Marchese Robinson Richard L, Roberts Kevin J, Martin Elaine B
School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, UK.
J Cheminform. 2018 Aug 29;10(1):44. doi: 10.1186/s13321-018-0298-3.
Predicting the equilibrium solubility of organic, crystalline materials at all relevant temperatures is crucial to the digital design of manufacturing unit operations in the chemical industries. The work reported in our current publication builds upon the limited number of recently published quantitative structure-property relationship studies which modelled the temperature dependence of aqueous solubility. One set of models was built to directly predict temperature dependent solubility, including for materials with no solubility data at any temperature. We propose that a modified cross-validation protocol is required to evaluate these models. Another set of models was built to predict the related enthalpy of solution term, which can be used to estimate solubility at one temperature based upon solubility data for the same material at another temperature. We investigated whether various kinds of solid state descriptors improved the models obtained with a variety of molecular descriptor combinations: lattice energies or 3D descriptors calculated from crystal structures or melting point data. We found that none of these greatly improved the best direct predictions of temperature dependent solubility or the related enthalpy of solution endpoint. This finding is surprising because the importance of the solid state contribution to both endpoints is clear. We suggest our findings may, in part, reflect limitations in the descriptors calculated from crystal structures and, more generally, the limited availability of polymorph specific data. We present curated temperature dependent solubility and enthalpy of solution datasets, integrated with molecular and crystal structures, for future investigations.
预测有机晶体材料在所有相关温度下的平衡溶解度对于化学工业中制造单元操作的数字化设计至关重要。我们当前出版物中报道的工作建立在最近发表的有限数量的定量结构-性质关系研究基础之上,这些研究对水溶解度的温度依赖性进行了建模。构建了一组模型来直接预测温度依赖性溶解度,包括针对在任何温度下都没有溶解度数据的材料。我们建议需要一种改进的交叉验证协议来评估这些模型。构建了另一组模型来预测相关的溶解焓项,该溶解焓项可用于根据同一材料在另一温度下的溶解度数据来估计某一温度下的溶解度。我们研究了各种固态描述符是否改进了通过各种分子描述符组合获得的模型:从晶体结构或熔点数据计算得到的晶格能或三维描述符。我们发现,这些描述符均未显著改进对温度依赖性溶解度或相关溶解焓终点的最佳直接预测。这一发现令人惊讶,因为固态对两个终点的贡献的重要性是显而易见的。我们认为,我们的发现可能部分反映了从晶体结构计算得到的描述符的局限性,更普遍地说,反映了多晶型物特异性数据的有限可用性。我们提供了经过整理的温度依赖性溶解度和溶解焓数据集,并将其与分子和晶体结构相结合,以供未来研究使用。