Influence of the number and type of functional groups on self-diffusion of some aromatic compounds in acetone: Nuclear magnetic resonance and molecular dynamics simulations

Abstract Self-diffusion of parabens (methylparaben and propylparaben), phenolic acids (syringic and gallic acids) and their derivative (protocatechualdehyde), hydroxycinnamic acids (caffeic, ferulic, sinapic, and p-coumaric acids), and tetramethylsilane in acetone has been investigated by the pulsed gradient spin-echo nuclear magnetic resonance (PGSE NMR) method and molecular dynamics simulation in ambient conditions. The self-diffusion coefficients obtained by the experimental and theoretical methods are in good agreement with each other. A detailed analysis of the average number of solute – acetone hydrogen bonds has made it possible to trace the influence of the molecular heteroassociation on the self-diffusion of the aromatic compounds. The degree of influence of solute – acetone molecular association on the solute self-diffusion defined as the ratio of the solute self-diffusion coefficient to the self-diffusion coefficient of its monomer has been calculated using the Stokes-Einstein equation. It has been found that for a number of aromatic compounds with the same type and number of functional groups, the parameter expressing the degree of influence of molecular association has similar values. This fact has allowed us to calculate the self-diffusion coefficients of the compounds in the given series at a known self-diffusion coefficient value of one of the series members.