sulphanilic acid vs sulfanilic acid

sulphanilic acid and sulfanilic acid both are nouns.

Word	Noun	Adjective	Verb	Adverb
sulphanilic acid	Yes	No	No	No
sulfanilic acid	Yes	No	No	No

As nouns, sulphanilic acid and sulfanilic acid are synonyms defined as:

sulphanilic acid and sulfanilic acid: a crystalline acid made from aniline and used as a dye

sulphanilic acid (noun)	sulfanilic acid (noun)
a crystalline acid made from aniline and used as a dye	a crystalline acid made from aniline and used as a dye