コバルト錯塩によるメチルアミン中のアンモニアの定量

抄録

The domestic market product of methylamine contains a large amount of NH₃ but there has been no method of determining the latter by a simple method. The author deviced a means of quantitative analysis of NH₃ by utilizing sodium cobaltinitrite, a reagent for potassium analysis, by the addition of which, with an equal amount of EtOH, NH₄ ion is completely precipitated and this is quantitatively determined by the Kjeldahl method. This reagent selectively precipitates ammonium ion in 97-99% amount even in the presence of aliphatic amines. By this means, it has been found that the market products of methylamine contain 8-12% of NH₃. Even the recrystallized methylamine hydrochloride from butyl alcohol contains 4% of NH₃.
Partially neutralized commercial methylamine hydrochloride, however, contains less than 1% of NH₃ which indicates that this method is the best for purification of methylamine.