Thermophysical properties of the thiophene family V. Anto ´n 1 • H. Artigas 1 • L. Lomba 2 • B. Giner 2 • C. Lafuente 1 Received: 7 November 2015 / Accepted: 3 April 2016 Ó Akade ´miai Kiado ´, Budapest, Hungary 2016 Abstract In this contribution, we have studied the ther- mophysical properties of three members of the thiophene family (thiophene, 2-methylthiophene, and 2,5-dimethylth- iophene) at atmospheric pressure in a wide temperature range. Density, speed of sound, dynamic viscosity, surface tension, and static permittivity have been determined from T = 278.15 to T = 338.15 K at atmospheric pressure, while the refractive index has been obtained under atmospheric pressure in a temperature range from 283.15 to 338.15 K. Vapour pressures of these compounds have been also mea- sured. Finally, several useful properties like isobaric expansibility, isentropic compressibility, molar refraction, and dipolar moment have been calculated from the experi- mental data. Keywords 2,5-Dimethylthiophene  2-Methylthiophene  Physicochemical properties  Thiophene Introduction Thiophene that is a five aromatic ring with an atom of sulphur was discovered as a contaminant in benzene by Victor Meyer in 1882. Thiophene and its derivatives is an important family of compounds that has attracted the attention of researchers due to the large number of appli- cations in different disciplines. In medicine, thiophene derivatives show among others antihypertensive activity [1], anti-inflammatory activity [2], antibacterial activity [3], and antitumour activity [4], while in material science, they have been used, for example, as inhibitors of corrosion of metals [5] or in the fabrication of light-emitting diodes [6–8]. More information about the relevance of thiophenes can be found in the paper of Mancuso and Gabriele [9]. The knowledge of both the thermophysical properties of these compounds and their dependence with structure and intermolecular interactions is fundamental in biochemistry and also in the chemical industry. There are some previous works [10–33] reporting thermophysical properties of thiophenes, but these studies are not systematic, and for most of the properties, there are only measurements at two or three temperatures in a quite limited range of tempera- ture. With the aim of increasing this knowledge, we have determined for thiophene, 2-methylthiophene, and 2,5- dimethylthiophene: densities, speeds of sound, refractive indices, dynamic viscosities, surface tensions, and static permittivities at atmospheric pressure in a wide tempera- ture range (T = 278.15–338.15 K) and we have also measured vapour pressures of these compounds. In addition, we have compared the results obtained for the three members of thiophene family with the homo- logues compounds of the furan family [34]. These two families of heterocyclic compounds only differ in the het- eroatom of the ring: oxygen atom (furans) or sulphur atom (thiophenes). This replacement has structural and energetic effects [35]. We have made a detailed perusal of the literature about thermophysical properties of these compounds. For thio- phene, there are some studies reporting properties like Electronic supplementary material The online version of this article (doi:10.1007/s10973-016-5448-0) contains supplementary material, which is available to authorized users. & C. Lafuente celadi@unizar.es 1 Departamento de Quı ´mica Fı ´sica, Facultad de Ciencias, Universidad de Zaragoza, 50009 Saragossa, Spain 2 Facultad de Ciencias de la Salud, Universidad San Jorge, Villanueva de Ga ´llego, 50830 Saragossa, Spain 123 J Therm Anal Calorim DOI 10.1007/s10973-016-5448-0