I came to this question when I say Herefishy mention an oil change to alkylbenzene to run an R12 compressor with R404a. I thought an oil change to POE was the way to go.

The application of mineral oil is fairly straightforward (is it?). It will work with hydrocarbon refrigerants, R22, and the zillion 'compatible' drop-ins for R12 and R22.

But then we have POE, AB and PAG. R134a, R404a, R507, R410a, R407, they all run well with POE. But why do automotive airconditioning systems use PAG instead of POE? When would one consider AB instead of POE? What are the specific advantages and disadvantages of each lubricant?