xu,Shuliang Ye
The reaction pathway of many Paal-Knorr reactions for pyrrolic compounds hasn’t been thoroughly studied and remains controversial. In this work, the synthesis of an important anti-ultraviolet agent N-butoxycarbonyl-2,5-dimethylpyrrole based on the Paal-Knorr reaction was studied via in-situ Fourier transform infrared (FTIR) analysis combined with density functional theory (DFT) calculation. The online spectral data were analyzed using K-means clustering in order to find the characteristic wavenumbers of intermediates. It was found that the reaction with 2,5-hexadione and butyl carbamate are more favorable to form the imine and enamine intermediates by nucleophilic addition, which is different from another Paal-Knorr reaction with 2, 5-hexadione and ethanolamine . In addition, the reaction kinetic model was established through chemometric methods, with parameters of two rate-limiting reaction steps calculated. This approach of FTIR analysis is proven to be an effective tool for mechanism study of organic synthesis.
研究领域:
有机化学
·
物理化学
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产品关联
DOI
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 25
·13688-13696
·
IF 6.895
Ping Li,Cheng Du,Xiaohui Gao,Zhihua Zhuang,Dong Xiang,Chunmei Zhang,Wei Chen
Morphology modulation and surface structure-controlled synthesis are two effective ways to tune the electrocatalytic activities of metal nanomaterials. Pt-based binary or ternary metal nanostructures have become a class of promising catalysts toward the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) for direct methanol fuel cells. Herein to reveal the morphology and surface structure effects of one-dimensional (1D) Pt-based nanostructures on their electrocatalytic properties, two types of 1D CuPt nanowires (CuPt NWs) and CuPt nanotubes (CuPt NTs) with tunable surface structures and compositions were fabricated using a convenient and easy strategy. It was found that among all the studied samples, CuPt2.22 NWs exhibited the highest efficiency catalytic performances for both the ORR and MOR in an acidic electrolyte. For the ORR, CuPt2.22 NWs exhibited an onset potential (Eonset) of 0.749 V and a half-wave potential (E1/2) of 0.577 V, which are more positive than those of the commercial Pt/C (0.668 V and 0.558 V). On the other hand, CuPt2.22 NWs show a specific activity of 20.76 mA cm−2 and a mass activity of 0.171 mA μgPt−1 for the MOR, which are 7.75 and 1.82 times, respectively, larger than those of Pt/C (2.679 mA cm−2 and 0.094 mA μgPt−1). Meanwhile, the reaction mechanism of the MOR on CuPt2.22 NWs was examined by in situ FTIR. From the enhanced IR absorption, the linear- and bridge-adsorbed CO intermediates can be determined during the methanol oxidation on CuPt2.22 NWs, from which the MOR proceeds through a dual reaction pathway. This work reveals that rationally tuning the electronic structures of 1D metal nanomaterials by well-controlling the composition and surface morphology on the nanoscale could greatly enhance the catalytic properties, which are very important for their application in fuel cells.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Data in Brief
·
2021
·
IF 0
Md Rasadujjaman,Jinming Zhang,Konstantin P. Mogilnikov,Alexey S. Vishnevskiy,Jing Zhang,Mikhail R. Baklanov
A dataset in this report is regarding an article, “A detailed ellipsometric porosimetry and positron annihilation spectroscopy study of porous organosilicate glass films with various ratios of methyl terminal and ethylene bridging groups” [1]. The data of porous organosilicate glass (OSG) low-k films was obtained by Fourier-Transform Infrared spectroscopy (FTIR), Ellipsometric Porosimetry (EP), Photoluminescence (PL) Spectroscopy. The data shows that the mechanical properties of OSG low-k films are principally controlled by introducing both terminal methyl and bridging organic groups, and porosity with proper pore size. The dataset presented here gives additional details regarding properties of carbon bridged OSGs presented in the paper [1]. Also, the data may give the impact of both terminal methyl and bridging ethylene groups on as deposited and thermally cured OSG films. Particularly, we added some details about FTIR, EP (especially related to calculation of the internal surface area) and UV induced luminescence. The data allow to test experimental and theoretical investigations of OSG low-k materials that might use in microelectronic fabrication industry and also might be used to extend beyond the analysis reported in the accompanying manuscript, and may aid for other applications of OSG materials.
研究领域:
材料科学
·
微电子学
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DOI
PubMed
CHEMICAL GEOLOGY
·
2018
·
IF 3.57
Yong Yuan,Xixi Cai,Bin Tan,Shungui Zhou,Baoshan Xing
Solid-phase humic substances (also termed humins, HMs) are the largest fraction of humic substances (HSs) in soils and sediments, which are recently shown to be capable of mediating electron transfer in many key biogeochemical processes. However, the redox properties of HMs remains poorly investigated, likely due to their structural complexity and the lack of efficient methodology. Herein, an electrochemical in situ FITR spectroscopic (EC-FTIRS) technique coupled with two-dimensional correlation spectroscopy (2D-COS) was employed for the first time to study the redox process of complex HMs at a molecular level. In situ FTIR identified that the IR bands of quinone and phenolic moieties in the HMs were potential dependent, suggesting that they were the main redox sites in response to the redox transformation of the HMs. Meanwhile, In situ FTIR characterizations showed that the significant variations in IR bands positioned at ~1500 and ~1470 cm −1 in response to the applied potentials, providing evidence for the presence of quinone radical and dianion intermediates during the redox process. The 2D-COS analysis was used to further explore variations in infrared intensities as a function of the potentials applied to reduce or oxidize the HMs, which indicated the occurrence of the typical redox reactions of quinone in the HMs. These results improve our understanding on the redox mechanism of HMs at the molecular level and have significant implication for in-depth understanding of biogeochemical processes.
研究领域:
环境科学
·
分子生物学
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2022
·
IF 4.831
Xiaohua Zhang,Tianyi Li,Anqi He,Limin Yang,Isao Noda,Yukihiro Ozaki,Yizhuang Xu
We proposed a modified and improved approach to removing the interference of moisture from an IR spectrum and the corresponding second derivative spectrum. The temperature fluctuation in the air of the optical path and baseline-drift lead to the small but persistent presence of the interference of moisture. The problem has been successfully addressed by adopting a double-matching strategy. Additionally, two-dimensional correlationspectra (2D-COS) are generated using the second derivative or third derivative spectrum of the negative base 10 logarithms of the single-beam spectra, thereby removing the linear slope or quadratic portion of baseline-drift. Using the newly adopted approach, the residual interferences of moisture are attenuated. We applied the new approach to the IR spectra and the second derivative spectra of neat hexadecanol and biaxially oriented polypropylene (BOPP) film, and some promising preliminary results are obtained. In hexadecanol, two highly overlapping peaks at 1464 and 1463 cm −1 are revealed. In BOPP, the envelope at 1458 cm −1 is found to be composed of a number of sub-peaks.
研究领域:
分析化学
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光谱学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 39
·期 8
·975-983
·
IF 3.603
Li Hui-Xian,Hou Lei,Wu Pei-Yi
The time-resolved attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is employed to investigate the transport mechanism of gel electrolytes by monitoring the diffusion behavior of propylene carbonate-lithium bis(trifluoromethylsulfonyl)imide (PC-LiTFSI) solution through poly(vinylidene fluoride- co -hexafluoropropylene) (P(VDF-HFP)) films. Fickian behavior has been observed for both TFSI − and PC. Higher temperature leads to faster diffusion of TFSI − and PC, which could be related to the increased free volume in P(VDF-HFP) matrix and rapid molecular movements upon heating. Various molecular interactions among LiTFSI, PC and P(VDF-HFP) have been recognized. During the diffusion process, PC molecules, in the form of small clusters, can firstly diffuse through the P(VDF-HFP) film and interact with P(VDF-HFP) by dipole-dipole interaction, acting as the plasticizer. Then, Li + diffuses into P(VDF-HFP) with the help of ion-dipole interactions between Li + and C-O of PC. Meanwhile, TFSI − diffuses through the polymer matrix in solvation states. In addition, slight ion-dipole interactions between Li + and P(VDF-HFP) have been observed as well. Results in this work contribute to a better understanding of transport process in gel polymer electrolytes for lithium-ion batteries and support the development of improved gel polymer electrolytes by rationally regulating molecular interactions.
研究领域:
高分子化学
·
电化学
·
能源材料
·
锂离子电池
·
光谱分析
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2020
·
IF 2.463
Li Yang,Le Yang,Suqin Sun,Qun Zhou,Ling Dong,Jianbo Chen
Rhubarb has a long history of medicinal applications in Asia and Europe. For some clinical applications of traditional Chinese medicine, rhubarb has to be stir-baked to scorch to eliminate the purgative activity, but increase the functions of blood-cooling and hemostasis. Understanding the chemical transitions during the stir-baking process is necessary for the quality assessment a quality control of scorched rhubarb. This research used the heated ATR-FTIR spectroscopy to study the thermal transitions of rhubarb and related compounds. Critical points during the heating process of rhubarb, emodin, emodin-8-glucoside, glucose and 5-HMF were recognized from PCA score plots. Two-dimensional correlation spectroscopy (2DCOS) was used to interpret the spectral changes of rhubarb during different thermal stages. It was found that the decomposition of anthraquinone glycosides and the formation of aromatic carbon networks at high temperature (above 170 °C) may be the primary reactions to generate scorched rhubarb. These results are helpful for the reasonable procedure optimization and quality control of the stir-baking process to produce scorched rhubarb.
研究领域:
药学
·
分析化学
·
中医
✓ 已验证
产品关联
DOI
高影响因子
POLYMER TESTING
·
2020
·
IF 3.275
Zhipeng He,Huichao Liu,Guang Yang,Chi Jiang,Muwei Ji,Jiali Yu,Mingliang Wang,Caizhen Zhu,Jian Xu
Cyclization reaction of poly(acrylonitrile-co-2-acrylamido-2-methylpropane sulfonic acid) [P(AN-co-AMPS)] copolymer during thermal oxidative stabilization (TOS) process was investigated by FTIR and two dimensional (2D) correlation analysis technique. The results showed the mechanism of cyclization reaction at different temperatures were varying. At 200 °C, the cyclization reactions generated by autocatalytic cyclization mechanism. While at higher temperatures, the cyclization reactions took place through ionic cyclization mechanism and free radical cyclization mechanism. The AMPS comonomer could reduce the heat release of cyclization reactions and improve the stability at 200 and 230 °C. At higher temperatures, the cyclization reactions were facilitated rapidly. However, the oxidation and degradation reactions were also intense, which will cause the molecular chain to break and defects in the final carbon fibers (CFs). This research has theoretical guiding significance for the optimization of heat treatment conditions for PAN copolymers used as CFs.
研究领域:
高分子化学
·
材料科学
·
光谱学
✓ 已验证
DOI
高影响因子
ANALYTICAL SCIENCES
·
2017
·Vol. 33
·期 1
·105-110
·
IF 1.228
Li Yan,Guo Ran,Liu Shengnan,He Anqi,Bao Yanan,Weng Shifu,Huang Yaping,Xu Yizhuang,Ozaki Yukihiro,Noda Isao,Wu Jinguang
In this study, the feasibility of using copper oxide (CuO) as an interface for the coupling of liquid chromatography (LC) and Fourier-transform infrared (FTIR) spectroscopy was investigated. CuO exhibits low absorption in the 4000 to 1000 cm −1 FTIR spectral region. In addition, LC-FTIR using CuO as the interface was extended to the analysis of sample mixtures containing benzamide and dioctyl sebacate; both analytes were successfully separated. After complete removal of (he mobile phase, benzamide and dioctyl sebacate were successfully identified from the FTIR spectrum. Surprisingly, the interference from adsorbed water or conventionally used LC solvents in the FTIR spectrum was completely eliminated by using CuO particles as the interface in the off-line hyphenation of LC-FTIR. Based on these results. CuO demonstrates potential as an ideal interface for LC-FTIR analysis.
研究领域:
分析化学
·
光谱学
✓ 已验证
DOI
PubMed
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2026
·
IF 3.3
Ran Wang,Liming Xu,Yifan Yang,Wenqing Wang,Mingzhe Liu,Xiaoye Su,Yu Shao
In recent years, oligonucleotide drugs, as a novel class of drug molecules, have provided new treatment modalities for patients with chronic diseases. Although the traditional synthesis process system for oligonucleotide drugs is continuously improving and maturing, the ammonolysis process still commonly uses offline methods. Especially during industrial scale-up, limitations such as difficulties in material transfer, nonuniform sampling, and monitoring of high-concentration supersaturation have highlighted the lack of an efficient, real-time, and accurate online control system for monitoring the oligonucleotide ammonolysis process. In this study, a novel online ammonolysis process system for oligonucleotides was constructed for the first time. This system is equipped with online Fourier transform infrared spectroscopy (FTIR), enabling real-time monitoring and endpoint control of the oligonucleotide ammonolysis process. The experimental results showed that under conditions of different temperatures and various types of solid supports, this method can stably and accurately reflect the oligonucleotide ammonolysis process. The detection results at multiple wavelengths (IR 1232 cm–1, 1457 cm–1, 1504 cm–1, 1635 cm–1) are comparable to the traditional offline ultraviolet (UV) detection method (UV 260 nm) (Pearson correlation coefficient r > 0.9). To the best of our knowledge, this study is the first to achieve real-time online infrared monitoring and control of the ammonolysis process for oligonucleotides within the public literature. This achievement lays a solid foundation for deploying IR process analytical technology on an industrial scale and realizing online quality control and process optimization for the production of oligonucleotide drugs.
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2024
·
IF 10.7
Fang Liu,Yinchun Liu,Youli Guo,Jianrui Liu,Jingwen Dong,Tengbin Wang,Di Hao,Yongqin Zhang
We developed and validated a novel Fourier transform infrared (FTIR) method to determine the degree of molar substitution (MS) for hydroxypropyl chitosan (HPCS) using nuclear magnetic resonance ( 1 H NMR) as a reference, and investigated the factors influencing the MS assay. Through extensive screening of integration methods for candidate bands in the FTIR spectrum of HPCS using 20 HPCS samples with degrees of acetylation (DA) ranging from 0.003 to 0.139, we found that when using band area at 2970 cm −1 as a probe integral, the MS values obtained via the 1 H NMR method exhibited linear correlations (R 2 > 0.98) with at least 16 integral ratios derived from their FTIR spectra. The optimal reference bands with high reliability are located at 3440 cm −1 and 1415 cm −1 , with R 2 exceeding 0.99 and a MS range of 0.17–1.92. The band at 2875 cm −1 is less affected by the trace moisture present in HPCS samples than the others. The results of the method validation demonstrated a mean recovery of 98.9 ± 2.8 % and an RSD below 10 %, suggesting a simple, robust, and highly accurate and precise method. This method could be extendable for the determination of the MS of insoluble HPCS derivatives and other hydroxypropylated polysaccharides .
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）