Complexity in Acid-Base Titrations: Multimer Formation Between Phosphoric Acids and Imines.

ABSTRACT: Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid-base aggregates challenging. Here, we track such acid-base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid-base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecul

SUBMITTER: Malm C 

PROVIDER: S-EPMC5582606 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature