john charles haas (may 22, 1918 – april 2, 2011) was an american businessman and philanthropist, at one time considered the second richest man in philadelphia. he was the chairman of global chemical company rohm and haas from 1974 to 1978. under his leadership, the family's william penn foundation became a $2 billion grantmaking institution, ranking as one of the largest such institutions in the united states.