Comparative investigations of silanes in UN Test O.2 (liquid oxidizer)

Abstract

Decachlorotetrasilane, octachlortrisilane and hexachlorodisilane show false-positive results in the UN Test O.2 (liquid oxidizer). The cause of this unexpected result had been explained in former investigations. To clarify whether it is possible to obtain false-positive test results in this statutory and legally required test also with other silanes, altogether 12 substances were compared with each other. The focus was on investigating chlorinated silanes. All silanes produced the expected result “non-oxidizing liquid” as required by the theory showing that the international UN O.2 test for other (chloro)silanes gives reliable results. The averaged pressure increase time of all investigated silanes were slower than those of the reference oxidant HNO3. Therefore, organo-silanes were outside the classification threshold for packing group III. Weaknesses and possibilities for improvement of this legally required test also had been provided.