I would like to make sure my itinerary.

I am going from South Korea to Beijing first. After I stay for less than 72 hours, I will leave at PEK Intl. airport to Bangkok Intl. airport. This flight has a connecting flight which is scheduled at HongKong Intl. airport. I guess it would be fine because HongKong immigration policy for foreigners is not affiliated with any mainland China policies. But I just wanted to make sure whether I can use the 72h free transit. See the following itinerary:
[Jan6 ICN] - [Jan8 PEK] - [Jan9 HNK] - [Jan9 BKK]
Feel free to give me suggestions. Thanks.