Promoter molecules were placed at the intersection of the straight and sinusoidal pores in the ZSM-5 structure. One promoter molecule was placed in each primitive unit cell, leading to 8 molecules in the simulation cell. Equilibration was then carried out at 10 K for 2 ns, the temperature was then increased to 423 K over the next 2 ns. A new set of velocities was assessed, and equilibration continued at 423 K for a further 2 ns. Placement of large molecules into the zeolite structure can lead to unphysically short interatomic separations with high potential energy and thus this careful equilibration process is required. Thermostatting was performed by a Nosé-Hoover chain of length 3, with a damping parameter of 200 fs. A timestep of 0.5 fs was used for aliphatic ester promoters and 1 fs for aromatic aldehyde promoters; a 0.5 fs timestep was trialled for aromatic aldehydes but was found to be too computationally expensive and did not provide simulations long enough, in the time frame of this study, for appropriate diffusion statistics. Ten production runs were performed for each promoter, during which the atomic positions was recorded every 2000 steps. These production simulations were run for sufficient time as to produce a linear dependence in the mean-squared displacement (MSD) with time, as shown in the ESI. †