Extension of a Group Contribution Method To Estimate the Critical Properties of Ionic Liquids of High Molecular Mass

The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama and co-workers in 2012 to estimate the critical properties of ionic liquids is extended to evaluate these properties for ionic liquids of higher molecular mass. The modifications are done to follow the behavior that these properties have for other type of substances, such as the asymptotic tendency of the normal boiling temperature as the molecular mass M increases. The magnitudes of the modifications are found so that the pressure test and the density test previously defined by the authors are fulfilled for most substances. The proposed extension does not change anything of the original method already in use which is valid for ILs with M M > 500 g/mol are considered in this work. Of these, 310 passed the pressure test. Also, 111 of these ILs have experimental density values and 103 pass the density test, with absolute average deviation of 4.1 %. A spreadsheet for calculating the critical properties and performing the tests is provided as Supporting Information. The spreadsheet file includes at present the properties for 1630 ionic liquids of molecular mass going from 77 to 1730.由Valderrama与Robles于2007年提出、并由Valderrama及其合作者于2012年更新的离子液体（ionic liquids）临界性质估算基团贡献法（group contribution method），本研究将其拓展以评估更高分子量离子液体的临界性质。本次修正旨在贴合其他类型物质的临界性质变化规律，例如常压沸点随分子量M增大所呈现的渐近趋势。修正幅度的设定需满足绝大多数物质可通过作者此前定义的压力测试与密度测试。本次提出的拓展未对已投入使用的原始方法做出任何改动，该原始方法适用于分子量大于500 g/mol的离子液体，本文共纳入此类离子液体。其中310种通过了压力测试。此外，其中111种离子液体拥有实验密度值，103种通过了密度测试，绝对平均偏差为4.1%。本研究提供了用于计算临界性质并完成测试的电子表格，作为补充材料（Supporting Information）。截至目前，该电子表格已收录1630种离子液体的相关性质，其分子量范围为77至1730。