Department of Chemistry and Biochemistry, Montclair State University, Montclair, NJ, USA.
Magnetic Resonance Laboratory "Annalaura Segre", ISB-CNR, Rome, Italy.
Magn Reson Chem. 2020 Sep;58(9):798-811. doi: 10.1002/mrc.5025. Epub 2020 Jun 3.
Heavy metal carboxylate or soap formation is a widespread deterioration problem affecting oil paintings and other works of art bearing oil-based media. Lead soaps are prevalent in traditional oil paintings because lead white was the white pigment most frequently chosen by old masters for the paints and in some cases for the ground preparations, until the development of other white pigments from approximately the middle of the 18th century on, and because of the wide use of lead-tin yellow. In the latter part of the 19th century, lead white began to be replaced by zinc white. The factors that influence soap formation have been the focus of intense study starting in the late 1990s. Since 2014, nuclear magnetic resonance (NMR) studies have contributed a unique perspective on the issue by providing chemical, structural, and dynamic information about the species involved in the process, as well as the effects of environmental conditions such as relative humidity and temperature on the kinetics of the reaction(s). In this review, we explore recent insights into soap formation gained through solid-state NMR and single-sided NMR techniques.
重金属羧酸盐或皂化作用是一种广泛存在的劣化问题，会影响油画和其他使用油性媒介的艺术品。在传统油画中，铅皂很常见，因为在过去，画家们最常选择铅白作为颜料，在某些情况下也会选择作为底料，直到大约 18 世纪中叶开始使用其他白色颜料，同时也因为广泛使用铅锡黄。在 19 世纪后期，铅白开始被锌白取代。自 20 世纪 90 年代末以来，影响皂化作用形成的因素一直是研究的重点。自 2014 年以来，核磁共振（NMR）研究通过提供有关参与该过程的物质的化学、结构和动态信息，以及环境条件（如相对湿度和温度）对反应动力学的影响，为该问题提供了独特的视角。在这篇综述中，我们探讨了通过固态 NMR 和单边 NMR 技术获得的有关皂化作用形成的最新见解。
