As part of his thesis research with his Ph.D. advisor Harold Hart, Eleuterio conducted fundamental mechanistic studies on important organic reactions such as nucleophilic aromatic substitution.

[5] While in graduate school, he married the future Marianne Eleuterio (née Kingsbury) who later became a genetics professor at West Chester University.

After completing his doctoral thesis in 1953, Eleuterio pursued post-doctoral research in synthetic organic chemistry at the Ohio State University, working in the laboratories of Melvin S. Newman.

[4] Working in the Petrochemicals Department of the DuPont Co. in 1957, Eleuterio discovered that certain catalysts convert propylene to a mixture containing ethylene and butene, a reaction he recognized as olefin metathesis.

[7] Many researchers followed on Eleuterio's initial discovery,[8] culminating in the 2005 Nobel Prize to Chauvin, Grubbs, and Schrock for the development of olefin metathesis for organic synthesis.

He discovered that hexafluoropropylene could be co-polymerized with tetrafluoroethylene to yield amorphous fluorinated ethylene propylene co-polymers with good characteristics as films.

He taught courses on managing research and development, typically with master's degree students in engineering, science, and business.