A series of 12-tungstophosphoric heteropolyacid and its cesium salts as n-pentane isomerization catalysts were prepared and characterized with various techniques. The BET surface area, pore structure, thermal stability and surface acidity of the catalysts are influenced strikingly by the amount of Cs in the heteropolyacid salts. The catalytic activity and selectivity of the catalysts for n-pentane isomerization at ambient temperature were investigated. The effects of activation temperature and Cs content on catalytic behavior of the catalysts were discussed in relation to the characterization results. 12- tungstophosphoric heteropolyacid and its acidic cesium salts are solid superacids. The acid strengths of H~3PW~1~2O~4~0 and Cs~2~.~2~5H~0~.~7~5PW~1~2O~4~0 are estimated to be in the range of H~0=-13～-12.4 by measuring the rate constants of n-pentane isomerization reaction at 35℃.

Key words: SALT, PENTANE, ACIDIC SALT, CESIUM COMPOUNDS, ISOMERIZATION REACTION, SUPERACID, SOLID ACID CATALYST, COMPOUND CHARACTERIZATION, CATALYTIC BEHAVIOUR