Triacontane and Behenyl Lignocerate Molecular Tilting in Crystals:
Theory, Monte Carlo Simulations and Predictions
Abstract
Oleogelators are molecules that, when combined with edible oils can form
semi-solid materials. Although many molecules have been tried as
oleogelators in the last 20 years, much is still unknown. Here, the
molecular structure of two possible oleogelators: triacontane (TC) and
behenyl lignocerate (BL) were studied using a mathematical model for
each molecule and carrying out computer simulation using the Metropolis
Monte Carlo (MMC) algorithm in which the only interaction is via
Lennard-Jones dispersion forces. The computer simulation explored the
possibility of having either rigidly-extended molecules or twisted ones
via the formation of gauche bonds. The results showed that both TL and
BL molecules create a monolayer that did not include any gauche bond so
that all molecules were effectively rigidly extended. The effective
thickness of the monolayer was compared with experimental data and with
the predictions of Peyronel et al. (in review) which assumed that the
molecules were rigidly-extended. The work reported here justified that
assumption. The conclusion was that the TC and BL molecules must be
packed with a tilt angle in relation to the methyl group plane to match
the experimental data. The angle of TC tilt was calculated to be
~27° which essentially confirms that reported by
Peyronel et al. (in review).