Chemical oxygen generation from peroxo-compounds for aviation purposes - from basic chemistry to prototype design

In pursuit of a next generation, low temperature oxygen generator for aviation purposes, the decomposition of hydrogen peroxide adduct compounds in ionic liquids was examined. Using metallate based imidazolium salts bearing iron and copper anions, the decomposition of different hydrogen peroxide adduct compounds was achieved. The reaction proceeds very fast, but the initiation could successfully be controlled by using compacted peroxide pellets. If these were combined with mixtures of differently active ionic liquids, a broad control over the gas generation time could be achieved. In preliminary scale-up experiments maximum reaction temperatures below 150 °C were observed. The results were crafted into a feasible generator concept characterized by a multi-reaction-chamber layout. Another feasible system developed in this work is based on the metal oxide catalyzed decomposition of hydrogen peroxide adduct compounds in ionic liquids. Activity was demonstrated for a broad variety of metal oxides and mixed metal oxides in various ionic liquids. This system was by far superior to the metallate based one considering reaction control, temperature and gas purity. The designated benchmark system, the decomposition of urea hydrogen peroxide using manganese dioxide in dimethylphosphate ionic liquids, produced a nearly constant gas stream over a time span determined by the ratio of catalyst, peroxide and ionic liquid. Reaction temperatures did not exceed 120 °C and gas impurities could almost completely be eliminated by applying different peroxide compounds and a suitable filter system. The respective generator concept allows a simpler design thus designating this metal oxide based solution as the preferable system for the development of a next generation oxygen generator.