I think is a typo, the correct spelling should be "difenile".

http://europa.eu.int/eur-lex/lex/LexUriServ/LexUriServ.do?ur...

ES : bifenilo; difenilo
***EN : biphenyl; diphenyl***
FR : biphényle; diphényle
***IT : bifenile; difenile***


difenile = bifenile (synonyms)
Also in english diphenyl = biphenyl

Biphenyl oil.

Environ Health Perspect 106-6, 1998: Forum
Schmidt found that ***biphenyl oil***, one of the substances found in the ... Moreover, further tests indicated that the biphenyl oil can be absorbed through the ...
www.ehponline.org/docs/1998/106-6/forum.html

PDF] Coal processing [EBRD - Sub-sectoral environmental guidelines]
oil, fluorene oil, ***biphenyl oil***, naphthalene, naphtha, carbazole and benzole. The more refined fractions can also be collected by direct removal from the ...
www.ebrd.com/about/policies/enviro/sectoral/mining.pdf