Abstract
Dielectric constant and loss data have been obtained at microwave frequencies for acridine, 4-methyl-pyridine, phthalazine, quinoline, and isoquinoline in both cyclohexane and p-xylene solution. The data have been used to calculate relaxation times and apparent dipole moments. For phthalazine, quinoline, and isoquinoline in cyclohexane at 50 °C the distribution coefficient is zero and their relaxation times are very similar. Although the axes about which these three molecules may relax lead to different volumes being swept out, no variation in relaxation behavior has been detected, and each system can be characterized by one relaxation time. The relaxation times for all the heterocyclic molecules except quinoline and acridine in p-xylene are appreciably longer than in cyclohexane. Relaxation time values appear a sensitive means of detecting the weak molecular interaction between the amine and the p-xylene. The difference in behavior between the quinoline and acridine as opposed to isoquinoline could be attributed to a more appreciable steric effect in the former two, hindering the approach of the π-electrons of the p-xylene molecules to the hybridized lone pair on the nitrogen atom. No interaction is, in fact, detectable in the case of quinoline and acridine. The importance of allowing for weak intermolecular forces, even in dilute solution, when relaxation values are being anticipated, is emphasized.
Publisher
Canadian Science Publishing
Subject
Organic Chemistry,General Chemistry,Catalysis
Cited by
18 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献