Flying from USA to Thailand with a stop over at Beijing

I am flying to Thailand in December and I would like to know if I can stay in Beijing for 72 hours before I continue on to Thailand. I would be buying a round trip flight from USA to Beijing, then I will buy another round trip flight from Beijing to Phuket, Thailand. I am interested to stay in Beijing for 72 hrs in both the inbound and outbound flights. Can I do that with the 72 hrs Visa Free Transit ?