The essential oil ofpittosporum eugenoides

✍ Scribed by Carter, C. L. ;Heazlewood, W. V.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1949
• Weight: 291 KB
• Volume: 68
• Category: Article
• ISSN: 0368-4075
• DOI: 10.1002/jctb.5000680110

✦ Synopsis

In this connexion, it may be notcd that the lower limit for upward propagation in z in. tubes is given as 15.3% for ammonia in oxygen as ccmpared with 16.10/, for ammonia in air under similar conditions. This may be considered reasonably normal since the lower limit of an inflammable gas in oxygen does not usually differ greatly from its corresponding value in air.4 On the other hand, the lower limit of ammonia in nitrous oxide is only about one-sixth of its value in air or oxygen, again suggesting some disturbing factor.

In describing the present experiments, it was remarked that difficulty was experienced in determining the lower limits of ammonia in nitrous oxide because explosions 6ccurred even with mixtures which appeared to be below the limit for normal flame propagation. These explosions were very violent and shattered the tubes, contrasting sharply wirh the customary slow-moving flame of a normal limit mixture. Thc lower limit of " normal " flame propagation would thus seem to have little significance in mixtures of ammonia and nitrous oxide, since the burning of the ammonia is liable to be superseded by a much mare violent reaction. This reaction is presumably the exothermic decomposition of nitrous oxide which appears to be sensitized, or catalyzed, by small amounts of ammonia. An interesting feature of this reaction is its extreme violence which suggests a different mechanism of propagation more akin to detonation than deflagration.