Flame suppression ability of metallocenes (nickelocene, cobaltcene, ferrocene, manganocene, and chromocene)

This article reports experimental investigation of flame suppression ability of metallocenes. In this study, chromocene (CrCp2), manganocene (MnCp2), ferrocene (FeCp2), cobaltcene (CoCp2), and nickelocene (NiCp2) are used. The experiments are conducted by combusting a filter paper on which the metallocene is absorbed, by thermogravimetric measurement for metallocene/cellulose systems, and by burning a solution of the metallocene in n-pentane. Their suppression abilities are characterized by three parameters: extinction limit; activation energy of degradation; and burning rate of the liquid fuel. These experiments confirm that (i) the metallocenes offer better flame suppression ability compared to ammonium dihydrogen phosphate, which is a conventional fire extinguishing agent; (ii) the metallocenes can exhibit the suppression effect not in solid phase but in gas phase; (iii) the suppression ability is in order of CrCp2>MnCp2>FeCp2>CoCp2>NiCp2, i.e., the metallocenes are arranged in order of the atomic number of their central metal. Although the metallocenes (except FeCp2) are chemically unstable, they are expected to be an excellent flame suppressant.

► We experimentally investigate metallocenes for flame suppression ability.
► Metallocenes exhibit the better flame suppression ability compared to NH4H2PO4.
► The order of the suppression ability is CrCp2>MnCp2>FeCp2>CoCp2>NiCp2.