I GO TO BEJUN, STAY THERE FOR 72 HOURS, AND I GO TO THAILAND BY THAI'S AIR WAY, IS IT POSSIBLE?

I WILL GO TO BEJING BY AMERICAN AIRLINES, STAYING BEJING FOR 72 HOURS, AND THEN I GO TO THAILAND BY THAI AIRWAYS ( SEPARATE TICKET) DO I QUALIFY FOR 72 HOURS FREE TRANSIT? I AM US CITIZEN WITH US PASSPORT