Phenolic stabilization of maleic anhydride

A composition consisting essentially of maleic anhydride and a heat stabilizing concentration of from 1 to 200 ppm based on the concentration of maleic anhydride of at least one phenolic compound selected from the group consisting of 4-alkylphenols having the structure ##STR2## and 4,4'-di(hydroxyphenyl) alkanes having the structure ##STR3## wherein R is an alkyl group of from 1 to 18 carbon atoms, R.sub.1 and R.sub.2 are independently hydrogen, alkyl groups of from 1 to 9 carbon atoms and R.sub.1 and R.sub.2 contain a total of 0 to 9 carbon atoms.