I have a 2006 mini van that has a rear AC unit seems to be leaking coolant.Is it possible to just disconnect the rear unit and loop the coolant as the cost of repair is to high for the age of the automobile

Grand Caravan? Known for rear leaks. There is an under hood block that you can plug but you need good sealant and don't use air for a couple of days.

Really, 2006 is not that old of a vehicle unless it has other issue. Maybe a trip to an A/C place to just find out how much it could possibly cost before blocking off the system and never being able to use it again. Just a suggestion.