The catalytic behaviors of a novel liquid acid catalyst (composed of heteropolyacid and acetic acid) for alkylation of isobutane with butene was investigated. As a solvent acetic acid had a synergistic effect. It enhanced the acid strength of HPA and its stability. The conditions for the formation of the catalytically active phase were studied systematically. The content of crystal water of HPA and the quantity of solvent affent the formation of active phase and the catalytic activity.Catalytically active phase consists of HPA, acetic acid and hydrocarbon produced from the reaction, as well as traces of water from the crystal water of HPA. This catalyst system in comparable to the sulfuric acid in catalytic activity.

Key words: HETEROPOLYACID, CATALYTIC BEHAVIOUR, ISOBUTANE, BUTENE, ALKYLATION