Phthalic anhydride
Phthalic anhydride is the anhydride of phthalic acid.
It has a normal melting point of 130.8°C and a normal boiling of 284.5°C.
It dissolves in alcohol and some other organic solvents.
Phthalic anhydride is obtained either by catalytic oxidation of ortho-xylene with O2 (oxygen) or by catalytic oxidation of naphthalene.
It is hydrolyzed by hot water, forming ortho-phthalic acid.
Phthalic anhydride is widely used in industry in the production of dyes (rhodamine, anthraquinone derivatives), insecticides, plasticizers, in pharmacy, in analytic chemistry, etc.