This is a pretty ambitious project due to the high voltage and current requirements. The mosfets that can handle this power level won't come cheap and you can easily fry 20-30 them to perfect the circuit. This is not something that can be expected to work the first time around.
Are you sure the motor is actually 2.5hp continuous? That's more current than what the typical 120v outlets can provide.
Why not start smaller, like 5 amps or so. A suitable mosfet might be the irf460. Did you come across possible bridge gate driver chips? I suspect that line powered ones are not that common.