Nissan Altima ac turns off

I have a 97 Nissan Altima. The ac works fine (super
cold) for for a few minutes when the engine is not
hot. After a while, in city driving, it stops working. If
I am driving over 75 miles an hour it seems to stay
on. At slower highway speeds, if I push the button
to turn it off before it stops by itself, and I wait a
few minutes and then turn it on, I can keep it
somewhat comfortable. If it turns off, but I don't
push the "off" button, it takes much longer to "cool
down" (I actually have to turn it off myself to start
the cool down cycle of whatever component has to
cool down.
is there some sort of thermostat on the system or
by the compressor that is affecting this?
One more point, if the engine is cold and I have it
running for a few minutes, the first time the
problem happens I can put it in neutral and rev the
engine really high until I hear the belt squeak and it
starts working again. This only will work a few
times until it gets too hot.
Would appreciate a professional or semi-
professional opinion.