phthalaldehyde
/(f)θəˈlaldɪhʌɪd/Chemistry
noun
Each of three isomeric compounds with the formula C8H6O2, having two formyl groups bonded directly to a benzene ring; specifically the ortho isomer, a yellow crystalline solid.
Origin
Late 19th century; earliest use found in Journal of the Chemical Society. From phthal- + aldehyde, after German Phtalaldehyd.