Transport coefficients of model lubricants up to 400 MPa from molecular dynamics.

In this paper, the predictive power of molecular dynamics methods is demonstrated for the cases of model paraffinic and aromatic lubricant liquids at pressures up to 400 MPa. The shear viscosity and self-diffusion coefficients are calculated for 2,2,4-trimethylpentane (CH) at 298 K and 1,1-diphenylethane (CH) at 333 K. Three force fields with different levels of accuracy are compared by the ability to predict the experimental data.

Bis-ortho-substitution by methyl groups dramatically increases the racemization barrier of Tröger bases.

We have shown through racemization kinetics studies that the enantiomerization barriers of the bis-ortho-methyl substituted Tröger bases 2 and 3 in acidic media are raised by 30 kJ mol(-1) relative to the parent compound 1, that is 130.4(4) and 131.6(4) kJ mol(-1), respectively (105 degrees C, pH 1, ethylene glycol).