The error for the output molar flow rates were all taken to be 5% of the total molar flow rate. Horn et al report uncertainties in the atom balances for H, C, and O, which gave uncertainties between 1% and 13% for each atom. Unfortunately, there are no details for specific uncertainties at each point in the reactor. Selection of 5% error for all species was somewhat arbitrary, but a convergence study was performed using 10% and 2.5% error, with negligible di↵erences between the models. Details of this study can be found in the supplementary data.