There is provided a process to recover phthalic anhydride from a plastic material which contains a phthalate ester as a plasticizer comprising the steps of:(a) heating the plastic material so that the plastic material is gasified to produce a first product,(b) contacting the first product with alumina catalyst so that the product is catalytically cracked to produce a first catalytically cracked product comprising phthalic anhydride; and(c) recovering phthalic anhydride from the first catalytically cracked product.