Synthesis and Characterization of Dicarboxylic Acid Esters of 1-Hexadecanol for a Thermal Energy Storage Application Range of 50-55 degrees C

Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in recent years because of their easy production, offering different temperatures, and providing solutions to the handicaps of fatty alcohols, which are potential TES materials. Dicarboxylic acid esters of 1-hexadecanol are synthesized herein from adipic, succinic, and oxalic acid for the first time as TES materials. The dicarboxylic acid esters are characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. Furthermore, the thermophysical properties of the dicarboxylic acid esters are examined by differential scanning calorimetry and thermogravimetric analysis methods. Additionally, the surface morphology features of the dicarboxylic acid esters are determined by polarized optical microscopy. The synthesized dicarboxylic acid esters of 1-hexadecanol exhibit curiously specific behaviors that they melt at 49.2, 54.1, 54.8, and 53.5 degrees C, respectively, and crystallize at 47.7, 50.4, 53.1, and 50.2 degrees C, respectively. The applicability analyses of the dicarboxylic acid esters are carried out with integral graphs showing the sum of sensible and latent heat in a certain temperature range, time-dependent heating and cooling graphs in a constant increasing temperature environment, and structural and thermal stability analyses after 1000 times heating-cooling thermal cycle.