| 光谱学与光谱分析 |
|
|
|
|
|
| Identification of Six Isomers of Dimethylbenzoic Acid by Using Terahertz Time-Domain Spectroscopy Technique |
| LIU Jian-wei, SHEN Jing-ling*, ZHANG Bo |
| Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048, China |
|
|
|
|
Abstract In this paper, the absorption spectra of 6 isomers of dimethylbenzoic acid, which were widely used in chemical and pharmaceutical production as intermediate substance, were measured by using the terahertz time-domain spectroscopy (THz-TDS) system in the range 0.2～2.2 THz at room temperature. The experimental results show that the six measured isomers present apparent different spectral response. However, the results of using infrared spectroscopy indicates that different isomers show high similarity in absorption spectra in the range 1 450～1 700 cm-1. The vibrational frequencies are calculated by using the density functional theory (DFT), and identification of vibrational modes are given. It is clear that the absorption peaks of the 6 isomers in the range 1 450～1 700 cm-1 come from the stretching vibration of benzene ring and CO, while the absorption peaks in the terahertz range are caused by the relative wagging of benzene ring and all the chains out of plane, which lead to the different absorption characteristics of the 6 isomers in the range 0.2～2.2 THz. The results suggest that the difference and similarity of the absorption spectra observed in the two different frequency range are resulted from the difference and similarity of the molecular structures of the six isomers. By using the different absorption characteristics, we can identify the six isomers of dimethylbenzoic acid effectively. Our study indicates that it is feasible to distinguish the isomers by using terahertz and infrared spectroscopy technique. It provides an effective way to identify different isomers and test the purity of the intermediate substance in the process of production quickly and accurately.
|
|
Received: 2014-11-11
Accepted: 2015-02-05
|
|
|
|
Corresponding Authors:
SHEN Jing-ling
E-mail: sjl-phy@cnu.edu.cn
|
|
[1] Ge H Y, Jiang Y J, Xu Z H, et al. Opt. Express, 2014, 20(10): 2533.
[2] Amenabar I, Lopez F, Mendikute A. J. Infrared, Millimeter, Terahertz Waves, 2013, 34(2): 152.
[3] He M, Yang G L, Xie H Y. Opt. Express, 2013, 21(5): 6346.
[4] Wang G Q, Shen J L, Jia Y. Appl. Phys., 2007, 102: 013106.
[5] Ma Y H, Wang Q, Li L, et al. Spectrosc. Radiat. Transf., 2013, 117: 7.
[6] Zheng Z P, Fan W H, Yan H. Chemical Physics Letters, 2012, 525: 140.
[7] Hu Y, Zhang C L, Guo L T, et al. Physics, 2007, 36(1): 68.
[8] YANG Hang, ZHAO Hong-wei, ZHANG Jian-bing, et al(杨 航，赵红卫，张建兵，等). J. Infrared Millim. Waves(红外与毫米波学报)，2014, 33(3)：263.
[9] Walther M, Plochocka P, Fischer B, et al. Biopolymers, 2002, 67(4-5): 310.
[10] GE Min, ZHAO Hong-wei, ZHANG Zeng-yan, et al(葛 敏，赵红卫，张增艳，等). Acta Phys. Chim. Sin.(物理化学学报)，2005, 21(9): 1063.
[11] JI Te, ZHAO Hong-wei, ZHANG Zeng-yan, et al(吉 特，赵红卫，张增艳，等). Acta Phys. Chim. Sin.(物理化学学报)，2006, 22(9): 1159.
[12] He T, Shen J L, Liang M Y. Measurement, 2011, 44(2): 391. |
| [1] |
WANG Dong1, 2, FENG Hai-zhi3, LI Long3, HAN Ping1, 2*. Compare of the Quantitative Models of SSC in Tomato by Two Types of NIR Spectrometers[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(05): 1351-1357. |
| [2] |
XIE Ying-ke1, 2, WANG Xi-chen2, LIANG Heng-heng2, WEN Quan3. A Near-Infrared Micro-Spectrometer Based on Integrated Scanning
Grating Mirror and Improved Asymmetric C-T Structure[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(02): 563-568. |
| [3] |
LI Xiao-fang1*, WANG Yan-cang2, WANG Li-mei1, LI Xiao-peng1, ZHANG Guo-dong1. Analysis of Spectral Characteristic Loss Law of Architectural Reflective Thermal Insulation Coatings Based on Hyperspectral Technology[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(12): 3745-3750. |
| [4] |
CAO Yu-qi2, KANG Xu-sheng1, 2*, CHEN Piao-yun2, XIE Chen2, YU Jie2*, HUANG Ping-jie2, HOU Di-bo2, ZHANG Guang-xin2. Research on Discrimination Method of Absorption Peak in Terahertz
Regime[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(10): 3058-3062. |
| [5] |
GE Deng-yun, XU Min-min, YUAN Ya-xian*, YAO Jian-lin*. Surface-Enhanced Raman Spectroscopic Investigation on the Effect of
Solution pH on Dehydroxylation of Hydroxythiophenol Isomers[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(07): 2076-2081. |
| [6] |
LI Jia-yi1, YU Mei1, LI Mai-quan1, ZHENG Yu2*, LI Pao1, 3*. Nondestructive Identification of Different Chrysanthemum Varieties Based on Near-Infrared Spectroscopy and Pattern Recognition Methods[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(04): 1129-1133. |
| [7] |
WAN Shun-kuan1, 2, LÜ Bo1, ZHANG Hong-ming1*, HE Liang1, FU Jia1, JI Hua-jian3, WANG Fu-di1, BIN Bin1, LI Yi-chao1, 2. Quick Measurement Method of Condensation Point of Diesel Based on Temperature-Compensation Model[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(10): 3111-3116. |
| [8] |
BAI Jun-peng1, 2, LI Bin1*, ZHANG Shu-juan2, CHEN Yi-mei1. Study on Norfloxacin Concentration Detection Based on Terahertz Time Domain Spectroscopy[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(09): 2710-2716. |
| [9] |
LI Hao-guang1, 2, YU Yun-hua1, 2, PANG Yan1 , SHEN Xue-feng1, 2. Study on Characteristic Wavelength Extraction Method for Near Infrared Spectroscopy Identification Based on Genetic Algorithm[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(08): 2437-2442. |
| [10] |
ZHANG Tian-yao1,2, ZHANG Zhao-hui1*, ZHAO Xiao-yan1, WEI Qing-yang1, CAO Can1, YU Yang1, LI Ying1, LI Xing-yue1. Polarizability Measurements for Salicylic Acid Embedded in Polymer Matrix Using Terahertz Time-Domain Spectroscopy[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(06): 1688-1694. |
| [11] |
WEI Ren1, XU Liang-ji2*, MENG Xue-ying1, WU Jian-fei1, ZHANG Kun1. Coal and Rock Identification Method Based on Hyper Spectral Feature Absorption Peak[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(06): 1942-1948. |
| [12] |
LIU Cui-ling1, YANG Yu-fei1*, TIAN Fang2, WU Jing-zhu1, SUN Xiao-rong1. Study on Quantitative Analysis of Edible Oil Peroxide Value by Terahertz Time Domain Spectroscopy[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(05): 1387-1392. |
| [13] |
CHEN Meng-qiu1, HE Ming-xia1*, LI Meng2, QU Qiu-hong2. Application of Interval Selection Methods in Quantitative Analysis of Water Content in Engine Oil by Terahertz Spectroscopy[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(05): 1393-1397. |
| [14] |
LIU Cui-mei, HAN Yu, JIA Wei, HUA Zhen-dong. Rapid Qualitative Analysis of New Psychoactive Substances by Infrared Spectroscopy[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2020, 40(12): 3925-3929. |
| [15] |
LI Peng1, LI Zhi2, XU Can2, FANG Yu-qiang2. Research on the Scattering Spectrum of GaAs-Based Triple-Junction Solar Cell Based on Thin-Film Interference Theory[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2020, 40(10): 3092-3097. |
|
|
|
|
