质子酸的酸性强弱比较

酸碱质子理论是大学无机化学教学中最重要的概念之一,溶液中的酸碱强弱的比较虽然可以通过查找酸碱解离常数来得到,但在数据缺失情况下的定性比较酸碱强弱在教学中也很重要,而且这种比较可以帮助学生理解物质结构与性质之间的相关性。本文根据质子酸碱的化学组成和分子结构分析它们的酸碱性,并主要根据分子结构信息,包括键的极性、键的强度、键的离域、氢键、分子中键的环境等,推导、比较它们酸碱性的相对强弱。

Comparison of Molecular Acidity of Proton Acids

The proton theory of acid-base is among the most important concepts in chemistry. While it is often the case that the strength of acids and bases in solution can be searched and quantitatively compared by their dissociation constants, however, for species whose experimental data are unavailable in the literature, qualitative estimation and comparison of their strengths by using molecular structure information are equally significant. The latter approach is more useful, especially in teaching, because it can be used to guide students to better understand the relationship between the structure and property. In this work, we identify a number of structural factors, including bond polarity, bond strength, bond delocalization, hydrogen bond and bond surrounding in molecule, which influence the strength of proton acids. Careful applications of these factors in solving real problems either in classroom or in scientific research are believed to be both instructive and rewarding.