Excess molar enthalpies of {diethyl oxalate + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa
Introduction
Diethyl oxalate (DEO, CASRN: 95-92-1) is an intermediate which is widely used in chemical synthesis, medicine, printing, dyeing, electronics industry and so on [1], [2], [3], [4]. The synthesis method [5], [6] and thermodynamic properties [7], [8], [9], [10], [11] of DEO have been developed and studied during the past years.
Until now, no excess molar enthalpies () data of systems containing (DEO + C1 to C4) alcohols could be found in the literature. In this paper, the values for four binary systems of {DEO + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} were determined by using a flow-mixing isothermal microcalorimeter at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa. The experimental data were correlated by using the Redlich–Kister equation and two local composition models: the NRTL model and the UNIQUAC model.
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Materials
Diethyl oxalate (guaranteed grade, purity >99.0%) was purchased from Shanghai Jiachen Chemical. Methanol (HPLC grade, purity >99.8%) and 2-propanol (HPLC grade, purity >99.5%) were provided by Tianjin Siyou Fine Chemical. Ethanol (HPLC grade, purity >99.7%) was purchased from Sinopharm Chemical Reagent. 1-Propanol (HPLC grade, purity >99.5%) was provided by Tianjin Saifu, China. The source and purity of solvents used in this work were listed in table 1. Before used, all chemicals were degassed
Results and discussion
The values of the four binary systems have been listed in TABLE 3, TABLE 4, TABLE 5, TABLE 6. As examples, values of {DEO (1) + methanol (2)} in table 3 and {DEO (1) + alcohols (2)} at T = 298.15 K and 101.3 kPa are plotted in figure 1 and figure 2, respectively.
The experimental values of the are correlated by using the Redlich–Kister equation and two local composition models (NRTL and UNIQUAC). The expressions of derived from the model were developed through the Gibbs–Helmholtz
Conclusions
In this work, the excess molar enthalpies of four binary systems {DEO + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} were measured at T = (288.2, 298.2, 313.2, 328.2, 338.2, and 348.2) K and p = 101.3 kPa. For the same system, the value increases as the temperature increases. At the same temperature, the value increases as the length and the branch chains increase. For all the systems, the values fitted by Redlich–Kister equation and the NRTL model are better than those fitted by
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