It may be possible - on a lot of laptops the CPU just plugs into a socket similarly to a desktop, and if you can find it you should be able to put a new one in.
However, there's more considerations than that with laptops - generally speaking they're not designed to be upgraded, so you have to be careful with other aspects - just because it's the same socket type are you sure the motherboard supports the newer processor? Is it going to be limited by the motherboard (and therefore won't make much if any difference?) Is it going to run hotter (and therefore will the laptop's cooling facilities still work?)
It may well be possible, but whether it's worth it or not may require some extra research.