Determination of Ammonia in Hydrazine

Acidity and N-methylation of N-aryl-N ′-cyanoguanidines †

“…The ρ value of ϩ1.53 compares with one of ϩ1.9 for the nitroguanidines. 6 The delocalisation of the negative charge formed on deprotonation predominantly involves the cyanoguanidine unit rather than the aryl group. This can be seen by comparing the ρ value of ϩ1.53 for the series 1 with that of ca.…”

“…2 The consequences of this low basicity for these and related molecules include a lack of prototropic tautomerisation in DMSO, 3 an unusual electron distribution 4 and neutrality in the solid state. 5 Moreover, nitroguanidine 2 and its amino-N-substituted derivatives are found to be relatively acidic with pK a values for proton loss in water ranging from 12.80 (2, R = H) to 7.5 (2, R = H 2 NCO); 2a, 6 these values are comparable with those of phenols! Given this, we were interested in determining pK a values for the cyanoguanidines and our results for the series 1 (R = various substituted phenyl; RЈ = H, Me) are reported in this paper.…”

Analysis of Ammonia-Hydrazine Mixtures for Both Components.

“…After a comprehensive study of available methods for the determination of ammonia, hydrazine, and ammoniahydrazine mixtures, oxidation-reduction titrimetry, easily adaptable to remote analysis, was selected for evaluation Spectrophotometric methods, applicable generally to very low concentrations of ammonia and hydrazine, and acid-base titration methods, requiring a distillation separation of the ammonia (6,15), were considered unsuitable.…”

“…std.% Re-Rel. std.pie Ammonia Hydrazine Molarity co very dev., % Molarity covery dev., % " Average of 5 determinations 6. Average of 4 determinations.…”