Preparation of aqueous solutions of thiocyanic acid and their stability

Corrosion Product Structures of Steel Samples Exposed to Amine Solutions Used for H2s Removal.

“…We propose that the probes are not ideal for this environment because the corrosion products formed have very different morphologies. In addition, the main corrosion product, FeS 2 , is a semiconductor, and this is likely to affect the corrosion probe readings, consistent with our earlier report (10). Corrosion probes base their results on corrosion products decreasing the element cross section and increasing the probe resistance; the formation of the semiconducting film could complicate these measurements and could explain the anomalous negative readings obtained in some of the solutions.…”

“…The acids were purchased from Sigma Aldrich except thiosulfuric and thiocyanic acid which were made in the MPR Services laboratory. This is because f the solutions of these acids are not stable and need to be prepared under the conditions of interest (10).…”

Preparation of Thiocyanate-Retaining Tannin Gel for Adsorption Recovery of Palladium from Strong Hydrochloric Acid Solutions

“…Decomposition of SCN À in Acid Solution. It has been long known that SCN À is decomposed in acid solutions through the hydrolysis of isothiocyanic acid, HNCS, as follows 42,43…”

“…It has been long known that SCN – is decomposed in acid solutions through the hydrolysis of isothiocyanic acid, HNCS, as follows , normalH + + HNCS + 2 normalH 2 normalO → normalH 2 normalS + CO 2 + NH 4 + Before SCN – loading into the TG, therefore, we examined the decomposition behavior of SCN – in 0–5 M HCl solutions at 298, 313, and 333 K, where the initial SCN – concentration was [SCN – ] ini = 0.001 M. The solution was vigorously shaken and sampled at different time intervals. The concentration of SCN – in the aqueous solution, [SCN – ], was determined by the colorimetric method, which was based on the complexation of SCN – with Fe(III) …”

Addition of Thiocyanic Acid to Chalcones: Practical Synthesis of 1,3-Diaryl-3-isothiocyanatopropan-1-ones

“…We suppose that some kind of equilibrium between chalcone 3b and isothiocyanate 4b was reached in the reaction mixture at 50 °C after 3 hours. Since aqueous solutions of HNCS were reported to be unstable at high concentrations, 16 with chalcone 3c we tried the addition of NH 4 NCS to the reaction mixture in portions (entry 17), but this had no effect on the isolated yield of 4c (entry 17 vs entry 16). At room temperature the addition of HNCS to chalcone 3b proceeded slower than at heating (entry 14 vs entry 8); however, an increase in the reaction time from 3 to 24 h led to a considerable increase in the isolated yield of isothiocyanate 4b (entry 14 vs entry 15).…”