Abstract: Improved processes for polymerizing C.sub.3 -C.sub.12 olefins (e.g. propylene) comprising polymerizing olefins in the presence of a solid phosphoric acid catalyst and an alkanol. As well as catalyzing the polymerization, the catalyst also catalyzes the decomposition of the alkanol into water and olefin. The water in turn replaces water lost from the catalyst during the polymerization thus maintaining a more constant phosphoric acid strength catalyst without subjecting said catalyst to excess liquid water and substantially improving overall polymerization conversions and catalyst life.

Abstract: A method for obtaining purified polycarboxylic anhydrides of good color stability which comprises combining and contacting a metal halide and P.sub.2 O.sub.5 or a perborate with the crude anhydride before final distillation of the crude anhydride. Preferred metal halides are alkaline earth and transition metal halides, with magnesium, calcium and iron chlorides being particularly preferred. The method is especially advantageously applied to maleic anhydride purification, especially maleic anhydride produced by butane oxidation.