-
本文对正丙醇、异丙醇、正丁醇、仲丁醇和仲戊醇5种链长相近、结构又略有差异的线型伯醇和仲醇进行了介电谱测量，发现异丙醇和正丁醇的介电谱存在异常变化的情况，即介电谱中强度最大的弛豫峰约在145 K-175 K的范围内随着温度的增加出现了逐渐升高的趋势。经过分析发现该异常变化来源于单羟基醇中的德拜介电弛豫强度在上述温区内的异常变化，结合单羟基醇德拜介电弛豫强度的理论模型进行分析，认为该异常变化是温度导致的德拜介电弛豫强度减小与分子运动性增加所致使的氢键分子链结构变化而引起的弛豫强度改变的共同结果；通过将这5种单羟基醇的弛豫时间进行对比，发现产生上述异常变化所要求的条件比较苛刻。另外，研究结果还表明仲醇中德拜弛豫过程的强度参量、弛豫单元的固有振动频率和高温极限下的激活能也具有随着碳原子数的增加而增大的特征，与伯醇中的规律是类似的。这些结果不仅能为单羟基醇奇异性质的研究提供新的切入点，而且也可以为分子链长对单羟基醇动力学影响的研究提供参考。The five linear primary and secondary alcohols, n-propanol, isopropanol, n-butanol, 2-butanol and 2-pentanol, have similar chain lengths and a little different structures and they are measured by dielectric spectroscopy in this paper to investigate the properties of monohydroxy alcohols. It is found that the dielectric spectra of isopropanol and n-butanol show an abnormal variation. i.e., the relaxation peaks with the highest strength gradually increases with rising temperature in the range of about 145 K-175 K. The analyses state that the abnormal variation originated from that of the Debye dielectric relaxation strength (DDRS) in the monohydroxy alcohols at above temperatures. According to the theoretical model of the DDRS for the monohydroxy alcohols, the abnormal variation is considered as the results of the combined action of decrease and increase of the DDRS due to temperature and the transformation of the structure of the hydrogen bonding molecular chain caused by the alteration of the mobility of molecules, respectively. By comparing the relaxation time of the five monohydroxy alcohols, it is found that the conditions should be harsher to induce the above abnormal variation. In addition, the results also show that strength parameter of Debye processes, intrinsic vibration frequency of the relaxation units and their activation energy in the high-temperature limit in secondary alcohols also raises with the increasing number of carbon atoms, similar to that in the case of primary alcohols. These results could not only provide a new breakthrough point for the investigation of exotic properties in monohydroxy alcohols but also give a reference to explore the effect of molecular chain length on their dynamics.
-
Keywords:
- Debye relaxation /
- monohydroxy alcohol /
- dielectric relaxation /
- abnormal variation
-
[1] Kennedy D, Norman C 2005 Science 309 75
[2] Böhmer R, Gainaru C, Richert R 2014 Phys. Rep. 545 125
[3] Tsai S D, Yao H Y, Chang T H 2024 J. Mol. Liq. 405 125043
[4] Arrese-Igor S, Alegría A, Colmenero J 2018 Phys. Chem. Chem. Phys. 20 27758
[5] Fragiadakis D, Roland C M, Casalini R 2010 J. Chem. Phys. 132 144505
[6] Bergman R, Jansson H, Swenson J 2010 J. Chem. Phys. 132 044504
[7] Huth H, Wang L M, Schick C, Richert R 2007 J. Chem. Phys. 126 104503
[8] Mandanici A, Huang W, Cutroni M, Richert R 2008 J. Chem. Phys. 128 124505
[9] Wang L M, Tian Y, Liu R, Richert R 2008 J. Chem. Phys. 128 084503
[10] Hu L N, Zhang C Z, Yue Y Z, Bian X F 2010 Chin. Sci. Bull. 55 457
[11] Gainaru C, Kastner S, Mayr F, Lunkenheimer P, Schildmann S, Weber H J, Hiller W, Loidl A, Böhmer R 2011 Phys. Rev. Lett. 107 118304
[12] Wikarek M, Pawlus S, Tripathy S N, Szulc A, Paluch M 2016J. Phys. Chem. B 120 5744
[13] Gainaru C, Meier R, Schildmann S, Lederle C, Hiller W, Rössler E A, Böhmer R 2010 Phys. Rev. Lett. 105 258303
[14] Ananiadou A, Papamokos G, Steinhart M, Floudas G 2021 J. Chem. Phys. 155 184504
[15] Sillrén P, Matic A, Karlsson M, Koza M, Maccarini M, Fouquet P, Götz M, Bauer T, Gulich R, Lunkenheimer P, Loidl A, Mattsson J, Gainaru C, Vynokur E, Schildmann S, Bauer S, Böhmer R 2014 J. Chem. Phys. 140 124501
[16] Bauer S, Burlafinger K, Gainaru C, Lunkenheimer P, Hiller W, Loidl A, Böhmer R 2013J. Chem. Phys. 138 094505
[17] Wang L N, Zhao X Y, Huang Y N 2019 Int. J. Mod. Phys. B 33 1950313
[18] Wang L N, Zhao X Y, Huang Y N 2019 Chin. Phys. Lett. 36 097701
[19] Wang L N, Zhao X Y, Shang J Y, Zhou H W 2023 Acta Phys. Sin. 72 037701(in Chinese) [王丽娜，赵兴宇，尚洁莹，周恒为2023物理学报72037701]
[20] Zhao X Y, Wang L N, He Y F, Zhou H W, Huang Y N 2020 Chem. Phys. 528 110473
[21] Zhao X Y, Wang L N, Han H B, Shang J Y 2024 Acta Phys. Sin. 73 147701(in Chinese) [赵兴宇，王丽娜，韩宏博，尚洁莹2024物理学报73147701]
[22] Havriliak S, Negami S 1966 J. Polym. Sci. 14 99
[23] Fulcher G S 1925 J. Am. Ceram. Soc. 8 339
[24] Tammann G, Hesse W 1926 Z. Anorg. Allg. Chem. 156 245
[25] Wang L M, Richert R 2005 J. Chem. Phys. 123 054516
[26] Xu D, Feng S, Wang J Q, Wang L M, Richert R 2020 J Phys Chem Lett. 11 5792
[27] Hu L N, Zhang C Z, Yue Y Z, Bian X F 2010 Chin Sci Bull. 55 115(in Chinese) [胡丽娜，张春芝，岳远征，边秀房2010科学通报55115]
计量
- 文章访问数: 9
- PDF下载量: 0
- 被引次数: 0
下载:
