Frankfurt - Shanghai - Romania

I have a US passport and a European passport. I would like to visit a friend in Shanghai. I was looking at a one-way flight from Frankfurt to Shanghai Pudong, then to stay for 144-hours in Shanghai, and utilize a separate one-way ticket out of Shanghai Pudong to Bucharest, Romania. Would this itinerary apply? Or do I need to go somewhere (e.g. Hong Kong) that would make my stay in Shanghai look like an actual "transit"?