What is the Class IB flammable liquid with the highest fusion enthalpy whose instance of is Class IB flammable liquid ?
select ?ent where { ?ent wdt:P31 wd:Q21009055 . ?ent wdt:P2066 ?obj . ?ent wdt:P31 wd:Q21009055 } ORDER BY DESC(?obj)LIMIT 5 
class ib flammable liquid: Q21009055 class ib flammable liquid: Q21009055