A.P.
22 months is still so young, maybe instead of trying to stop him from hitting you could give him something he can hit. Maybe he's mad or frustrated and has no idea how to deal with these feelings. Do you have a large stuffed animal you can call the angry bear that he can hit? As he gets older you can tell him how you feel when you're mad and how you deal with it instead of hitting.
I worked with 2-3 year olds and some of them just needed to release their frustrations, I had an angry corner where they could throw soft balls and beat up pillows. After a few weeks I didn't even have to tell them to not hit each other or push each other they would remove themselves from the situation before they melted down and beat up the pillows then come back to the group.