What is the Class IIIB combustible liquid with the highest flash point that is used in insecticides?
select ?ent where { ?ent wdt:P31 wd:Q21009059 . ?ent wdt:P2128 ?obj . ?ent wdt:P2868 wd:Q181322 } ORDER BY DESC(?obj)LIMIT 5 
class iiib combustible liquid: Q21009059 insecticide: Q181322