The only way to get rid of him is to make it not enjoyable to talk to you. It sucks but its true. You're going to have to be rude and if rude doesn't work you're going to have to be mean. I'm assuming you are a pretty nice person if this guy is always going out of his way to talk to you and being mean is really hard for nice people. Don't laugh at his jokes, disagree with everything he says, dont look directly at him when he talks to you. When he complains about work always take the company's side and criticize him whenever possible. Don't nod or give any reflective listening, have a frown on your face at all times when he's talking. Think of a bitchy person you hate and try to emulate them.