A laboratory research technician entered a lab to begin preparing samples that were to ultimately be purged in an anaerobic chamber (glove box) located in that room. As the technician walked into the lab, she looked at the chamber to see if it was adequately inflated. This chamber is equipped with a gas concentration meter, capable of simultaneously displaying the oxygen and hydrogen concentrations of the chamber atmosphere. Under normal operating conditions, the atmosphere inside the chamber is comprised of 0% oxygen (as intended/desired for an anaerobic atmosphere), approximately 2-3% hydrogen, and with the remaining balance being nitrogen (approximately 98-97%). Under such normal operating conditions, the hydrogen concentration inside the chamber is less than the lower explosive view more
An individual inadvertently connected a pure hydrogen gas bottle to a chamber/glove box as opposed to a 10% hydrogen (in nitrogen) bottle that should have been used. [The wrong bottle had mistakenly been delivered, and the inexperienced individual did not know the difference.] The hydrogen concentration increased within the chamber to about 9%. Since there was insufficient oxygen in the chamber to support combustion, the hydrogen did not burn, and was quickly diluted with nitrogen.
An incident occurred when Ti-doped sodium alanate was exposed to air, apparently resulting in an unstable compound that experienced a rapid exothermic reaction.
The sample consisted of mechanically milled NaAlH4 with 4% TiCl3 dopant which was prepared in an argon atmosphere. The sample was sealed and placed in the probe head of an NMR magic angle-spinning (MAS) rotor and spun at approximately 9,000-13,000 rpm. During the process, the sealing cap dislodged and exposed the sample to ambient air for a little less than 24 hours. When discovered, the sample was visually inspected and showed no evidence of oxidation. The sample was re-capped and returned to an argon environment for removal. Most of the sample material was removed using a small stainless steel needle, but a residual view more