Reactions of n-propyl fluoroformate in a variety of pure and binary solvents have been studied at 40.0 {^{circ}C}. The extended (two-term) Grunwald-Winstein equation has been applied to the specific rates of solvolysis of npropyl fluoroformate. The sensitivities (l = 1.80 ${pm}$ 0.17 and m = 0.96 ${pm}$ 0.10) to changes in solvent nucleophilicity and solvent ionizing power and the $k_F/k_{Cl}$ values are similar to those for solvolyses of n-octyl fluoroformate over the full range of solvents, suggesting that the addition step of an addition-elimination mechanism is ratedetermining. These observations are also compared with those previously reported for the corresponding chloroformate and fluoroformate esters.