Greetings!
Putting 5 days as random, as I don't know how much data you have. I have experience in searching contact information on internet and have to say one thing about your project.
From work email to get personal email, there are two ways, first search website then search key contact and then it's email. Second method is directly search work email for the linkedin profile associated with it.
Final method would be selected upon examining the data you have.
Kind Regards