de Leeuw den Bouter Anouk W N, Vogels Esther J M, Miquelot Adeline, Brito Larissa, Olivier Pierre, van der Schaaf John
Sustainable Process Engineering, Chemical Engineering and Chemistry, Eindhoven University of Technology, Het Kranenveld 14, 5612 AZ Eindhoven, The Netherlands.
Lab Hydrogen, ENGIE Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France.
ACS Omega. 2025 Jun 25;10(26):27735-27744. doi: 10.1021/acsomega.4c10897. eCollection 2025 Jul 8.
In this work, we investigate the effect of the alkyl chain length of the nitrogenous cation on the ionicity of formic acid-trialkylamine mixtures at 298.15 K, and the nature of the formed bonds using a combination of Fourier transform infrared (FTIR) and H NMR. FTIR revealed the formic acid-trialkylamine complexes to be a mixture of ionic and neutral species. Besides chemical equilibria, the studied systems also have a phase equilibrium. Our results reveal the phase equilibrium to be independent of alkyl chain length at a molar ratio of 1.5:1 acid to amine. Interestingly, it was observed that while the degree of proton transfer decreases as a function of alkyl chain length, the hydrogen bonding characteristic increases, resulting in a constant acid-to-amine ratio of 1.5 mol of formic acid per mole of amine.
在本研究中，我们利用傅里叶变换红外光谱（FTIR）和氢核磁共振（H NMR）相结合的方法，研究了含氮阳离子的烷基链长度对298.15 K下甲酸 - 三烷基胺混合物离子性的影响，以及所形成键的性质。FTIR显示甲酸 - 三烷基胺配合物是离子物种和中性物种的混合物。除了化学平衡外，所研究的体系还存在相平衡。我们的结果表明，在酸与胺的摩尔比为1.5:1时，相平衡与烷基链长度无关。有趣的是，观察到虽然质子转移程度随烷基链长度的增加而降低，但氢键特征增强，导致每摩尔胺对应1.5摩尔甲酸的酸与胺的比例保持恒定。
