The Study on Solvent Effects of Amide by Ftir Spectroscopy
|Keywords||Infrared spectrum Solvent effect Single solvent systems Binary solvent systems Hydrogen bond benzamide phenylacetamide salicylamide acetanilide 4-fluoro-N-methylbenzamide|
The frequencies of the carbonyl stretching vibrations of benzamide, phenylacetamide, salicylamide, acetanilide and 4-fluoro-N-methylbenzamide measured in single solvent systems and binary solvent systems were undertaken to investigate solvent effects.The frequency of the carbonyl stretching vibrations (v(C=O)) in single solvent systems were correlated with empirical parameters of solvent polarity that include single empirical parameters and multiparameter approaches. The applicability of these empirical parameters to the experimental data was discussed in this thesis. The single empirical parameters include solvent acceptor number (AN), Brownstein’s parameter S, Dimroth and Reichardt’s parameter Et(30), and Schleyer’s linear free energy equation (LFE). The multiparameter approaches are Koppel-Palm equation, linear solvation energy relationships (LSER), and Swain’s two-parameter treatment of solvent effects. Preferably regression results were obtained with use of solvent acceptor number (AN), Swain’s two-parameter, and linear solvation energy relationships (LSER).Binary solvent systems were applied to study the effects of solvent-composition change on solute-solvent interaction. Qualitative assignments of v(C=O) in both single and binary solvents were also provided. The binary solvents were composed of polar solvents (butanol, chloroform,or tetrahydrofuran) and non-polar solvents (cyclohexane or tetrachloromethane). The results showed that two kinds of hydrogen bond formed between chloroform and the studied solutes except salicylamide in this thesis. Because there is intramolecular hydrogen bond in salicylamide, the interactions between salicylamide and solvents are different from the other solutes. Tetrachloromethane might interact with hydrogen of solutes that have Lewis acidity in form of weak hydrogen bond. The effects of reaction field on v(C=O) could not be ignored.