During World War II, at the National Center for Agricultural Utilization Research and as a post-doc at the University of Illinois, Skell took part in the early work on the production of Penicillin.
At Penn State, Skell's field of research were then hypothetical very short-lived Reaction intermediates like free radicals, Carbonium ions, Tricarbon and Carbene, whose existence and properties he could demonstrate by use of Chemical traps.
His contributions have been characterized as follows: Another class of intermediates, containing divalent carbon atoms, were suggested by John Nef early in this century but his ideas were generally rejected.
However, the concept was revived with vigor when Philip Skell showed that: CCl2, dichlorocarbone, was formed as a reaction intermediate.
[3]Philip S. Skell created an internationally renowned school of leading chemists, one of them being his postdoctoral associate Wolfgang A. Herrmann (1975/76), President of the Technical University of Munich from 1995 to 2019.