基于SAFT理论关联醇与DMF体系的^1H NMR

Correlation of 1H NMR for Alcohol + DMF Systems Based on SAFT

混合物核磁共振化学位移可以用不同的化学缔合理论研究,但当形成的缔合体种类很多时,需要很多优化参数。作者从统计缔合流体理论(SAFT)出发,提出了一个能关联混合物核磁共振化学位移,但又不需要假设缔合平衡常数的模型。对于醇与N,N-二甲基甲酰胺(DMF)体系,关联的均方根偏差小于1.01％。讨论了醇与DMF体系和醇与正己烷体系核磁共振化学位移随醇的浓度变化趋势的差异,认为醇与DMF形成比醇的自缔更强的交叉缔合是造成这种变化趋势不同的主要原因。

Various chemical association models have been developed to fit the NMR chemical shift data of mixtures. However, pure chemical models retain the primary disadvantage of multiple adjustable parameters which must be obtained especially for systems with a large number of different aggregates formed. A novel associated model based on statistic associating fluid theory (SAFT) , which has less parameters, is proposed for correlating NMR chemical shift data for mixtures. The root mean square deviations (RMSD) of correlation for alcohol + N, N-dimethylformamide (DMF) systems are less than 1. 01%. Furthermore, the difference of δH-x curve trend between methanol + DMF system and methanol + hexane system is discussed. The crossing-association between alcohol and DMF which is stronger than self-association of alcohols is regarded as the main reason of such difference.