The CO-to-H2 conversion factor (αCO) is critical to studying molecular gas and star formation in galaxies. The value of αCO has been observed to vary in different regions of a galaxy, and it is dependent on environmental parameters such as gas densities and temperatures. Previous observations on ~kpc scales revealed lower αCO values in the centers of some nearby star-forming galaxies, including NGC 3351. We present new ALMA Band 3, 6, and 7 observations of 12CO, 13CO and C18O rotational lines on ~50 pc scales in the center of NGC 3351. Using multi-line modeling and a Bayesian likelihood analysis, we constrain possible values of the H2 density, kinetic temperature, CO column density, and CO isotopologue abundances at each pixel. The αCO distribution can be derived from the CO column densities and then compared with other parameters. We present initial results from this analysis investigating the physical processes that control αCO in galaxy centers.