Acrylic acid conformers and their interactions with dibutyl ether

Fourier Transform Infrared spectra of pure acrylic acid (ARA), dibutyl ether, and their binary solutions at various acid concentrations have been recorded. Density functional theory calculations on ARA monomers and dimers have been carried out. In addition to the <i>cis</i>–<i>cis</i> and <i>trans</i>–<i>trans</i> dimers, <i>cis</i>–<i>trans</i> dimers also exist in liquid acid. The dimer ring formed by carboxyl group has an asymmetry. The experimental asymmetric and symmetric hydroxyl and carbonyl stretching bands have been assigned. Shifts suffered by the absorption bands in binary solutions have been analyzed in view of the formation of heteromolecular hydrogen bonds.

已采集纯丙烯酸（acrylic acid, ARA）、二丁醚，以及不同酸浓度下二者二元溶液的傅里叶变换红外光谱（Fourier Transform Infrared spectra）。针对丙烯酸单体与二聚体开展了密度泛函理论（density functional theory）计算。除<i>顺式</i>–<i>顺式</i>与<i>反式</i>–<i>反式</i>二聚体外，液态丙烯酸中还存在<i>顺式</i>–<i>反式</i>二聚体。由羧基形成的二聚体环具有不对称性。对实验观测到的不对称与对称羟基、羰基伸缩振动峰进行了归属。结合异分子氢键的形成机制，分析了二元溶液中吸收峰发生的位移情况。